Sweeney, C. Lamont-Doherty Earth Observatory, csweeney@ldeo.columbia.edu
Hansell, D. A. Burmuda Biological Station for Research, dennis@bbsr.edu
Millero, F. University of Miami,Rosentiel School of Marine and Atmospheric Sciences, millero@oj.rsmas.miami.edu
Carlson, C. A. Burmuda Biological Station for Research, ccarlson@bbsr.edu
Codispoti, L. A. Old Dominion University, lou@ccpo.odu.edu
Smith, W. O. The college of William and Mary, Virginia Institute of Marine Science, wos@vims.edu
Takahashi, T. Lamont-Doherty Earth Observatory, taka@ldeo.columbia.edu

 
THE BIOGEOCHEMICAL REGIMES IN THE ROSS SEA INDICATED BY NET UTILIZATION OF CARBON AND NUTRIENT AND NET PRODUCTION OF ORGANIC CARBON
 
The net community production (NCP) calculated from seasonal carbon drawdowns measured during a period starting in mid-October, 1996 and ending in mid-February, 1997 was estimated to be 25+/-10 Tg of carbon in the Ross Sea. By mid-February, 45+/-25% of the NCP had been removed from the upper 100 meters. Total carbon dioxide measurements suggest that 73+/-25% of this exported carbon was remineralized between 100 and 500 meters depth. Analysis of the seasonal drawdown of nutrients and carbon revealed three distinct biogeochemical regimes in the Ross Sea. 1) The southwestern Ross Sea was distinguished by shallow mixed layers, high NCP's, and high silicate to carbon utilization ratios of 0.13+/-0.04 indicating diatom dominance. 2) The center of the southern Ross Sea polynya also had high NCP (4.3-10.7 molC/m^2/yr) but deeper mixed layers and much lower silicate to carbon uptake ratios, illustrating the dominance of Phaeocystis Antarctica. Re-occupation of selected stations showed the persistence of diatoms late into the bloom period. 3) The shelf break area of the Ross Sea had a wider range of silicate to carbon ratios (0.10-0.38), and low NCP's.
 
Day: Thursday, Feb. 4
Time: 03:45 - 04:00pm
Location: Sweeney Center
 
Code: SS31TH0345S