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Tagoro is one of the few submarine volcanoes in the world that has been monitored since its early eruptive stage in 2011 to present day. After six multidisciplinary oceanographic cruises conducted between 2014 and 2023 to gather a comprehensive dataset of georeferenced video-imagery and in situ measurements of hydrothermal flow velocities and hydrothermal fluid samples, we provide a robust characterization of the ongoing hydrothermal fluid velocity, heat flux, and nutrient release, along with an accurate delimitation of the hydrothermal field area. Our results reveal that Tagoro hydrothermal system extends from the main hydrothermal crater up to the summit, covering an area of 7600 m2. This hydrothermal field comprises thousands of small individual vents, displaying diverse morphologies such as crevices and delicate chimney-like structures, irregularly scattered across the dominant diffuse venting surface. Hydrothermal fluid temperatures and velocities at the substratum level reveal a clustered spatial distribution, ranging from 21.0 to 33.3 °C and 1.6–26.8 cm min−1, respectively. Furthermore, our findings indicate a discernible correlation between hydrothermal fluid temperature and vent density, while significant differences were observed between velocities from diffuse and focused areas. Additionally, heat fluxes exceed 200 MW across the entire active region, with heat flux values ranging from 6.06 to 146.87 kW m−2 and dissolve inorganic nutrient concentrations exhibit significant enrichments, comparable to the magnitude of important nutrient sources in the area as upwelling systems or mesoscale structures.

Growing knowledge of the host-microbiota of vertebrates has shown the prevalence of sex-specific differences in the microbiome. However, there are virtually no studies assessing sex-associated variation in the microbiome of cephalopods. Here we assess sex-specific variation in the common octopus (Octopus vulgaris) skin microbiome using amplicon sequencing targeting the V4 hypervariable region of prokaryote 16S rRNA genes. Skin and mantle-associated mucus was collected from wild adult individuals of common Octopus (Octopus vulgaris) (9 males and 7 females of similar size). There were no significant differences in the alpha diversity of microbial communities associated with skin or mantle mucosa between sexes. However, our results clearly indicate that adult octopus males and females have a distinct microbial community composition in both skin and mantle associated mucus communities, with female microbiome being dominated by Firmicutes (48.1%), while that of males contained a majority of Proteobacteria (60.5%), with Firmicutes representing only 3.30%, not finding significant differentiation in the microbial communities between the tissues explored. The dominance of different taxa in the skin of O. vulgaris females and males (e.g., Mycoplasmatales and Lactococcus in females and Rhizobiales and Rhodobacteriales in males) suggests a sex-specific symbiosis in which those microbes benefit from easy access to distinct substrates present in female and male skin, respectively. Given the lack of differences in size between specimens of both sexes in this study, we hypothesize differences in hormone profile, as well as behavioral or ecological differences between sexes in the wild, as the main drivers of microbiome differentiation between sexes. Most knowledge of cephalopod microbiota is limited to the digestive tract and the reproductive system. However, cephalopod skin is an organ with a plethora of functions. This is a first attempt to characterize cephalopod skin microbiota

The technical and intellectual capabilities of past societies are reflected in the monuments they were able to build. Tracking the provenance of the stones utilised to build prehistoric megalithic monuments, through geological studies, is of utmost interest for interpreting ancient architectures as well as to contribute to their protection. According to the scarce information available, most stones used in European prehistoric megaliths originate from locations near the construction sites, which would have made transport easier. The Menga dolmen (Antequera, Malaga, Spain), listed in UNESCO World Heritage since July 2016, was designed and built with stones weighting up to nearly 150 tons, thus becoming the most colossal stone monument built in its time in Europe (c. 3800-3600 BC). Our study (based on high-resolution geological mapping as well as petrographic and stratigraphic analyses) reveals key geological and archaeological evidence to establish the precise provenance of the massive stones used in the construction of this monument. These stones are mostly calcarenites, a poorly cemented detrital sedimentary rock comparable to those known as 'soft stones' in modern civil engineering. They were quarried from a rocky outcrop located at a distance of approximately 1 km. In this study, it can be inferred the use of soft stone in Menga reveals the human application of new wood and stone technologies enabling the construction of a monument of unprecedented magnitude and complexity.

The volcanic eruption that occurred in La Palma Island (Canary Islands, Spain) in 2021 resulted in molten lava flowing into the ocean and forming a delta in the coastline, besides the emission of large amounts of ashes being deposited in a vast area around the Canary Islands. In order to assess the effects of the eruption on seawater, two oceanographic cruises were carried out, one at the beginning of the eruption and a second one a month later. We used an oceanographic CTD rosette sampler for collecting seawater in different areas of La Palma coastline together with Unmanned Aerial Vehicles (UAVs) equipped with a sampling device to collect surface samples near the delta newly formed on the coastal fringe. We sequenced the 16S rRNA gene in order to assess the response of bacterioplankton to such natural disturbance. The results show that the abundance of Thiomicrospirales, Gammaproteobacteria capable of oxidizing poly-metal sulfides, increased significantly in UAV samples collected near the lava delta. Moreover, in stations where the largest physical-chemical anomalies were recorded with the CTD, sequence data showed drastic changes in the prokaryotic community structure; cyanobacterial abundance decreased while the ammonia-oxidizing archeon Nitrosopelagicus and the bacterial SAR324 clade, with potential sulfur-based chemolithoautotrophic lifestyle, dominated the communities. The combined used of shipboard operations and UAVs provided a unique opportunity to study the prokaryotic response to a massive lava input, an event that is rarely observed and sampled in real time.

