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1. Warming could shift the phenological responses of benthic microalgae in temperate intertidal zones

Author: Raphaël Savelli, Vincent Le Fouest, Mélanie Becker, Garance Perrois, Fabienne Rousset, Christine Dupuy, Marc Simard, and Dimitris Menemenlis
Subjects: Geology, QE1-996.5, Environmental sciences, GE1-350
Abstract: Abstract Intertidal mudflats colonized by sediment-dwelling microphytobenthos deliver a wide range of ecosystem services. Here we simulate the response of microphytobenthos, located on a temperate tidal mudflat along the French Atlantic coast in Northwestern Europe, exposed to changes in light, temperature, and sea level conditions predicted by the Intergovernmental Panel on Climate Change. Without sea level rise, microphytobenthos benefit from the balancing effect of net primary production fluctuations, experiencing an increase in winter and a decrease in summer. Under the worst emissions scenario, microphytobenthos bloom up to 14 days earlier in spring and 5 days later in fall, thereby extending the low-level microphytobenthos biomass period by an additional 3 weeks in summer. Sea level rise reduces light exposure leading to a pronounced decline in microphytobenthos under the medium-low emissions and worst emissions scenarios. We provide evidence that the anticipated warmer climate and sea level rise will have an impact on microphytobenthos, potentially triggering cascading effects across the entire food web and disrupting ecosystem services.
Published: 2024
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2. Morphological, calorific and nutritive characteristics of 656 freshwater invertebrates taxa

Author: Axelle Moreau, Christine Dupuy, Pierrick Bocher, and Sébastien Farau
Subjects: freshwater invertebrates, invertebrate biometry, Biology (General), QH301-705.5
Abstract: The Freshwater Animal Diversity Assessment (FADA) project estimated that freshwater animal species represent 9.5% of the 1.2 million species described. Knowing that freshwater represents only 0.01% of the earth's surface, these wetlands are suitable habitats for a great part of the world's total biodiversity. However, it has been shown that there is a lack of knowledge on these species, including freshwater invertebrates. Nevertheless, they play a key role in the majority of freshwater ecosystems and in their foodweb networks. Freshwater invertebrates are the food resource of many species, such as fish and birds. The knowledge of their morphological, energetic and nutritive characteristics allows a better understanding of their selection by predators (size, energy intake etc.), but also leads to the improvement of wetland management. Although information about freshwater invertebrates exists in literature, they are generally heterogeneous, dispersed and difficult to collect. To facilitate the accessibility of these data and, thus, optimise and accelerate research projects including freshwater invertebrates, we propose a literature review describing 14 morphological and nutritive characteristics (size, dry weight, gross energy, crude protein etc.) for 656 taxa of freshwater invertebrates.This dataset is a review from 104 publications from 1935 to 2020, compiling 14 characteristics when available (size, dry weight, gross energy, crude protein etc.) for 656 taxa of freshwater invertebrates.
Published: 2021
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3. Designing Coastal Adaptation Strategies to Tackle Sea Level Rise

Author: Théophile Bongarts Lebbe, Hélène Rey-Valette, Éric Chaumillon, Guigone Camus, Rafael Almar, Anny Cazenave, Joachim Claudet, Nicolas Rocle, Catherine Meur-Férec, Frédérique Viard, Denis Mercier, Christine Dupuy, Frédéric Ménard, Bernardo Aliaga Rossel, Lauren Mullineaux, Marie-Alexandrine Sicre, Anna Zivian, Françoise Gaill, and Agathe Euzen
Subjects: climate change, sea level rise, adaptation, governance, nature-based solutions, multidisciplinary approach, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Faced with sea level rise and the intensification of extreme events, human populations living on the coasts are developing responses to address local situations. A synthesis of the literature on responses to coastal adaptation allows us to highlight different adaptation strategies. Here, we analyze these strategies according to the complexity of their implementation, both institutionally and technically. First, we distinguish two opposing paradigms – fighting against rising sea levels or adapting to new climatic conditions; and second, we observe the level of integrated management of the strategies. This typology allows a distinction between four archetypes with the most commonly associated governance modalities for each. We then underline the need for hybrid approaches and adaptation trajectories over time to take into account local socio-cultural, geographical, and climatic conditions as well as to integrate stakeholders in the design and implementation of responses. We show that dynamic and participatory policies can foster collective learning processes and enable the evolution of social values and behaviors. Finally, adaptation policies rely on knowledge and participatory engagement, multi-scalar governance, policy monitoring, and territorial solidarity. These conditions are especially relevant for densely populated areas that will be confronted with sea level rise, thus for coastal cities in particular.
Published: 2021
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4. Site Characteristics More Than Vegetation Type Influence Food Web Structure of Intertidal Salt Marshes

Author: Denis Lafage, Alexandre Carpentier, Sylvain Duhamel, Christine Dupuy, Eric Feunteun, Sandric Lesourd, and Julien Pétillon
Subjects: diet partitioning, trophic position, fish nursery, Dicentrarchus labrax, Chelon ramada, salt-marsh plants, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Salt marshes are under increasing anthropogenic pressures that have been reported to affect the diet of fish (e.g., change in prey composition and availability), eventually resulting in alterations in their nursery function. Most studies in Europe are based on fish gut content analysis, which only reflect a small proportion of pressures to salt marshes, and do not necessarily reflect long-term disturbances. In this study, we investigated the impact of salt-marsh vegetation type on trophic network structures (i.e., fish diet and trophic position). Primary producers (particulate organic matter, microphytobenthos, and dominant terrestrial plants), potential aquatic and terrestrial prey, and fish of two dominant species (sea bass and thinlip mullet) were sampled during the summer of 2010 in four creeks from two sites from Western France (the Mont-Saint-Michel Bay and the Seine Estuary). Analysis was undertaken using C and N stable-isotope compositions. Tested response variables (diet and trophic position) suggested a dominant site effect and a weaker effect of surrounding vegetation type. Site effect was attributed to differences in anthropogenic nitrogen inputs (with a steep increase in the Mont-Saint-Michel Bay) and tidal regime between the two bays, with more marine signatures associated with a higher frequency and duration of tidal flooding events in the Seine Estuary. A second hypothesis is that invasive Elytrigia acuta, which has recently replaced typical salt-marsh vegetation in Mont-Saint-Michel Bay, negatively impacted the native salt-marshes nursery function by modifying the access to terrestrial prey on this site. The trophic position of the sea bass and the thinlip mullet was unchanged by local salt-marsh vegetation, and considered consistent with their diet. This study highlights the relevance of stable-isotopes analyses for assessing long-term and integrative effects of changes in vegetation resulting from human disturbances in salt marshes.
Published: 2021
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5. Mapping the Intertidal Microphytobenthos Gross Primary Production, Part II: Merging Remote Sensing and Physical-Biological Coupled Modeling

Author: Raphaël Savelli, Vona Méléder, Philippe Cugier, Pierre Polsenaere, Christine Dupuy, Johann Lavaud, Alexandre Barnett, and Vincent Le Fouest
Subjects: microphytobenthos, intertidal mudflat, gross primary production, remote sensing, physical-biological modeling, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Microphytobenthos (MPB) at the sediment surface of intertidal mudflats are known to show a high spatial and temporal variability in response to the biotic and abiotic conditions prevailing at the mud surface. It makes long-term and large-scale monitoring of MPB Gross Primary Production (GPP) difficult to set up. In this study, we developed the first 3D physical-biological coupled model (MARS-3D) that explicitly simulates GPP of intertidal MPB at the mudflat scale, and we compared the outputs with in situ and space remote sensing MPB GPP data. We discuss the sources of discrepancies between the modeling and the remote sensing approach in the light of future developments to be done. For instance, the remote sensing algorithm provides a very synoptic view of the mudflat GPP. It is well-suited to achieve diagnostic estimates of MPB GPP at the synoptic spatial and temporal scale. By contrast, the MARS-3D model provides a more dynamic representation of the MPB activity and prognostic estimates of MPB GPP over the mudflat. It is very relevant to resolve the seasonal and inter-annual dynamics of MPB. Getting comparable GPP estimates derived from the remote sensing algorithm and 3D physical-biological coupled model will further require a better convergence in terms of equations structure, biological constants parameterization, and source data used (i.e., vegetation index vs. chlorophyll a). Setting a common parameterization in both the numerical model and remote sensing algorithm might be challenging in a perspective of mapping MPB PP over large mudflats from a synoptic to inter-annual time scale, but it could open the door to a new way of quantifying MPB GPP over large intertidal mudflats.
Published: 2020
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6. Environmental Factors and Pollution Stresses Select Bacterial Populations in Association With Protists

Author: Songbao Zou, Qianqian Zhang, Xiaoli Zhang, Christine Dupuy, and Jun Gong
Subjects: antibiotic resistance, interkingdom interaction, light, metal resistance, protozoa, warming, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Digestion-resistant bacteria (DRB) refer to the ecological bacterial group that can be ingested, but not digested by protistan grazers, thus forming a specific type of bacteria-protist association. To test the hypothesis that the environment affects the assembly of DRB in protists, a mixotrophic ciliate, Paramecium bursaria, and a heterotrophic ciliate, Euplotes vannus, were reared at different temperatures, light conditions, and concentration gradients of antibiotic oxytetracycline and heavy metals. Community profiling indicated that the composition of DRB in both species varied significantly across the manipulated conditions, except for in P. bursaria under light/dark treatments. Clone library analysis of bacterial 16S rRNA genes showed that DRB were diverse. Pseudomonas became more abundant during the warmer treatment of P. bursaria, whereas the dominance of Pseudoalteromonas weakened and Vibrio became more abundant in E. vannus at a higher temperature. During the treatment of diel light:dark cycles, Aestuariibacter and Alteromonas were selected for in E. vannus but not Pseudoalteromonas, which was highly represented in the all-light and all-dark treatments. In contrast, P. bursaria consistently hosted Nevskia, Curvibacter, and Asticcacaulis under all light conditions. There were many bacterial species co-resistant to oxytetracycline and to protistan digestion, in which Sphingomonas, Alteromonas, Aestuariibacter, Puniceicoccaceae (Verrucomicrobia), Pseudomonas, and Sulfitobacter were frequently abundant. Flectobacillus and Aestuariibacter were major lead-resistant bacteria associated with the studied protists. Acinetobacter and Hydrogenophaga were abundant in the P. bursaria treated with a high dose of mercury. Aestuariibacter was found as a dominant group of DRB in E. vannus across all cadmium treatments. In summary, this study demonstrates for the first time that environmental stress selects for bacterial populations associated with protists and that there are diverse bacterial species that not only are resistant to pollution stresses but can also survive protistan predation. This work highlights that bacteria-protists associations need to be taken into account in understanding ecological and environmental issues, such as resilience of bacterial community and function, microbial co-occurrence, and quantity and distribution of antibiotic resistant bacteria and genes.
Published: 2020
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7. Mapping the Intertidal Microphytobenthos Gross Primary Production Part I: Coupling Multispectral Remote Sensing and Physical Modeling

Author: Vona Méléder, Raphael Savelli, Alexandre Barnett, Pierre Polsenaere, Pierre Gernez, Philippe Cugier, Astrid Lerouxel, Anthony Le Bris, Christine Dupuy, Vincent Le Fouest, and Johann Lavaud
Subjects: microphytobenthos, intertidal mudflat, gross primary production, remote sensing, NDVI, modeling, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: The gross primary production (GPP) of intertidal mudflat microphytobenthos supports important ecosystem services such as shoreline stabilization and food production, and it contributes to blue carbon. However, monitoring microphytobenthos GPP over a long-term and large spatial scale is rendered difficult by its high temporal and spatial variability. To overcome this issue, we developed an algorithm to map microphytobenthos GPP in which the following are coupled: (i) NDVI maps derived from high spatial resolution satellite images (SPOT6 or Pléiades), estimating the horizontal distribution of the microphytobenthos biomass; (ii) emersion time, photosynthetically active radiation (PAR), and mud surface temperature simulated from the physical model MARS-3D; (iii) photophysiological parameters retrieved from Production–irradiance (P–E) curves, obtained under controlled conditions of PAR and temperature, using benthic chambers, and expressing the production rate into mg C h–1 m–2 ndvi–1. The productivity was directly calibrated to NDVI to be consistent with remote-sensing measurements of microphytobenthos biomass and was spatially upscaled using satellite-derived NDVI maps acquired at different seasons. The remotely sensed microphytobenthos GPP reasonably compared with in situ GPP measurements. It was highest in March with a daily production reaching 50.2 mg C m–2 d–1, and lowest in July with a daily production of 22.3 mg C m–2 d–1. Our remote sensing algorithm is a new step in the perspective of mapping microphytobenthos GPP over large mudflats to estimate its actual contribution to ecosystem functions, including blue carbon, from local and global scales.
Published: 2020
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8. The Vertical Migratory Rhythm of Intertidal Microphytobenthos in Sediment Depends on the Light Photoperiod, Intensity, and Spectrum: Evidence for a Positive Effect of Blue Wavelengths

