Spatial and Temporal Variability in Phytoplankton Carbon and It's Ratio to Chlorophyll a in the South China Sea Based on Satellite Data

Due to their important roles in biogeochemical cycles, the spatial-temporal distribution and long-term trend of phytoplankton biomass have been widely studied. Chlorophyll a (Chl-a), often used as a predictor for monitoring phytoplankton biomass, is a distinctive component of autotrophic organisms. However, it has been long recognized that variability in intracellular Chl-a content from the complex effects of light, nutrients and temperature confounds the relationship between Chl-a and phytoplankton biomass. Here we present a regional adjust bio-optical algorithm for retrieve phytoplankton carbon, as an alternative index of phytoplankton biomass, from satellite the SCS. Then, the spatial and temporal variability of phytoplankton carbon and Carbon : Chl-a were investigated. Both phytoplankton carbon concentrations and Carbon : Chl-a showed a significant seasonality in the SCS. Phytoplankton carbon concentrations were high in the northern and western of SCS, but were very low in the deep basin on the Philippine side of the SCS during November to February. The ranges of mean Carbon : Chl-a in the northern basin, central basin and western basin of SCS are 64.13±11.08, 74.83±17.98, and 67.73±13.23, respectively. The variability of Carbon : Chl-a may be related to the phytoplankton physiological and phytoplankton community.