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8. Impact of farming non-indigenous scallop Argopecten irradians on benthic ecosystem functioning: a case-study in Laizhou Bay, China

Author

Huang, Q, Olenin, S, Sun, S, and De Troch, M

Subjects
Aquaculture. Fisheries. Angling, SH1-691, Ecology, QH540-549.5
Abstract

The farming of the non-indigenous bay scallop Argopecten irradians in coastal waters generates large amounts of biodeposits that potentially change the trophic pathways and quality of the benthic food web at lower trophic levels such as meiobenthos. To understand the trophic link between faecal pellets of bay scallop and meiobenthos in the aquaculture area, we investigated the resource use of harpacticoid copepods and nematodes inside and outside of 3 bay scallop farms in Laizhou Bay (Bohai Sea, China) using natural abundance of stable carbon and nitrogen isotopes together with fatty acid profiling. Faeces were found to be enriched in δ15N compared to all other food sources, which made faecal matter traceable. The enriched δ15N in several meiobenthos at the farms, together with the mixing model results, indicated that faeces could be a new food source for most of harpacticoid copepods and some nematodes. The quantities and the pathways of assimilation differed between the copepod families, depending on their feeding behaviors and the receiving environment. Furthermore, due to the presence of higher levels of polyunsaturated fatty acids, in particular docosahexaenoic acid, the dominant copepod family Canuellidae that abundantly consumed scallop faeces showed enhanced nutritional quality compared with those in the control sites. Thus, aquaculture of non-indigenous bay scallops provided a food source that was directly and indirectly consumed by meiobenthos underneath the scallop farms and improved the quality of lower level consumers as a food item in the benthic food web.

Published
2018
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9. Sunlight and sediment improve the environment of a litter biofilm-based shrimp culture system

Author

Gatune, C, Vanreusel, A, and De Troch, M

Subjects
Aquaculture. Fisheries. Angling, SH1-691, Ecology, QH540-549.5
Abstract

In silvofishery, where shrimp culture is integrated with mangrove trees, the mangrove leaf litter may modify the environment in these culture systems. This study tested the potential of submerged leaf litter of Rhizophora mucronata and associated biofilm in providing a favorable environment for post-larval shrimp Penaeus monodon. Litter decomposition and assembly of microalgae and epifauna were assessed under exposure to sunlight or shade, and presence or absence of sediment. Litter incubated with sediment and exposed to sunlight was rapidly decomposed and supported the highest biomass and diversity of microalgae and epifauna. The litter also supported the highest abundance of diatoms, polychaetes and nematodes during the 4th week of decomposition. Cyanobacteria of the genus Microcystis dominated litter incubated without sediment, in sunlight, after decomposition for 5 wk. Under shaded conditions, diatoms of the genus Navicula and the Cyanobacteria Anabaena spp. and Oscillatoria spp. continued to grow at high total ammonium nitrogen, low dissolved oxygen, low temperature and low pH. Our study illustrates synergy between sediment and direct sunlight in promoting diversity of microalgae and polychaetes (of dietary benefit to shrimps), inhibiting growth of Cyanobacteria and maintaining water quality at levels favorable to culture of post-larval shrimp. Our findings support 4 practices for a healthy environment in fish ponds: (1) locating ecological shrimp culture in less forested areas, (2) promoting sediment conditions in artificial shrimp culture systems, (3) exposing litter-derived biofilm within ponds to sunlight and incubating with sediment to maintain favorable water quality and control Cyanobacteria blooms, and (4) minimizing the use of pond liners and related sludge removal.

Published
2017
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10. 32nd International Austrian Winter Symposium: Zell am See, the Netherlands. 20-23 January 2016

