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A photographic seabed survey conducted off the Antarctic Peninsula region provided the opportunity to study spatial patterns, abundance and behaviour of the notothenioid benthic fish fauna. Overall, a total of 12,715 images taken with the Ocean Floor Observation System (OFOS) along 26 transects in three ecoregions (Joinville Island, Bransfield Strait and Drake Passage) were analysed. The fish fauna consisted of at least 34 species belonging to four families of both low-Antarctic and high-Antarctic origin. Nototheniids showed the highest relative abundance and species richness, followed by channichthyids, bathydraconids and artedidraconids. Direct in-situ observations in OFOS seabed images allowed descriptions of fish behaviour, such as aggregation of individuals (Notothenia coriiceps), specific body postures (Cygnodraco mawsoni and Cryodraco antarcticus) and parental care (Chaenodraco wilsoni, Chionodraco rastrospinosus, Pagetopsis macropterus and Trematomus hansoni). Fish density and species richness was primarily correlated with the occurrence of bryozoans, ascidians, and large cup-shaped sponges, providing a three-dimensional habitat suitable for fish settling, foraging, breeding and refuge from predators. Fish diversity was higher (a) off Joinville Island and in Bransfield Strait than in Drake Passage, where almost exclusively low-Antarctic species were recorded, and (b) between 100 and 600 m than at greater depths. Overall, the benthic fish fauna off the northern Antarctic Peninsula is zoogeographically composite and widespread, with well-structured spatial partitioning.

Marine imagery is a comparatively cost-effective way to collect data on seafloor organisms, biodiversity and habitat morphology. However, annotating these images to extract detailed biological information is time-consuming and expensive, and reference libraries of consistently annotated seafloor images are rarely publicly available. Here, we present the Antarctic Seafloor Annotated Imagery Database (AS-AID), a result of a multinational collaboration to collate and annotate regional seafloor imagery datasets from 19 Antarctic research cruises between 1985 and 2019. AS-AID comprises of 3,599 georeferenced downward facing seafloor images that have been labelled with a total of 615,051 expert annotations. Annotations are based on the CATAMI (Collaborative and Automated Tools for Analysis of Marine Imagery) classification scheme and have been reviewed by experts. In addition, because the pixel location of each annotation within each image is available, annotations can be viewed easily and customised to suit individual research priorities.This dataset can be used to investigate species distributions, community patterns, it provides a reference to assess change through time, and can be used to train algorithms to automatically detect and annotate marine fauna.

Special issue The Weddell Sea and the ocean off Dronning Maud Land: unique oceanographic conditions shape circumpolar and global processes – a multi-disciplinary study (OS/BG/TC inter-journal SI).-- 30 pages, 5 figures.-- Data availability: The data (sets) used for the illustrations in some figures are referenced in the figure captions: bathymetry (water depth) in Fig. 1 (Dorschel et al., 2022); bathymetry in Figs. 2a and 3 (Arndt et al., 2013); and sea ice, chlorophyll, and temperature in Fig. 4 (Lavergne et al., 2019, and http://oceandata.sci.gsfc.nasa.gov/, last access: 23 August 2022). No addition data sets were used in this publication, Systematic long-term studies on ecosystem dynamics are largely lacking from the East Antarctic Southern Ocean, although it is well recognized that they are indispensable to identify the ecological impacts and risks of environmental change. Here, we present a framework for establishing a long-term cross-disciplinary study on decadal timescales. We argue that the eastern Weddell Sea and the adjacent sea to the east, off Dronning Maud Land, is a particularly well suited area for such a study, since it is based on findings from previous expeditions to this region. Moreover, since climate and environmental change have so far been comparatively muted in this area, as in the eastern Antarctic in general, a systematic long-term study of its environmental and ecological state can provide a baseline of the current situation, which will be important for an assessment of future changes from their very onset, with consistent and comparable time series data underpinning and testing models and their projections. By establishing an Integrated East Antarctic Marine Research (IEAMaR) observatory, long-term changes in ocean dynamics, geochemistry, biodiversity, and ecosystem functions and services will be systematically explored and mapped through regular autonomous and ship-based synoptic surveys. An associated long-term ecological research (LTER) programme, including experimental and modelling work, will allow for studying climate-driven ecosystem changes and interactions with impacts arising from other anthropogenic activities. This integrative approach will provide a level of long-term data availability and ecosystem understanding that are imperative to determine, understand, and project the consequences of climate change and support a sound science-informed management of future conservation efforts in the Southern Ocean, Stefanie Arndt, Heike Link and Christoph Held have received financial support from the Deutsche Forschungsgemeinschaft (DFG) in the framework of the priority programme 1158 “Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas”. The article processing charges for this open-access publication were covered by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