Underwater hydrothermal systems release nutrient-rich fluids that are favorable for microbial activity. This allows the growth of a plethora of microorganisms that can be found inhabiting hydrothermal plumes, metalliferous sediments, or forming dense microbial biofilms or mats on the surrounding of the vents. Most of the current knowledge on the microbiology associated with underwater volcanic activity comes from the study of deep-sea hydrothermal vents. However, much less is known about shallow underwater hydrothermal systems. The submarine volcanic eruption that took place near El Hierro (Canary Islands) in October 2011 and gave rise to the Tagoro volcano, located only 1.8 km from land and approximately 89 m below the sea surface, provided a rare occasion to study almost in real time the microbiology associated with an underwater eruptive process, from its birth to the current degassing state, allowing investigations of its effects on the surrounding pelagic and benthic communities. In this chapter, we summarize what is known 10 years after the formation of the Tagoro submarine volcano, and we discuss what questions should be pursued in order to foster our knowledge of the microbiology associated with this volcano and its surrounding waters

The shallow Tagoro submarine volcano monitoring represents a unique opportunity not only for improving our sparse understanding of submarine volcanic processes in specific scientific fields as physical and chemical oceanography or marine geology but also its interactions over the marine biology in one of the richest marine ecosystems in Europe. This chapter aims to summarize the most relevant physical–chemical, geological and biological changes that occurred in the marine ecosystem of El Hierro island, at the Marine Reserve Punta de La Restinga—El Mar de Las Calmas, due to the genesis of the new underwater volcano Tagoro (27º37′07″N–017º59′28″W) in October 2011. During the first six months of the eruption, extreme physical–chemical perturbations caused by this event, comprising thermal increase from up to + 18.8 °C, water acidification with a pH decrease of 2.9 units, deoxygenation to anoxic levels and extremely high metal enrichment among others, resulted in significant and dramatic alterations of the marine ecosystem. After March 2012, once the eruptive phase was finished, the new submarine volcano entered an active hydrothermal phase involving the release of heat with smaller but still significant and important thermal anomalies of up to + 2.55 °C around the craters, density decrease of − 1.43 kg m−3, pH decrease of − 1.25 units, and high concentrations of metals and inorganic nutrients similar to upwelling zones. These enrichments are still active up to date, producing clear signs of marine recovery not only in the benthonic strata but also in the whole water column compared with pre-eruptive data. Since its eruption ten years ago, an unprecedented monitoring effort has turned into the longest and most complete multidisciplinary time-series for the study of a shallow submarine volcano, with the realization of 31 oceanographic multidisciplinary expeditions that systematically measure more than 40 different physical–chemical and biological variables. All this info

The eruption of the Cumbre Vieja volcano started on September 19, 2021, on the island of La Palma, following a seismic swarm that affected the southern half of the island. The lava flowed westward and reached the coastline 8 days later in the area between Punta de la Bombilla and Tazacorte harbour. Four oceanographic cruises on board the research vessels Ramón Margalef and Ángeles Alvariño (Spanish Institute of Oceanography, IEO-CSIC) aimed to (i) characterizing the petrologic features prior to the arrival of the lava flows into the coastline, (ii) assessing the variations of the water-magma system when the lava flowed into the sea, and (iii) evaluating the main changes in the system after the end of the eruption. High-resolution bathymetric maps obtained with the multibeam echosounder EM710, combined with submarine high- definition ROV LIROPUS images and rocks samples collected from the sea bottom, showed that lava flowed down the shelf and upper slope as block (aa) and pillow lava flows, being conditioned by small gullies on the upper slope. Significant morphological changes have been defined in the subaerial northern and southern lava deltas (areas of 5,4 and 43 ha, respectively), and on a submarine area of ~30 ha. Volcanic material has been identified as far as 1.2 km from the original coastline at ~305 m seawater depth. Preliminary petrographic studies determine that the began as tephrites and later evolved intro basanites with olivine, pyroxene, amphibole and plagioclase phenocrysts within a glassy matrix with variable number of vesicles. The total volume of lava reaching the submarine environment is estimated of around 3 Mm3 with maximum thickness ca. 40 m along previous submarine slope gullies. Integrated with multidisciplinary analyses of the water column and ecosystem changes, this study will improve the knowledge of the magmatic evolution from depth up to eruption and will be useful for the risk management of future eruptive events.