Author

Langsteger, W, Rezaee, A, Loidl, W, Geinitz, HS, Fitz, F, Steinmair, M, Broinger, G, Pallwien-Prettner, L, Beheshti, M, Imamovic, L, Beheshti, M, Rendl, G, Hackl, D, Tsybrovsky, O, Steinmair, M, Emmanuel, K, Moinfar, F, Pirich, C, Langsteger, W, Bytyqi, A, Karanikas, G, Mayerhöfer, M, Koperek, O, Niederle, B, Hartenbach, M, Beyer, T, Herrmann, K, Czernin, J, Rausch, I, Rust, P, DiFranco, MD, Lassen, M, Stadlbauer, A, Mayerhöfer, ME, Hartenbach, M, Hacker, M, Beyer, T, Binzel, K, Magnussen, R, Wei, W, Knopp, MU, Flanigan, DC, Kaeding, C, Knopp, MV, Leisser, A, Nejabat, M, Hartenbach, M, Kramer, G, Krainer, M, Hacker, M, Haug, A, Lehnert, Wencke, Schmidt, Karl, Kimiaei, Sharok, Bronzel, Marcus, Kluge, Andreas, Wright, CL, Binzel, K, Zhang, J, Wuthrick, Evan, Maniawski, Piotr, Knopp, MV, Blaickner, M, Rados, E, Huber, A, Dulovits, M, Kulkarni, H, Wiessalla, S, Schuchardt, C, Baum, RP, Knäusl, B, Georg, D, Bauer, M, Wulkersdorfer, B, Wadsak, W, Philippe, C, Haslacher, H, Zeitlinger, M, Langer, O, Bauer, M, Feldmann, M, Karch, R, Wadsak, W, Zeitlinger, M, Koepp, MJ, Asselin, M-C, Pataraia, E, Langer, O, Zeilinger, M, Philippe, C, Dumanic, M, Pichler, F, Pilz, J, Hacker, M, Wadsak, W, Mitterhauser, M, Nics, L, Steiner, B, Hacker, M, Mitterhauser, M, Wadsak, W, Traxl, A, Wanek, Thomas, Kryeziu, Kushtrim, Mairinger, Severin, Stanek, Johann, Berger, Walter, Kuntner, Claudia, Langer, Oliver, Mairinger, S, Wanek, T, Traxl, A, Krohn, M, Stanek, J, Filip, T, Sauberer, M, Kuntner, C, Pahnke, J, Langer, O, Svatunek, D, Denk, C, Wilkovitsch, M, Wanek, T, Filip, T, Kuntner-Hannes, C, Fröhlich, J, Mikula, H, Denk, C, Svatunek, D, Wanek, T, Mairinger, S, Stanek, J, Filip, T, Fröhlich, J, Mikula, H, Kuntner-Hannes, C, Balber, T, Singer, J, Fazekas, J, Rami-Mark, C, Berroterán-Infante, N, Jensen-Jarolim, E, Wadsak, W, Hacker, M, Viernstein, H, Mitterhauser, M, Denk, C, Svatunek, D, Sohr, B, Mikula, H, Fröhlich, J, Wanek, T, Kuntner-Hannes, C, Filip, T, Pfaff, S, Philippe, C, Mitterhauser, M, Hartenbach, M, Hacker, M, Wadsak, W, Wanek, T, Halilbasic, E, Visentin, M, Mairinger, S, Stieger, B, Kuntner, C, Trauner, M, Langer, O, Lam, P, Aistleitner, M, Eichinger, R, Artner, C, Eidherr, H, Vraka, C, Haug, A, Mitterhauser, M, Nics, L, Hartenbach, M, Hacker, M, Wadsak, W, Kvaternik, H, Müller, R, Hausberger, D, Zink, C, Aigner, RM, Cossío, U, Asensio, M, Montes, A, Akhtar, S, te Welscher, Y, van Nostrum, R, Gómez-Vallejo, V, Llop, J, VandeVyver, F, Barclay, T, Lippens, N, Troch, M, Hehenwarter, L, Egger, B, Holzmannhofer, J, Rodrigues-Radischat, M, Pirich, C, Pötsch, N, Rausch, I, Wilhelm, D, Weber, M, Furtner, J, Karanikas, G, Wöhrer, A, Mitterhauser, M, Hacker, M, Traub-Weidinger, T, Cassou-Mounat, T, Balogova, S, Nataf, V, Calzada, M, Huchet, V, Kerrou, K, Devaux, J-Y, Mohty, M, Garderet, L, Talbot, J-N, Stanzel, S, Pregartner, G, Schwarz, T, Bjelic-Radisic, V, Liegl-Atzwanger, B, Aigner, R, Stanzel, S, Quehenberger, F, Aigner, RM, Marković, A Koljević, Janković, Milica, Jerković, V Miler, Paskaš, M, Pupić, G, Džodić, R, Popović, D, Fornito, MC, Familiari, D, Koranda, P, Polzerová, H, Metelková, I, Henzlová, L, Formánek, R, Buriánková, E, Kamínek, M, Thomson, WH, Lewis, C, Thomson, WH, O’Brien, J, James, G, Notghi, A, Huber, H, Stelzmüller, I, Wunn, R, Mandl, M, Fellner, F, Lamprecht, B, Gabriel, M, Fornito, MC, Leonardi, G, Thomson, WH, O’Brien, J, James, G, Hudzietzová, J, Sabol, J, and Fülöp, M

Published
2016
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27. State of art and best practices for fatty acid analysis in aquatic sciences