24 pages, 2 figures, 1 table, supporting Information https://doi.org/10.1111/brv.12679, Important findings from the second decade of the 21st century on the impact of environmental change on biological processes in the Antarctic were synthesised by 26 international experts. Ten key messages emerged that have stakeholder¿relevance and/or a high impact for the scientific community. They address (i) altered biogeochemical cycles, (ii) ocean acidification, (iii) climate change hotspots, (iv) unexpected dynamism in seabed¿dwelling populations, (v) spatial range shifts, (vi) adaptation and thermal resilience, (vii) sea ice related biological fluctuations, (viii) pollution, (ix) endangered terrestrial endemism and (x) the discovery of unknown habitats. Most Antarctic biotas are exposed to multiple stresses and considered vulnerable to environmental change due to narrow tolerance ranges, rapid change, projected circumpolar impacts, low potential for timely genetic adaptation, and migration barriers. Important ecosystem functions, such as primary production and energy transfer between trophic levels, have already changed, and biodiversity patterns have shifted. A confidence assessment of the degree of `scientific understanding¿ revealed an intermediate level for most of the more detailed sub¿messages, indicating that process¿oriented research has been successful in the past decade. Additional efforts are necessary, however, to achieve the level of robustness in scientific knowledge that is required to inform protection measures of the unique Antarctic terrestrial and marine ecosystems, and their contributions to global biodiversity and ecosystem services, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Multiple environmental factors control benthic community patterns, and their relative importance varies with spatial scale. Since this variation is difficult to evaluate quantitatively, extensive sampling across a broad range of spatial scales is required. Here, we present a first case study on Southern Ocean shelf benthos, in which mega-epibenthic communities and biota-environment relationships have been explored at multiple spatial scales. The analyses encompassed 20 seafloor, water-column, and sea-ice parameters, as well as abundances of 18 mega-epibenthic taxa in a total of 2799 high-resolution seabed images taken at 28 stations at 32–786 m depth off the northern Antarctic Peninsula. Based on a priori nesting of sampling stations into ecoregions, subregions, and habitats, analyses indicated most pronounced patchiness levels at finest (within transects among adjacent seabed photos) and largest (among ecoregions) spatial scale considered. Using an alternative approach, explicitly involving the spatial distances between the geo-referenced data, Moran’s Eigenvector mapping (MEM) classified the continuum of spatial scales into four categories: broad (> 60 km), meso (10–60 km), small (2–10 km), and fine (< 2 km). MEM analyses generally indicated an increase in mega-epibenthic community complexity with increasing spatial scale. Moreover, strong relationships between biota and environmental drivers were found at scales of > 2 km. In contrast, few environmental variables contributed to explaining biotic structures at finer scales. These are likely rather determined by nonmeasured environmental variables, as well as biological traits and interactions that are assumed to be most effective at small spatial scales.

Where polar ice sheets meet the coast, they can flow into the sea as floating ice shelves. The seabed underneath is in complete darkness, and may be Earth's least known surface habitat. Few taxa there have been fully identified to named species (see Supplemental information) - remarkable for a habitat spanning nearly 1.6 million km

The Long-Term Ecological Research (LTER) observatory HAUSGARTEN, in the eastern Fram Strait, provides us the valuable ability to study the composition of benthic megafaunal communities through the analysis of seafloor photographs. This, in combination with extensive sampling campaigns, which have yielded a unique data set on faunal, bacterial, biogeochemical and geological properties, as well as on hydrography and sedimentation patterns, allows us to address the question of why variations in megafaunal community structure and species distribution exist within regional (60–110km) and local (

Gutt, Julian ... et al.-- 17 pages, 4 figures, The biodiversity, ecosystem services and climate variability of the Antarctic continent and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disciplinary studies are especially important in Antarctic research. The conceptual study presented here is based on a workshop initiated by the Research Programme Antarctic Thresholds – Ecosystem Resilience and Adaptation of the Scientific Committee on Antarctic Research, which focussed on challenges in identifying and applying cross-disciplinary approaches in the Antarctic. Novel ideas and first steps in their implementation were clustered into eight themes. These ranged from scale problems, through risk maps, and organism/ecosystem responses to multiple environmental changes and evolutionary processes. Scaling models and data across different spatial and temporal scales were identified as an overarching challenge. Approaches to bridge gaps in Antarctic research programmes included multi-disciplinary monitoring, linking biomolecular findings and simulated physical environments, as well as integrative ecological modelling. The results of advanced cross-disciplinary approaches can contribute significantly to our knowledge of Antarctic and global ecosystem functioning, the consequences of climate change, and to global assessments that ultimately benefit humankind, In addition to the employers of the authors this study was funded by the SCAR SRPs AnT-ERA, AntClim21 and AntEco

Free-living marine nematode communities of the Larsen B embayment at the eastern Antarctic Peninsula were investigated to provide insights on their response and colonization rate after large-scale ice-shelf collapse. This study compares published data on the post-collapse situation from 2007 with new material from 2011, focusing on two locations in the embayment that showed highly divergent communities in 2007 and that are characterized by a difference in timing of ice-shelf breakup. Data from 2007 exposed a more diverse community at outer station B.South, dominated by the genus Microlaimus. On the contrary, station B.West in the inner part of Larsen B was poor in both numbers of individuals and genera, with dominance of a single Halomonhystera species. Re-assessment of the situation in 2011 showed that communities at both stations diverged even more, due to a drastic increase in Halomonhystera at B.West compared to relatively little change at B.South. On a broader geographical scale, it seems that B.South gradually starts resembling other Antarctic shelf communities, although the absence of the genus Sabatieria and the high abundance of Microlaimus still set it apart nine years after the main Larsen B collapse. In contrast, thriving of Halomonhystera at B.West further separates its community from other Antarctic shelf areas.