Author: Alexandre Barnett, Vona Méléder, Christine Dupuy, and Johann Lavaud
Subjects: blue light, diatoms, intertidal flats, pigments, migration, photoperiod, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Estuarine intertidal flats strong biological productivity is mainly based on the activity of benthic microalgae communities or microphytobenthos (MPB), mostly dominated by diatoms. Epipelon is a major MPB growth form comprising motile species, which perform repeated “vertical migration” patterns in the upper sediment layers according to tidal and diurnal cycles with upward migration at the beginning of the daylight emersion and downward migration before immersion starts. Although this fascinating behavior has been extensively studied for more than a century, many of its features remain uncharacterized. Epipelon migratory rhythms are believed to be driven by an endogenous internal clock of unknown nature in combination with diverse environmental stimuli. Among the environmental stimuli impacting on MPB vertical migration, light is probably the most important. Rhythmic changes in surface abundance of natural MPB assemblages were therefore continuously assessed at high frequency by Imaging-PAM fluorimetry in fresh sediment sampled at different seasons, comprising 85 migration profiles from 40 sediment samplings over 2 years, and exposed to different light conditions without any other environmental stimuli (i.e., no tidal-like water flow and stable optimal temperature). In particular, we manipulated (i) the 24-h natural photoperiod MPB that was acclimated to in order to disentangle the tight link between the diurnal and tidal rhythmicity of epipelon migration, and (ii) the light spectrum in order to potentially influence MPB accumulation at the surface of sediment. We found that the migration rhythmicity mapped onto the tidal cycle but that it was modulated, and even overridden, by the diurnal cycle and by the irradiance level during daytime periods with a positive phototactic upward migration up to a certain threshold (in our conditions, 120 μmol photons m–2 s–1 of white light). Also, we found blue wavelengths (465 nm) triggered MPB surface accumulation, as compared to other wavelengths (white, green, and red) in patterns that were intensity-dependent and species-dependent. In particular, we found two species, Navicula spartinetensis and Gyrosigma fasciola, which strongly migrate up under blue light and could potentially be used as model species for further studying the light-responses of intertidal MPB.
Published: 2020
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9. Subtidal Microphytobenthos: A Secret Garden Stimulated by the Engineer Species Crepidula fornicata

Author: Thibault Androuin, Lubos Polerecky, Priscilla Decottignies, Stanislas F. Dubois, Christine Dupuy, Cédric Hubas, Bruno Jesus, Erwan Le Gall, Martin P. Marzloff, and Antoine Carlier
Subjects: Crepidula fornicata, engineer species, subtidal microphytobenthos, fertilization, hyperspectral imaging, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: The slipper limpet Crepidula fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. fornicata (live and dead) placed on top of sieved and homogenized sediment collected in situ. We used hyperspectral imaging to non-invasively map the development of MPB biomass, and to assess the potential influence of C. fornicata and its spatial extent. Our results showed that live C. fornicata significantly promote MPB growth through both physical and biological effects, with the biological effect dominating over the pure physical one. The highest stimulation was observed on the shells, suggesting that dissolved metabolic products excreted by C. fornicata were likely the main factor stimulating MPB growth in our short-term experiment. Our findings provide first direct evidence that stimulation of MPB growth by the biological activity of larger benthic epifauna occurs not only in intertidal but also in shallow subtidal habitats. More research is needed to assess the contribution of this fertilization effect to the trophic functioning of subtidal benthic systems.
Published: 2018
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10. Disturbance increases microbial community diversity and production in marine sediments

Author: Pierre E Galand, Sabrina Lucas, Sonja K Fagervold, Erwan Peru, Audrey M Pruski, Gilles Vétion, Christine Dupuy, and Katell Guizien
Subjects: Ecology, Metagenome, Oxygen, RNA, diversity, marine sediment, Microbiology, QR1-502
Abstract: Disturbance strongly impacts patterns of community diversity, yet the shape of the diversity-disturbance relationship remains a matter of debate. The topic has been of interest in theoretical ecology for decades as it has practical implications for the understanding of ecosystem services in nature. One of these processes is the remineralization of organic matter by microorganisms in coastal marine sediments, which are periodically impacted by disturbances across the sediment-water interface. Here we set up an experiment to test the hypothesis that disturbance impacts microbial diversity and function during the anaerobic degradation of organic matter in coastal sediments. We show that during the first 3 weeks of the experiment, disturbance increased both microbial production, derived from the increase in microbial abundance, and diversity of the active fraction of the community. Both community diversity and phylogenetic diversity increased, which suggests that disturbance promoted the cohabitation of ecologically different microorganisms. Metagenome analysis also showed that disturbance increased the relative abundance of genes diagnostic of metabolism associated with the sequential anaerobic degradation of organic matter. However, community composition was not impacted in a systematic way and changed over time. In nature, we can hypothesize that moderate storm disturbances, which impact coastal sediments, promote diverse and productive communities. These events, rather than altering the decomposition of organic matter, increase the substrate turnover and, ultimately, remineralization rates.
Published: 2016
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11. Key features of intertidal food webs that support migratory shorebirds.

Author: Blanche Saint-Béat, Christine Dupuy, Pierrick Bocher, Julien Chalumeau, Margot De Crignis, Camille Fontaine, Katell Guizien, Johann Lavaud, Sébastien Lefebvre, Hélène Montanié, Jean-Luc Mouget, Francis Orvain, Pierre-Yves Pascal, Gwenaël Quaintenne, Gilles Radenac, Pierre Richard, Frédéric Robin, Alain F Vézina, and Nathalie Niquil
Subjects: Medicine, Science
Abstract: The migratory shorebirds of the East Atlantic flyway land in huge numbers during a migratory stopover or wintering on the French Atlantic coast. The Brouage bare mudflat (Marennes-Oléron Bay, NE Atlantic) is one of the major stopover sites in France. The particular structure and function of a food web affects the efficiency of carbon transfer. The structure and functioning of the Brouage food web is crucial for the conservation of species landing within this area because it provides sufficient food, which allows shorebirds to reach the north of Europe where they nest. The aim of this study was to describe and understand which food web characteristics support nutritional needs of birds. Two food-web models were constructed, based on in situ measurements that were made in February 2008 (the presence of birds) and July 2008 (absence of birds). To complete the models, allometric relationships and additional data from the literature were used. The missing flow values of the food web models were estimated by Monte Carlo Markov Chain--Linear Inverse Modelling. The flow solutions obtained were used to calculate the ecological network analysis indices, which estimate the emergent properties of the functioning of a food-web. The total activities of the Brouage ecosystem in February and July are significantly different. The specialisation of the trophic links within the ecosystem does not appear to differ between the two models. In spite of a large export of carbon from the primary producer and detritus in winter, the higher recycling leads to a similar retention of carbon for the two seasons. It can be concluded that in February, the higher activity of the ecosystem coupled with a higher cycling and a mean internal organization, ensure the sufficient feeding of the migratory shorebirds.
Published: 2013
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12. Metazoan zooplankton in the Bay of Biscay: 16 years of individual sizes and abundances from the ZooScan and ZooCAM imaging systems.

Author: Nina, Grandremy, Paul, Bourriau, Edwin, Daché, Marie-Madeleine, Danielou, Mathieu, Doray, Christine, Dupuy, Bertrand, Forest, Laetitia, Jalabert, Martin, Huret, Sophie, Le Mestre, Antoine, Nowaczyk, Pierre, Petitgas, Philippe, Pineau, Justin, Rouxel, Morgan, Tardivel, and Jean-Baptiste, Romagnan
Subjects: IMAGING systems, WEB-based user interfaces, METADATA, ZOOPLANKTON, OCEAN bottom, EDIACARAN fossils, CONTINENTAL shelf
Abstract: This paper presents two metazoan zooplankton datasets obtained by imaging samples collected on the Bay of Biscay continental shelf in spring during the PELGAS integrated surveys, over the 2004-2019 period. The samples were collected at night, with a WP2 200 µm mesh size fitted with a Hydrobios (back-run stop) mechanical flowmeter, hauled vertically from the sea floor to the surface with a maximum depth set at 100 m when the bathymetry is deeper. The first dataset originates from samples collected from 2004 to 2016, imaged on land with the ZooScan and is composed of 1,153,507 imaged and measured objects. The second dataset originates from samples collected from 2016 to 2019, imaged on board the R/V Thalassa with the ZooCAM and is composed of 702,111 imaged and measured objects. The imaged objects is composed of zooplankton individuals, zooplankton pieces, non-living particles and imaging artefacts, ranging from 300 µm to 3.39 mm Equivalent Spherical Diameter, individually imaged, measured and identified. Each imaged object is geolocated, associated to a station, a survey, a year and other metadata. Each object is described by a set of morphological and grey level based features (8 bits encoding, 0 = black, 255 = white), including size, automatically extracted on each individual image. Each object was taxonomically identified using the web based application Ecotaxa with built-in, random forest and CNN based, semi-automatic sorting tools followed by expert validation or correction. The objects were sorted in 172 taxonomic and morphological groups. Each dataset features a table combining metadata and data, at the individual object granularity, from which one can easily derive quantitative population and communities descriptors such as abundances, mean sizes, biovolumes, biomasses, and size structure. Each object's individual image is provided along with the data. These two datasets can be used combined together for ecological studies as the two instruments are interoperable, or as training sets for ZooScan and ZooCAM users. [ABSTRACT FROM AUTHOR]
Published: 2023
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13. Climate change influences chlorophylls and bacteriochlorophylls metabolism in hypersaline microbial mat

Author: M.A. Perdrau, Cédric Hubas, C. Mazière, M. Bodo, Christine Dupuy, Robert Duran, Cristiana Cravo-Laureau, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Station de Biologie Marine de Concarneau, Direction générale déléguée à la Recherche, à l’Expertise, à la Valorisation et à l’Enseignement-Formation (DGD.REVE), Muséum national d'Histoire naturelle (MNHN)-Muséum national d'Histoire naturelle (MNHN), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
Subjects: 0106 biological sciences, Chlorophyll, Chlorophyll a, Environmental Engineering, Climate Change, [SDE.MCG]Environmental Sciences/Global Changes, Chlorosome, 01 natural sciences, Hypersaline microbial mats, 03 medical and health sciences, chemistry.chemical_compound, Phototrophic communities, Environmental Chemistry, Humans, Seawater, Microbial mat, Waste Management and Disposal, Bacteriochlorophylls, 030304 developmental biology, 0303 health sciences, Phototroph, Chlorophyll derivatives, 010604 marine biology & hydrobiology, Chlorophyll A, Ocean acidification, Hydrogen-Ion Concentration, Pollution, Anoxygenic photosynthesis, Mesocosms, chemistry, 13. Climate action, Environmental chemistry, [SDE]Environmental Sciences, Bacteriochlorophyll, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; This study aimed to determine the effect of the climatic change on the phototrophic communities of hypersaline microbial mats. Ocean acidification and warming were simulated alone and together on microbial mats placed into mesocosms. As expected, the temperature in the warming treatments increased by 4 °C from the initial temperature. Surprisingly, no significance difference was observed between the water pH of the different treatments despite of a decrease of 0.4 unit pH in the water reserves of acidification treatments. The salinity increased on the warming treatments and the dissolved oxygen concentration increased and was higher on the acidification treatments. A total of 37 pigments were identified belonging to chlorophylls, carotenes and xanthophylls families. The higher abundance of unknown chlorophyll molecules called chlorophyll derivatives was observed in the acidification alone treatment with a decrease in chlorophyll a abundance. This change in pigmentary composition was accompanied by a higher production of bound extracellular carbohydrates but didn't affect the photosynthetic efficiency of the microbial mats. A careful analysis of the absorption properties of these molecules indicated that these chlorophyll derivatives were likely bacteriochlorophyll c contained in the chlorosomes of green anoxygenic phototroph bacteria. Two hypotheses can be drawn from these results: 1/ the phototrophic communities of the microbial mats were modified under acidification treatment leading to a higher relative abundance of green anoxygenic bacteria, or 2/ the highest availability of CO2 in the environment has led to a shift in the metabolism of green anoxygenic bacteria being more competitive than other phototrophs.
Published: 2022
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14. Do microbial planktonic communities reflect the ecological changes of Glorieuses coral reefs (Iles Eparses, Western Indian Ocean)?

