In March 1988 a north‐south transect at longitude 150°W was carried out in the equatorial Pacific between latitude 15°N and 15°S. Observations of suspended particulate matter in the euphotic zone included particulate carbon, nitrogen, and chlorophyll, with a few samples taken for counting picoplankton and nanoplankton. Nearly all the particulate nitrogen is accounted for by bacteria and phytoplankton. The standing stock of bacterial C and N exceeded that of phytoplankton. The residence time of particulate organic carbon in the surface water was only 4–5 days in the equatorial upwelling, but 10–15 days to the north and south, suggesting relatively rapid removal by recycling and lateral a