During the austral summer expedition PS81, ANT-XXIX/3 with the German research ice breaker Polarstern in 2013, research was carried out to investigate the role of environmental factors on the distribution of benthic communities and marine mammal and krill densities around the northern tip of the Antarctic Peninsula. For these studies collated in this special issue and studies in this area, we present a collection of environmental parameters with probable influence on the marine ecosystems around the Antarctic Peninsula.

‘Evolution is the major unifying principle of biology,and evidence of evolutionary processespervades all levels of biological organisationfrom molecules to ecosystems.’(Eastman 2000)Evolution has p...

In this chapter, the effects of temperature change—as a main aspect of climate change—on marine biodiversity are assessed. Starting from a general discussion of species responses to temperature, the chapter presents how species respond to warming. These responses comprise adaptation and phenotypic plasticity as well as range shifts. The observed range shifts show more rapid shifts at the poleward range edge than at the equator-near edge, which probably reflects more rapid immigration than extinction in a warming world. A third avenue of changing biodiversity is change in species interactions, which can be altered by temporal and spatial shifts in interacting species. We then compare the potential changes in biodiversity to actual trends recently addressed in empirical synthesis work on local marine biodiversity, which lead to conceptual issues in quantifying the degree of biodiversity change. Finally we assess how climate change impacts the protection of marine environments.

Established in the Fram Strait in 1999, the LTER (Long-Term Ecological Research) observatory HAUSGARTEN enables us to study changes on the deep Arctic seafloor. Repeated deployments of a towed camera system (Ocean Floor Observation System) along the same tracks allowed us to build a time series longer than a decade (2004 - 2015). Here, we present the first time-series results from a northern and the southernmost station of the observatory (N3 and S3, ~2650m and 2350m depth respectively) obtained via the analysis of still imagery. We assess temporal variability in community structure, megafaunal densities and diversity, and use a range of biotic and abiotic factors to explain the patterns observed. There were significant temporal differences in megafaunal abundances, diversity and abiotic factors at both stations. A particularly high increase in megafaunal abundance was recorded at N3 from 12.08 (±0.39; 2004) individuals m-2 to 35.21 (±0.97; 2007) ind. m-2 alongside a ten-fold increase in (drop-)stones. At S3, megafaunal densities peaked in 2015 (22.74 ±0.61 ind. m-2) after an increasing trend since 2004 (12.44 ±0.32 ind. m-2). Holothurians showed particularly striking temporal differences: densities of the small sea cucumber Elpidia heckeri densities rose ten-fold from 0.31 ind. m-2 (±0.04; 2004) to 3.74 ind. m-2 (±0.14; 2015) at S3, coinciding with a sustained increase in phytodetritial matter (chloroplastic pigment equivalents) at the seafloor. Initially entirely absent from N3, densities of the larger holothurian Kolga hyalina peaked in 2007 (5.87 ±0.22 ind. m-2) and declined continuously since then. Overall diversity (γ) increased at both stations over the course of the study, however, with varying contributions of α and β diversities. Our results highlight the importance of time-series studies as megafaunal community composition is characterised by continuous changes. This indicates that epibenthic communities from the deep seafloor are reactive and dynamic, with no “null” community state. To continue to monitor them is therefore crucial in understanding natural and anthropogenic impacts in an area exposed to the effects of climate change.

Both Southern Ocean and terrestrial systems contain three-dimensional biotic components that are key in shaping and defining their respective ecosystems and communities. Antarctic suspension-feeding communities, which inhabit the shelf of the Southern Ocean, resemble “Terrestrial Vegetation Forests” (TVF) or shrublands and support the concept of “Antarctic Marine Animal Forests” (AMAF). They comprise mostly sessile animals, provide microniches for an associated mobile fauna, and are fragmented and regionally mixed with other communities. On land, only high mountains and very dry regions are unsuitable for TVF, analogous to the virtual absence of AMAF from the deep sea (>1000 m). Besides fundamental differences between these systems in energy flow and other ecological drivers such as light requirements and dispersal opportunities, both “forests” experience similar disturbances, which impact ecosystem dynamics and diversity in similar ways. While land use affects and reduces terrestrial forests, climate change and fishing impacts are the most serious threats to the Southern Ocean ecosystem. Research priorities for a better understanding of “Antarctic Marine Animal Forests” demand (1) mapping biotic communities and their structural and functional diversity, especially in terms of hot and cold spots; (2) understanding ecological function, including ecosystem productivity and dynamics; (3) cross-system comparison to identify generality or uniqueness in ecosystem structure and dynamics; and (4) implication of existing and new research approaches and conservation strategies.

The Paris Agreement, being the main result of the COP21 UN climate conference in 2015, included the ever most clearly defined political statement on anthropogenic climate change and the need for it to be reduced. In an opinion survey, Antarctic ecosystem researchers expressed their views, in which direction science should develop, after their mission to provide evidence for the existence of anthropogenic climate change and its impacts is accomplished. Four options for answers were offered. The majority voted in support for research for a better ecosystem understanding under climate change, since overarching questions seem to not yet be sufficiently answered. Applied research for mitigation received an intermediate amount of support. Similar amount of support was received for no changes in research strategies. This might be a result of an already existing lively progression of new developments, but might also be due to some old and burning questions, which still remain unanswered, e.g. on the Southern Ocean acting as a biological CO2 sink. Fewest experts thought that scientists should define totally new scientific themes. The results were also analysed separately for different groups of respondents in terms of stage of career, employing institutions (mission orientated or independent), and terrestrial or marine scientists. New student courses and university degrees are proposed, since new requirements by stakeholders demand new research strategies but traditional academic education and creativity is also still needed.

30 pages, 3 figures, Both Southern Ocean and terrestrial systems contain three-dimensional biotic components that are key in shaping and defining their respective ecosystems and communities. Antarctic suspension-feeding communities, which inhabit the shelf of the Southern Ocean, resemble “Terrestrial Vegetation Forests” (TVF) or shrublands and support the concept of “Antarctic Marine Animal Forests” (AMAF). They comprise mostly sessile animals, provide microniches for an associated mobile fauna, and are fragmented and regionally mixed with other communities. On land, only high mountains and very dry regions are unsuitable for TVF, analogous to the virtual absence of AMAF from the deep sea (>1000 m). Besides fundamental differences between these systems in energy flow and other ecological drivers such as light requirements and dispersal opportunities, both “forests” experience similar disturbances, which impact ecosystem dynamics and diversity in similar ways. While land use affects and reduces terrestrial forests, climate change and fishing impacts are the most serious threats to the Southern Ocean ecosystem. Research priorities for a better understanding of “Antarctic Marine Animal Forests” demand (1) mapping biotic communities and their structural and functional diversity, especially in terms of hot and cold spots; (2) understanding ecological function, including ecosystem productivity and dynamics; (3) cross-system comparison to identify generality or uniqueness in ecosystem structure and dynamics; and (4) implication of existing and new research approaches and conservation strategies

This chapter reviews the major known monospecific and multispecific sponge aggregations in the world’s oceans. They are shown to occur from the intertidal to abyssal depths, in tropical, temperate, and high latitudes and sometimes to create spectacular formations, such as glass sponge reefs, lithistid reef-like fields, and carnivorous sponge grounds. Sponge aggregations are recognized as singular vulnerable habitats that deserve special research attention and legal protection. However, this review reveals that there is only a poor and fragmentary understanding of the main biological, environmental, and geochemical factors that favor and maintain these systems, including the food supply, which is fundamental knowledge. There is also a particular lack of information regarding reproductive biology, growth rates, life spans, and the main factors causing mortality, all crucial drivers for understanding population and community dynamics and for developing conservation strategies. The sponge aggregations have been shown to increase the structural complexity of the habitats, attracting a larger variety of organisms and locally enhancing biodiversity. From the very few cases in which sponge biomass and sponge physiology have been reliably approached jointly, phenomenal fluxes of matter and energy have been inferred. Through their benthic-pelagic coupling, some of the densest sponge aggregations have a significant local or regional impact on major biogeochemical cycles and food webs. Physical damage and habitat destruction derived from man-driven activities along with epidemic diseases facilitated by global environmental alterations emerge as major threats to the future of the sponge aggregations., This study has benefitted from funding by the Spanish Ministry of Economy and Competitiveness (CTM2012-37787) to MM; from the Caribbean Coral Reef Ecosystems Program and the National Museum of Natural History, Washington to KR, CD, and MM (Contribution Number 986); from Stiftung Drittes Millennium, Fundación Biodiversidad, and the Ministerio de Agricultura, Alimentación y Medio Ambiente to Oceana and RA; from NIWA, New Zealand Foundation for Research, Science and Technology, and CSIRO’s Division of Marine and Atmospheric Research to MK; the Natural Sciences and Engineering Council of Canada for Discovery and Ship Time grants to SPL; from the Norwegian Research Council to RJB and HTR; from The Norwegian Oil and Gas and the Norwegian Biodiversity Information Centre to HTR; and from the Natural Sciences and Engineering Council of Canada for Discovery and Ship Time grants to SPL.