Author: Marc Bouvy, Alice Bélières, Claire Carré, Patrice Got, Marc Pagano, Hélène Agogué, Béatrice Bec, Cécile Roques, Lionel Bigot, Pascale Chabanet, Christine Dupuy, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), and Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [SDE.MCG]Environmental Sciences/Global Changes, Ecological changes, Microorganisms, atoll, picoplankton, Aquatic Science, Oceanography, Dissolved Organic Matter, 01 natural sciences, mozambique channel, diversity, 03 medical and health sciences, senegal river, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, cyclonic eddy, Humans, 14. Life underwater, mediterranean sea, Indian Ocean, 030304 developmental biology, Synechococcus, 0303 health sciences, Coral Reefs, 010604 marine biology & hydrobiology, Anthropogenic Effects, Microbiota, 15. Life on land, Plankton, Pollution, Cyclone, tuamotu archipelago, 13. Climate action, phytoplankton communities, flow-cytometry, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Pristine ecosystem
Abstract: WOS:000737215300006; International audience; Ecological baselines for the structure and functioning of ecosystems in the absence of human activity can provide essential information on their health status. The Glorieuses islands are located in the Western Indian Ocean (WIO) and can be considered as "pristine" ecosystems that have not been subjected to anthropogenic pressure. Their nutrient context and the microbial assemblages were assessed by determining the abundance of heterotrophic prokaryotes (archaea and bacteria), picocyanobacteria, picoeukaryotes, microphytoplankton and protozooplankton communities in five stations, during two contrasted periods (November 2015 and May 2016). Chlorophyll-a concentrations were always under 1 mu g/L and associated to very low levels in orthophosphates, nitrate and dissolved organic carbon, revealing an ultra-oligotrophic status for the Glorieuses waters. Picocyanobacteria confirmed the ultra-oligotrophic status with a predominance of Synechococcus. Zeaxanthin associated with the presence of picocyanobacteria represented the major pigment in both surveys. Three indices of diversity (species richness, Shannon and Pielou indexes) from microscopy observations highlighted the difference of diversity in microphytoplankton between the surveys. A focus on a 16S metabarcoding approach showed a high dominance of picocyanobacteria, Alpha- and Gammaproteobacteria, regardless of station or period. Multivariate analyses (co-inertia analyses) revealed a strong variability of ecological conditions between the two periods, with (i) high nutrient concentrations and heterotrophic nanoflagellate abundance in November 2015, and (ii) high heterotrophic prokaryote and picoeukaryote abundance in May 2016. The impact of a category 5 tropical cyclone (Fantala) on the regional zone in April 2016 is also advanced to explain these contrasted situations. Relative importance of top-down factors between bacterial and heterotrophic nanoflagellates was observed in November 2015 with an active microbial food web. All the results indicate that three microbial indexes potentially can be considered to assess the ecological change in Glorieuses marine waters.
Published: 2022
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15. Projet Seine-Aval 6 PHARESEE « Productivité microphytobenthique des HAbitats intertidaux en lien avec la dynamique sédimentaire, biogéochimique et les ingénieurs d'écosystème de la faune benthique : implication pour des enjeux de modélisation et de REhabilitation des vasières de la SEine Estuarienne »

Author: Francis Orvain, Arnaud Huguet, Jérôme Morelle, Bénédicte Thouvenin, Edith Parlanti, Olivier Maire, Anaïs Richard, Christiane Rakotomalala, Raphael Savelli, Benoit Lebreton, Anniet Laverman, Céline Roose-Amsaleg, Valérie Mesnage, Julien Deloffre, Nicolas lecoq, Vincent Lefouest, Christine Dupuy, Florent Grasso, Luuk van den Heijden, Eric Viollier, Matthieu Sebilo, Katell Guizien, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Normandie Université (NU), Biogéochimie et écologie des milieux continentaux (Bioemco), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique hydrodynamique et sédimentaire (PHYSED), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), ASTRIUM, EADS - European Aeronautic Defense and Space, Université Grenoble Alpes - UFR Médecine (UGA UFRM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Institut national des sciences de l'Univers (INSU - CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Service de neurologie [Poitiers], Centre hospitalier universitaire de Poitiers (CHU Poitiers), CIC AP-HP (pitie-Salpetriere)/inserm, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Morphodynamique Continentale et Côtière (M2C), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Kenta Biotech Ltd, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'océanographie biologique de Banyuls (LOBB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), GIP Seine-Aval, Orvain, Francis, Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Grenoble Alpes (UGA), and Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )
Subjects: [SDE] Environmental Sciences, [SDE]Environmental Sciences
Published: 2022

16. Hydrology and small pelagic fish drive the spatio–temporal dynamics of springtime zooplankton assemblages over the Bay of Biscay continental shelf

Author: Nina Grandremy, Jean-Baptiste Romagnan, Christine Dupuy, Mathieu Doray, Martin Huret, and Pierre Petitgas
Subjects: Geology, Aquatic Science
Published: 2023
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17. Potential Impact of Photoinhibition on Microphytobenthic Primary Production on a Large Intertidal Mudflat

Author: João Serôdio, Vincent Le Fouest, Philippe Cugier, Vona Méléder, Raphaël Savelli, Pierre Polsenaere, Christine Dupuy, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, Photoinhibition, microphytobenthos, 010504 meteorology & atmospheric sciences, Soil Science, Aquatic Science, 01 natural sciences, physical-biological coupled model, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Potential impact, Primary (chemistry), photoinhibition, Ecology, 010604 marine biology & hydrobiology, Paleontology, Forestry, 13. Climate action, [SDE]Environmental Sciences, intertidal mudflat, Environmental science, Tidal flat, primary production
Abstract: Microphytobenthos (MPB) are a key primary producer of intertidal mudflats. MPB face strong variability in incident irradiance during low tides. Despite photoprotection and photoacclimation, such variations can translate into photoinhibition of MPB cells. This study explores the effect of photoinhibition on MPB primary production (PP) over a large and productive temperate mudflat (Brouage mudflat, NW France). We used a regional and high-resolution tri-dimensional hydrodynamic model coupled to a MPB model with or without photoinhibition. Photoinhibition leads to a 20% (-0.79 t C) decrease of the simulated MPB PP over the entire mudflat. As the upper shore is exposed to light more frequently and longer than the lower shore, the decrease of MPB PP is higher on the upper shore (-29%) than on the lower shore (-5%). With the highest photosynthetically active radiation cumulated over the mudflat, the decrease of MPB PP due to photoinhibition is the highest during spring and spring tides (-22% and -23%, respectively). The model suggests MPB photoinhibition is sensitive to the photoacclimation status of MPB cells through the light saturation parameter. This first modeling attempt to account for MPB photoinhibition is highly constrained by our current theoretical knowledge and limitations on the MPB growth physiology, but it suggests that this process can have a substantial impact on the MPB PP. As such, assessing the MPB photosynthetic response to the highly variable environmental conditions that prevail in large and productive intertidal mudflats is a real challenge for quantifying MPB PP from a synoptic to inter-annual time scale. Plain Language Summary Benthic micro-algae or microphytobenthos (MPB) inhabiting the surficial sediment sustain the high biological production of intertidal mudflats. MPB achieve photosynthesis by aggregating into a dense biofilm at the mud surface during daytime low tides. As MPB can be exposed to short-term variations and high light levels, they change their short-term physiology and position within the sediment to protect themselves. However, such strategies can be outbalanced by a too long stressful light exposure. In this study, we explore with a numerical model the impact of photoinhibition on MPB primary production (PP) over a large and very productive mudflat (NW France). The model suggests that photoinhibition can strongly impact MPB PP. With photoinhibition, the yearly PP decreases by 20 % over the whole mudflat. The model suggests MPB PP is sensitive to the photoacclimation status of MPB cells, i.e. their light use efficiency at a given light level. This first modeling attempt to account for MPB photoinhibition is highly constrained by our current theoretical knowledge and limitations on the MPB growth physiology, but it suggests that this process can have a substantial impact on the MPB PP.
Published: 2021
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18. Drivers for primary producers’ dynamics: New insights on annual benthos pelagos monitoring in anthropised freshwater marshes (Charente-Maritime, France)

Author: Raphaël, Moncelon, Edouard, Metzger, Philippe, Pineau, Claire, Emery, Eric, Bénéteau, Charlotte, de Lignières, Olivier, Philippine, François-Xavier, Robin, and Christine, Dupuy
Subjects: Geologic Sediments, Environmental Engineering, Wetlands, Ecological Modeling, Phytoplankton, Water, Fresh Water, Phosphorus, Eutrophication, Pollution, Waste Management and Disposal, Water Science and Technology, Civil and Structural Engineering
Abstract: Wetlands, especially marshes, support many services such as carbon catchment control or water purification led by primary producers such as phytoplankton and microphytobenthos (PB). The impact of the sedimentary compartment, as source and sink of essential nutrients for the water column, is often neglected in the study of their dynamics and water purification capacity of the systems. This work compared monthly (between February 2020 and April 2021) the benthic and pelagic primary producers' dynamics in two anthropised freshwater marshes (Marans and Genouillé), with the simultaneous follow-up of physico-chemical parameters of the water column and nutrient fluxes at the sediment-water (SWI) interface. It was suggested a strong contribution of phytoplankton (pumping) and the benthic compartment (denitrification) to the water purification of these two nitrates (NO
Published: 2022
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19. Morphological, calorific and nutritive characteristics of 656 freshwater invertebrates taxa

Author: Sébastien Farau, Axelle Moreau, Pierrick Bocher, Christine Dupuy, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Fédération Départementale des Chasseurs de la Vendée
Subjects: 0106 biological sciences, QH301-705.5, [SDV]Life Sciences [q-bio], water, Biodiversity, Wetland, Biology, 010603 evolutionary biology, 01 natural sciences, Freshwater ecosystem, freshwater invertebrates, Predation, Freshwater, gross energy, Dry weight, lipid, 14. Life underwater, invertebrate biometry, Biology (General), Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, Invertebrata, Invertebrate, geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, ash, 15. Life on land, Data Paper (Biosciences), Taxon, Habitat, Zoology & Animal Biology, nitrogen free extract, protein, fiber
Abstract: The Freshwater Animal Diversity Assessment (FADA) project estimated that freshwater animal species represent 9.5% of the 1.2 million species described. Knowing that freshwater represents only 0.01% of the earth's surface, these wetlands are suitable habitats for a great part of the world's total biodiversity. However, it has been shown that there is a lack of knowledge on these species, including freshwater invertebrates. Nevertheless, they play a key role in the majority of freshwater ecosystems and in their foodweb networks. Freshwater invertebrates are the food resource of many species, such as fish and birds. The knowledge of their morphological, energetic and nutritive characteristics allows a better understanding of their selection by predators (size, energy intake etc.), but also leads to the improvement of wetland management. Although information about freshwater invertebrates exists in literature, they are generally heterogeneous, dispersed and difficult to collect. To facilitate the accessibility of these data and, thus, optimise and accelerate research projects including freshwater invertebrates, we propose a literature review describing 14 morphological and nutritive characteristics (size, dry weight, gross energy, crude protein etc.) for 656 taxa of freshwater invertebrates. This dataset is a review from 104 publications from 1935 to 2020, compiling 14 characteristics when available (size, dry weight, gross energy, crude protein etc.) for 656 taxa of freshwater invertebrates.
Published: 2021

20. New insights in bacterial and eukaryotic diversity of microbial mats inhabiting exploited and abandoned salterns at the Ré Island (France)

Author: Isabelle Lanneluc, Ingrid Fruitier-Arnaudin, Cristiana Cravo-Laureau, Sophie Sablé, Christine Cagnon, Camille Mazière, Christine Dupuy, Robert Duran, Hélène Agogué, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), and Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Microbial diversity, Biodiversity, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Microbiology, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, RNA, Ribosomal, 16S, Environmental Microbiology, 14. Life underwater, Microbial mat, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecosystem, 030304 developmental biology, 2. Zero hunger, Islands, 0303 health sciences, biology, Bacteria, 030306 microbiology, Ecology, Eukaryota, 15. Life on land, biology.organism_classification, 16S ribosomal RNA, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, [SDE.ES]Environmental Sciences/Environmental and Society, France, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Archaea, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract: International audience; In order to understand the effect of human practices on microbial mats organisation, the study aimed to investigate the biodiversity within microbial mats from exploited and abandoned salterns. Despite several attempts, archaeal 16S rRNA gene fragment sequences were not obtained, indicating that microbial mats were probably dominated by Bacteria with very low abundance of Archaea (< 1%). Thus, the study compared the bacterial and meiofaunal diversity of microbial mats from abandoned and exploited salterns. The higher salinity (101 ± 3.7 psu vs. 51.1 ± 0.7 psu; Welch t-test p < 0.05) of the exploited site maintained lower bacterial diversity in comparison to the abandoned site where the salinity gradient was no longer maintained. However, the microbial mats exhibited similar bacterial class composition while the eukaryotic diversity was significantly higher in the exploited saltern. The abandoned saltern was dominated by sulfate-reducing bacteria and Nematoda, while the exploited saltern was characterized by the presence of halophilic bacteria belonging to Marinobacter, Salinivibrio and Rhodohalobacter genera, and the larger abundance of Hypotrichia (ciliates). Such bacterial and eukaryotic diversity difference might be explained by human actions for salt recovery in exploited salterns such as scraping the surface of microbial mat and increasing salinity renewing the microbial mat each year. Such action decreases the bacterial diversity changing the food web structure that favour the presence of a larger diversity of eukaryotic organisms. Our study provides new insights on microbial mat communities inhabiting salterns, especially the consequences of abandoning saltern exploitation.
Published: 2021
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21. Diuron effects on photosynthesis and vertical migration of microphytobenthos: Potential rapid bioassessment of herbicide toxicity in coastal sediments