Tagoro is one of the few worldwide submarine volcanoes that satisfies the following features: i) is an intraplate and shallow- water volcano; ii) comprises diffuse low-temperature hydrothermal fields; and iii) its physical-chemical and biological characteristics that have been monitored since its first eruption in 2011. Despite a decade of widespread investigation, there is still a gap of knowledge on Tagoro volcano hydrothermal system. Hence, this preliminary research aims to report a precise estimation on the amount and distribution of hydrothermal vents, as well as an estimative quantification of the heat and nutrient fluxes associated therein. The hydrothermal vents distribution was determined through video imagery recorded by the Remote Operated Vehicle (ROV) Liropus-2000 during four oceanographic expeditions in 2014, 2017, 2018 and 2021 on board the R/V Ángeles Alvariño. Moreover, fluid flow velocities were estimated using a previously proposed sampling technique involving a custom-built particle-tracker device, designed to be manipulated by ROV Liropus-2000 on the hydrothermal areas. This device was deployed during oceanographic cruises in 2021 and 2022 on board the R/V Ángeles Alvariño. Lastly, hydrothermal fluids were sampled directly from vents using a piston-driven suction device coupled to the ROV Liropus-2000 during the 2022 cruise. Preliminary results highlight the remarkably vast richness and complexity of the Tagoro hydrothermal system, which is generally distributed in the main crater and main cone. The system is composed of various morphologies including diffuse- discharge fields, crevices and very fragile chimneys. Additionally, our results show important heat outflows into the ocean, ranging from 200 to 580 MW. This comprehensive study contributes to the broadening knowledge of the magnitude of hydrothermal activity at Tagoro submarine volcano and builds a reference for further studies.

On September 2021 a fissure eruption occurred and the Cumbre Vieja volcano situated on the Canary Island of La Palma, resulting in the expulsion of a substantial amount of lava that flowed westward reaching the coastline 8 days later. Our data indicate that lava flowed down the shelf and upper slope as block (aa) and pillow lava flows, channeled by small gullies on the upper slope. Significant morphological changes have been detected in the subaerial northern and southern lava deltas (areas of 43 and 5.4 ha, respectively), and on a submarine area of ~30 ha. New volcanic materials halve been identified as far as 1.2 km from the original coastline at ~305 mbsl.

The shallow submarine volcano Tagoro releases high amounts of inorganic nutrients (N, P, Si, Fe) into the surrounding waters. These emissions have been intensely monitored during both the eruptive stage (October 2011–March 2012) and the post-eruptive hydrothermal stage (March 2012—ongoing). The obtained seven-years dataset comprises over 3300 water samples analysed for concentrations of silicate (Si(OH)4), phosphate (PO4), nitrate + nitrate(NO3− + NO2−), ammonium (NH4+), and iron (Fe(II)) in the area affected by the volcanic emissions (> 250 km2) as well as outside of this area for reference. This chapter provides an overview on the main results obtained from this comprehensive dataset, as well as contextualizing these results by comparison with other volcanic and hydrothermal nutrient sources in the world. The results show that the hydrothermal emissions from Tagoro volcano cause nutrient enrichments both in the vicinities of the vents (88–130 m depth) and the water column up to 50 m above the seabed. The emissions can occasionally also be injected into the mixed layer and might even reach the surface. The transport of these emissions presents a flux of comparable magnitude to other important nutrient fluxes in the region, such as those related to the NW-African coastal upwelling, when compared per unit of area. We highlight the importance of accounting for shallow hydrothermal and volcanic inputs worldwide as significant nutrient sources that can exert an important influence on the ecosystems of superficial nutrient-poor waters. © 2023 The Author(s), under exclusive license to Springer Nature Switzerland AG

The shallow, near-shore submarine volcano Tagoro erupted in October 2011 at the Mar de las Calmas marine reserve, south of El Hierro island. The injection of lava into the ocean had its strongest episode during November 2011 and lasted until March 2012. During this time, in situ measurements of dissolved oxygen were carried out, using a continuous oxygen sensor constantly calibrated with water samples. A severe deoxygenation was observed in the area, particularly during October-November 2011, which was one of the main causes of the high mortality observed among the local marine ecosystem. The measured O2 concentrations were as low as 7.71 µmol kg-1, which represents a -96% decrease with respect to unaffected waters. The oxygen depletion was found in the first 250 m of the water column, with peaks between 70-120 m depth. The deoxygenated plume covered an area of at least 464 km2, distributed particularly south and south-west of the volcano, with occasional patches found north of the island. The oxygen levels were also monitored through the following years, during the degassing stage of the volcano, when oxygen depletion was no longer observed. Additionally, during the eruption, an island-generated anticyclonic eddy interacted with the volcanic plume and transported it for at least 80 km, where the O2 measurements still showed a -8% decrease after mixing and dilution. This feature draws attention to the permanence and transport of volcanic plumes far away from their source and long after the emission.

The Columbretes Archipelago and their submerged surroundings are part of an unusual, Pleistocene volcanic field located in the Western Mediterranean designated as a Site of Community Importance (SCI) of the Natura 2000 Network. In the present study, 4 benthic habitats of community interest (1110, 1170, 1180 and 8330) have been identified by analyzing several sources of information. Generalized additive models (GAMs) have been used to model the potential distribution of reefs (1170) and maërl beds (1110). Our results highlight the diversity and extent of these habitats and allow comparisons to other marine SCIs of Spain. This can be attributed to the variability of the environment of this site. The Columbretes Islands combine a relatively shallow environment with volcanic structures, hydrothermalism with active degassing, current-driven sedimentary lobes and the influence of inland flows. Understanding high biodiversity spots is crucial as they offer natural laboratories to describe how ecosystems respond to the effects of global change. The knowledge obtained will be of paramount importance for the conservation of species and habitats. Furthermore, it will establish a baseline for future monitoring and assist in the development of effective management plans.

En La Palma (Islas Canarias), tras un enjambre sísmico que afectó a la mitad sur de la isla, se inició, el 19 de septiembre de 2021, la erupción del volcán en Cumbre Vieja. El flujo de la lava discurrió hacia el oeste, llegando al mar el 28 de septiembre a las 23:00h canaria entre las costas de la Punta de La Bombilla y el puerto de Tazacorte. El Instituto Español de Oceanografía (IEO-CSIC), con dos representantes en el comité científico del Plan de Emergencia por Riesgo Volcánico de Canarias (PEVOLCA), actuó de inmediato, enviando a la zona los dos buques más modernos de los que dispone, los buques de investigación R/V Ramón Margalef y R/V Ángeles Alvariño. Esta actuación, por requerimiento Ministerial, tuvo un doble objetivo: i) velar por las medidas de seguridad y prevención contempladas en la normativa vigente dentro del PEVOLCA y ii) realizar investigación multidisciplinar y asesoramiento, enmarcados dentro del proyecto VULCANA (Vulcanología Canaria Submarina), liderado y financiado por el IEO-CSIC desde 2011.

The eastern North Atlantic region receives large Saharan dust deposition inputs, providing nutrients and trace metals to the surface waters. We assessed the effects of intense dust deposition on phytoplankton and bacteria cell abundances, metabolic activity, and community structure, along a surface productivity gradient in the Mauritanian-Senegalese upwelling system. Dust concentrations above 4 mg L-1 were added to triplicate microcosms in four bioassay experiments, each lasting three days, increasing nitrate, phosphate and, to a lesser extent, silicate seawater concentrations. Even though dust deposition enhanced both heterotrophic and photosynthetic activity, bacterial production responded faster and stronger than primary production, especially as oligotrophic conditions increased. Bacterial production rates in oligotrophic waters almost tripled one day after the enrichment. However, such favorable response could not be observed on the total organic carbon production until a lag phase of 2 days and whilst under moderate eutrophic conditions. Dust enrichment benefited the presence of certain planktonic groups over others according to their nutrient requirements. Indicator species analysis revealed that our dust-treated microcosms were consistently characterized by Raphid-pennate diatoms, as well as by Hyphomonas genus of Alphaproteobacteria and several species of Alteromonas Gammaproteobacteria. Yet, changes in microbial community structure and composition were primarily shaped by the starting conditions of each experiment. These findings indicate that increasing dust deposition events and the weakening of the Mauritanian-Senegalese upwelling system under climate change may result in a more heterotrophic system, particularly in oligotrophic waters, reducing its potential to function as an atmospheric carbon sink.

The deep sea, the largest ocean’s compartment, drives planetary-scale biogeochemical cycling. Yet, the functional exploration of its microbial communities lags far behind other environments. Here we analyze 58 metagenomes from tropical and subtropical deep oceans to generate the Malaspina Gene Database. Free-living or particle-attached lifestyles drive functional differences in bathypelagic prokaryotic communities, regardless of their biogeography. Ammonia and CO oxidation pathways are enriched in the free-living microbial communities and dissimilatory nitrate reduction to ammonium and H2 oxidation pathways in the particle-attached, while the Calvin Benson-Bassham cycle is the most prevalent inorganic carbon fixation pathway in both size fractions. Reconstruction of the Malaspina Deep Metagenome-Assembled Genomes reveals unique non-cyanobacterial diazotrophic bacteria and chemolithoautotrophic prokaryotes. The widespread potential to grow both autotrophically and heterotrophically suggests that mixotrophy is an ecologically relevant trait in the deep ocean. These results expand our understanding of the functional microbial structure and metabolic capabilities of the largest Earth aquatic ecosystem

KEYNOTE POINTS 1. Marine genetic resources continue to be the focus of an expanding range of commercial and non-commercial applications. 2. Rapidly decreasing sequencing and gene synthesis costs and swift advances in the metabolic engineering and synthetic biology fields within the biotechnology sector have rendered scientists less reliant on physical samples and increasingly dependent on the exponentially expanding public databases of genetic sequence data. 3. Sponges and algae continue to attract substantial interest for the bioactive properties of their natural compounds. 4. Within the context of the Sustainable Development Goals, capacity-building issues persist, with entities in a handful of countries conducting the majority of research and development associated with marine genetic resources. 5. International processes and agreements with relevance to marine genetic resources include the Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from Their Utilization to the Convention on Biological Diversity, and the Inter-Governmental Conference on an international legally binding instrument under the United Nations Convention on the Law of the Sea on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction.