Cross-system studies on the response of different ecosystems to global change will support our understanding of ecological changes. Synoptic views on the planet's two main realms, the marine and terrestrial, however, are rare, owing to the development of rather disparate research communities. We combined questionnaires and a literature review to investigate how the importance of anthropogenic drivers of biodiversity change differs among marine and terrestrial systems and whether differences perceived by marine vs. terrestrial researchers are reflected by the scientific literature. This included asking marine and terrestrial researchers to rate the relevance of different drivers of global change for either marine or terrestrial biodiversity. Land use and the associated loss of natural habitats were rated as most important in the terrestrial realm, while the exploitation of the sea by fishing was rated as most important in the marine realm. The relevance of chemicals, climate change and the increasing atmospheric concentration of CO2 were rated differently for marine and terrestrial biodiversity respectively. Yet, our literature review provided less evidence for such differences leading to the conclusion that while the history of the use of land and sea differs, impacts of global change are likely to become increasingly similar.

Recent advances in underwater imaging technology allow for the gathering of invaluable scientific information on seafloor ecosystems, such as direct in situ views of seabed habitats and quantitative data on the composition, diversity, abundance, and distribution of epibenthic fauna. The imaging approach has been extensively used within the research project DynAMo (Dynamics of Antarctic Marine Shelf Ecosystems) at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research Bremerhaven (AWI), which aimed to comparatively assess the pace and quality of the dynamics of Southern Ocean benthos. Within this framework, epibenthic spatial distribution patterns have been comparatively investigated in two regions in the Atlantic sector of the Southern Ocean: the shelf areas off the northern tip of the Antarctic Peninsula, representing a region with above-average warming of surface waters and sea-ice reduction, and the shelves of the eastern Weddell Sea as an example of a stable high-Antarctic marine environment that is not (yet) affected by climate change. The AWI Ocean Floor Observation System (OFOS) was used to collect seabed imagery during two cruises of the German research vessel Polarstern, ANT-XXIX/3 (PS81) to the Antarctic Peninsula from January to March 2013 and ANT-XXXI/2 (PS96) to the Weddell Sea from December 2015 to February 2016. Here, we report on the image and data collections gathered during these cruises. During PS81, OFOS was successfully deployed at a total of 31 stations at water depths between 29 and 784 m. At most stations, series of 500 to 530 pictures ( > 15 000 in total, each depicting a seabed area of approximately 3.45 m2 or 2.3 × 1.5 m) were taken along transects approximately 3.7 km in length. During PS96, OFOS was used at a total of 13 stations at water depths between 200 and 754 m, yielding series of 110 to 293 photos (2670 in total) along transects 0.9 to 2.6 km in length. All seabed images taken during the two cruises, including metadata, are available from the data publisher PANGAEA via the two persistent identifiers at https://doi.org/10.1594/PANGAEA.872719 (for PS81) and https://doi.org/10.1594/PANGAEA.862097 (for PS96).

Epibenthos communities play an important role in the marine ecosystems of the Weddell Sea. Information on the factors controlling their structure and distribution are, however, still rare. In particular, the interactions between environmental factors and biotic assemblages are not fully understood. Nachtigaller Hill, a newly discovered seabed structure on the over-deepened shelf of the northwest Weddell Sea (Southern Ocean), offers a unique site to study these interactions in a high-latitude Antarctic setting. Based on high-resolution bathymetry and georeferenced biological data, the effect of the terrain and related environmental parameters on the epibenthos was assessed. At Nachtigaller Hill, both geomorphological and biological data showed complex distribution patterns, reflecting local processes such as iceberg scouring and locally amplified bottom currents. This variability was also generally reflected in the variable epibenthos distribution patterns although statistical analyses did not show strong correlations between the selected environmental parameters and species abundances. By analysing the interactions between environmental and biological patterns, this study provides crucial information towards a better understanding of the factors and processes that drive epibenthos communities on the shelves of the Weddell Sea and probably also on other Antarctic shelves.

Die Lebensvielfalt mariner Okosysteme wird durch eine Reihe okologischer Umwelteinflusse masgeblich gepragt. Dieses Kapitel erlautert anhand von Beispielen und Hypothesen, welche dieser „treibenden Krafte“ in den Polargebieten am wichtigsten sind. Hierzu zahlen Eisbergstrandungen, die besonders das artenreiche antarktische Bodenleben zunachst kleinraumig zerstoren, die darauf folgende Wiederbesiedlung kann aber diversitatserhohend wirken. In Kaltwasserkorallenriffen der Nordhalbkugel werden durch biologische Wechselwirkungen zusatzliche okologische Nischen fur eine reiche Begleitfauna erschlossen.

