Search

39 pages, 6 figures, 2 tables, This paper presents major gaps and challenges for implementing the UN Decade of Ocean Science for Sustainable Development (2021-2030) in the Mediterranean region. The authors make recommendations on the scientific knowledge needs and co-design actions identified during two consultations, part of the Decade preparatory-phase, framing them in the Mediterranean Sea’s unique environmental and socio-economic perspectives. According to the ‘Mediterranean State of the Environment and Development Report 2020’ by the United Nations Environment Programme Mediterranean Action Plan and despite notable progress, the Mediterranean region is not on track to achieve and fully implement the Sustainable Development Goals of Agenda 2030. Key factors are the cumulative effect of multiple human-induced pressures that threaten the ecosystem resources and services in the global change scenario. The basin, identified as a climate change vulnerability hotspot, is exposed to pollution and rising impacts of climate change. This affects mainly the coastal zones, at increasing risk of extreme events and their negative effects of unsustainable management of key economic assets. Transitioning to a sustainable blue economy is the key for the marine environment’s health and the nourishment of future generations. This challenging context, offering the opportunity of enhancing the knowledge to define science-based measures as well as narrowing the gaps between the Northen and Southern shores, calls for a joint (re)action. The paper reviews the state of the art of Mediterranean Sea science knowledge, sets of trends, capacity development needs, specific challenges, and recommendations for each Decade’s societal outcome. In the conclusions, the proposal for a Mediterranean regional programme in the framework of the Ocean Decade is addressed. The core objective relies on integrating and improving the existing ocean-knowledge, Ocean Literacy, and ocean observing capacities building on international cooperation to reach the “Mediterranean Sea that we want”, With the institutional support of the ‘Severo OchoaCentre of Excellence’ accreditation (CEX2019-000928-S)

This study investigated the biogeography, the presence and diversity of potentially harmful taxa harbored, and potential interactions between and within bacterial and eukaryotic domains of life on plastic debris in the Mediterranean. Using a combination of high-throughput DNA sequencing (HTS), Causal Network Analysis, and Scanning Electron Microscopy (SEM), we show regional differences and gradients in the Mediterranean microbial communities associated with marine litter, positive causal effects between microbes including between and within domains of life, and how these might impact the marine ecosystems surrounding them. Adjacent seas within the Mediterranean region showed a gradient in the microbial communities on plastic with non-overlapping endpoints (Adriatic and Ligurian Seas). The largest predicted inter-domain effects included positive effects of a novel red-algal Plastisphere member on its potential microbiome community. Freshwater and marine samples housed a diversity of fungi including some related to disease-causing microbes. Algal species related to those responsible for Harmful Blooms (HABs) were also observed on plastic pieces including members of genera not previously reported on Plastic Marine Debris (PMD).

The Mediterranean Sea is now acknowledged to be a hot spot for marine litter. However, little is known about Floating Macro Litter (FML) concentration at the scale of the entire basin; predictions regarding this would greatly help guide policymaking to fight this scourge. While previous studies have shown high spatio-temporal variability in FML distribution, the aim of this study was to accurately identify seasonal debris accumulation patterns on regional and local spatial scales across the Mediterranean basin. The objective was then to quantitatively compare this distribution model to other simulations and empirical data. We first studied FML distribution with a 2-D Lagrangian model coupled to an oceanic general circulation model (OGCM) at a horizontal resolution of 1/ 12 ° . From an initial homogeneous deployment, we deployed a set of > 10 8 virtual particles across the whole basin and tracked each particle during 3-month journeys. Then we described the FML distribution model outputs and compared them both to empirical observations at the scale of the whole basin (gathered from a review of scientific papers on surface debris distribution), and to other numerical FML simulations from previous studies. The results of our offshore modeled distribution of FML fully agreed with characteristic debris accumulation patterns analyzed in our review of other studies. This indicates that our model could allow the prediction of monthly litter accumulation patterns at the scale of the entire Mediterranean Sea.

