SA Agulhas II embarks on voyage to Marion Island

Source: www.sanap.ac.za

Aboard the ship is a host of researchers and participants from Department of Environmental Affairs (DEA), Department of Public Works, the South African Weather Service and various tertiary institutions. The Marion 72 expedition team will be the fourth of its kind to inhabit the new base since its commission in March 2011 and will occupy it for a period of 14 months.

During this voyage, scientists from the DEA's Oceans and Coasts Research unit, as well as from various universities in South Africa, will jointly continue to monitor oceanographic processes - both physical and chemical changes in planktic and benthic communities. Population estimates and assessments of feeding and breeding behaviours of top predators in the Southern Ocean and at the Prince Edward Islands, where marine and terrestrial biological communities have shown responses to climate change, will also be monitored.

Invasive species

These responses are evident in an increase in the spreading of terrestrial invasive species, including invertebrate and vascular plant species. In addition, warming of surface waters have been associated with a possible regime shift in zoo-plankton communities because of the increasing presence of subtropical species and a concomitant decline in Antarctic species over the past 30 years.

Moreover, an observed southward movement of the sub-Antarctic Front and associated changes in oceanographic conditions have been linked to a decrease in the frequency and intensity of the 'island mass effect' resulting in less productivity in the waters around the islands. This is supported by a decrease in chlorophyll concentration near the islands since the 1970s, which in effect is probable cause of recent declines in populations of some inshore feeding seabirds off Marion Island.

Data-poor area

Despite ongoing research and monitoring efforts, the Southern Ocean is still regarded as a comparatively data-poor area and it is therefore important that South Africa, being a party member to the Antarctic Treaty and CCAMLR, carries out its responsibility over its territory and surrounding high seas within the Southern Ocean.

Surveys need to be repeated to characterise changes in diversity and community structure of marine, benthic and terrestrial communities to assess changes possibly associated with the recent climatic shifts, including the presence of invasive species. These surveys also serve as a scientific reference point to monitor further changes and inform the future management of the area, which is one of the objectives of the recently declared Prince Edward Islands Marine Protected Area.