From data to marine ecosystem assessments of the Southern Ocean: Achievements, challenges, and lessons for the future

Southern Ocean ecosystems offer numerous benefits to human society and the global environment, and maintaining them requires well-informed and effective ecosystem-based management. Up to date and accurate information is needed on the status of species, communities, habitats and ecosystems and the impacts of fisheries, tourism and climate change. This information can be used to generate indicators and undertake assessments to advise decision-makers. Currently, most marine assessments are derivative: reliant on the review of published peer-reviewed literature. More timely and accurate information for decision making requires an integrated Marine Biological Observing and Informatics System that combines and distributes data. For such a system to work, data needs to be shared according to the FAIR principles (Findable, Accessible, Interoperable, and Reusable), use transparent and reproducible science, adhere to the principle of action ecology and complement global initiatives. Here we aim to provide an overview of the components of such a system currently in place for the Southern Ocean, the existing gaps and a framework for a way forward

Observing change in pelagic animals as sampling methods shift: the case of Antarctic krill

Understanding and managing the response of marine ecosystems to human pressures including climate change requires reliable large-scale and multi-decadal information on the state of key populations. These populations include the pelagic animals that support ecosystem services including carbon export and fisheries. The use of research vessels to collect information using scientific nets and acoustics is being replaced with technologies such as autonomous moorings, gliders, and meta-genetics. Paradoxically, these newer methods sample pelagic populations at ever-smaller spatial scales, and ecological change might go undetected in the time needed to build up large-scale, long time series. These global-scale issues are epitomised by Antarctic krill (Euphausia superba), which is concentrated in rapidly warming areas, exports substantial quantities of carbon and supports an expanding fishery, but opinion is divided on how resilient their stocks are to climatic change. Based on a workshop of 137 krill experts we identify the challenges of observing climate change impacts with shifting sampling methods and suggest three tractable solutions. These are to: improve overlap and calibration of new with traditional methods; improve communication to harmonise, link and scale up the capacity of new but localised sampling programs; and expand opportunities from other research platforms and data sources, including the fishing industry. Contrasting evidence for both change and stability in krill stocks illustrates how the risks of false negative and false positive diagnoses of change are related to the temporal and spatial scale of sampling. Given the uncertainty about how krill are responding to rapid warming we recommend a shift towards a fishery management approach that prioritises monitoring of stock status and can adapt to variability and change

Observing change in pelagic animals as sampling methods shift: the case of Antarctic krill

Understanding and managing the response of marine ecosystems to human pressures including climate change requires reliable large-scale and multi-decadal information on the state of key populations. These populations include the pelagic animals that support ecosystem services including carbon export and fisheries. The use of research vessels to collect information using scientific nets and acoustics is being replaced with technologies such as autonomous moorings, gliders, and meta-genetics. Paradoxically, these newer methods sample pelagic populations at ever-smaller spatial scales, and ecological change might go undetected in the time needed to build up large-scale, long time series. These global-scale issues are epitomised by Antarctic krill (Euphausia superba), which is concentrated in rapidly warming areas, exports substantial quantities of carbon and supports an expanding fishery, but opinion is divided on how resilient their stocks are to climatic change. Based on a workshop of 137 krill experts we identify the challenges of observing climate change impacts with shifting sampling methods and suggest three tractable solutions. These are to: improve overlap and calibration of new with traditional methods; improve communication to harmonise, link and scale up the capacity of new but localised sampling programs; and expand opportunities from other research platforms and data sources, including the fishing industry. Contrasting evidence for both change and stability in krill stocks illustrates how the risks of false negative and false positive diagnoses of change are related to the temporal and spatial scale of sampling. Given the uncertainty about how krill are responding to rapid warming we recommend a shift towards a fishery management approach that prioritises monitoring of stock status and can adapt to variability and change

Chevreuxiopsis franki gen. n., sp. n. (Crustacea, Amphipoda, Thoriellidae) from the deep sea southwest of Tasmania