The mesozooplankton community was analyzed over a 6-year period (2013-2018) during the post-eruptive stage of the submarine volcano Tagoro, located south of the island of El Hierro (Canary Archipelago, Spain). Nine cruises from March 2013 to March 2018 were carried out in two different seasons, spring (March-April) and autumn (October). A high-resolution study was carried out across the main cones of Tagoro volcano, as well as a large number of reference stations surrounding El Hierro (unaffected by the volcano). The zooplankton community at the reference stations showed a high similarity with more than 85% of the variation in abundance and composition attributable to seasonal differences. Moreover, our data showed an increase in zooplankton abundance in waters affected by the volcano with a higher presence of non-calanoid copepods and a decline in the diversity of the copepod community, indicating that volcanic inputs have a significant effect on these organisms. Fourteen different zooplankton groups were found but copepods were dominant (79%) with 59 genera and 170 species identified. Despite the high species number, less than 30 presented a larger abundance than 1%. Oncaea and Clausocalanus were the most abundant genera followed by Oithona and Paracalanus (60%). Nine species dominated (>2%): O. media, O. plumifera, and O. setigera among the non-calanoids and M. clausi, P. nanus, P. parvus, C. furcatus, C. arcuicornis, and N. minor among the calanoids. After the initial low abundance of the copepods as a consequence of the eruption, an increase was observed in the last years of the study, where besides the small Paracalanus and Clausocalanus, the Cyclopoids seem to have a good adaptive strategy to the new water conditions. The increase in zooplankton abundance and the decline in the copepod diversity in the area affected by the volcano indicate that important changes in the composition of the zooplankton community have occurred. The effect of the volcanic emission

The Integrated Ocean Carbon Research (IOC-R) programme is a formal working group of the Intergovernmental Oceanographic Commission (IOC) that was formed in 2018 in response to the United Nations (UN) Decade of Ocean Science for Sustainable Development (2021-2030), “the Decade.” The IOC-R will contribute to the science elements of the overarching Implementation Plan for the Decade1. The Implementation Plan is a high-level framework to guide actions by which ocean science can more effectively deliver its contribution and co-development with other entities to achieve the societal outcomes outlined in the Decade plan and the sustainable development goals (SDGs) of the UN.

The global upper ocean has been warming during the last decades accompanied with a chlorophyll-a (Chl-a) and productivity decrease. Whereas subtropical gyres show similar trends, Eastern Boundary Upwelling Systems are thought to increase in productivity due to increased trade winds. This study analyzes recent trends in sea surface temperature (SST), Chl-a, net primary production (NPP) and meridional wind stress in the Eastern North Atlantic subtropical gyre (NASE) in order to examine if the global trends can be detected in open ocean and upwelling areas and how the ocean biota responds. Satellite data of such variables of the last 15–40 years were analyzed to calculate mean trends in upwelling areas in the Canary upwelling system and open ocean areas around the Azores, Madeira and the Canary Islands. Our results show significant warming in the area with a maximum of 2.7°C per century for the Azores. Moreover, a general decreasing trend for Chl-a and NPP seems to be more evident in the permanent upwelling areas, which will be responsible for a loss of 0.13% of the global NPP per century. Our results also highlight a significant expansion of the oceanic desert area of 10% with an increase in unproductive days of up to 84 days in the last 20 years. The competitive relationship of stratification and wind stress in the Canary upwelling system might be a more plausible explanation for the decrease in Chl-a and NPP in upwelling areas linked to the increase in upwelling favorable wind stress and the surface warming.

The ocean is home to a vast diversity of life forms constituting a rich source of marine genetic resources, that is, genetic material of marine origin containing functional units of heredity of actual or potential value, characterized by high biological and chemical diversity (Appeltans and others, 2012; United Nations, 2017). Over 34,000 marine natural products have been described, with recent discovery rates reaching more than 1,000 compounds each year (Lindequist, 2016; Carroll and others, 2019). A total of 188 new marine natural products from deep-sea organisms (Bryozoa, Chordata, Cnidaria, Echinodermata, Mollusca, Porifera and microbes) have been described since 2008 (Skropeta and Wei, 2014). Approximately 75 per cent of those novel products have remarkable bioactivity, with 50 per cent exhibiting moderate to high cytotoxicity towards a range of human cancer cell lines. Although the bioactivity of many marine natural products suggests high potential for drug discovery, only 13 marine-derived drugs have gained market approval to date (Liang and others, 2019; Mayer and others, 2010).5 However, at the time of writing, 28 candidates were in clinical trials (Alves and others, 2018). Marine antifoulant research is currently focused on identifying viable non-toxic substances, and a recent review has estimated that more than 198 antifouling compounds have been obtained from marine invertebrates, specifically sponges, gorgonians and soft corals (Qi and Ma, 2017), in addition to the products derived from macroalgae and microalgae highlighted in the first World Ocean Assessment (United Nations, 2017). Innovative research has also identified ingredients from discarded fish that are suitable for use in high-end cosmetics and a number of other products (Young, 2014). As of 2018, a total of 76 publicly available cosmeceutical ingredients from marine natural products had been marketed, reflecting a new growth sector (Calado and others, 2018). At the same time, consumer demand

The microbial response to environmental changes in coastal waters of the eastern Cantabrian Sea was explored for four years by analysing a broad set of environmental variables along with bacterial community metabolism and composition. A recurrent seasonal cycle emerged, consisting of two stable periods, characterized by low bacterial metabolic activity (winter) from October to March, and high bacterial metabolic activity (summer) from May to August. These two contrasting periods were linked by short transition periods in April (TA ) and September (TS ). The phylogenetic groups Alphaproteobacteria and Bacteroidetes were dominant during winter and summer respectively, and their recurrent alternation was mainly driven by the bloom of eukaryotic phytoplankton before TA and the bloom of prokaryotic phytoplankton before TS . Bacterial growth efficiency remained high and stable during the winter and summer periods but dropped during the two short transition periods. Our results suggest that bacterial growth efficiency should be considered a very resilient property that reflects different stages in the adaptation of the bacterial community composition to the environmental changes occurring throughout the seasonal cycle in this coastal ecosystem.

