Organic carbon dynamics within CalCOFI/CCE

Continental margins and upwelling zones are significant contributors to the uptake of atmospheric carbon via biological productivity and advection of accumulating carbon pools away from the system; and biological productivity in the California Current responds to climate change on a variety of different time scales. As part of the California Cooperative Oceanic Fisheries Investigations (CalCOFI; 128-124˚W, 30-31˚N) and the California Current Ecosystem Long Term Ecological Research (CCE-LTER) Program, we measure total organic carbon (TOC) during quarterly cruises. Upwelling in the California Current acts to bring low TOC (40-50 μM C) high nutrient waters to the surface while stimulating production of new carbon via carbon fixation; however, key components to balancing the carbon source-sink problem will be to effectively monitor both the vertical mixing and the horizontal advection of water masses of varying carbon concentration and bio-optical properties. Previous studies have demonstrated that the TOC pool of the California Current experiences seasonal shifts in its sources of carbon but the extent to which it acts as either a source of TOC to the North Pacific or a sink of gyre-originating TOC remains unclear.