Author: Guo-Ying Du, Shuai Che, Johann Lavaud, Xue-Feng Zhong, Christine Dupuy, College of Marine Life Science, Ocean University of China, Ocean University of China (OUC), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Chlorophyll, microphytobenthos, [SDE.MCG]Environmental Sciences/Global Changes, Quantum yield, Intertidal zone, 010501 environmental sciences, Aquatic Science, Oceanography, Photosynthesis, 01 natural sciences, chemistry.chemical_compound, Herbicide toxicity, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Fluorometry, vertical migration, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Diel vertical migration, Bioassessment, 0105 earth and related environmental sciences, Quenching (fluorescence), photosynthesis, bioassessment Heading: diuron effects on microphytobenthos, Chemistry, Herbicides, 010604 marine biology & hydrobiology, Microphytobenthos, Pollution, Electron transport chain, diuron, 13. Climate action, Diuron, Environmental chemistry, Toxicity, herbicide toxicity, Vertical migration, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology
Abstract: International audience; The effects of herbicide diuron on photosynthesis and vertical migration of intertidal microphytobenthos (MPB) assemblages were investigated using chlorophyll fluorometry. The results shown diuron ≤ 60 μgꞏL-1 had no obvious effect on MPB vertical migration during 24 h indicated by consistent rhythm. Low concentration of 10 μgꞏL-1 diuron had no significant influence on MPB photosynthesis throughout, however, high concentrations of 40, 50, and 60 μgꞏL-1 had significant impacts exhibited by decreased parameters of maximum relative electron transport rate (rETRmax), maximal PS II quantum yield (Fv/Fm) and non-photochemical quenching (NPQ). For middle concentrations of 20 and 30 μgꞏL-1 , above decreased 3 parameters recovered sooner or later after 2 h or 16.5 h. Comparatively, rETRmax, Fv/Fm and NPQ are concentration dependent and more sensitive than other parameters in assessing diuron toxicity. This study revealed the potential of using MPB assemblages and chlorophyll fluorometry for rapid assessing diuron toxicity in coastal sediments.
Published: 2021
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22. Coupling between sediment biogeochemistry and phytoplankton dynamics in anthropised freshwater marshes of Charente Maritime, France

Author: Christine Dupuy, Edouard Metzger, Raphaël Moncelon, Philippe Pineau, Olivier Philippine, Eric Bénéteau, and François-Xavier Robin
Subjects: geography, Oceanography, Marsh, geography.geographical_feature_category, Coupling (computer programming), Phytoplankton, Environmental science, Biogeochemistry, Sediment
Published: 2021
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23. Coupling between sediment biogeochemistry and phytoplankton development in a temperate freshwater marsh (Charente-Maritime, France): Evidence of temporal pattern

Author: Christine Dupuy, Martine Bréret, François-Xavier Robin, Edouard Metzger, Eric Bénéteau, Olivier Philippine, Philippe Pineau, Marie Gouazé, Raphaël Moncelon, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique - Angers (LPG-ANGERS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Union des marais de la Charente-Maritime (UNIMA)
Subjects: Geologic Sediments, Environmental Engineering, nutrient fluxes, 0208 environmental biotechnology, Fresh Water, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, nitrogen, chemistry.chemical_compound, Water column, iron, Nitrate, Nanophytoplankton, Phytoplankton, 14. Life underwater, phosphorus, Waste Management and Disposal, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, Freshwater marsh, Ecological Modeling, Sediment, Eutrophication, Pollution, Anoxic waters, 6. Clean water, 020801 environmental engineering, chemistry, 13. Climate action, Wetlands, Environmental chemistry, [SDE]Environmental Sciences, phytoplankton, Environmental science, early diagenesis, France, Water quality
Abstract: International audience; In freshwater systems, sediment can be an important source for the internal loading of phosphate (PO4). The limiting character of this element in such system leads to consider this phenomenon in terms of eutrophication risks and water quality stakes. A four-months follow-up (January, March, April and May 2019) was carried out in a strong PO4 limited secondary channel from an artificial irrigation system of Charente Maritime (France) to link the mobilization of remineralization products in the upper 6 cm layer of sediment (conventional core slicing/centrifugation and DET probes) and the phytoplankton biomass dynamics in the water column. Results showed congruent patterns between the temporal succession of the organic matter mineralization processes in the sediment and the primary biomass dynamics in the water column. In January and March (considered in winter), PO4 proved to be retained by adsorption onto iron oxides in anoxic sediment since pore water nitrate inhibited for about a month the respiration of metal oxides in the first cm of sediment, thus limiting PO4 availability and the phytoplankton growth. In April and May (early spring), after exhaustion of pore water nitrate, the dissolutive reduction of iron oxides released PO4 into pore water generated a significant diffusive outgoing flux from the sediment to the water column with a maximum in April (-1.10E-04±2.81E-05 nmol cm-2 s-1). This release coincided with the nanophytoplankton bloom (5.50 µg Chla L-1) and a potential increase of PO4 concentration in the water column. This work provides some insight on the importance of benthic-pelagic coupling in anthropogenic systems. This conceptual model has to be deployed on other sites of interest where internal loading of P takes precedence over external inputs and nitrate mitigation drives its benthic recycling and ultimately its bioavailability. This is to be essential to characterize the aquatic environment quality in order to limit eutrophication risks.
Published: 2020
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24. The Vertical Migratory Rhythm of Intertidal Microphytobenthos in Sediment Depends on the Light Photoperiod, Intensity, and Spectrum: Evidence for a Positive Effect of Blue Wavelengths

Author: Johann Lavaud, Vona Méléder, Alexandre Barnett, Christine Dupuy, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Takuvik Joint International Laboratory ULAVAL-CNRS, and Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:QH1-199.5, Water flow, [SDV]Life Sciences [q-bio], pigments, Intertidal zone, Ocean Engineering, Aquatic Science, lcsh:General. Including nature conservation, geographical distribution, Oceanography, migration, photoperiod, 01 natural sciences, diatoms, Diurnal cycle, Phototaxis, 14. Life underwater, lcsh:Science, Diel vertical migration, 0105 earth and related environmental sciences, Water Science and Technology, Global and Planetary Change, biology, 010604 marine biology & hydrobiology, Sediment, biology.organism_classification, blue light, Benthic zone, Navicula, [SDE]Environmental Sciences, Environmental science, intertidal flats, lcsh:Q
Abstract: International audience; Estuarine intertidal flats strong biological productivity is mainly based on the activity of benthic microalgae communities or microphytobenthos (MPB), mostly dominated by diatoms. Epipelon is a major MPB growth form comprising motile species, which perform repeated "vertical migration" patterns in the upper sediment layers according to tidal and diurnal cycles with upward migration at the beginning of the daylight emersion and downward migration before immersion starts. Although this fascinating behavior has been extensively studied for more than a century, many of its features remain uncharacterized. Epipelon migratory rhythms are believed to be driven by an endogenous internal clock of unknown nature in combination with diverse environmental stimuli. Among the environmental stimuli impacting on MPB vertical migration, light is probably the most important. Rhythmic changes in surface abundance of natural MPB assemblages were therefore continuously assessed at high frequency by Imaging-PAM fluorimetry in fresh sediment sampled at different seasons, comprising 85 migration profiles from 40 sediment samplings over 2 years, and exposed to different light conditions without any other environmental stimuli (i.e., no tidal-like water flow and stable optimal temperature). In particular, we manipulated (i) the 24-h natural photoperiod MPB that was acclimated to in order to disentangle the tight link between the diurnal and tidal rhythmicity of epipelon migration, and (ii) the light spectrum in order to potentially influence MPB accumulation at the surface of sediment. We found that the migration rhythmicity mapped onto the tidal cycle but that it was modulated, and even overridden, by the diurnal cycle and by the irradiance level during daytime periods with a positive phototactic upward migration up to a certain threshold (in our conditions, 120 µmol photons m −2 s −1 of white light). Also, we found blue wavelengths (465 nm) triggered MPB surface accumulation, as compared to other wavelengths (white, green, and red) in patterns that were intensity-dependent and species-dependent. In particular, we foundtwo species, Navicula spartinetensis and Gyrosigma fasciola, which strongly migrate up under blue light and could potentially be used as model species for further studying the light-responses of intertidal MPB.
Published: 2020
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25. Maturation of the European sardine Sardina pilchardus under experimental conditions strengthens bioenergetic estimate

Author: Christel Lefrançois, Elodie Réveillac, Aurélie Dessier, Christine Dupuy, Emmanuel Dubillot, Sébastien Lefebvre, Pierre Morinière, Marie Vagner, Paco Bustamante, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Écologie et santé des écosystèmes (ESE), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Aquarium La Rochelle, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), European Project: REPRODUCE, Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-AGROCAMPUS OUEST, Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), AGROCAMPUS OUEST, and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: 0106 biological sciences, Bioenergetics, Dynamic energy budget, media_common.quotation_subject, Sardina pilchardus, Length-weight relationship, Small pelagic fish, Aquatic Science, Biology, Oceanography, Von bertalanffy, 010603 evolutionary biology, 01 natural sciences, Animal science, Bioenergetic modelling, [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology, Sexual maturity, Animals, 14. Life underwater, Gonads, media_common, 010604 marine biology & hydrobiology, ACL, Sardine, Fishes, General Medicine, Pollution, Otoliths, Seafood, First sexual maturity, Reproduction, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Energy Metabolism, Energy allocation
Abstract: International audience; This study aims at (1) experimentally estimating first sexual maturation of the European sardine S. pilchardus, (2) using the results to calibrate existing bioenergetic models. During the 183 days-experiment, fish growth and body condition were assessed by biometry, and gonads were weighed when present. Age, wet weight and total length at first maturity were estimated at 262 days, 10.79 ± 0.75 g, and 11.26 ± 0.21 cm, respectively. Including these traits in biphasic Von Bertalanffy models did not significantly improve simulations for either length or weight data, meaning that energy allocation was not impacted by these traits. The implementation of the results in the Dynamic Energy Budget (DEB) calibration procedure strengthened the parameter set of the existing model, but resulted in significant changes in the energy allocation. Our results are a first step that will allow the design of new experiments to further quantify maturation and reproduction rates in diverse environmental conditions, consolidating DEB model calibration
Published: 2020
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26. Microbial functional structure and stable isotopic variation of leptocephali across three current zones in the western South Pacific

Author: Tsuguo Otake, Shun Watanabe, Eric Feunteun, Mari Kuroki, Leopold Ghinter, Jun Aoyama, Michael J. Miller, Christine Dupuy, Camilla Liénart, Anthony Acou, Katsumi Tsukamoto, Alexander Carpentier, Christel Lefrançois, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Université du Québec à Rimouski (UQAR), Nihon University, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Université de Rennes (UR), The University of Tokyo (UTokyo), Stockholm University, Kindai University, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Microbial loop, Aquatic Science, 01 natural sciences, Isotopic signature, Latitude, Leptocephali, Meso-macro-zooplankton, 14. Life underwater, Micronekton, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Marine snow, POM, biology, 010604 marine biology & hydrobiology, Western South Pacific, Geology, Plankton, biology.organism_classification, Food web, Oceanography, Trichodesmium, Environmental science, Hydrography
Abstract: International audience; The ecology of leptocephali remains poorly known but they appear to feed on marine snow that can vary spatially and temporally according to the food web dynamics. This study provided new information about the position of leptocephali within the functional structure of microbial plankton and other food web components of the western South Pacific (WSP) region at a large geographic scale including the New Caledonia, Fiji, and Samoa islands. The hydrographic structure varied with latitude, and nutrient levels were generally low but somewhat variable. Stable isotopic signatures were examined in relation to the 3 current zones of the eastward flowing South Equatorial Countercurrent (SECC; north), the westward South Equatorial Current (SEC; mid-latitudes), and the eastward South Tropical Countercurrent (STCC; south), and all zones were found to be primarily based on a heterotrophic planktonic functioning that were co-limited by inorganic nitrogen and phosphorus, with biomasses of planktonic groups varying with depth. Isotopic signatures of leptocephali were compared to the signatures of other mesozoplankton, micronekton, and Trichodesmium components of the food web, and in relation to the signatures of particulate organic matter (POM) that varied among the 3 collection depths. The isotopic signatures of six taxa of leptocephali, other taxonomic groups and POM showed interesting variability according to latitude and among some stations. The presence of Trichodesmium at the surface in the STCC zone influenced the isotopic signatures of POM and thus the signatures of leptocephali. The signatures of leptocephali were therefore linked with the overall food web and were consistent with the larvae feeding on marine snow components of POM. The two apparent groups of leptocephali with different isotopic signatures that have also been observed in other oceanic areas may be explained by feeding behavior at different depths or on different types of marine snow.
Published: 2020
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27. Ecological succession and resilience of plankton recovering from an acute disturbance in freshwater marshes

Author: Christine Dupuy, Hélène Agogué, Martine Bréret, François-Xavier Robin, Sébastien Tortajada, Valérie David, Olivier Philippine, Alexandre Barnett, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Union des marais de la Charente-Maritime (UNIMA), and Délégation interministérielle à l'aménagement et à la compétitivité des territoires (DIACT)
Subjects: planktonic trophic pathways, Environmental Engineering, Marsh, 010504 meteorology & atmospheric sciences, Biodiversity, Submersion (coastal management), Fresh Water, Ecological succession, ecological succession, 010501 environmental sciences, 01 natural sciences, Ecological resilience, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Phytoplankton, Environmental Chemistry, Ecosystem, 14. Life underwater, Waste Management and Disposal, 0105 earth and related environmental sciences, Acute disturbance, geography, ecosystem maturation, geography.geographical_feature_category, Ecology, 15. Life on land, Plankton, Pollution, 13. Climate action, Wetlands, phytoplankton, Environmental science, open system, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; The increase in extreme events such as storms is one of the major threats that coastal ecosystems will have to face in the near future. In such a context, both maturation and ecological successions processes remain at the core of ecology to better anticipate the changes to ecosystem biodiversity and functions facing environmental stressors. However, these concepts are mainly approached through closed experimental studies that oversimplify the mechanisms. A survey was carried out on a ‘natural’ and open ecosystem subjected to an acute disturbance, i.e. a marine submersion of freshwater drained marshes, occurring after a storm. Plankton biomass, production and taxonomic/functional phytoplankton diversity were followed weekly at four stations over 2 months. Most of the stations were disrupted by this acute disturbance and displayed gradual growth and development, as described in the classical maturation process. The main differences between stations were attributed to the heterogeneity of the communities before the storm, the intensity of the disturbance and the different human actions performed to recover the freshwater environment. The concept of ‘ecological resilience’ was thus better suited than ‘engineering resilience’ for such open systems facing constant fluctuations in environmental drivers. With regard to ecological succession, the more impacted stations were marked by a significant change in taxonomic beta-diversity, with numerous stochastic processes, due to taxa dispersion. They first exhibited a convergence in functional traits due to the increase in nutrient availability drained from the catchment basin and then an increase in divergence when nutrients became limited.
Published: 2020
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28. Monitoring small pelagic fish in the Bay of Biscay ecosystem, using indicators from an integrated survey

