Sinking particles between the equatorial and subarctic regions (0°N-46°N) in the central Pacific

Sinking particles play an important role in the transfer of atmospheric CO2 into the deep sea. We deployed six moorings of sediment traps across 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 generally reflected primary productivity. Mean opal fluxes showed similar 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 decreased from the equatorial to the subarctic regions. The opal/carbonate ratios increased from mid to high latitudes. These trends are essentially compatible with the prevalent plankton community structure in the upper ocean. Diatoms predominate over calcareous nannoplankton and foraminifera in higher latitudes. In spite of different plankton communities flourishing along the 175 degrees E, C/N atomic ratios of sinking particles varied within a small range (6.0-8.7). The high export flux of organic carbon and high C-org/C-carbonate ratio in sinking particles were potentially responsible for diminished partial pressure of CO2 in surface water in the middle latitudes of the central Pacific during late spring.