The Southern Ocean and Climate Change
Jack DiTullio, Department of Biology, Grice Marine Laboratory, College of Charleston
20 Apr 2007
Marine phytoplankton populations represent a vital link in the global carbon cycle as they contribute roughly half of the biosphere's net primary productivity. The Southern Ocean comprises about 20% of the World Ocean but is thought to play a disproportionately important role in controlling the climate of both the present day and geological past. Numerical atmosphere-ocean coupled models predict that climate change will have the greatest impact on the Southern Ocean. Past climate change research has focused on how marine biogeochemical cycles affect various climate change variables. In contrast, comparatively few studies have addressed how climate change variables will impact phytoplankton community struture and biogeochemical cycling of carbon and nutrients. Preliminary data will be presented from our recent (2005-06) cruises to the Ross Sea, Antarctica as part of the CORSACS project (Controls On Ross Sea Algal Community Structure). The effects of varying temperature, light, iron, vitamins and CO2 levels on regulating phytoplankton community structure, biogenic sulfur compounds and photosynthetic rates will be discussed in relation to global biogeochemical cycles and climate change.