Author: Jean-Baptiste Romagnan, Jérôme Spitz, Erwan Duhamel, Mathieu Doray, Martin Huret, Matthieu Authier, Pierre Petitgas, Christine Dupuy, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Ecosystem variability, 0106 biological sciences, 010504 meteorology & atmospheric sciences, Fishing, Aquatic Science, Pelagic ecosystem, 01 natural sciences, Marine Strategy Framework Directive, Anchovy, Marine ecosystem, Ecosystem, 14. Life underwater, Survey-based indicators, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Biomass (ecology), Min/max autocorrelation factors, biology, Time correlation, 010604 marine biology & hydrobiology, Geology, Pelagic zone, Bay of Biscay, biology.organism_classification, Oceanography, 13. Climate action, Environmental science, Bay
Abstract: This paper is a practical contribution to two important debates raised by the implementation of marine ecosystem based management: (i) which ecosystem data can be provided by a fisheries survey optimised for ecosystem monitoring; and (ii) how to combine/select potential indicators to derive useful information on marine ecosystem status and dynamics? A suite of 143 potential indicators, including spatial indices, representing small pelagic fish and their biotic and abiotic environments are presented. Indicators were routinely derived from the PELGAS integrated ecosystem survey conducted in spring in the Bay of Biscay (BoB). The general patterns over time in this suite of 5–16 years, non-stationary time series are characterised using a methodology based on min–max autocorrelation factors (MAF), to select the most continuous indicators within, and across, several ecosystem components: hydrology, phytoplankton, mesozooplankton, small pelagic fish and megafauna. Potential interactions between selected indicators and external forcing variables, including climate and fishing, were assessed. The results confirm the importance of river discharges, bottom temperature, chlorophyll-a and mesozooplankton biomass in the dynamics of the BoB pelagic ecosystem. Small pelagic fish species appear to have followed distinct trajectories during the last 15 years. A marked decrease in anchovy and sardine mean weights at ages 1 and 2 over the last 15 years was highlighted; potentially caused by density-dependent competition. The quasi-absence of significant correlation between selected survey indicators and climate and fishing pressure proxies suggests a moderate exploitation rate of small pelagic fish resources, and confirms the so far limited effects of large-scale climate forcing on the BoB pelagic ecosystem. Perspectives for the assessment of marine ecosystem status on the basis of suites of indicators derived from integrated ecosystem surveys are discussed.
Published: 2018
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29. Variability of energy density among mesozooplankton community: New insights in functional diversity to forage fish

Author: Aurélie Dessier, Paco Bustamante, Jérôme Spitz, Christine Dupuy, Françoise Mornet, Matthieu Authier, Anaïs Kerric, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ressources Halieutiques (LRH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Observatoire PELAGIS UMS 3462 (PELAGIS), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Prey-predator relationship, 0106 biological sciences, copepods, Fisheries, Aquatic Science, Biology, 010603 evolutionary biology, 01 natural sciences, Copepods, prey-predator relationship, Engraulis, Anchovy, profitability, Profitability, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Ecology, 010604 marine biology & hydrobiology, Geology, Interspecific competition, Bay of Biscay, biology.organism_classification, Oceanography, fisheries, Forage fish, Common spatial pattern, Spatial variability, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, Copepod
Abstract: International audience; To assess one of the dimensions of mesozooplankton functional diversity, this study quantifies energy density during the springtime in the Bay of Biscay considering both taxonomic and size-classes diversity. Energy density among copepods species (Centropages typicus, Anomalocera patersoni, Calanus helgolandicus, and Labidocera wollastoni), as well as anchovy eggs (Engraulis encrasicolus) ranges from 0.5 to 6.7 kJ/g on a taxonomic basis. Considering size-classes, energy density varies from 0.74 to 1.26 kJ/g. C. helgolandicus exhibits with average energy density estimates generally higher in the plume of the Gironde estuary. In contrast, no spatial coherence is found in the variability of mesozooplankton energy density by size-classes. Our results show that the mesozooplanktonic resource is not homogeneous in terms of quality in the Bay of Biscay. During spring, some species and some geographical areas seems thus to be more profitable to predators than others. We argue that the energy density is a key functional trait of mesozooplankton, but the assessment of mesozooplankton quality should be preferentially based on taxonomy rather than on size-classes. We conclude that interspecific and spatial variability of energy density among the mesozooplankton community can have important implications on fish population dynamics.
Published: 2018
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30. Diel Rhythm Does Not Shape the Vertical Distribution of Bacterial and Archaeal 16S rRNA Transcript Diversity in Intertidal Sediments: a Mesocosm Study

Author: Céline Lavergne, Mylène Hugoni, Hélène Agogué, Cédric Hubas, Christine Dupuy, and Didier Debroas
Subjects: DNA, Bacterial, 0301 basic medicine, Geologic Sediments, Chlorophyll a, Thaumarchaeota, Soil Science, Intertidal zone, Mesocosm, 03 medical and health sciences, chemistry.chemical_compound, RNA, Ribosomal, 16S, 14. Life underwater, Diel vertical migration, Ecosystem, Phylogeny, Ecology, Evolution, Behavior and Systematics, Bacteria, Ecology, biology, Sediment, Biodiversity, Sequence Analysis, DNA, biology.organism_classification, Archaea, DNA, Archaeal, 030104 developmental biology, chemistry, Benthic zone
Abstract: In intertidal sediments, circadian oscillations (i.e., tidal and diel rhythms) and/or depth may affect prokaryotic activity. However, it is difficult to distinguish the effect of each single force on active community changes in these natural and complex intertidal ecosystems. Therefore, we developed a tidal mesocosm to control the tidal rhythm and test whether diel fluctuation or sediment depth influence active prokaryotes in the top 10 cm of sediment. Day- and nighttime emersions were compared as they are expected to display contrasting conditions through microphytobenthic activity in five different sediment layers. A multiple factor analysis revealed that bacterial and archaeal 16S ribosomal RNA (rRNA) transcript diversity assessed by pyrosequencing was similar between day and night emersions. Potentially active benthic Bacteria were highly diverse and influenced by chlorophyll a and phosphate concentrations. While in oxic and suboxic sediments, Thaumarchaeota Marine Group I (MGI) was the most active archaeal phylum, suggesting the importance of the nitrogen cycle in muddy sediments, in anoxic sediments, the mysterious archaeal C3 group dominated the community. This work highlighted that active prokaryotes organize themselves vertically within sediments independently of diel fluctuations suggesting adaptation to physicochemical-specific conditions associated with sediment depth.
Published: 2017
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31. Meiofauna versus macrofauna as a food resource in a tropical intertidal mudflat

Author: Johan Chevalier, Christine Dupuy, Pierrick Bocher, Hien T. Nguyen, Pierre-Yves Pascal, Christel Lefrançois, Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and University of sciences and technologies of hanoi (USTH)
Subjects: 0106 biological sciences, Meiobenthos, goby, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, foodweb, Predation, Optimal foraging theory, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, crab, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Trophic level, Ecology, biology, 010604 marine biology & hydrobiology, Goby, biology.organism_classification, Benthic zone, shrimp, diet, Portunidae, Callinectes bocourti, mudflat, Tanaidacea, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract: International audience; Evaluations of the functioning of benthic marine food webs could be improved by quantifying organic matter fluxes from the meiofauna to higher trophic levels. In this study, we measured the simultaneous ingestion of meiofauna and macrofauna by common dwellers of a tropical intertidal mudflat on the coast of Amazonia. The meiofauna and macrofauna (tanaid) communities of a tropical intertidal mudflat of French Guiana were separately enriched with 15N and 13C, respectively. The enriched preys were then used as tracers during feeding experiments with common predators of different sizes and feeding mechanisms: a Portunidae crab (Callinectes bocourti), a Penaeidae shrimp (Farfantepenaeus subtilis), and a Gobiidae fish (Gobionellus oceanicus). In feeding experiments with all predators except crabs, feeding rates increased with the availability of meiofauna and macrofauna food sources. The ability of consumers to ingest their food selectively was evaluated by calculating the differences in the ratio of macrofauna to meiofauna between the (1) ingested material and (2) that available in the environment. Larger predators showed a higher degree of preferential macrofauna ingestion than smaller predators, consistent with the optimal foraging theory. For large predators, the meiofauna would be important only during early life or in the absence of large food items.
Published: 2019
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32. Modelling the functioning of a coupled microphytobenthic-EPS-bacterial system in intertidal mudflats

Author: Francis Orvain, Christiane Rakotomalala, Karine Grangeré, Christine Dupuy, Katell Guizien, S. Lefebvre, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, carbon and nitrogen ratio, Intertidal zone, Aquatic Science, Oceanography, migration, 010603 evolutionary biology, 01 natural sciences, Mesocosm, Nutrient, Extracellular polymeric substance, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Biomass, Photosynthesis, Overflow metabolism, Diel vertical migration, Ecosystem, Diatoms, Biomass (ecology), Bacteria, Ecology, Chemistry, biogeochemical model, Extracellular Polymeric Substance Matrix, 010604 marine biology & hydrobiology, Microphytobenthos, General Medicine, Pollution, 13. Climate action, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bioturbation
Abstract: International audience; A mechanistic and biogeochemical model was developed to analyze the interactions between microphytobenthos (MPB), bacteria and nutrients in a tidal system. Behavioral vertical migration was hypothesized as being controlled by exogenous factors (tide and light) but also by endogenous factors (carbon and nitrogen requirements). The secretion of Extracellular Polymeric Substances (EPS) during photosynthesis (overflow metabolism) and migration of diatoms was also formulated. Similarities in MPB dynamics between observations and simulations support the assumption that carbon and nitrogen ratios are additional key processes behind the vertical migration of diatoms in the sediment. The model satisfactorily reproduced the three growth phases of the MPB development observed in a mesocosm (the lag phase, the logarithmic growth, and the plateau). Besides, nutrient availability, which could be induced by faunal bioturbation, significantly determined the extent of MPB biomass and development. The plateau phase observed in the last days of simulations appeared to be attributed to a nutrient depletion in the system, emphasizing the importance of nutrient availability. The model, although improvable especially on the formulation of the EPS excretion and bacteria development, already updated understanding of several aspects of benthic-system functioning during experimental conditions.
Published: 2019
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33. Spatio-temporal drivers of microphytoplankton community in the Bay of Biscay: Do species ecological niches matter?

Author: Martin Huret, Christine Dupuy, Emilie Houliez, Aurélie Dessier, Elise Marquis, Martine Bréret, Sébastien Lefebvre, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Sciences et Technologies Halieutiques (STH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Ifremer, BP 70, 29280 Plouzané, France
Subjects: 0106 biological sciences, Outlying mean index, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Ecological niche, Aquatic Science, Biology, 01 natural sciences, Zooplankton, Spatial processes, Phytoplankton, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Biomass (ecology), 010604 marine biology & hydrobiology, Community structure, Geology, Pelagic zone, Plankton, Oceanography, WitOMI, Bay
Abstract: From 2000 to 2016, substantial changes in biomass and community structure of small pelagic fish and mesozooplankton have been reported in the Bay of Biscay. Since significant relationships have been found between phytoplankton chlorophyll a and mesozooplankton as well as between phytoplankton chlorophyll a and shifts in sardine body condition, it was hypothesized that phytoplankton communities may have also been affected during this period and may have played a role in these changes. However, the available data were insufficient to validate this hypothesis and the causes of these changes remained unexplained. The present study analyzed a spatio-temporal marine microphytoplankton dataset collected during the annual PELGAS (PELagiques GAScogne) surveys from 2003 to 2014. The thorough analysis of microphytoplankton taxonomic composition, with an approach integrating the relative role of environmental conditions as well as biotic interactions and applying the concept of ecological niche, confirmed that significant modifications in microphytoplankton community structure occurred during this period. Temporal changes were stronger than spatial differences at these sampling scales. Three main periods, 2003–2005, 2006 and 2007–2014, showing different community structure, diversity and dominant taxonomic units were highlighted. Twenty eight taxonomic units were involved in these community changes. Among them, five were identified as the protagonists (Pseudo-nitzschia spp., Gymnodinium spp. + Gyrodinium spp., Leptocylindrus danicus, Leptocylindrus minimus and Chaetoceros sp.). Variations in water temperature and equivalent freshwater depth constrained the realized ecological niches of these species and explained, at least in part, changes in community structure. This study stresses the need to improve our knowledge of phytoplankton species ecological niches and to take into account biotic interactions for a thorough understanding of the processes shaping plankton communities and the resulting diversity patterns.
Published: 2021
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34. Impact of biofilm resuspension on mesozooplankton in a shallow coastal ecosystem characterized by a bare intertidal mudflat

