SINKING PARTICLES BETWEEN THE EQUATORIAL AND SUB-ARCTIC REGIONS (0-DEGREES-N-46-DEGREES-N) IN THE CENTRAL PACIFIC

Sinking particles play an important role in the transfer of atmospheri c CO2 into the deep sea. We deployed six moorings of sediment traps ac ross the transect at 175 degrees E from 0 degrees N to 46 degrees N in the central Pacific. Mean organic matter fluxes along the transect ge nerally reflected primary productivity. Mean opal fluxes showed simila r profile, but increased markedly between 34 degrees N and 46 degrees N. The increase in mean total fluxes was accompanied with the increase in fluxes of organic matter and opal. Carbonate contents generally de creased from the equatorial to the subarctic regions. The opal/carbona te ratios increased from mid to high latitudes. These trends are essen tially compatible with the prevalent plankton community structure in t he upper ocean. Diatoms predominate over calcareous nannoplankton and foraminifera in higher latitudes. In spite of different plankton commu nities flourishing along the 175 degrees E, C/N atomic ratios of sinki ng particles varied within a small range (6.0-8.7). The high export fl ux of organic carbon and high C-org/C-carbonate ratio in sinking parti cles were potentially responsible for diminished partial pressure of C O2 in surface water in the middle latitudes of the central Pacific dur ing late spring.