DISSOLVED ORGANIC-CARBON IN THE UPPER OCEAN OF THE CENTRAL EQUATORIALPACIFIC-OCEAN, 1992 - DAILY AND FINESCALE VERTICAL VARIATIONS

Detailed depth profiles of dissolved organic carbon (DOG) were determi ned at the JGOFS Equatorial Pacific Time Series site at 0 degrees, 140 degrees W in March/April and October 1992. DOC concentrations in the top 200 m, determined with the high temperature combustion (HTC) metho d, showed no elevated values over previous wet chemical estimates and ranged from an average of 67 mu M C in the surface waters to 46 mu M C at 200 m. The average integrated DOC concentration over 200 m was 11. 4 mol C m(-2) in March/April and 11.0 mol C m(-2) in October. Variabil ity frequency (i.e. seasonal) was minimal despite large changes in man y biogeochemical parameters. Vertical distribution of DOC was highly c orrelated with physical properties and remained relatively independent of biological properties. High frequency variability appeared to be g overned by physical processes. DOC production and consumption in the e quatorial Pacific were tightly coupled, resulting in little accumulati on and export of labile DOC.