Reliable statements about variability and change in marine ecosystems and their underlying causes are needed to report on their status and to guide management. Here we use the Framework on Ocean Observing (FOO) to begin developing ecosystem Essential Ocean Variables (eEOVs) for the Southern Ocean Observing System (SOOS). An eEOV is a defined biological or ecological quantity, which is derived from field observations, and which contributes significantly to assessments of Southern Ocean ecosystems. Here, assessments are concerned with estimating status and trends in ecosystem properties, attribution of trends to causes, and predicting future trajectories. eEOVs should be feasible to collect at appropriate spatial and temporal scales and are useful to the extent that they contribute to direct estimation of trends and/or attribution, and/or development of ecological (statistical or simulation) models to support assessments. In this paper we outline the rationale, including establishing a set of criteria, for selecting eEOVs for the SOOS and develop a list of candidate eEOVs for further evaluation. Other than habitat variables, nine types of eEOVs for Southern Ocean taxa are identified within three classes: state (magnitude, genetic/species, size spectrum), predator–prey (diet, foraging range), and autecology (phenology, reproductive rate, individual growth rate, detritus). Most candidates for the suite of Southern Ocean taxa relate to state or diet. Candidate autecological eEOVs have not been developed other than for marine mammals and birds. We consider some of the spatial and temporal issues that will influence the adoption and use of eEOVs in an observing system in the Southern Ocean, noting that existing operations and platforms potentially provide coverage of the four main sectors of the region — the East and West Pacific, Atlantic and Indian. Lastly, we discuss the importance of simulation modelling in helping with the design of the observing system in the long term.Regional boundary: south of 30°S.

Understanding thermal ranges and limits of organisms becomes important in light of climate change and observed effects on ecosystems as reported by the IPCC (2014). Evolutionary adaptation to temperature is presently unable to keep animals and other organisms in place; if they can these rather follow the moving isotherms. These effects of climate change on aquatic and terrestrial ecosystems have brought into focus the mechanisms by which temperature and its oscillations shape the biogeography and survival of species. For animals, the integrative concept of oxygen and capacity limited thermal tolerance (OCLTT) has successfully characterized the sublethal limits to performance and the consequences of such limits for ecosystems. Recent models illustrate how routine energy demand defines the realized niche. Steady state temperature-dependent performance profiles thus trace the thermal window and indicate a key role for aerobic metabolism, and the resulting budget of available energy (power), in defining performance under routine conditions, from growth to exercise and reproduction. Differences in the performance and productivity of marine species across latitudes relate to changes in mitochondrial density, capacity, and other features of cellular design. Comparative studies indicate how and why such mechanisms underpinning OCLTT may have developed on evolutionary timescales in different climatic zones and contributed to shaping the functional characteristics and species richness of the respective fauna. A cause-and-effect understanding emerges from considering the relationships between fluctuations in body temperature, cellular design, and performance. Such principles may also have been involved in shaping the functional characteristics of survivors in mass extinction events during earth's history; furthermore, they may provide access to understanding the evolution of endothermy in mammals and birds. Accordingly, an understanding is emerging how climate changes and variability throughout earth's history have influenced animal evolution and co-defined their success or failure from a bio-energetic point of view. Deepening such understanding may further reduce uncertainty about projected impacts of anthropogenic climate variability and change on the distribution, productivity and last not least, survival of aquatic and terrestrial species.

Many countries are very active in marine research and operate their own research fleets. In this decade, a number of research vessels have been renewed and equipped with the most modern navigation systems and tools. However, much of the research gear used for biological sampling, especially in the deep-sea, is outdated and dependent on wired operations. The deployment of gear can be very time consuming and, thus, expensive. The present paper reviews wire-dependent, as well as autonomous research gear for biological sampling at the deep seafloor. We describe the requirements that new gear could fulfil, including the improvement of spatial and temporal sampling resolution, increased autonomy, more efficient sample conservation methodologies for morphological and molecular studies and the potential for extensive in situ real-time studies. We present applicable technologies from robotics research, which could be used to develop novel autonomous marine research gear, which may be deployed independently and/or simultaneously with traditional wired equipment. A variety of technological advancements make such ventures feasible and timely. In proportion to the running costs of modern research vessels, the development of such autonomous devices might be already paid off after a discrete number of pioneer expeditions.

