HR: 10:35h
AN: OS32A-02    [Abstracts]
TI: Seasonal and Interannual fCO2 Variability in a Tropical Coastal Upwelling System
AU: * Astor, Y
EM: yastor@edimar.org
AF: Fundacion La Salle de Ciencias Naturales, Estacion de Investigaciones Marinas de Margarita, Apartado 144, Porlamar, 6301 Venezuela
AU: Scranton, M I
EM: mscranton@notes.cc.sunysb.edu
AF: State University of New York at Stony Brook, Marine Science Research Center Stony Brook, New York, NY 11794-5000 United States
AU: Muller-Karger, F E
EM: carib@seas.marine.usf.edu
AF: University of South Florida, 140 7th. Avenue South, St. Petersburg, FL 33701 United States
AU: Garcia, J
EM: mactub@cantv.net
AF: Fundacion La Salle de Ciencias Naturales, Estacion de Investigaciones Marinas de Margarita, Apartado 144, Porlamar, 6301 Venezuela
AB: Monthly seawater pH and alkalinity measurements were collected between January 1996 and December 2000 at 10ø 30' N and 64ø 40' W as part of the CARIACO oceanographic time series (CArbon Retention In A Colored Ocean Program). The objective was to study temporal variability in Total CO2 (TCO2) concentrations and the CO2 fugacity (fCO2) at a tropical coastal wind-driven upwelling site. The difference between atmospheric and surface ocean CO2 concentrations (ŽfCO2) ranged from -64.3 to +62.3 æatm. Physical and biochemical factors, specifically upwelling, temperature, primary production, and TCO2 concentrations, interact to control temporal variation fCO2. Air-sea CO2 fluxes showed interannual variability. They were typically depressed (0 to +10 mmol C m-2 d-1) in the first few months of the year during the upwelling season and rose during June-November (+10 to 20 mmol C m-2 d-1). While fluxes were not related to changes in salinity, very low positive flux values were seen during the period of very heavy rains and land-derived runoff which depressed surface salinities during the second half of 1999. During the period examined, two events of negative air-sea CO2 flux were observed, namely in March 1997 (\$sim\$ -10 mmol C m-2 d-1) and in March 1998 (\$sim\$ 50 mmol C m-2 d-1), when extremely strong but short upwelling events occurred. Therefore, the Cariaco Basin generally acts as a source of CO2 to the atmosphere in spite of annual primary productivity in excess of between 300 and 600 gC m-2 y-1.
DE: 4805 Biogeochemical cycles (1615)
DE: 4820 Gases
DE: 4279 Upwelling and convergences
DE: 4504 Air/sea interactions (0312)
DE: 4536 Hydrography
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting