pic: Icicles form as meltwater drips from winter sea ice grounded as the tide drops. Rothera Point, Adelaide Island, Antarctica. Pete Bucktrout (British Antarctic Survey)
In order to understand how climate change is affecting the Southern Ocean ecosystem, it is necessary to understand the context in which change occurs. What was the Southern Ocean ecosystem like 10 years ago, 50 years ago or 5,000 years ago?
Long-term monitoring combined with techniques which provide clues about the distant past, such as ice-coring, can help to build an accurate picture of how much and how fast the earth system is changing.
ICED-IPY Changing Earth projects
During the International Polar Year, the ICED programme is leading a cluster of related IPY projects under ICED-IPY. Understanding more about how climate processes affect the marine ecosystem of the Southern Ocean is a key focus of the ICED programme. ICED is forging new links between scientists working in different areas to improve understanding of the links between climate and biology.
ICED is concerned with Southern Ocean ecosystems and is working in partnership with the European Network of Excellence EUR-OCEANS Southern Ocean System. The ICED programme will continue for a decade and will build on the important findings from the IPY. Below are details of some of the ICED-IPY related projects which are directly relevant to the current IPY Day:
For more information on the ICED Programme visit the ICED website.
Adélie Penguins on Litchfield Island—Extinct
pic: Adélie penguins in ice burrows, Litchfield Island, Antarctica. Bill Fraser (Polar Oceans Research Group)
By 30 November 2007, the evidence could no longer be denied, and it was formally transcribed into our field notebooks and databases. It was the peak of the Adélie penguin breeding season and no pairs had arrived to breed on Litchfield Island, a colony off Palmer Station, Anvers Island, in the western Antarctic Peninsula. Monitored since 1974 when the first complete censuses were conducted and the colony held about 1000 breeding pairs, this was the first recorded extinction of an entire colony in the 34-year history of this study. Even more significant, however, is that the paleoecological record indicates that this was the first time in at least the last 600 years that Adélie penguins have not returned to breed on this island, where the presence of ancient, abandoned nest sites suggests that up to 15,000 pairs may have annually used the colony at one time.
Mid-winter temperatures in the western Antarctic Peninsula are increasing at five times the global average, about 6° C in the last 55 years. As a result, the winter ocean is now more often than not ice-free, and in spring, when Adélie penguins breed, deep snows due to blizzards are becoming more frequent. Adélie penguins depend on sea ice during critical periods in their life history, and having evolved in the polar desert that is Antarctica, are ironically not well suited to handle deep snow and moisture. The latter floods nests when it melts, drowning eggs and chicks. Winter sea ice acts as a platform from which Adélie penguins forage, and is therefore critical to their survival because they are flightless and highly constrained in their abilities to search the ocean for food. Thus, as sea ice continues to decrease, the food-rich offshore regions on which Adélie penguins depend are becoming increasingly more difficult to reach. As a result, if warming continues, the future for this species in the western Antarctic Peninsula does not look promising. Some populations have decreased by up to 80%, suggesting a trend towards more local to regional extinctions.
For more information on Adelie penguins at Litchfield Island contact:
Bill Fraser, President – Polar Oceans Research Group, Principal Investigator - Palmer Long-Term Ecological Research Programme
Data Rescue project looks back to the heroic age of exploration for new insights on the changing Southern Ocean Ecosystem.
During the International Polar Year a one-year project, funded by the EUR-OCEANS network, has begun to revisit a variety of historical sources in order to extract information about the distribution and abundance of Southern Ocean species. The study will include data on species across all trophic levels (from phytoplankton to whales) and will use modern GIS techniques to visualise and analyse the data retrieved.
The project will revisit field data from the Discovery Expeditions, which began in 1925 with a series of surveys by the RRS Discovery; the ship which had previously been used in Scott’s early voyage to Antarctica in 1901. The Discovery Expeditions formed the first scientific survey of the Southern Ocean. More recent research cruises revisited under the project will include the Biological Investigations of Marine Antarctic of Systems and Stocks (BIOMASS) cruises which formed a major international collaborative field campaign in the late 1980s.
Modern methods for analysis and visualisation will bring new perspectives to these historic data and help to build an accurate picture of the circumpolar Southern Ocean ecosystem.
For more information on the EUR-OCEANS data rescue project contact:
Claire Tancell, British Antarctic Survey
www.antarctica.ac.uk
www.eur-oceans.eu
CLImatechange in ANTarctica: A pelagic-benthic coupling approach to the extremes of the Weddell Sea (CLIMANT)
One of a series of three images showing the collapse of the Larsen B ice shelf. Image acquired by the MODIS sensor on NASA’s Terra satellite. Larsen B is a large area of floating ice in the centre of the image. It is fed by ice from the mountains of the Antarctic peninsular on the left and flows into the Weddell Sea on the right. This image is associated with the 2005-2010 British Antarctic Survey science programme GRADES – Glacial Retreat in Antarctica and Deglaciation of the Earth System.
Ice shelves are sensitive indicators of regional climate change. For example, in 1995, the sections A and B of the huge Larsen ice shelf at the eastern Antarctic Peninsula collapsed and rapidly disintegrated uncovering thousands of square kilometres of continental shelf. Since then, this recently opened ecosystem has been partially surveyed. First results show significant changes in the ecosystem structure. Further south, Larsen ice shelf C now appears to be thinning and threatens to collapse in the same way as sections A and B, probably sometime in the present century. As air temperature continues to rise and climate changes, unique Antarctic ecosystems dwelling below ice shelves are in danger of extinction.
Based on the idea that climate change forces environmental characteristics that in turn affect the ecosystem, the CLIMANT project is attempting to determine the actual environmental characteristics of the area formerly covered by the Larsen ice shelves A and B, and to identify their relationship with the organisms and the new ecosystem under development. This will be accomplished by a multidisciplinary study of the links between the open water and seabed ecosystems in the recently opened area. The study will be complemented by a comparison between this “new” environment and the south eastern Weddell Sea shelf, which hosts one of the highest benthic (bottom-dwelling) biomasses in the Antarctic Ocean. In addition, the fate of benthic shelf communities after long glacial periods will be investigated. This key process has scarcely been explored in the Antarctic. The opening of this new area represents a unique opportunity to study re-colonization processes.
For more information on the CLIMANT project contact:
Enrique Isla or Profr. Josep-Maria Gili
Institut de Ciències del Mar-CSIC, Spain
www.icm.csic.es
www.recercaenaccio.cat/agaur_reac/AppJava/ca/projecte/061109-canvi-climatic-a.jsp
www.api-spain.es/Proyectos/Proy_CambioClimatico.html