28 research outputs found

    Zaključna riječ kardinala Franje Kuharića na Teološko-pastoralnom tečaju za svećenike 25. siječnja 1991.

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    The Southern Ocean archipelago, the South Orkney Islands (SOI), became the world's first entirely high seas marine protected area (MPA) in 2010. The SOI continental shelf (~44 000 km2), was less than half covered by grounded ice sheet during glaciations, is biologically rich and a key area of both sea surface warming and sea-ice losses. Little was known of the carbon cycle there, but recent work showed it was a very important site of carbon immobilization (net annual carbon accumulation) by benthos, one of the few demonstrable negative feedbacks to climate change. Carbon immobilization by SOI bryozoans was higher, per species, unit area and ice-free day, than anywhere-else polar. Here, we investigate why carbon immobilization has been so high at SOI, and whether this is due to high density, longevity or high annual production in six study species of bryozoans (benthic suspension feeders). We compared benthic carbon immobilization across major regions around West Antarctica with sea-ice and primary production, from remotely sensed and directly sampled sources. Lowest carbon immobilization was at the northernmost study regions (South Georgia) and southernmost Amundsen Sea. However, data standardized for age and density showed that only SOI was anomalous (high). High immobilization at SOI was due to very high annual production of bryozoans (rather than high densities or longevity), which were 2x, 3x and 5x higher than on the Bellingshausen, South Georgia and Amundsen shelves, respectively. We found that carbon immobilization correlated to the duration (but not peak or integrated biomass) of phytoplankton blooms, both in directly sampled, local scale data and across regions using remote-sensed data. The long bloom at SOI seems to drive considerable carbon immobilization, but sea-ice losses across West Antarctica mean that significant carbon sinks and negative feedbacks to climate change could also develop in the Bellingshausen and Amundsen seas

    Observations and models to support the first Marine Ecosystem Assessment for the Southern Ocean (MEASO)

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    Assessments of the status and trends of habitats, species and ecosystems are needed for effective ecosystem-based management in marine ecosystems. Knowledge on imminent ecosystem changes (climate change impacts) set in train by existing climate forcings are needed for adapting management practices to achieve conservation and sustainabililty targets into the future. Here, we describe a process for enabling a marine ecosystem assessment (MEA) by the broader scientific community to support managers in this way, using a MEA for the Southern Ocean (MEASO) as an example. We develop a framework and undertake an audit to support a MEASO, involving three parts. First, we review available syntheses and assessments of the Southern Ocean ecosystem and its parts, paying special attention to building on the SCAR Antarctic Climate Change and Environment report and the SCAR Biogeographic Atlas of the Southern Ocean. Second, we audit available field observations of habitats and densities and/or abundances of taxa, using the literature as well as a survey of scientists as to their current and recent activities. Third, we audit available system models that can form a nested ensemble for making, with available data, circumpolar assessments of habitats, species and food webs. We conclude that there is sufficient data and models to undertake, at least, a circumpolar assessment of the krill-based system. The auditing framework provides the basis for the first MEASO but also provides a repository (www.SOKI.aq/display/MEASO) for easily amending the audit for future MEASOs. We note that an important outcome of the first MEASO will not only be the assessment but also to advise on priorities in observations and models for improving subsequent MEASOs

    Delivering Sustained, Coordinated, and Integrated Observations of the Southern Ocean for Global Impact

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    The Southern Ocean is disproportionately important in its effect on the Earth system, impacting climatic, biogeochemical and ecological systems, which makes recent observed changes to this system cause for global concern. The enhanced understanding and improvements in predictive skill needed for understanding and projecting future states of the Southern Ocean require sustained observations. Over the last decade, the Southern Ocean Observing System (SOOS) has established networks for enhancing regional coordination and research community groups to advance development of observing system capabilities. These networks support delivery of the SOOS 20-year vision, which is to develop a circumpolar system that ensures time series of key variables, and deliver the greatest impact from data to all key end-users. Although the Southern Ocean remains one of the least-observed ocean regions, enhanced international coordination and advances in autonomous platforms have resulted in progress towards addressing the need for sustained observations of this region. Since 2009, the Southern Ocean community has deployed over 5700 observational platforms south of 40°S. Large-scale, multi-year or sustained, multidisciplinary efforts have been supported and are now delivering observations of essential variables at space and time scales that enable assessment of changes being observed in Southern Ocean systems. The improved observational coverage, however, is predominantly for the open ocean, encompasses the summer, consists of primarily physical oceanographic variables and covers surface to 2000 m. Significant gaps remain in observations of the ice-impacted ocean, the sea ice, depths more than 2000 m, the air-sea-ice interface, biogeochemical and biological variables, and for seasons other than summer. Addressing these data gaps in a sustained way requires parallel advances in coordination networks, cyberinfrastructure and data management tools, observational platform and sensor technology, platform interrogation and data-transmission technologies, modeling frameworks, and internationally agreed sampling requirements of key variables. This paper presents a community statement on the major scientific and observational progress of the last decade, and importantly, an assessment of key priorities for the coming decade, towards achieving the SOOS vision and delivering essential data to all end users
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