20-Year Plankton Study Maps Major Changes in Southern Ocean
22.10.2010 - Water & Oceans, Flora & Fauna, Antarctic
Over the past 20 years, an Australian Antarctic Division (AAD) study of the Southern Ocean has identified various changes in the composition, distribution and diversity of plankton and krill. Thanks to the Australian Continuous Plankton Recorder project, which involves towing recording equipment behind a ship, AAD scientists have been able to map and monitor plankton populations in the Southern Ocean since 1991.
The various samples collected over the last two decades have shown significant changes in the composition of plankton, with the scientists catching less krill – possibly indicating either a decline in numbers or a change in their distribution. At the same time, the team found increased numbers of smaller zooplankton in samples from the sea ice zone and sudden massive blooms of other plankton species spread over large areas.
While the exact drivers behind these changes are yet to be identified, the changes in sea-ice and ocean temperature appear to be already affecting the Antarctic food web. Thus far, the project has covered 70% of the Southern Ocean, taken 30,000 samples, identified and mapped 230 species and towed the recorder over more than 278,000 kilometers. Having led to the publication of the first Zooplankton Atlas, the Continuous Plankton Recorder will be deployed again during the upcoming Antarctic season.