This work presents a comprehensive study on concentrations and elemental composition of total suspended atmospheric particulates for a semi-urban site on the Red Sea coast, and on-board a research vessel, which collected off-shore samples along the Red Sea. We conducted one of the most extended measurement campaigns of atmospheric particulates ever for the region, with continuous measurements over 27 months. The overall mean concentrations (± st. dev.) of TSP were 125 ± 197 µg m−3 for the permanent semi-urban site, and 108 ± 193 µg m−3 for the off-shore mobile site. The region is frequently severely impacted by both localised and widespread dust storms, which on occasion, can increase atmospheric particulate concentrations to levels above mg m−3 (> 1000 µg m−3). Median concentrations were not as variable between seasons, indicating a stable, permanent presence of atmospheric particulates independent of the time of year. The primary chemical elements contributing to particulate mass were Na, Ca, S, Al and Fe. We employed Positive Matrix Factorisation (EPA PMF v5.0.14) to identify different major sources of particulates, which were crustal, marine, fuel oil combustion/secondary sulphate and mixed anthropogenic. The crustal source was characterised by tracers Al, Fe, K, Mg and Sn, and was present to some extent in the other identified sources due to the permanent presence of dust particles in the atmosphere. The fuel oil combustion/secondary sulphate source was identifiable by the almost exclusive presence of S, and to a lesser extent V, emitted from oil combustion as primary emissions and also secondary sulphate formation following the release of S to the atmosphere. A mixed anthropogenic source was characterised by Zn, Ni, Cr, Cu and Pb, emitted from traffic, industry, power generation and water desalination. This study highlights that the natural sources of particulates in this desert region give rise to frequent episodes of extremely poor air quality, and this prob

POSEIDON "Persistence of Organic Substrates Explained In Diluted Oceanic eNvironments". Dissolved Organic Matter (DOM) is the second largest reservoir of organic carbon in the biosphere equivalent to all the living organisms or over 200 times all living marine organisms. Most of the oceanic DOM is stored in deep waters under 1,000 m locked away from the atmosphere. This makes the DOM pool so important for the regulation of the Earth’s climate that variations in the amount of DOM stored in the deep ocean have been linked to climate change in past geological times. This large amount of carbon seems to be unavailable to microbial decomposers, a fact that has puzzled scientists for decades. The classic explanation has been that DOM is composed of highly recalcitrant substances which cannot be degraded by microbes. However, despite decades of research, there is virtually no indication specific compounds accumulating in the DOM pool. Instead, the DOM seems to be composed of thousands to hundreds of thousands of different molecules, each of them in very low concentrations. Our team tested recently the alternative hypothesis that the compounds that make the bulk of the DOM pool in the deep ocean are not intrinsically recalcitrant but their utilization is simply limited by the extremely low concentrations of each individual molecule. This change of paradigm opens a new avenue for research and leads to new hypotheses that may help better understand the mechanisms behind one of the largest reservoirs of organic carbon in the biosphere. The aim of project POSEIDON is to address some of those new hypotheses though a combination of in situ measurements and experimental manipulations of naturally occurring DOM

[CAT] La campanya POSEIDÓN, organitzada per l’Instituto Español de Oceanografía (IEO), travessarà bona part de l’Atlàntic, viatjant des de Punta Arenas (Xile) a Les Palmes de Gran Canària, tot creuant l’Equador, i estudia el consum del carboni orgànic dissolt i la seva relació amb les comunitats microbianes que habiten l’oceà profund. - Equip i reptes - Diari de Campanya. Ciència i vida a bord: · 28 de febrer 2019. Marxem de campanya! · Les campanyes oceanogràfiques: ciència, burocràcia o aventura? Sortida des de Punta Arenas. Arrenca la Campanya Poseidón · Preparant-nos pel primer mostreig · 8 de marzo, Día Internacional de la Mujer · A la deriva · Carbono milenario almacenado en las profundidades oceánicas… · Under pressure · ¿A quién no le gusta una tarta? · Tothom pendent del CTD · El poder del mar i de l’observació · Investigating microbial communities of deep waters · Un mar de dades · L’exploració de l’oceà · Illes de Sargassum · El que amaga l’oceà superficial · Les “òmiques” del mar. Òmica? I què és això de l‘òmica? · Terra a la vista! - Exploradors del mar: · Converses des de l’Atlàntic · Parents llunyans · L’essencial és invisible als ulls · L'àtom de la vida. El carboni al mar. Anem a veure què passa amb el C al mar des del punt de vista químic… El paper fonamental dels microorganismes en el cicle del C al mar… · Les constants vitals del mar. La navegació. Paràmetres meteorològics. Paràmetres físics i químics de l’aigua de mar. Temperatura. La densitat. Les masses d’aigua i la circulació termohalina. La pressió · Lynn Margulis i l’origen de la cèl·lula eucariota · Ernst Haeckel · Les dones i l'oceanografia · Charles Darwin, [ES] ¿Quienes habitan las capas iluminadas del océano? Estudiamos los microorganismos marinos y su papel fundamental el océano

