Antarctic Ocean Legacy: Towards Protection of the Weddell Sea Region
MEDIA FAST FACTS
Life in the Weddell Sea:
- Several species of whales and dolphins and six species of seals are found in the Weddell Sea, as well as a diversity of fish and seabirds. Even at depths of 6,000 metres, life has been found, underscoring the incredible diversity of life in the region.
- Despite being a harsh environment, the Weddell Sea seafloor hosts many diverse habitats. It is home to many hundreds of invertebrate species. Two hundred and thirty different species of amphipods can be found on the eastern Weddell Sea continental shelf alone.
- More sponges are known from the Weddell Sea than any other location of the Southern Ocean contributing up to 96% of the biomass in undisturbed areas of the eastern Weddell Sea continental shelf representing hundreds of differentspecies.
- Communities containing sponges, bryozoans, cnidarians, and ascidians are found in abundance along the shelf of the south-eastern Weddell Sea and Lazarev Sea along the Queen Maud Land – Lazarev Sea Coastal Zone
- Levels of diversity for some organisms including isopods (crustaceans like woodlice or pill bugs), bivalves and gastropods were found to be comparable to tropical and temperate regions.
- Fishing in the Weddell Sea MPA planning region occurs in the CCAMLR statistical subdivisions 48.5 and 48.6. Longline fishing began in the Weddell Sea MPA planning region off the Queen Maud Land – Lazarev Sea Coastal Zone in 1997, but has occurred only recently in the Weddell Sea itself since the start of the 2012-13 fishing season. Overall, the region is considered “data-poor” by CCAMLR.
- Harsh sea ice conditions had previously made fishing difficult in much of the region in the 1970s, when many other Southern Ocean fish populations were beginning to be exploited.
- Originally classed as a new fishery, the fishery north of the Queen Maud Land –Lazarev Sea Coastal Zone was reclassified as an exploratory fishery in 1999 due to recognised high levels of Illegal, Unreported and Unregulated (IUU) fishing. Catches initially focused on Patagonian toothfish well to the north of the MPA planning region, but over time effort moved southern area with increasing catches of Antarctic toothfish.
- Current catch limits for the exploratory toothfish fishery in the seas north of Queen Maud Land, but south of 60° south are for 210 tonnes.
- Scientific research fishing in the Weddell Sea began in the 2012/13 fishing season with a catch of approximately 60.6 tonnes.
- Due to the dramatic disintegration of parts of the Larsen Ice Shelf in 1995 and 2002, changes in the Weddell Sea region have played a highly visible role in fuelling the global discussion on climate.
- Located in the western Weddell Sea adjacent to the Antarctic Peninsula, two of the three segments of the ice shelf (Larsen A and B) have completely disintegrated thus far, resulting in the accelerated flow of glaciers from land into the sea, a phenomenon predicted by many climate change scientists.
- Reductions of the ice shelf and the resultant acceleration of glacier flow into the ocean contributes to sea level rise. In the years to come, the Weddell Sea will be a focal point for studies of global and regional climate change impacts.
- Climate change impacts in the Weddell Sea contrast sharply. The western Weddell Sea adjacent to the Antarctic Peninsula, one of the fastest warming areas on the planet, is experiencing warming conditions and decreasing sea ice while in the eastern Weddell Sea, sea ice is increasing over the past few decades contributing significantly to an overall increase in Southern Ocean sea ice extent.
- Changes in sea ice are also likely to impact on important processes such as carbon sequestration and the productivity of plankton, since melting sea ice and icebergs contribute nutrients that allow the development of phytoplankton blooms.
- Although there is uncertainty about the local effects of climate change, it seems likely that the Weddell Sea will undergo significant changes, some of which will take place on short timescales.
- Changes in temperature, ice sheet mass, sea ice extent and glaciers will impact polar species, many of which are long-lived and slow-growing – characteristics that tend to inhibit rapid adaptation to changing conditions. Many Antarctic benthic organisms are particularly affected by any significant changes to ice.
- Over the last 200 years, the oceans have become 30% more acidic. If this trend continues, calcifying organisms will suffer. The increased acidity can dissolve their shells and skeletons, while the influx of CO2 decreases the availability of carbonate ions hindering their ability to build shells and skeletons.
- The cold waters of the Southern Ocean are naturally lower in calcium carbonate than warmer waters and are thus closer to the tipping point at which organisms will begin to suffer negative effects.
- Scientists predict that within the next two decades key planktonic species, such as pteropods (small marine snails) will no longer be able to build robust shells. In time, they may not be able to build shells at all. If pteropods, or other shell-building animals perish, it will have adverse ramifications that will cascade throughout the Southern Ocean ecosystem.