Author

Couturier, L.I.E., Michel, L.N., Amaro, T., Budge, S.M., da Costa, E., De Troch, M., Di Dato, V., Fink, Patrick, Giraldo, C., Le Grand, F., Loaiza, I., Mathieu-Resuge, M., Nichols, P.D., Parrish, C.C., Sardenne, F., Vagner, M., Pernet, F., Soudant, P., Couturier, L.I.E., Michel, L.N., Amaro, T., Budge, S.M., da Costa, E., De Troch, M., Di Dato, V., Fink, Patrick, Giraldo, C., Le Grand, F., Loaiza, I., Mathieu-Resuge, M., Nichols, P.D., Parrish, C.C., Sardenne, F., Vagner, M., Pernet, F., and Soudant, P.

Abstract

Determining the lipid content and fatty acid (FA) composition of aquatic organisms has been of major interest in trophic ecology, aquaculture, and nutrition for over half a century. Although protocols for lipid analysis are well-described, their application to aquatic sciences often requires modifications to adapt to field conditions and to sample type. Here, we present the current state of knowledge of methods dedicated to both marine and freshwater lipid analyses, from sampling to data treatment. We review: (i) sample preservation, storage and transport protocols, and their effects on lipids, (ii) lipid extraction, separation of polar and neutral lipids, derivatization, and detection methods, and (iii) available tools for the statistical analysis of FA data. We provide recommendations for best practices in field situations and advocate for protocol standardization and interlaboratory calibration.

Published
2020

28. Fatty acid bioconversion in harpacticoid copepods in a changing environment: a transcriptomic approach

Author

Boyen, J., Fink, Patrick, Mensens, C., Hablützel, P.I., De Troch, M., Boyen, J., Fink, Patrick, Mensens, C., Hablützel, P.I., and De Troch, M.

Abstract

By 2100, global warming is predicted to significantly reduce the capacity of marine primary producers for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis. Primary consumers such as harpacticoid copepods (Crustacea) might mitigate the resulting adverse effects on the food web by increased LC-PUFA bioconversion. Here, we present a high-quality de novo transcriptome assembly of the copepod Platychelipus littoralis, exposed to changes in both temperature (+3°C) and dietary LC-PUFA availability. Using this transcriptome, we detected multiple transcripts putatively encoding for LC-PUFA-bioconverting front-end fatty acid desaturases and elongases, and performed phylogenetic analyses to identify their relationship with sequences of other (crustacean) taxa. While temperature affected the absolute fatty acid concentrations in copepods, LC-PUFA levels remained unaltered even when copepods were fed a LC-PUFA-deficient diet. While this suggests plasticity of LC-PUFA bioconversion within P. littoralis, none of the putative front-end desaturase or elongase transcripts were differentially expressed under the applied treatments. Nevertheless, the transcriptome presented here provides a sound basis for future ecophysiological research on harpacticoid copepods.

Published
2020

29. Selective and context-dependent effects of chemical stress across trophic levels at the basis of marine food webs

Author

Mensens, C., De Laender, F., Janssen, C., Rivera, F.C., Sabbe, K., and De Troch, M.

Subjects
fungi
Abstract

Human activities increasingly impact the functioning of marine food webs, but anthropogenic stressors are seldom included in ecological study designs. Diet quality, as distinct from just diet quantity, has moreover rarely been highlighted in food web studies in a stress context. We measured the effects of metal and pesticide stress (copper and atrazine) on the contribution of a benthic intertidal diatom community to two processes that are key to the functioning of intertidal systems: biomass (diet quantity) and lipid (diet quality) production. We then examined if stressors affected diatom functioning by selectively targeting the species contributing most to functioning (selective stress effects) or by changing the species’ functional contribution (context‐dependent effects). Finally, we tested if stress‐induced changes in diet quality altered the energy flow to the diatoms’ main grazers (harpacticoid copepods). Diatom diet quantity was reduced by metal stress but not by low pesticide levels due to the presence of an atrazine‐tolerant, mixotrophic species. Selective effects of the pesticide reduced diatom diet quality by 60% and 75% at low and high pesticide levels respectively, by shifting diatom community structure from dominance by lipid‐rich species toward dominance by an atrazine‐tolerant, but lipid‐poor, species. Context‐dependent effects did not affect individual diatom lipid content at low levels of both stressors, but caused diatoms to lose 40% of their lipids at high copper stress. Stress‐induced changes in diet quality predicted the energy flow from the diatoms to their copepod consumers, which lost half of their lipids when feeding on diatoms grown under low and high pesticide and high metal stress. Selective pesticide effects were a more important threat for trophic energy transfer than context‐dependent effects of both stressors, with shifts in diatom community structure affecting the energy flow to their copepod grazers at stress levels where no changes in diatom lipid content were detected.