Author: Christine Dupuy, Hélène Montanié, Valérie David, Francis Orvain, Alexandre Barnett, Martine Bréret, Hans J. Hartmann, LIttoral ENvironnement et Sociétés - UMR 7266 ( LIENSs ), Université de La Rochelle ( ULR ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), ANR-06-BLAN-0393,VASIREMI,Trophic significance of microbial biofilms in tidal flats ( 2006 ), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU), and ANR-06-BLAN-0393,VASIREMI,Trophic significance of microbial biofilms in tidal flats(2006)
Subjects: 0106 biological sciences, planktonic trophic pathways, biofilm resuspension, mesozooplankton, microphytobenthos, 010504 meteorology & atmospheric sciences, growth, Aquatic Science, Biology, 01 natural sciences, Zooplankton, Predation, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Water column, [ SDV.EE.IEO ] Life Sciences [q-bio]/Ecology, environment/Symbiosis, grazing, Ecosystem, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Trophic level, [ SDE.BE ] Environmental Sciences/Biodiversity and Ecology, [ SDU.STU.OC ] Sciences of the Universe [physics]/Earth Sciences/Oceanography, Ecology, 010604 marine biology & hydrobiology, fungi, somatic production, Pelagic zone, Plankton, [ SDV.EE.ECO ] Life Sciences [q-bio]/Ecology, environment/Ecosystems, Oceanography, Benthic zone, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract: electronic publication at this time; International audience; A prey–predator experimental setup was conducted in a shallow coastal ecosystem characterized by a bare intertidal mudflat to test if benthic biofilm resuspension causing microalgae inputs and carbon export toward nanoflagellates would favour the highest planktonic trophic level (i.e. mesozooplankton) when nutrient concentrations are high in the water column. Mesozooplankton predation and somatic production were studied by comparing the evolution of the prey assemblage (diversity and abundances) in the presence and absence of these predators during 24 h experiments. The results were then statistically analysed according to the cross-calculation method. Biofilm resuspension caused (i) a direct input of benthic microorganisms that had changed prey structure in term of diversity and/or size and (ii) a differential growth ability between prey taxa. Both reasons implied a bottom-up control on both micro- and mesozooplankton. The carbon export toward heterotrophic nanoflagellates favoured pelagic ciliate growth while mesozooplankton benefited from largest diatoms with high growth rates, both benthic and R-strategist pelagic species. Even if these microbial and herbivorous pathways are controlled by benthic inputs, they seemed to be totally disconnected since ciliates represented only a small part of mesozooplankton diet. The sensitivity of mesozooplankton production appeared species-dependent with the most tolerant taxa dominating the zooplankton assemblages. This suggests a role of the intensities and the frequencies of biofilm resuspension on the spatio-temporal structuring of mesozooplankton in macrotidal coastal ecosystems.
Published: 2016
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35. Geographic variation in stable isotopic and fatty acid composition of anguilliform leptocephali and particulate organic matter in the South Pacific

Author: Tsuguo Otake, Mari Kuroki, Katsumi Tsukamoto, Michael J. Miller, Jean-Michel Mortillaro, Cédric Hubas, Tarik Meziane, Alexandre Carpentier, Jun Aoyama, Camilla Liénart, Shun Watanabe, Eric Feunteun, Christine Dupuy, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Station marine Dinard, Centre National de la Recherche Scientifique (CNRS), University of Tokyo (UTokyo), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Biodiversité et gestion des territoires EA 7316
Subjects: L51 - Physiologie animale - Nutrition, 0106 biological sciences, Azote, [SDV]Life Sciences [q-bio], Heterotroph, Organisme indicateur, Aquatic Science, Biology, 010603 evolutionary biology, 01 natural sciences, Comportement alimentaire, Matière organique, Autotroph, isotope, Ecology, Evolution, Behavior and Systematics, chemistry.chemical_classification, Ecology, Primary producers, δ13C, Stable isotope ratio, 010604 marine biology & hydrobiology, Fatty acid, δ15N, Acide gras, chemistry, Larve de poisson, Environmental chemistry, M40 - Écologie aquatique, Écologie animale, Composition (visual arts), Alimentation des poissons
Abstract: International audience; ABSTRACT: The feeding ecology of leptocephali has remained poorly understood because they apparently feed on particulate organic matter (POM), which varies in composition, and it is unclear which components of the POM they assimilate. The δ13C and δ15N stable isotope (SI) and fatty acid (FA) compositions of 3 families of leptocephali and POM were compared in 3 latitudinal current zones of the western South Pacific. The δ15N signatures of leptocephali and POM overlapped, with both having their lowest values in the southern current zone. POM in general (across all zones) contained 38 FAs and was rich in saturated FAs (SFA) (16:0, 18:0, 14:0), while leptocephali contained 50 FAs, with high proportions of 16:0, and higher contributions of 22:6ω3, 20:5ω3, 18:1ω9, 16:1ω7 and other FAs than found in the POM. Serrivomeridae leptocephali in the north had higher δ15N signatures and were also distinguished from Nemichthyidae and Muraenidae larvae by their FA compositions (higher SFAs, lower 22:6ω3 and 20:5ω3). Although SI signatures of the Serrivomeridae larvae did not clearly vary with size, 16:0 and 18:0 FA proportions decreased with increasing larval size, and 22:6ω3 and 16:1ω7 increased in larger larvae. Correspondences between the latitudinal variations in nitrogen SI signatures and FA compositions of POM with those of leptocephali and the presence of FA markers of both autotrophic and heterotrophic organisms were consistent with leptocephali feeding on POM. POM can contain various materials from primary producers and heterotrophic microorganisms, but differences in the SI signatures and FA compositions in leptocephali remain to be explained through further research
Published: 2016
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36. On biotic and abiotic drivers of the microphytobenthos seasonal cycle in a temperate intertidal mudflat: a modelling study

Author: Raphaël Savelli, Christine Dupuy, Laurent Barillé, Astrid Lerouxel, Katell Guizien, Anne Philippe, Pierrick Bocher, Pierre Polsenaere, Vincent Le Fouest, Université de La Rochelle (ULR), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Mer, molécules et santé EA 2160 (MMS), Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN)-Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnement Ressources des Pertuis Charentais (LER/PC), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: Peringia ulvae, benthic, microphytobenthos, [SDV]Life Sciences [q-bio], lcsh:QE1-996.5, lcsh:Life, lcsh:Geology, lcsh:QH501-531, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, 13. Climate action, micro-algae, lcsh:QH540-549.5, seasonal cycle, grazing, lcsh:Ecology, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, mudflat, primary production, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract: Microphytobenthos (MPB) from intertidal mudflats are key primary producers at the land-ocean interface. MPB can be more productive than phytoplankton and sustain both benthic and pelagic higher trophic levels. The objective of this study is to assess the contribution of light, mud temperature, and gastropod Peringia ulvae grazing pressure in shaping the seasonal MPB dynamics on the Brouage mudflat (NW France). We use a physical-biological coupled model applied to the sediment first centimeter for the year 2008. The simulated data compare to observations including time-coincident remotely sensed and in situ data. The model suggests a MPB annual cycle characterized by a main spring bloom, a biomass depression in summer, and a moderate fall bloom. In early spring, high simulated photosynthetic rates due to mud surface temperature (MST) values close to the MPB temperature optimum for photosynthesis and to increasing solar irradiance trigger the onset of the MPB spring bloom. After the bloom, high MST values lead to synoptic events when MPB thermo-inhibition (39.5 % of summer) and limitation by P. ulvae grazing (8.7 % of summer) superimpose. During these synoptic events of thermo-inhibition and grazing combination, 14 % of the simulated annual MPB primary production is channeled towards the P. ulvae secondary production through ingestion. The model suggests that such a combined effect is highly linked to the MPB biomass depression in summer. The model ability to infer on biotic and abiotic mechanisms driving the seasonal MPB dynamics could open the door to a new assessment of the export flux of biogenic matter at the land-ocean interface and, more generally, of the contribution of productive intertidal biofilms to the coastal carbon cycle.
Published: 2018
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37. There's no harm in having too much: A comprehensive toolbox of methods in trophic ecology

Author: Michael Danger, Aurélie Dessier, Priscilla Decottignies, Alexandre Bec, Thibaut Powolny, Nicolas Hette-Tronquart, Christian Desvilettes, Stanislas F. Dubois, Christine Dupuy, Mickaël Hedde, Regis Sabbadin, Benjamin Pey, Nabil Majdi, Nathalie Peyrard, Cédric Gaucherel, Marie-Elodie Perga, Bruno Cognie, Etienne Auclair, Franck Jabot, Elisa Thébault, Martin P. Marzloff, Sébastien Lefebvre, Clémentine Fritsch, Tiphaine Chouvelon, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Hydrosystèmes et Bioprocédés (UR HBAN), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), GRET, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Benthique Côtière (LEBCO), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), PESSAC, Institut National de la Recherche Agronomique (INRA), Laboratoire d'ingénierie pour les systèmes complexes (UR LISC), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Laboratoire Sols et Environnement (LSE), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Unité de Biométrie et Intelligence Artificielle (ancêtre de MIAT) (UBIA), Unité de Mathématiques et Informatique Appliquées de Toulouse (MIAT INRA), Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Hydrosystèmes et bioprocédés (UR HBAN), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Université d'Auvergne - Clermont-Ferrand I (UdA), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), Unité de Biométrie et Intelligence Artificielle (UBIA), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Feeding interactions, Trophic models, Ecology (disciplines), FLUX OF ENERGY, Population, TROPHIC MODELS, 010603 evolutionary biology, 01 natural sciences, Empirical research, FOOD WEB, Ecosystem, 14. Life underwater, education, Food web, Flux of energy, Computer simulations, Ecology, Evolution, Behavior and Systematics, Organism, Trophic level, education.field_of_study, Ecology, 010604 marine biology & hydrobiology, COMPUTER SIMULATIONS, 15. Life on land, Geography, 13. Climate action, [SDE]Environmental Sciences, FEEDING INTERACTIONS, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Biological organisation
Abstract: [Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE [ADD1_IRSTEA]Dynamique et fonctionnement des écosystèmes; International audience; Trophic ecology is the study of feeding interactions and food acquisition by organisms. It includes the causes and consequences of those behaviours at all levels of biological organisation. As a field of research, it crosses many disciplinary boundaries and provides knowledge that is pertinent to many other areas of ecology. Here we list and categorise the methods available to trophic ecologists whose toolbox has broadened considerably in recent years. They encompass empirical and numerical approaches with focus ranging from molecules to ecosystems. We further examine the relationship of each method to features such as the scale of observation (from microbes to largest organisms) and organisational level (from individuals to ecosystems) as well as the ecological question the method is capable of answering (from detecting predator-prey relationships to studying implications and consequences at different scales). Our survey reveals a very wide range of methodologies, each more-or-less appropriate for a particular line of research. It also identifies deficits, for example, trophic interactions at microscopic scales, for which empirical methods have hardly been used, as well as trophic models that have failed to consider fluxes at the ecosystem scale. Furthermore, we note that the combination of methodologies remains under-exploited despite great opportunities to solve complex ecological questions and to foster the emergence of new insights and hypotheses regarding organism, population and/or ecosystem properties.
Published: 2018
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38. The spring mesozooplankton variability and its relationship with hydrobiological structure over year-to-year changes (2003–2013) in the southern Bay of Biscay (Northeast Atlantic)

Author: Elise Marquis, Françoise Mornet, Christine Dupuy, Martin Huret, Martine Bréret, Cécilia Pignon-Mussaud, Marc Pagano, Aurélie Dessier, Paco Bustamante, Frédéric Rousseaux, Tiphaine Chouvelon, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Sciences et Technologies Halieutiques (STH), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), URS Qatar, European Project: REPRODUCE, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Écologie et Modèles pour l'Halieutique (IFREMER EMH), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD), Laboratoire Biogéochimie des Contaminants Métalliques (LBCM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre atlantique, Nantes, Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), and Unité de recherche Sciences et Technologies Halieutiques (STH)
Subjects: 0106 biological sciences, Biomass (ecology), 010504 meteorology & atmospheric sciences, biology, 010604 marine biology & hydrobiology, Geology, Aquatic Science, biology.organism_classification, 01 natural sciences, Salinity, Oceanography, Hydrology (agriculture), [SDE]Environmental Sciences, Phytoplankton, [SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery, Common spatial pattern, Environmental science, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, Copepod, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Trophic level
Abstract: International audience; Mesozooplankton can be considered the most important secondary producers in marine food webs because they hold an intermediate position between the phytoplankton assemblage and the upper trophic levels. They also are a robust indicator of climatic and hydrological conditions. We conducted an analysis of the interannual variability of the spring mesozooplankton assemblage, as sampled by the PELGAS fisheries survey in the southern part of the Bay of Biscay (Northeast Atlantic Ocean) between 2003 and 2013. We examined hydrology and trophic drivers to explain the variability. Our results revealed that the subsurface temperature, the subsurface salinity, the biomasses of subsurface pico-, nano-, and microphytoplankton, and the copepod assemblage exhibited a recurrent spatial pattern that was driven mainly by freshwater and nutrient inputs from the main rivers. The mesozooplankton assemblage was dominated by copepods (82%), composed of coastal, neritic, and oceanic copepod genera that paralleled the various hydrological fronts converging in the southern Bay of Biscay. The copepod community displayed high temporal-variability; there were three periods of abundant adult copepods throughout the southern Bay of Biscay. The copepod community was structured primarily around the drive for resource control, especially by the microphytoplankton biomass (24.3% of the total variability), and to a lesser extent by hydrological features (13.7% of the total variability).
Published: 2018
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39. Coccolith-derived turbidity and hydrological conditions in May in the Bay of Biscay