Efforts to model marine food-webs are generally undertaken by small teams working separately on specific regions (

International audience; The ocean ecosystems around the west Antarctic Peninsula and South Georgia are two of the best described regional ecosystems of the Southern Ocean. They therefore provide a useful basis for developing comparative analyses of ocean ecosystems around the Antarctic. There are clear and expected differences in seasonality and species composition between the two ecosystems, but these mask an underlying similarity in ecosystem structure and function. This similarity results from the two ecosystems being part of a continuum, from more ice covered regions in the south to open water regions in the north. Within this continuum the major factors affecting ecosystem structure and function are the sea ice, the biogeochemical conditions and the connectivity generated by the flow of the Antarctic Circumpolar Current. Antarctic krill are central to the food web in both ecosystems, but the other species of plankton and predators present are different. These different species provide alternative pathways of energy transfer from primary production to the highest trophic levels. The relative dominance of these species can provide indicators of change in ecosystem structure and function. Both ecosystems are changing as a result of physically and biologically driven processes, and the ecological responses being observed are complex and variable across different species and within the two regions. Species in parts of the northern Antarctic Peninsula are being replaced by species that currently dominate farther north in more oceanic areas such as at South Georgia. The similarity of structure and strong connectivity, mean that projections of future change will require generic models of these ecosystems that can encompass changes in structure and function within a connected continuum from ice covered to open water in winter.

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.

Atmosphere-Ocean General Circulation Models (AOGCMs) predict changes in the sea ice environment and in atmospheric precipitations over larger areas of Antarctica. These changes are expected to affect the population dynamics of seabirds and marine mammals, but the extent of this influence is not clear. We investigated the future population trajectories of the colony of Adélie penguins at Edmonson Point, in the Ross Sea, from 2010 to 2100. To do so, we incorporated the relationship between sea ice and demographic parameters of the studied colony into a matrix population model. Specifically, we used sea ice projections from AOGCMs and a proxy for snowfall precipitation. Simulations of population persistence under future climate change scenarios showed that a reduction in sea ice extent (SIE) and an increase in precipitation events during the breeding season will drive the population to extinction. However, the population growth rate estimated by the model was lower than the population growth rate observed during the last decades, suggesting that recruits from other colonies maintain the observed population dynamics at Edmonson Point. This local “rescue” effect is consistent with a metapopulation dynamic for Adélie penguins in the Ross Sea, in which neighboring colonies might exhibit contrasting population trends and different density-dependent effects. In the hypothesis that connectivity with larger source colonies or that local recruitment would decrease, the sink colony at Edmonson Point is predicted to disappear, This work was supported by the Italian Antarctic Research Program (PNRA) and by the Italian Ministry for University and Research (MIUR). Tosca Ballerini was supported by a doctoral fellowship in Polar Science 2003–2006, University of Siena. Stephanie Jenouvrier acknowledges support from the Grayce B. Kerr Fund and the Penzance Endowed Fund in Support of Assistant Scientists and Grant ANT- 0944411.

The productivity and linkages in the food web of the southern region of the west Antarctic Peninsula continental shelf were investigated using a multi-trophic level mass balance model. Data collected during the Southern Ocean Global Ocean Ecosystem Dynamics field program were combined with data from the literature on the abundance and diet composition of zooplankton, fish, seabirds and marine mammals to calculate energy flows in the food web and to infer the overall food web structure at the annual level. Sensitivity analyses investigated the effects of variability in growth and biomass of Antarctic krill (Euphausia superba) and in the biomass of Antarctic krill predators on the structure and energy fluxes in the food web. Scenario simulations provided insights into the potential responses of the food web to a reduced contribution of large phytoplankton (diatom) production to total primary production, and to reduced consumption of primary production by Antarctic krill and mesozooplankton coincident with increased consumption by microzooplankton and salps. Model-derived estimates of primary production were 187-207gCm-2y-1, which are consistent with observed values (47-351gCm-2y-1). Simulations showed that Antarctic krill provide the majority of energy needed to sustain seabird and marine mammal production, thereby exerting a bottom-up control on higher trophic level predators. Energy transfer to top predators via mesozooplanton was a less efficient pathway, and salps were a production loss pathway because little of the primary production they consumed was passed to higher trophic levels. Increased predominance of small phytoplankton (nanoflagellates and cryptophytes) reduced the production of Antarctic krill and of its predators, including seabirds and seals. Fil: Ballerini, Tosca. Old Dominion University; Estados Unidos Fil: Hofmann, Eileen E.. Old Dominion University; Estados Unidos Fil: Ainley, David G.. H.T. Harvey & Associates; Estados Unidos Fil: Daly, Kendra. University of South Florida; Estados Unidos Fil: Marrari, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of South Florida; Estados Unidos Fil: Ribic, Christine A.. University of Wisconsin; Estados Unidos Fil: Smith, Walker O.. The College of William and Mary; Estados Unidos Fil: Steele, John H.. Woods Hole Oceanographic Institution; Estados Unidos