Published
2018

31. Effects of a herbicide and copper mixture on the quality of marine plankton

Author

Filimonova, V., De Troch, M., Gonçalves, F., Marques, J.C., Marques, S.M., Gonçalves, A.M.M., and De Laender, F.

Subjects
fungi, Fatty acids, Plankton, Biomarkers
Abstract

Pesticides and metals are often used in agriculture and are therefore often simultaneously discharged to nearby estuarine and marine areas. The effects of this organic-inorganic chemical mixture on food quality of aquatic organisms are currently unknown. In this study we test if a mixture of copper (inorganic) and the herbicide Primextra® Gold TZ (organic) affects the quality of the diatom Thalassiosira weissflogii and the copepod Acartia tonsa - two key species that fuel the local food-web. We quantified quality (i.e. energy content as food for the next trophic level) in terms of fatty acids, proteins and thiobarbituric acid reacting substances. We found non-additive effects (positive and negative) of the metal-herbicide mixture on the diatom and copepod species. In general, nutritionally important biochemical parameters of Acartia tonsa were most sensitive to the chemical stressors.

Published
2018

34. The food web of Potter Cove (Antarctica): complexity, structure and function

Author

Marina, T.I., Salinas, V., Cordone, G., Campana, G., Deregibus, D., Torre, L., Sahade, R., Tatián, M., Barrera Oro, E., De Troch, M., Doyle, S., Quartino, M.L., Saravia, L.A., and Momo, F.R.

Subjects
Antarctica
Abstract

Knowledge of the food web structure and complexity are central to better understand ecosystem functioning. A food-web approach includes both species and energy flows among them, providing a natural framework for characterizing species’ ecological roles and the mechanisms through which biodiversity influences ecosystem dynamics. Here we present for the first time a high-resolution food web for a marine ecosystem at Potter Cove (northern Antarctic Peninsula). Eleven food web properties were analyzed in order to document network complexity, structure and topology. We found a low linkage density (3.4), connectance (0.04) and omnivory percentage (45), as well as a short path length (1.8) and a low clustering coefficient (0.08). Furthermore, relating the structure of the food web to its dynamics, an exponential degree distribution (in- and out-links) was found. This suggests that the Potter Cove food web may be vulnerable if the most connected species became locally extinct. For two of the three more connected functional groups, competition overlap graphs imply high trophic interaction between demersal fish and niche specialization according to feeding strategies in amphipods. On the other hand, the prey overlap graph shows also that multiple energy pathways of carbon flux exist across benthic and pelagic habitats in the Potter Cove ecosystem. Although alternative food sources might add robustness to the web, network properties (low linkage density, connectance and omnivory) suggest fragility and potential trophic cascade effects.

Published
2018

36. Development of potential yield loss indicators to assess the effect of seaweed farming on fish landings

Author

Préat, N., De Troch, M., van Leeuwen, S., Taelman, S.E., De Meester, S., Allais, F., Dewulf, J., Préat, N., De Troch, M., van Leeuwen, S., Taelman, S.E., De Meester, S., Allais, F., and Dewulf, J.

Abstract

In recent years, several indicators have been proposed to assess the effect of human activities on ecosystems provisioning capacity. Some of these methods focus on the Net Primary Production (NPP) available for ecosystem functioning through the comparison between the Human Appropriated Net Primary Production (HANPP) and the ecosystem's initial NPP at a given reference year. While some approaches have been proposed for marine ecosystems, most of the HANPP studies focus on terrestrial systems. This study highlights the relation between the HANPP methods and the production of natural resources in marine ecosystems. The linkage between current overfishing and future fish provisioning (ecosystem service) is well known. However, less studied before, is the relation between seaweed aquaculture and fish provisioning through the marine food web. Seaweed growth requires nutrients and light that will consequently be no longer available for natural phytoplankton production. As seaweed is periodically harvested, a fraction of the ecosystem's NPP (HANPP) is no longer available for ecosystem production. The HANPP of aquaculture reduces the ecosystem carrying capacity and thus affects commercial fish stocks. Therefore, an integrative approach is proposed in this study to assess the potential effect of seaweed farming on fish landings in the Greater North Sea. Three indicators are proposed to assess the Lost Potential Yield (LPY) in fish landings: LPYB, LPYV and LPYE, accounting respectively for reduction in biomass, monetary value and eco-exergy. For these three aspects, the LPY results remains smaller than the seaweed production, meaning that the overall natural resources balance for seaweed farming is positive.

Published
2018

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