Airborne particles comprise not only mineral dust but also a significant fraction of microbes and biogenic particles. Surveys of microbial diversity conducted in the last decades across all kinds of marine and terrestrial ecosystems have uncovered a striking diversity of microbial life. Yet, the abundance and composition of airborne microbial assemblages have received little attention as compared to terrestrial and marine environments. The few studies available focus mostly on continental or coastal air masses, while the organisms suspended in the atmosphere over the open oceans, which cover most of the Earth’s surface, remain unexplored. This study presents the first global survey of airborne microbes conducted over the Atlantic, Indian and Pacific Oceans during the Malaspina Circumnavigation Expedition. Thousands of taxonomically different microbes were found, uncovering a large diversity of airborne microbes comparable to that of terrestrial and marine environments. Our results show a large contribution of marine organisms to the total found in the global atmosphere, but also that terrestrial contributions make a large fraction of the airborne microorganisms found at remote marine locations. We estimate that atmospheric circulation may transfer microbes as fast as thousands of kilometers per day, sufficient to allow for intercontinental transport of microbes

The impact of organic pollutants on oceanic ecosystem functioning is largely unknown. Prochlorococcus, the most abundant known photosynthetic organism on Earth, has been suggested to be especially sensible to exposure to organic pollutants, but the sub-lethal effects of organic pollutants on its photosynthetic function at environmentally relevant concentrations and mixtures remain unexplored. Here we show the modulation of the expression of two photosynthetic genes, rbcL (RuBisCO large subunit) and psbA (PSII D1 protein), of oceanic populations of Prochlorococcus from the Atlantic, Indian and Pacific Oceans when exposed to mixtures of organic pollutants consisting of the non-polar fraction of a seawater extract. This mixture included most persistent organic pollutants, semivolatile aromatic-like compounds, and the unresolved complex mixture of hydrocarbons. Prochlorococcus populations in the controls showed the expected diel cycle variations in expression of photosynthetic genes. However, exposure to a complex mixture at concentrations only 2-fold above the environmental levels resulted in a decrease of expression of both genes, suggesting an effect on the photosynthetic function. While organic pollutant effects on marine phytoplankton have been already demonstrated at the cellular level, this is the first field study showing alterations at the molecular level of the photosynthetic function due to organic pollutants.

The atmosphere plays a fundamental role in the transport of microbes across the planet but it is often neglected as a microbial habitat. Although the ocean represents two thirds of the Earth’s surface, there is little information on the atmospheric microbial load over the open ocean. Here we provide a global estimate of microbial loads and air-sea exchanges over the tropical and subtropical oceans based on the data collected along the Malaspina 2010 Circumnavigation Expedition. Total loads of airborne prokaryotes and eukaryotes were estimated at 2.2 × 1021 and 2.1 × 1021 cells, respectively. Overall 33–68% of these microorganisms could be traced to a marine origin, being transported thousands of kilometres before re-entering the ocean. Moreover, our results show a substantial load of terrestrial microbes transported over the oceans, with abundances declining exponentially with distance from land and indicate that islands may act as stepping stones facilitating the transoceanic transport of terrestrial microbes.

The atmosphere plays a fundamental role in the transport of microbes across the planet but it is often neglected as a microbial habitat. Although the ocean represents two thirds of the Earth’s surface, there is little information on the atmospheric microbial load over the open ocean. Here we provide a global estimate of microbial loads and air-sea exchanges over the tropical and subtropical oceans based on the data collected along the Malaspina 2010 Circumnavigation Expedition. Total loads of airborne prokaryotes and eukaryotes were estimated at 2.2 × 1021 and 2.1 × 1021 cells, respectively. Overall 33–68% of these microorganisms could be traced to a marine origin, being transported thousands of kilometres before re-entering the ocean. Moreover, our results show a substantial load of terrestrial microbes transported over the oceans, with abundances declining exponentially with distance from land and indicate that islands may act as stepping stones facilitating the transoceanic transport of terrestrial microbes

