Ecological Studies On The Picoplankton In Southern Taiwan Strait

The studies on the temporal, spatial distribution patterns, composition and environmental control of Prochlorococcus,Synechococcus,picoeukaryotes and heterotrophic bacteria in Southern Taiwan Strait were carried out by flow cytometry during two cruises (summer 2004 and summer 2005). Main conclusions are listed as below:1. Within picophytoplankton, the biomass was dominated by picoeukaryotes in the coastal area, Synechococcus in the shelf water, and Prochlorococcus in open sea. This distribution pattern was likely due to the different niches of the corresponding picoplankton groups.2. The environmental controlling factors in the distribution of each picoplankton group were not all the same. Except for picoeukaryotes, temperature seemed to be the key factor determining the distributions of picoplankton. In contrast, nutrient is not necessarily the limiting factor in the study area.3. Both the endogenous dissolved organic matter excreted by phytoplankton and the exogenous dissolved organic matter were the basis for the heterotrophic bacteria.