Gutt, Julian ... et al.-- 21 pages, 6 figures, 4 tables, The Southern Ocean ecosystem at the Antarctic Peninsula has steep natural environmental gradients, e.g. in terms of water masses and ice cover, and experiences regional above global average climate change. An ecological macroepibenthic survey was conducted in three ecoregions in the north-western Weddell Sea, on the continental shelf of the Antarctic Peninsula in the Bransfield Strait and on the shelf of the South Shetland Islands in the Drake Passage, defined by their environmental envelop. The aim was to improve the so far poor knowledge of the structure of this component of the Southern Ocean ecosystem and its ecological driving forces. It can also provide a baseline to assess the impact of ongoing climate change to the benthic diversity, functioning and ecosystem services. Different intermediate-scaled topographic features such as canyon systems including the corresponding topographically defined habitats ‘bank’, ‘upper slope’, ‘slope’ and ‘canyon/deep’ were sampled. In addition, the physical and biological environmental factors such as sea-ice cover, chlorophyll-a concentration, small-scale bottom topography and water masses were analysed. Catches by Agassiz trawl showed high among-station variability in biomass of 96 higher systematic groups including ecological key taxa. Large-scale patterns separating the three ecoregions from each other could be correlated with the two environmental factors, sea-ice and depth. Attribution to habitats only poorly explained benthic composition, and small-scale bottom topography did not explain such patterns at all. The large-scale factors, sea-ice and depth, might have caused large-scale differences in pelagic benthic coupling, whilst small-scale variability, also affecting larger scales, seemed to be predominantly driven by unknown physical drivers or biological interactions, Thanks are due to the SCAR biology programme ‘Antarctic Thresholds-Ecosystem Resilience and Adaptation’(AnT-ERA) due to financial support of a post-expedition workshop held in Dijon, France, in 2014 and to the Deutsche Forschungsgemeinschaft for financial support of project JA-1063/17-1. ME was funded by the Actions thematiques du Muséum ‘Emergences’ of the Muséum national s’Histoire naturelle, Paris, France,and the Institut polaire français Paul Emile Victor (IPEV). [...] Support of cruise participation of PLG, IMB, NT by Spanish Project ECOWED (CTM2012-39350-C02-01)

Ascidians (Ascidiacea: Tunicata) are sessile suspension feeders that represent dominant epifaunal components of the Southern Ocean shelf benthos and play a significant role in the pelagic–benthic coupling. Here, we report the results of a first study on the relationship between the distribution patterns of eight common and/or abundant (putative) ascidian species, and environmental drivers in the waters off the northern Antarctic Peninsula. During RV Polarstern cruise XXIX/3 (PS81) in January–March 2013, we used seabed imaging surveys along 28 photographic transects of 2 km length each at water depths from 70 to 770 m in three regions (northwestern Weddell Sea, southern Bransfield Strait and southern Drake Passage), differing in their general environmental setting, primarily oceanographic characteristics and sea-ice dynamics, to comparatively analyze the spatial patterns in the abundance of the selected ascidians, reliably to be identified in the photographs, at three nested spatial scales. At a regional (100-km) scale, the ascidian assemblages of the Weddell Sea differed significantly from those of the other two regions, whereas at an intermediate 10-km scale no such differences were detected among habitat types (bank, upper slope, slope, deep/canyon) on the shelf and at the shelf break within each region. These spatial patterns were superimposed by a marked small-scale (10-m) patchiness of ascidian distribution within the 2-km-long transects. Among the environmental variables considered in our study, a combination of water-mass characteristics, sea-ice dynamics (approximated by 5-year averages in sea-ice cover in the region of or surrounding the photographic stations), as well as the seabed ruggedness, was identified as explaining best the distribution patterns of the ascidians.

A dedicated aerial cetacean survey was con- ducted concurrently to a standardised net trawl survey for krill in order to investigate distribution patterns of large whales and different krill species and to investigate relationships of these. Distance sampling data were used to produce density surface models for humpback (Megaptera novaeangliae) and fin whales (Balaenoptera physalus) around the West Antarctic Peninsula (WAP). Abundance for both species was estimated over two strata in the Bransfield Strait and Drake Passage. Distinct distribution patterns suggest horizontal niche partitioning of the two whale species around the WAP, with fin whales aggregating at the shelf edge of the South Shetland Islands in the Drake Passage and humpback whales in the Bransfield Strait. Krill biomass estimated from the concurrent krill survey was used along with CTD data from the same expedition, bathymetric parameters and satellite data on chlorophyll-a and ice concentration to model krill distribution. Comparisons of the predicted distributions of both whale species with the predicted distributions of Euphausia superba, Euphausia crystallorophias and Thysanoessa macrura suggest a complex relationship rather than a straightforward correlation between krill and whales. However, results indicate that fin whales were feeding in an area dominated by T. macrura , while humpback whales were found in areas of higher E. superba biomass. Our results provide abundance estimates for humpback whales and, for the first time, fin whales in the WAP and contribute important information on feeding ecology and habitat use of these two species in the Southern Ocean.

International audience; The Southern Ocean is experiencing relentless change. The Antarctic and Southern Ocean community, represented by 75 scientists and policy-makers from 22 countries, recently met to formulate a collective vision on the priorities for Antarctic research for the next two decades and beyond. Here, we assess high-interest research areas related specifically to Southern Ocean life and ecology that, although not all retained as the 80 top priorities among the addressed scientific domains, are of considerable relevance to the biology and ecology of the Southern Ocean. As certain regions of the Southern Ocean ecosystems have witnessed abiotic and biotic changes in the last decades (e.g., warming, climate variability, changes in sea ice, and abundance of marine organisms), such an exercise was urgently needed. We concluded that basic biological information on the taxonomy of numerous organisms is still lacking in areas, such as the deep-ocean floor or the under-ice environments. Furthermore, there is a need for knowledge about the response and resilience of Antarctic marine ecosystems to change. The continuation of a long-term commitment and the development and use of innovative technology to adequately monitor the Southern Ocean ecosystems is required. Highlighting the most important Southern Ocean research topics allow the identification of the challenges and future requirements in technological development, and both research and funding strategies for the various stakeholders.