A new amphipod species and genus, Chevreuxiopsis franki, found in a pelagic sediment trap southwest of Tasmania is described. The new species can be recognized by its unique antenna 2, which consists of a narrow peduncle, and a 4-articulate flagellum, which has a massively developed, article 1, large, posteriorly drawn out articles 2 and 3, and an elongate lanceolate 4th article. The pereopod 1 basis surrounds large maxillipedal plates. Pereopod 3 to 6 are equipped with subchelate propodus dactylus arrangements. The bases of pereopods 5–7 are narrow

Five reasons to take the precautionary approach to deep sea exploitation

Extractive activities in the deep sea are poised to advance faster than the science needed to evaluate risks. Here, we call for a strong precautionary approach in developing these industries

Controls on Polar Southern Ocean Deep Chlorophyll Maxima: Viewpoints From Multiple Observational Platforms

International audienceDeep Chlorophyll Maxima (DCMs) are ubiquitous in low-latitude oceans, and of recognized biogeochemical and ecological importance. DCMs have been observed in the Southern Ocean, initially from ships and recently from profiling robotic floats, but with less understanding of their onset, duration, underlying drivers, or whether they are associated with enhanced biomass features. We report the characteristics of a DCM and a Deep Biomass Maximum (DBM) in the Inter-Polar-Frontal-Zone (IPFZ) south of Australia derived from CTD profiles, shipboard-incubated samples, a towbody, and a BGC-ARGO float. The DCM and DBM were ∼20 m thick and co-located with the nutricline, in the vicinity of a subsurface ammonium maximum characteristic of the IPFZ, but ∼100 m shallower than the ferricline. Towbody transects demonstrated that the co-located DCM/DBM was broadly present across the IPFZ. Large healthy diatoms, with low iron requirements, resided within the DCM/DBM, and fixed up to 20 mmol C m−2 d−1. The BGC-ARGO float revealed that DCM/DBM persisted for >3 months. We propose a dual environmental mechanism to drive DCM/DBM formation and persistence within the IPFZ: sustained supply of both recycled iron within the subsurface ammonium maxima, and upward silicate transport from depth. DCM/DBM cell-specific growth rates were considerably slower than those in the overlying mixed layer, implying that phytoplankton losses such as herbivory are also reduced, possibly because of heavily silicified diatom frustules. The light-limited seasonal termination of the observed DCM/DBM did not result in a "diatom dump", rather ongoing diatom downward export occurred throughout its multi-month persistence

Future risk for Southern Ocean ecosystem services under climate change

The Southern Ocean supports ecosystem services that are important on a global scale. Climate change and human activities (tourism, fishing, and research) will affect both the demand for, and the provision of, these services into the future. Here we synthesize recent assessments of the current status and expected future climate-driven changes in Southern Ocean ecosystems and evaluate the potential consequences of these changes for the provision of ecosystem services. We explore in detail three key services (the ‘blue carbon’ pathway, the Antarctic krill fishery, and Antarctic tourism), tracing the consequences of climate change from physical drivers through biological impacts to the benefits to humans. We consider potential non-climatic drivers of change, current and future demands for the services, and the main global and regional policy frameworks that could be used to manage risks to the provision of these services in a changing climate. We also develop a formal representation of the network of interactions between the suite of potential drivers and the suite of services, providing a framework to capture the complexity of this network and its embedded feedback loops. Increased consideration of the linkages and feedbacks between drivers and ecosystem services will be required to underpin robust management responses into the future

