Redfield stoichiometry in Arabian Sea subsurface waters

A linear inverse mixing model is applied to hydrographic, nutrient, and car bon data collected during Joint Global Ocean Flux Study and World Ocean Cir culation Experiment cruises in 1995 to estimate the Delta C-org/Delta N/Del ta P/Delta Si/-Delta O-2 remineralization ratios within the Arabian Sea bet ween 550 and 4500 m. The observed concentrations are separated into mixing fractions of source water masses and changes caused by remineralization pro cesses, while the effect of denitrification is considered. In contrast to e arlier investigations, diapycnal mixing, which plays an important role in d issolved matter fluxes in the Arabian Sea, is accounted for. The ratios are found to be variable with depth, especially in the upper 2000 m of the wat er column. We suppose that in general nutrients are released faster than ca rbon dioxide during remineralization. The Delta C-org/Delta C-inorg decreas e from similar to 4 +/- 1 at 550 m to 2 +/- 0.2 at 2000 m and 1.2 +/- 0.3 a t 4000 m, suggesting that the dissolution of calcium carbonate above the ca lcite lysocline is a potentially important process within the Arabian Sea.