Ocean acidification impacts on krill and
krill predators in the Southern Ocean
University of North Carolina at Wilmington
March 28, 2018
Pacific Forum—11:00 a.m.
The Western Antarctic Peninsula region of the Southern Ocean, a National Science Foundation Long-Term Experimental Research Site, has exhibited a subtle but steady increase in surface water temperature and a rapid decline of sea ice during recent decades, posing an eventual threat to the physiological and biochemical adaptations of krill, Euphausia superba “Dana 1850.” The decline in krill densities may deprive predators such as penguins including Pygoscelis adeliae “Hombron and Jacquinot 1841” (with 1.5 million now found by Landsat satellite imagery in the Danger Islands, northern part of Antarctic Peninsula), krill-eating seals, and baleen whales. There is also evidence of a decrease in pH as a consequence of increasing pCO2 in the midwater pelagic ecosystem (200 to 1,000 meters). Risk maps of ocean acidification in the Southern Ocean around Antarctica from now to two centuries from now (2200) will be discussed. The increase in temperature may result in a shoaling of the krill hatching depth from 1,000 meters to 400 meters where signs of ocean acidification are now evident. In the Amundsen Sea, there is a small ice shelf that has slowly melted (1972 to 2003) and not reformed, creating a new geographic feature named Elizabeth City State University Bay. Recent research from the Rosenstiel School of Marine Science in Miami indicated that deoxygenation occurred in the Amundsen Sea to create low-oxygen zones at mid-ocean depths that may, in two decades, become a new hypoxic (oxygen minimum) zone. This seminar will also address potential avenues to avoid pelagic ecosystem collapse as potentially induced by ongoing climate change processes.
Next: Melissa Omand