13 pages, 6 figures, 2 tables, The distribution and population structure of the eurybathic gorgonian Corallium rubrum were studied off Cap de Creus (Costa Brava, Northwestern Mediterranean Sea). Red coral is endemic to the Mediterranean Sea and the adjacent NE Atlantic coast, where it has been over exploited for centuries. This study presents, the first quantitative data on the spatial distribution and structure of a population extending between 50 (common SCUBA limits) and 230 m depth, and compared it with shallow populations previously studied in the same area. Different remotely operated vehicles (ROV) and two methodological approaches were employed during four cruises between 2002 and 2006: 1-Extensive surveys: sea to coast transects in which red coral density and patch frequency were recorded; 2-Intensive surveys, in which parameters describing colony morphology were recorded. Most of the hard substrate between 50 and 85 m depth was inhabited by red coral colonies, showing a patch frequency of 8.3 ± 7.9 SD patches per 100 m-transect (total transect area: 34 m2), and within-patch colony densities of 16–376 colonies m−2 (mean of 43 ± 53 colonies m−2). Below 120 m depth red coral was less abundant, and rather than forming dense patches as in shallow water, isolated colonies were more common. The population structure differed between sites that are easily accessible to red coral fishermen, and remote ones (both at similar depth, 60–80 m), as colonies in easily accessible locations were smaller in height and diameter, and showed a less developed branching pattern. At shallower locations (10–50 m depth) the population structure was significantly different from those at deeper locations, due to the heavy harvesting pressure they are exposed to in the shallows. Twenty-five to forty-six percentage of the deeper colonies were taller than 6 cm, while only 7–16% of the shallow water colonies exceeded 6 cm colony height. Forty-six to seventy-nine percentage of the colonies in deeper waters were large enough to be legally harvested, while only 9–20% of the shallow water colonies met the 7 mm legal basal diameter to be collected. The branching pattern was also better developed in deeper colonies, as up to 16% of the colonies showed fourth order branches, compared to less than 1% of the shallow water colonies (of which 96% consisted of only one single branch). The results thus confirm that C. rubrum populations above 50 m depth are exposed to a higher harvesting intensity than deeper populations in the same area, This study was funded by European funds to the Department of Fisheries and Agriculture of the Government of Catalonia in Spain, PCC:30103, European Project Hermes (Contract number GOCE-CT-2005-511234-I) and the MEC project Deep-Coral CTM2005-07756-C02-01/MAR

A partly new classification of shelf inhabiting Antarctic macro-zoobenthic communities is proposed in this review. The main components are two core communities. One is dominated by sessile suspension feeders supported by food entrained in strong near-bottom currents. Variants of this community include assemblages without sponges, those that prefer sponge spicule mats as substratum and predator-driven systems. The second core community is dominated by the infauna and mobile epifauna and controlled by vertical phytodetritus flux and soft sediments. This community is obviously restricted to areas with low current velocity, particularly in areas that are sheltered due to a heterogeneous coastal and sea floor topography. In addition, in physically controlled shallow water a small number of representatives of all these ecological guilds can become very abundant. Between both core communities a broad range of mixed assemblages exists that can be explained by a gradient in environmental conditions and trophic amensalism. A concept is also proposed for the ecological functioning of systems with extremely low abundances within ecological guilds, such as those that occur under and close to ice shelves, which cannot satisfactorily be explained by trophic limitation. These extremely low abundances may result from a shift during ontogenesis from a state with predominantly mismatched environmental conditions and ecological demands of young recruits, to a state where a match occurs.

High-latitude, shelf Antarctic benthic communities are highly diversified and structured, dominated by benthic suspension feeders, and are subject to major natural disturbances. This study focuses on spatial patterns of the Antarctic benthos emphasizing the succession process after iceberg disturbance. For this purpose, underwater photographs (1 m2 each) from the southeastern Weddell Sea shelf (

Gutt, Julian ... et. al.-- 20 pages, 6 figures, 1 table, supporting information http://onlinelibrary.wiley.com/doi/10.1111/gcb.12794/suppinfo, A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on the marine ecosystem shows: (i) large proportions of the SO are and will be affected by one or more climate change processes; areas projected to be affected in the future are larger than areas that are already under environmental stress, (ii) areas affected by changes in sea-ice in the past and likely in the future are much larger than areas affected by ocean warming. The smallest areas (, This study is an output of SCAR's ‘Antarctic Thresholds - Ecosystem Resilience and Adaptation’ (AnT-ERA) and ‘AntClim21’ programs