International audience; Ecosystems are composed of the physical environment and the species that live in them (the abiotic and biotic components of an ecosystem, respectively). Today there is great concern for the effects of climate change (change in the abiotic component) on Antarctic marine ecosystems, while relatively little attention is being given to the effects of harvesting of living resources (change in the biotic component). However, direct impacts on the biotic components of an ecosystem have the potential to affect the structure of the food web, including creating possible cascades that affect biogeochemistry, over time scales that are faster than those resulting from physical changes. Since the late 1800s, commercial removal of seals, whales and finfish changed food web structure in waters of the Antarctic Peninsula and insular shelves, e.g., that of the Scotia Sea, before baseline scientific data on these ecosystems were acquired and before the first signs of global warming became evident. Until 1997, the Ross Sea marine ecosystem remained relatively unaffected by human extraction, so that its food webs are arguably the closest worldwide to those that existed in a 'pristine' ocean prior to human harvesting. The consequences of harvesting are difficult to measure, but throughout the Southern Ocean important changes in ecosystem structure due to excessive exploitation have been observed. These changes include the collapse or diminishment of marine mammal and fish stocks and the reduction in average individual size of fish from targeted populations. Several conceptual models have been developed to explain these changes and/or to predict possible consequences (reduced population viability; trophic cascades; reduced carrying capacity). Robust predictions about the consequences of continuing the business as usual approach to harvesting Southern Ocean resources can be made based on comparisons with exploited marine ecosystems elsewhere. Current Ross Sea harvesting rates have the potential to reduce fish stocks below a level at which they may be self-sustaining, foment trophic cascades and alter food web structure. These changes will be accompanied by loss of ecosystem and commercial values, with those metrics related to conservation values still poorly defined and not taken into account in the management decision process.

International audience; Southern Ocean (SO) ecosystems are integral to the Earth System, influencing global climate and biogeochemical cycles. Some SO ecosystems have been heavily exploited and today they are undergoing rapid environmental changes. Theme 6 of the Southern Ocean Observing System (SOOS) aims to understand the impacts of global change on the structure and functioning of SO ecosystems to help inform sustainable management of marine resources. Managers need to distinguish the effects of harvesting from the effects of climate variability and change. Food web models can help to disentangle these interacting effects and to identify the most important biological variables to measure in order to detect changes in ecosystem structure. Extensive biological datasets are available and collection of new data continues under programs such as the Southern Ocean Sentinel and SOOS. These data are being used to develop qualitative and quantitative food web models, which are useful tools for integrating observations from different sources and for testing conceptual models of ecosystem structure and functioning. Quantitative network models provide information on ecosystem structure by identifying the principal pathways of energy transfer from primary producers to top predators. A new generation of end-to-end models couple food web models with biogeochemical models and quantify the contribution of upper trophic levels to nutrient recycling and thus to biogeochemical budgets. Inclusion of variability around model parameters provides a measure of the uncertainty in predictions and could be used in management risk assessment. The Integrated Climate and Ecosystem Dynamics program (ICED) is developing regional food web models based on a generic circumpolar food web structure. These models could provide a framework for comparing the responses of regional ecosystems to common environmental drivers and a basis for linking food web models to larger integrated ecosystem models that include the physics and biogeochemistry of the SO.

International audience; Similarly structured food web models of four coastal ecosystems (Northern California Current, Central Gulf of Alaska, Georges Bank, southwestern Antarctic Peninsula) were used to investigate competition among whales, fishes, pinnipeds, and humans. Two analysis strategies simulated the effects of historic baleen and odontocete whale abundances across all trophic levels: food web structure scenarios and time-dynamic scenarios. Direct competition between whales and commercial fisheries is small at current whale abundances; whales and fisheries each take similar proportions of annual pelagic fish production (4-7%). Scenarios show that as whale populations grow, indirect competition between whales and fish for zooplankton would more likely impact fishery production than would direct competition for fish between whales and commercial fisheries. Increased baleen whale abundance would have greater and broader indirect effects on upper trophic levels and fisheries than a similar increase in odontocete abundance. Time-dynamic scenarios, which allow for the evolution of compensatory mechanisms, showed more modest impacts than structural scenarios, which show the immediate impacts of altered energy pathways. Structural scenarios show that in terms of energy availability, there is potential for large increases in whale abundance without major changes to existing food web structures and without substantial reduction of fishery production. For each ecosystem, a five-fold increase in baleen whale abundance could be supported with minor disruptions to existing energy flow pathways. However, such an increase would remain below historical population levels for many cetaceans. A larger expansion (20X) could be accommodated only with large reductions in energy flow to competitor groups. The scope for odontocete expansion varies between ecosystems but may be more restricted than the scope for baleen expansion because they feed at higher, less productive trophic levels.