The role of biota in the Southern Ocean carbon cycle

The Southern Ocean, although relatively understudied owing to its harsh environment and geographical isolation, has been shown to contribute substantially to processes that drive the global carbon cycle. For example, phytoplankton photosynthesis transforms carbon dioxide into new particles and dissolved organic carbon. The magnitude of these transformations depends on the unique oceanographic and biogeochemical properties of the Southern Ocean. In this Review, we synthesize observations of biologically mediated carbon flows derived from the expanded observational network provided by remote-sensing and autonomous platforms. These observations reveal patterns in the magnitude of net primary production, including under-ice blooms and subsurface chlorophyll maxima. Basin-scale annual estimates of the planktonic contribution to the Southern Ocean carbon cycle can also be calculated, indicating that the export of biogenic particles and dissolved organic carbon to depth accounts for 20-30% (around 3 Gt yr-1) of the global export flux. This flux partially compensates for carbon dioxide outgassing following upwelling, making the Southern Ocean a 0.4-0.7 Gt C yr-1 sink. This export flux is surprisingly large given that phytoplankton are iron-limited with low productivity in more than 80% of the Southern Ocean. Solving such enigmas will require the development of four-dimensional regional observatories and the use of data-assimilation and machine-learning techniques to integrate datasets. The Southern Ocean represents a substantial carbon sink and heavily influences global carbon fluxes. This Review describes how an expanding suite of observations are providing increasing insight into the contribution of biota and plankton to the carbon cycle in the Southern Ocean. Increasing coverage from a suite of observations from autonomous platforms will reduce uncertainties on estimates of key processes in the regional carbon cycle that determine the magnitude of the Southern Ocean carbon sink.Episodic storms enhance chlorophyll stocks, presumably owing to enhanced iron supply from depth, but also drive concurrent carbon dioxide outgassing, with unknown cumulative effects on the regional carbon cycle.The influence of climate change on the Southern Ocean and Antarctica is expected to alter the partitioning of basin-scale net primary production between open water, sea ice and under ice.Observations from profiling robotic floats are providing important insights into how the fate of phytoplankton carbon drives regional patterns in export flux in the ocean's interior over multiple annual cycles.The inability to remotely measure dissolved iron or dissolved organic carbon concentrations makes it difficult to understand pivotal processes in the Southern Ocean carbon cycle.Models using data assimilation are already providing promising guidelines on how to deploy autonomous platforms to address key questions around the regional carbon cycle

Overcoming the Obstacles Faced by Early Career Researchers in Marine Science: Lessons From the Marine Ecosystem Assessment for the Southern Ocean

Marine Ecosystem Assessment for the Southern Ocean: Meeting the Challenge for Conserving Earth Ecosystems in the Long Term.-- 9 pages, 1 figure, 1 table, supplementary material https://www.frontiersin.org/articles/10.3389/fmars.2020.00692/full#supplementary-material.-- All datasets presented in this study are included in the article/Supplementary MaterialPressure in academia and science is rapidly increasing and early career researchers (ECRs) have a lot to gain from being involved in research initiatives such as large international projects. But just how inclusive are they? Here we discuss experiences of ECRs directly involved in the Marine Ecosystem Assessment for the Southern Ocean (MEASO), an Australian led international research project to assess the status and trends of Southern Ocean ecosystems. We review the benefits of ECR involvement in large-scale initiatives to the project deliverables, the leadership team and ECRs themselves. Using insights from MEASO, we outline the obstacles that may become barriers to ECRs in scientific research in general but with a focus on large-scale research projects and suggest potential actions to overcome these at the individual, institutional and scientific community level. We consider the potential for ECRs to lead future Antarctic science programmes with a focus on science communication and applied research for policy makers within a global settingMB, CW, and SM were supported by the Antarctic Climate & Ecosystems Cooperative Research Centre and PEW Charitable Trusts. JC acknowledged the support from the Alexander von Humboldt Foundation in the form of a Humboldt Research Fellowship for Postdoctoral Researchers. BF was supported by a postdoctoral contract Juan de la Cierva-Incorporación (IJCI-2017-31478) of Ministerio de Ciencia, Innovación y Universidades. NH was funded by the NSF grant (Award #: 1840927) under a postdoctoral contract at Georgia Institute of Technology, United States. JH was funded through FONDECYT (POSTDOCTORADO 3180152) and CONICYT (FONDAP-IDEAL 15150003). EC was supported by the United Kingdom Natural Environment Research Council research programme grant NE/S000348/1. RS and PP were supported by the IMAS and University of Tasmania (UTAS) Tasmanian Graduate Research Scholarship. SH was supported by the Australian Research Council through a Laureate awarded to Philip Wallace Boyd, IMAS, UTAS, Australia (FL160100131)With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)Peer reviewe