Author: Luis Lampert, Martin Huret, Paul Bourriau, Pascale Malestroit, Laurie Perrot, Christine Dupuy, Francis Gohin, Aurélie Dessier, Diana Ruiz-Pino, Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Équipe CO2 (E-CO2), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sciences et Technologies Halieutiques (STH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Écologie et Modèles pour l'Halieutique (EMH), Conseil Régional de Poitou-Charentes, European Project: REPRODUCE, Dynamiques de l'Environnement Côtier (DYNECO), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Département Sciences et Technologies halieutiques - Laboratoire Biologie halieutique (STH-LBH), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Écologie et Modèles pour l'Halieutique (IFREMER EMH), and Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique)
Subjects: 0106 biological sciences, Coccoliths, 010504 meteorology & atmospheric sciences, Coccolithophore, Aquatic Science, 01 natural sciences, ocean colour, Coccolith, Turbidity, coccoliths, Water column, stratification, Ocean colour, Photic zone, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, biology, Continental shelf, 010604 marine biology & hydrobiology, Geology, Suspended particulate matter, biology.organism_classification, Bay of Biscay, suspended particulate matter, turbidity, Oceanography, Environmental science, Stratification, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bloom, Bay
Abstract: International audience; Coccolithophore blooms occur regularly from April to June in the Bay of Biscay where they have been observed for many years from ocean-colour imagery thanks to the ability of their calcite plates to scatter light. They are easily depicted on interpolated images of non-algal Suspended Particulate Matter (SPM) derived from satellite reflectance data in May, at the time of the PELGAS (PELagique GAScogne) annual surveys. Over the springs 2012 to 2015, the PELGAS surveys provided in-situ data on the turbidity throughout the water column and on the hydrological environment prevailing during the blooms in the vicinity of the continental shelf break. The satellite-derived SPM in the area of coccolithophore blooms was closely related to measured turbidity in the euphotic zone. The deep maxima of coccolithophore-derived biomass were well observed in the turbidity signal throughout the water column. Despite the recurrence of SPM patterns due to coccolithophores in the well-mixed waters over the shelf break in spring, the variability of the satellite-derived SPM and the turbidity profiles was particularly high during the four years studied. The year 2013 showed persistent blooms from mid-April to the end of May over large areas inside and outside the shelf waters, whereas no bloom was observed in 2014, neither on SPM images nor through turbidity profiles. The presence or absence of coccolithophore blooms during the years 2012-2015 seem related to the level of stratification of the water column, with more intense blooms occurring during mixed conditions. These results should improve classification of the PELGAS surveys from those occurring in a coccolith-rich environment, synonymous with mixed and cold waters, to those occurring in a coccolith-poor environment where surface waters are warmer and more stratified.
Published: 2018
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40. The PELGAS survey: ship-based integrated monitoring of the Bay of Biscay pelagic ecosystem

Author: Ghislain Dorémus, Matthieu Authier, Florence Sanchez, Jean-Baptiste Romagnan, Martin Huret, Paul Bourriau, Laurent Berger, Erwan Duhamel, Jérôme Spitz, Pierre Petitgas, Patrick Grellier, Mathieu Doray, Christine Dupuy, Jacques Masse, Écologie et Modèles pour l'Halieutique (IFREMER EMH), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Observatoire PELAGIS UMS 3462 (PELAGIS), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Ecosystem variability, ecosystem variability, 010504 meteorology & atmospheric sciences, Context (language use), Aquatic Science, Fish stock, 01 natural sciences, Pelagic ecosystem, pelagic ecosystem, Marine Strategy Framework Directive, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, fishing vessels, Marine ecosystem, Ecosystem, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, integrated ecosystem monitoring survey, Biomass (ecology), 010604 marine biology & hydrobiology, Fishing vessels, Geology, Bay of Biscay, Fishery, Geography, Oceanography, 13. Climate action, Integrated ecosystem monitoring survey, Survey data collection, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract: International audience; The Pélagiques Gascogne (PELGAS) integrated survey has been developed by a multidisciplinary team of Ifremer and La Rochelle University scientists since 2000, joined by commercial fishermen in 2007. Its initial focus was to assess the biomass and predict the recruitment success of anchovy in the Bay of Biscay in spring. Taking advantage of the space and versatility of R/V Thalassa II, sampling has been progressively extended to other ecosystem components. PELGAS therefore further developed the second objective of monitoring and studying the dynamic and diverse Biscay pelagic ecosystem in springtime. The PELGAS survey model has allowed for the establishment of a long-term time-series of spatially-explicit data of the Bay of Biscay pelagic ecosystem since the year 2000. Main sampled components of the targeted ecosystem are: hydrology, phytoplankton, mesozooplankton, fish and megafauna. The survey now provides two main ecosystem products: standard raster maps of ecosystem parameters, and a time series dataset of indicators of the Bay of Biscay pelagic ecosystem state. They are used to inform fish stock and ecosystem-based management, and support ecosystem research. The present paper introduces the PELGAS survey, as a practical example of an integrated, vessel-based, ecosystem survey. The evolution of the PELGAS scientific team and sampling protocols are presented and analysed, to outline factors crucial to the success of the survey. Data and results derived from PELGAS are reviewed, to exemplify scientific questions that can be tackled by integrated ecosystem survey data. Advantages and challenges of the survey are discussed and put into the context of marine ecosystem surveys in the European Marine Strategy Framework Directive and the Common Fisheries Policy.
Published: 2018
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41. Impact of human activities on the spatio-seasonal dynamics of plankton diversity in drained marshes and consequences on eutrophication

Author: Olivier Philippine, Martine Bréret, Valérie David, François-Xavier Robin, Christine Dupuy, Sébastien Tortajada, Nicolas Lachaussée, Nicolas Savoye, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Union des marais de la Charente-Maritime (UNIMA)
Subjects: Environmental Engineering, Marsh, 0208 environmental biotechnology, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Zooplankton, Phytoplankton, Dominance (ecology), Animals, Humans, Human Activities, 14. Life underwater, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, geography, geography.geographical_feature_category, Ecology, Ecological Modeling, Hypoxia (environmental), Pelagic zone, 15. Life on land, Plankton, Eutrophication, Pollution, 6. Clean water, 020801 environmental engineering, 13. Climate action, Wetlands, [SDE]Environmental Sciences, Environmental science, Seasons, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: The functional diversity of two planktonic functional compartments, the nano-microphytoplankton and the mesozooplankton was used in order to better understand i) the drained marshes functioning and their related ecological functions, ii) the impacts of human control (replenishment) and human activities on the catchment basin (urbanization and catchment basin size). It was based on a monthly seasonal survey on 7 freshwater drained marshes. Both nano-microphyto- and mesozooplankton displayed high seasonal variations linked to the environmental fluctuations and human control on sea lock gates. Winter presented the lower biomasses of both compartments. Winter that is characterized by low water temperature, low light availability and high flood is actually related to the dominance of tychopelagic phytoplankton and K-strategists zooplankton. Spring and summer were characterized by i) the succession of pelagic large cells, small cells and then taxa with alternatives food strategies due to nitrogen limitation and phosphorous desorption from the sediment leading to eutrophication processes and ii) the dominance of r-strategists for mesozooplankton. The artificial summer replenishment acts positively on water quality by decreasing the eutrophication processes since the nitrogen inputs limit the proliferation of phytoplankton mixotrophs and diazotrophs and increase the ecological efficiency during the warm period. Both small and large catchment basins may lead to summer eutrophication processes in drained marshes since the largest ones imply higher hydrodynamic features at the root of large inputs of nitrogen nutrient favoring the phytoplankton development while the smallest ones exhibit hypoxia problems due to high proliferation of macrophytes. Urbanized marshes are less subjected to eutrophication during summer than non urbanized marshes due to more recurrent nutrient inputs from urban waste. However they exhibited a lower ecological efficiency. The results suggest that a better management of the hydrodynamics of such anthropogenic systems can avoid eutrophication risks on coastal areas.
Published: 2018
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42. First evidence of the presence and activity of archaeal C3 group members in an Atlantic intertidal mudflat

Author: Céline Lavergne, Mylène Hugoni, Christine Dupuy, Hélène Agogué, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Valparaíso (PUCV), Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Ecole Nationale Vétérinaire de Lyon (ENVL), Charente Maritime department, program CPER of Poitou-Charentes, french national program EC2CO/CNRS-INSU ('CAPABIOC'), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Vétérinaire de Lyon (ENVL)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)
Subjects: biosphère, Geologic Sediments, lcsh:R, lcsh:Medicine, Biodiversity, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Archaea, Article, communauté, base de données de séquences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, vasiere, séquençage à haut débit, lcsh:Q, atlantique, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, lcsh:Science, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Atlantic Ocean, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract: International audience; The phylogenetic assignment of archaeal communities is constantly evolving, and the recent discovery of new phyla that grouped into superphyla has provided novel insights into archaeal ecology and evolution in ecosystems. In intertidal sediments, archaea are known to be involved in key functional processes such as organic matter turnover, but the ecological relevance of the rarest archaeal groups is poorly investigated, due partly to the lack of cultivated members. The high resolution of microbial diversity provided by high-throughput sequencing technologies now allows the rare biosphere to be described. In this work, we focused on the archaeal C3 group, showing that this phylum is not only present (at the DNA level) independently of sediment depth but also active (at the RNA level) in specific sediment niches depending on vertical physicochemical gradients. Moreover, we highlight the ambiguous phylogenetic affiliation of this group, indicating the need of further research to get new insights into the role of the C3 group.
Published: 2018
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43. Supplementary material to 'On biotic and abiotic drivers of the microphytobenthos seasonal cycle in a temperate intertidal mudflat: a modelling study'

Author: Raphaël Savelli, Christine Dupuy, Laurent Barillé, Astrid Lerouxel, Katell Guizien, Anne Philippe, Pierrick Bocher, Pierre Polsenaere, and Vincent Le Fouest
Published: 2018
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44. Ecosystem spatial structure revealed by integrated survey data

Author: Jérôme Spitz, Martin Huret, Pierre Petitgas, Mathieu Doray, Matthieu Authier, Jean-Baptiste Romagnan, Christine Dupuy, Laboratoire Ressources Halieutiques (LRH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Écologie et Modèles pour l'Halieutique (IFREMER EMH), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Observatoire PELAGIS UMS 3462 (PELAGIS), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Spatial structure, Aquatic Science, 01 natural sciences, Ecosystems, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Multi-factor analysis, Ecosystem, Integrated surveys, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Multi-Factor Analysis, business.industry, Ecology, 010604 marine biology & hydrobiology, Environmental resource management, Sampling (statistics), Geology, 15. Life on land, Grid, Bay of Biscay, Oceanography, Pelagic, 13. Climate action, Seascapes, Spatial ecology, Survey data collection, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, business, Scale (map), Row
Abstract: Integrated marine survey series such as PELGAS provide comprehensive geo-referenced data over large sea areas in major ecosystem components with defined biological resolution and spatio-temporal sampling scale. These data enable to develop product at different levels of biological organization and spatial scale that are useful for ecosystem integrated assessments. Using the PELGAS integrated data series, we applied a generic procedure made of several steps to identify and map ecologically coherent ecosystem spatial units in the Bay of Biscay. First, the data were interpolated on a common spatial grid and organized as a time series of matrices containing at each time the variables as columns and the grid cell values as rows. The multi-table analysis method known as Multi-Factor Analysis (MFA) was then applied on the series of matrices, thus separating in the analysis the spatial from the temporal variability. Grouping the spatial grid cells based on their relative positions in the MFA space resulted in mapping ecosystem spatial entities based on common spatial patterns across ecosystem components. The result of the analysis is a map of ecosystem seascapes that are consistent over the years together with a map of their inter-annual variability. The ecosystem sub-units were in agreement with sub-regional production systems in the Bay of Biscay. This study thus highlights the possibility to characterize and monitor ecosystem spatial structure and develop indicators thereof for their use in ecosystem assessments. Also, it highlights the importance of identifying spatial limits of production systems for ecosystem description, assessment and management.
Published: 2018
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45. Microphytobenthos and an indicator of environmental quality status in intertidal flats:Case study of coastal ecosystem in Pertuis Charentais, France