International audience; Prior to the inception of the Antarctic Treaty (AT), marine mammals and fish stocks were commercially overexploited in the Southern Ocean (SO) without regard for the consequences for individual species and for the ecosystems. The AT resulted in the development of bodies with an interest in ecosystem-based management, which in turn stimulated a large number of marine ecology studies. These studies, largely undertaken under the umbrella of the Committee for Environmental Protection (CEP) and the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), have been ongoing for 30 years and resulted in the development of a wealth of scientific knowledge on SO marine ecology. Despite the knowledge acquired, effective protection measures for SO marine ecosystems are still lacking and recent development of a Ross Sea Antarctic toothfish fishery has the potential to alter ecosystem structure and function of regions of the SO until today relatively untouched by human activities. The Antarctic toothfish is a top predator with slow growth rates and delayed maturity. Removals of corresponding species in other marine ecosystems altered the equilibrium of the food webs, determined trophic cascades, and reduced the value of the ecosystem services. Concern for the expansion of the Antarctic toothfish fishery has been expressed by the SO scientific community and by Non-Governmental Organizations (NGOs). Despite the importance of these issues, the general public and the non-specialized scientific community seem not understand that even with the high level of environmental protection assured to the Antarctic continent through the AT the threats to SO ecosystems still remain. A way to ensure protection of SO ecosystems is through development of a network of representative marine protected areas (MPAs) where fishing activities are strictly regulated or excluded. More than 500 Antarctic and non-Antarctic scientists supported designation of a MPA for the whole Ross Sea and 15 environmental NGOs started a worldwide campaign in support of establishment of a network of SO MPAs. CCAMLR and the AT have agreed to work toward the development of a network of SO MPAs by 2012. They have the support of the scientific community in this and it is important that action occurs rapidly to mitigate the effects of expanding fisheries. This is an opportunity to develop for SO marine ecosystems the same level of protection as that provided for the Antarctic continent.

The population dynamics of Antarctic seabirds are influenced by variations in winter sea ice extent and persistence; however, the type of relationship differs according to the region and the demographic parameter considered. We used annual presence/absence data obtained from 1,138 individually marked birds to study the influence of environmental and individual characteristics on the survival of Adélie penguins Pygoscelis adeliae at Edmonson Point (Ross Sea, Antarctica) between 1994 and 2005. About 25% of 600 birds marked as chicks were reobserved at the natal colony. The capture and survival rates of Adélie penguins at this colony increased with the age of individuals, and five age classes were identified for both parameters. Mean adult survival was 0.85 (SE = 0.01), and no effect of sex on survival was evident. Breeding propensity, as measured by adult capture rates, was close to one, indicating a constant breeding effort through time. Temporal variations in survival were best explained by a quadratic relationship with winter sea ice extent anomalies in the Ross Sea, suggesting that for this region optimal conditions are intermediate between too much and too little winter sea ice. This is likely the result of a balance between suitable wintering habitat and food availability. Survival rates were not correlated with the Southern Oscillation Index. Low adult survival after a season characterized by severe environmental conditions at breeding but favorable conditions during winter suggested an additional mortality mediated by the reproductive effort. Adélie penguins are sensitive indicators of environmental changes in the Antarctic, and the results from this study provide insights into regional responses of this species to variability in winter sea ice habitat. © Springer-Verlag 2009., This work was supported by the Italian Antarctic Research Program (PNRA) and by the Italian Ministry for University and Research (MIUR). The Australian Antarctic Division (AAD) provided the APMS

We are among the scientists objecting to the eco-certification of Ross Sea Antarctic toothfish (Dissostichus mawsoni), as described by E. Stokstad in his News Focus story "Behind the eco-label, a debate over Antarctic toothfish" (24 September, p. 1596). The public perceives a certification by the Marine Stewardship Council (MSC) to mean an environmentally friendly fishery, not one characterized by the "dearth of key data" as indicated in the article.