During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1–100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP). Viral lytic production, lysogeny, and mortality rates of prokaryotes due to viruses and protists were estimated at surface (0.1–1 m) and at the Deep Fluorescence Maximum (DFM, 12–55 m) at eight representative stations of the three areas. The average viral lytic production ranged from 1.0 ± 0.3 × 107 viruses ml−1 d−1 in the Bellingshausen Sea to1.3 ± 0.7 × 107 viruses ml−1 d−1 in the Bransfield Strait, while lysogeny, when detectable, recorded the lowest value in the Bellingshausen Sea (0.05 ± 0.05 × 107 viruses ml−1 d−1) and the highest in the Weddell Sea (4.3 ± 3.5 × 107 viruses ml−1 d−1). Average mortality rates due to viruses ranged from 9.7 ± 6.1 × 104 cells ml−1 d−1 in the Weddell Sea to 14.3 ± 4.0 × 104 cells ml−1 d−1 in the Bellingshausen Sea, and were higher than averaged grazing rates in the Weddell Sea (5.9 ± 1.1 × 104 cells ml−1 d−1) and in the Bellingshausen Sea (6.8 ± 0.9 × 104 cells ml−1 d−1). The highest impact on prokaryotes by viruses and main differences between viral and protists activities were observed in surface samples: 17.8 ± 6.8 × 104 cells ml−1 d−1 and 6.5 ± 3.9 × 104 cells ml−1 d−1 in the Weddell Sea; 22.1 ± 9.6 × 104 cells ml−1 d−1 and 11.6 ± 1.4 × 104 cells ml−1 d−1 in the Bransfield Strait; and 16.1 ± 5.7 × 104 cells ml−1 d−1 and 7.9 ± 2.6 × 104 cells ml−1 d−1 in the Bellingshausen Sea, respectively. Furthermore, the rate of lysed cells and PHP showed higher sensitivity to

Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget

Biological nitrogen fixation by diazotrophic bacteria in seagrass rhizosphere and leaf epiphytic community is an important source of nitrogen required for plant growth. However, the presence of endophytic diazotrophs remains unclear in seagrass tissues. Here, we assess the presence, diversity and taxonomy of nitrogen-fixing bacteria within surface-sterilized roots of Posidonia oceanica. Moreover, we analyze the nitrogen isotopic signature of seagrass tissues in order to notice atmospheric nitrogen fixation. We detected nitrogen-fixing bacteria by nifH gene amplification in 13 out of the 78 roots sampled, corresponding to 9 locations out of 26 meadows. We detected two different types of bacterial nifH sequences associated with P. oceanica roots, which were closely related to sequences previously isolated from the rhizosphere of a salt marsh cord grass and a putative anaerobe. Nitrogen content of seagrass tissues showed low isotopic signatures in all the sampled meadows, pointing out the atmospheric origin of the assimilated nitrogen by seagrasses. However, this was not related with the presence of endophytic nitrogen fixers, suggesting the nitrogen fixation occurring in rhizosphere and in the epiphytic community could be an important source of nitrogen for P. oceanica. The low diversity of nitrogen-fixing bacteria reported here suggests species-specific relationships between diazotrophs and P. oceanica, revealing possible symbiotic interactions that could play a major role in nitrogen acquisition by seagrasses in oligotrophic environments where they form lush meadows.

Experimental results on the hypothesis that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization.

We examined the responses of two different natural arctic plankton communities to warming in an attempt to find temperature thresholds for abrupt changes in growth or biomass. We conducted two experiments in situ using two different plankton communities; incubation temperatures represented the annual variation in these Arctic waters plus 3–4 °C to account for the potential warming expected for the Arctic Ocean during the twenty-first century. We evaluated changes in nutrient and chlorophyll a concentrations, primary production, cell abundances, and growth rates as well as cell biovolume and percentage of living cells for the main groups found during our study. Phytoplankton communities were composed of diatoms, Phaeocystis sp., Micromonas, as well as other flagellates. Results indicate a decrease in chlorophyll a concentration and growth rate at the highest temperatures tested. We also found a differing effect on cell abundance and growth rates depending on the taxonomic group or cell size: diatom abundance decreased with warming while small-sized phytoplankton showed an increasing trend at the intermediate temperature treatments. Biovolume estimates also tended to decrease with increasing temperature. We find a perceptible change in trends at intermediate temperature treatments for most of the parameters which suggests a possible thermal threshold around 5–6 °C for the arctic plankton communities examined here

The dark ocean is one of the largest biomes on Earth, with critical roles in organic matter remineralization and global carbon sequestration. Despite its recognized importance, little is known about some key microbial players, such as the community of heterotrophic protists (HP), which are likely the main consumers of prokaryotic biomass. To investigate this microbial component at a global scale, we determined their abundance and biomass in deepwater column samples from the Malaspina 2010 circumnavigation using a combination of epifluorescence microscopy and flow cytometry. HP were ubiquitously found at all depths investigated down to 4000 m. HP abundances decreased with depth, from an average of 72±19 cells ml-1 in mesopelagic waters down to 11±1 cells ml-1 in bathypelagic waters, whereas their total biomass decreased from 280±46 to 50±14 pg C ml-1. The parameters that better explained the variance of HP abundance were depth and prokaryote abundance, and to lesser extent oxygen concentration. The generally good correlation with prokaryotic abundance suggested active grazing of HP on prokaryotes. On a finer scale, the prokaryote:HP abundance ratio varied at a regional scale, and sites with the highest ratios exhibited a larger contribution of fungi molecular signal. Our study is a step forward towards determining the relationship between HP and their environment, unveiling their importance as players in the dark ocean's microbial food web. © 2015 International Society for Microbial Ecology All rights reserved