Author: Christine Dupuy, Guo-Ying Du, HongMei Yan, College of Marine Life Science, Ocean University of China, Ocean University of China (OUC), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, microphytobenthos, [SDV]Life Sciences [q-bio], Pertuis Charentais, Intertidal zone, Aquatic Science, Intertidal ecology, Oceanography, 01 natural sciences, intertidal ecosystem, Organic matter, Ecosystem, 14. Life underwater, 0105 earth and related environmental sciences, chemistry.chemical_classification, Biomass (ecology), bioassessment, biology, Ecology, 010604 marine biology & hydrobiology, Sediment, 15. Life on land, biology.organism_classification, chemistry, 13. Climate action, Navicula, Environmental science, community, Species richness, France
Abstract: International audience; Microphytobenthos communities of different sediment types were investigated in intertidal flats of the coastal area around La Rochelle (Pertuis Charentais, France) in July 2014 and January 2015. Biotic variables of biomass, abundance and species composition of microphytobenthos were evaluated together with environmental variables, including irradiance, sediment temperature, grains size, pore water salinity, pH, nutrients, organic matter, water content and heavy metal concentrations in the sediment. The relationships between biotic and environmental parameters showed that: (1) the microphytobenthos biomass and community structures showed significant differences among different sediment types; (2) variation in the microphytobenthos communities were significantly correlated with environmental variables, especially with the heavy metals, grain size, irradiance, pore water salinity, organic matter and concentration of PO4 3+ and Si(OH)4; (3) the species number and richness were both significantly correlated with organic matter, and (4) the species Entomoneis corrugate, Navicula aitchelbee and Gyrosigma cf.limosum were positively correlated to heavy metals, and so were N. phylleptosoma, Surirella brebissonii to Si(OH)4 and NH4 + concentrations, and G. acuminatum and S. brebissonii to PO4 3+ and NH4 +. It is suggested that the spatial variation in biodiversity of microphytobenthos may reflect environmental quality status in coastal intertidal ecosystems.
Published: 2017
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46. Factors influencing prokaryotes in an intertidal mudflat and the resulting depth gradients

Author: Céline Lavergne, Rutger de Wit, Martine Bréret, Mélanie Raimonet, Hélène Agogué, Philippe Pineau, Aude Leynaert, Christine Dupuy, Nicolas Lachaussée, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), School of Biochemical Engineering (EIB), Pontificia Universidad Católica de Valparaíso (PUCV), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Département Charente Maritime, CPER 2006-2014, EC2CO CAPABIOC, CNRS, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD)
Subjects: 0106 biological sciences, 0301 basic medicine, [SDE.MCG]Environmental Sciences/Global Changes, Stratification (water), Intertidal zone, microbial communities, Aquatic Science, Intertidal ecology, Oceanography, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 01 natural sciences, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Ecosystem, 14. Life underwater, sediment depth, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ecology, 010604 marine biology & hydrobiology, benthic ecology, ACL, Sediment, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, 15. Life on land, Salinity, 030104 developmental biology, Benthic zone, Environmental science, intertidal mudflat, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract: International audience; Intertidal mudflats are rich and fluctuating systems. The upper 20 cm support a high diversity and density of microorganisms that ensure diversified roles. The depth profiles of microbial abundances and activities were measured in an intertidal mudflat (Marennes-Oléron Bay, SW France) at centimeter-scale resolution (0-10 cm below the sediment surface). The aim of the study was to detect microbial stratification patterns within the sediments and how this stratification is shaped by environmental drivers. Two sampling dates, i.e. one in summer and another in winter, were compared. The highest activities of the microbial communities were observed in July in the surface layers (0-1 cm), with a strong decrease of activities with depth. In contrast, in February, low microbial bulk activities were recorded throughout the sediment. In general, prokaryotic abundances and activities were significantly correlated. Variation partitioning analysis suggested a low impact of predation and a mainly bottom-up-controlled prokaryotic community. Hence, in the top layer from the surface to 1–3.5 cm depth, microbial communities were mainly affected by physicochemical variables (i.e., salinity, phosphate and silicate concentrations). Below this zone and at least to 10 cm depth, environmental variables were more stable and prokaryotic activities were low. The transition zone between both layers probably represents a rather smooth gradient (environmental ecocline). The results of our study provide a better understanding of the complex interactions between micro-organisms and their environment in a fluctuating ecosystem such as an intertidal mudflat.
Published: 2017
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47. Low Benthic Macrofauna Diversity in Dynamic, Tropical Tidal Mudflats: Migrating Banks on Guiana's Coast, South America

Author: Christine Dupuy, Pierrick Bocher, David Mizrahi, Nyls de Pracontal, Jérôme Jourde, Hien T. Nguyen, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), New Jersey Audubon Society, and Groupe d’Etude et de Protection des Oiseaux de Guyane
Subjects: 0106 biological sciences, Delta, Amazonian, [SDV]Life Sciences [q-bio], tropical mudflats, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, 14. Life underwater, soft-bottom macrobenthos, Ecology, Evolution, Behavior and Systematics, Polychaete, Ecology, biology, Discharge, Amazon rainforest, 010604 marine biology & hydrobiology, biology.organism_classification, Substrate (marine biology), communities, Geography, Oceanography, Benthic zone, Amazon influence, Species richness
Abstract: In tropical South America, the mudflats of the Amazonian coast are unique because of their large size and unrivaled migration dynamics. On Guiana’s coast, macrofaunal communities are believed to be well-adapted to these dynamic conditions. In this study, the benthic macrofauna was sampled in April 2012 in the Awala-Yalimapo region of western French Guiana and at two sites in Suriname: Warappa Kreek and Bigi Pan. These sites are found 800, 920, and 1140 km from the Amazon delta, respectively. The richness, diversity, and densities of the macrofaunal communities in these mudflats are here described for the first time. Only 38 operational taxonomic units (OTUs) were recorded, among which two species were common and widely distributed: the tanaid crustacean Halmyrapseudes spaansi and the polychaete Sigambra grubii; the former represented 84% of all individuals collected, with densities reaching up to 73,000 individuals m−2. Most of the OTUs consisted of relatively small individuals (
Published: 2017
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48. Behavioral responses of juvenile golden gray mullet Liza aurata to changes in coastal temperatures and consequences for benthic food resources

Author: Serena Como, Enrico Maggi, Christine Dupuy, Christel Lefrançois, Fabio Antognarelli, CNR Institute for Coastal Marine Environment (IAMC), Consiglio Nazionale delle Ricerche (CNR), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Biologia, University of Pisa - Università di Pisa, and Consorzio Nazionale Interuniversitario per le Scienze del Mare [Rome, Italie] (CoNISma)
Subjects: 0106 biological sciences, spatial variance, microphytobenthos, feeding behavior, Photosynthetic efficiency, Biology, Aquatic Science, Spatial distribution, Oceanography, 010603 evolutionary biology, 01 natural sciences, Mullet, Mesocosm, Animal science, Grazing, [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology, Golden gray mullets, Juvenile, grazing, 14. Life underwater, Grey mullets, Liza aurata, Ecology, Evolution, Behavior and Systematics, Ecology, 010604 marine biology & hydrobiology, temperature, biology.organism_classification, Benthic zone, Spatial variability
Abstract: International audience; Temperature is an important factor for fish. Yet, little is known about its effects on the feeding behavior of fish and the subsequent consequences of these behavioral changes on the spatial distribution of resources. We analyzed the differences in the feeding behavior of two sizes of juvenile Liza aurata at two water temperatures (i.e. 10°C and 20°C), using laboratory mesocosms. We also examined whether temperature-induced changes in feeding behavior of the smaller size of L. aurata would affect the spatial distribution of the microphytobenthos (MPB) biomass, an important resource in coastal systems. Both the number of feeding events and the swimming velocity during feeding in juvenile L. aurata were higher at 20°C than at 10°C, independently of the fish size. The time spent feeding did not vary between 10°C and 20°C, while the distance covered during feeding was significantly smaller at 20°C than at 10°C. Grazing did not affect the mean MPB biomass, but did increase its spatial variance at the smaller scale (i.e. a few centimeters) at 20°C. A high number of feeding events, a high swimming velocity during feeding and a small distance covered during feeding in 20°C-acclimated L. aurata most likely represented an adaptation to an increase in metabolism, as well as to the need to reduce the energy costs of feeding at 20°C. Results also indicated that changes in feeding behavior of the 20°C-acclimated L. aurata were responsible for the increase in small-scale spatial variability in the MPB biomass. We suggested that the enhanced spatial patchiness due to grazing by fish at 20°C might yield a local increase in the mean MPB biomass, probably increasing photosynthetic efficiency of cells and algal growth that counterbalance the negative effect of algal removal by fish, and resulting in the lack of an overall significant effect on the mean.
Published: 2014
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49. How does the resuspension of the biofilm alter the functioning of the benthos–pelagos coupled food web of a bare mudflat in Marennes-Oléron Bay (NE Atlantic)?

Author: Blanche Saint-Béat, Christine Dupuy, Hélène Agogué, Alexandre Carpentier, Julien Chalumeau, Serena Como, Valérie David, Margot De Crignis, Jean-Claude Duchêne, Camille Fontaine, Eric Feunteun, Katell Guizien, Hans Hartmann, Johann Lavaud, Sébastien Lefebvre, Christel Lefrançois, Clarisse Mallet, Hélène Montanié, Jean-Luc Mouget, Francis Orvain, Pascaline Ory, Pierre-Yves Pascal, Gilles Radenac, Pierre Richard, Alain F. Vézina, Nathalie Niquil, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Station marine Dinard, Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), CNR Institute for Coastal Marine Environment (IAMC), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Service de biologie moléculaire, Hôpital Pontchaillou, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Lab-STICC_CNRS_CID_SFIIS, Département Image et Traitement Information (ITI), Université européenne de Bretagne - European University of Brittany (UEB)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Université européenne de Bretagne - European University of Brittany (UEB)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Biologie des mollusques marins et des écosystèmes associés (BioMEA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de biologie et environnement marins - LBEM (LBEML), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Consiglio Nazionale delle Ricerche (CNR), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Microbial food web, Ecology, Intertidal zone, Pelagic zone, Aquatic Science, Sedimentation, Oceanography, Food web, Water column, Benthos, 13. Climate action, [SDE]Environmental Sciences, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Environmental science, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, Trophic level
Abstract: International audience; Intertidal mudflats are ecosystems submitted to natural hydrodynamical forcings during each tide. When the off-shore water flows at high tide, a proportion of the biofilm produced at low tide can be resuspended in the water column and interact with the pelagic food web. As a consequence, the resuspension creates a link between the benthos and the pelagos, modifying their properties and the stability of the meta-ecosystem they form together. The aim of this study is to describe the consequences of the microbial biofilm resuspension on the pelagic food web, and to investigate the question of the stability of the benthos–pelagos coupling resulting from the biofilm resuspension. Two food webs were considered, corresponding to different hydrodynamical conditions in sum-mer condition: one allowing the biofilm massive resuspension, and one without resuspension, but with particle sedimentation. The Monte-Carlo Markov Chain Linear Modelling was used to estimate the unknown flows of the food web. The comparison of the Ecological Network Analysis indices for the two food webs allowed defining their respective differences of structure and functioning. The results showed that the massive resuspension of the microbial biofilm stimulates pelagic primary production and microbial food web via a higher bacterivory. The higher activity of the whole system coupled with both a drop in the specialisation of the trophic pathways and a low cycling activity demonstrated that when massive resuspension occurs, the system is disturbed. In con-trast, when sedimentation occurs, the food webs show functioning features pointing out to a higher stability of the whole system.
Published: 2014
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50. Feeding ecology of Liza spp. in a tidal flat: Evidence of the importance of primary production (biofilm) and associated meiofauna

Author: Christine Dupuy, Serena Como, Eric Feunteun, Alexandre Carpentier, Christel Lefrançois, Biodiversité et gestion des territoires EA 7316, CNR Institute for Coastal Marine Environment (IAMC), Consiglio Nazionale delle Ricerche (CNR), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), This study was supported by the French ANR (National Research Agency) through the VASIREMI project 'Trophic significance of microbial biofilms in tidal flats' (contract ANR-420 06-BLAN-0393-01)., ANR-06-BLAN-0393,VASIREMI,Trophic significance of microbial biofilms in tidal flats(2006), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Gray Mullets, Meiofauna, Meiobenthos, Mudflat, Aquatic Science, Oceanography, 010603 evolutionary biology, 01 natural sciences, Mullet, Ecosystem, 14. Life underwater, Feeding Ecology, Ecology, Evolution, Behavior and Systematics, Trophic level, Isotope analysis, geography, geography.geographical_feature_category, biology, Ecology, 010604 marine biology & hydrobiology, Microphytobenthos, Biofilm, biology.organism_classification, Habitat, Salt marsh, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; Grey mullets are unique among temperate-region fish species in their ability to feed on mudflat biofilm. In this study, we examined mullet feeding strategies on biofilm and associated meiofauna by using a diet study and stable isotope analysis to explore functional interactions between mullets and tidal flats. A stomach vacuity investigation showed that mullets did not import any materials from subtidal areas into the mudflat but exported mud, biofilm, and associated meiofauna. The results of mullet stomach content and fecal analyses, when compared to the availability of tidal flat resources, showed evidence of mullets' ability to ingest and assimilate biofilm and to concentrate major meiofauna grazers such as nematodes, copepods and, secondarily, foraminifers and ostracods. Isotopic ratios confirmed diet investigations, and as recently shown in salt marsh habitats, mullets exhibited an intermediate trophic position, supporting the hypothesis that they can assimilate both biofilm and major meiofauna grazers. The function of the tidal flat as a feeding habitat for gray mullets and the role of mullets as the main export pathway of biofilm from tidal flat ecosystems are discussed.
Published: 2014
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