International audience; Understanding the functioning of Antarctic marine ecosystems and projecting their possible responses to environmental drivers require analysis of extensive data sets, mathematical models to integrate these data, and assessment of data uncertainty on the model projections. In this study, a generic food web model with 22 trophic groups was used to describe the structure and functioning of two Antarctic marine food webs that are representative of a region with heavy sea ice (southern region of the Western Antarctic Peninsula, sWAP) and one with little sea ice (South Georgia, SG). For each food web, ecosystem metrics were calculated using Monte Carlo methods that take into account uncertainty in the data used to define model parameters. Common scenario simulations were used to investigate possible changes in the structure of these food webs to changes in sea ice extent and biomass of dominant food web components. The uncertainty associated with data sets from the two regions was similar, average sWAP CV = 0.5 and average SG CV = 0.46. In both systems, microzooplankton consume 2 times more small phytoplankton production than large phytoplankton production, while mesozooplankton and macrozooplankton consume 3 times more large phytoplankton production. Overall, the microbial part of the food web consumes a large percentage of the primary production in both systems (68% in sWAP and 46% +- 16 in SG), suggesting that improved definition of these processes is needed. Simulations show that a reduction in Antarctic krill (Euphausia superba) biomass corresponds to an almost linear reduction in the biomass of top predator (penguins, crabeater seals, baleen whales) biomass in both systems (coefficient of correlation = 0.90). This result is in agreement with common understanding of the importance of Antarctic krill as diet component for top predators. Simulated shifts from large to small phytoplankton caused decreases in top predator production in the sWAP (coefficient of correlation = 0.82) but not at SG, where modelled zooplankton groups were also less sensitive to phytoplankton type. More diet data for all zooplankton groups are needed to investigate if this is due to actual differences in the food web structure between the two regions or to uncertainty in the data used to parameterize the models. This generic food web model structure provided a useful framework for consistent comparisons of the responses of two ecosystems to common environmental drivers. As such, it provides a basis for input to larger integrated ecosystem models that include the physics and biogeochemistry of the Southern Ocean. This type of common framework will facilitate the comparison among different regional food webs and the integration in larger ecosystem models for the Southern Ocean.

End-to-end models were constructed to examine and compare the trophic structure and energy flow in coastal shelf ecosystems of four US Global Ocean Ecosystem Dynamics (GLOBEC) study regions: the Northern California Current, the Central Gulf of Alaska, Georges Bank, and the Southwestern Antarctic Peninsula. High-quality data collected on system components and processes over the life of the program were used as input to the models. Although the US GLOBEC program was species-centric, focused on the study of a selected set of target species of ecological or economic importance, we took a broader community-level approach to describe end-to-end energy flow, from nutrient input to fishery production. We built four end-to-end models that were structured similarly in terms of functional group composition and time scale. The models were used to identify the mid-trophic level groups that place the greatest demand on lower trophic level production while providing the greatest support to higher trophic level production. In general, euphausiids and planktivorous forage fishes were the critical energy-transfer nodes; however, some differences between ecosystems are apparent. For example, squid provide an important alternative energy pathway to forage fish, moderating the effects of changes to forage fish abundance in scenario analyses in the Central Gulf of Alaska. In the Northern California Current, large scyphozoan jellyfish are important consumers of plankton production, but can divert energy from the rest of the food web when abundant.

International audience; Upper trophic level responses to changes in lower trophic level composition and production were compared for the US-GLOBEC study regions in the Southern Ocean (SO), Northern California Current (NCC), coastal Gulf of Alaska (CGoA), and Georges Bank (GB). Similarly structured end-to-end food web models were used to investigate effects on vertebrate predator production of hypothesized future predominance of smaller phytoplankton and zooplankton functional groups in response to climate change. Simulations include: increased small (< 20 μm) vs large (>20 μm) phytoplankton production; increased microzooplankton production at competitive expense to other zooplankton grazers; and reduced euphausiid production with surplus phytoplankton production benefiting copepods and gelatinous zooplankton. Changes in phytoplankton groups had greatest impact on SO top predator production while changes in microzooplankton had greatest effect on GB vertebrate predators. Reduced euphausiid production affected upper trophic level production in SO, NCC and CGoA but not in GB where euphausiids contribute little to vertebrate production. All regions showed large potential impacts from changes in the plankton assemblage size composition.