The spatial and temporal variability of particulate organic carbon in the tropical Pacific: a data-model synthesis study

Particulate organic carbon (POC) is an important carbon pool in marine ecosystem, playing a large role in the oceanic carbon cycle via downward flux of dead materials as particles, the so-called “biological pump”. In contrast to significant attention paid to the ocean-atmosphere CO2 fluxes, less attention has been paid to POC dynamics. Here, we present a combined study employing a coupled OGCM-ecosystem model and satellite data to examine the spatial and temporal variability of POC in the tropical Pacific. Our study shows a general agreement in the surface POC between the model and satellite data. Model simulation shows that under normal conditions, the maximum POC is at ~80 m in the western Pacific (40 mg C m-3), but near surface in the eastern Pacific (60 mg C m-3). There is a strong interannual variability in POC, which is associated with the El Niño-Southern Oscillation (ENSO) events. In general, a deep POC maximum disappears in La Niña year in the western warm pool, but appears at subsurface in El Niño year in upwelling region.