The Ecological Study Of The Picoplankton In The East China Sea And Yellow Sea

We investigated the distribution of the picoplankton in the East China Sea and Yellow Sea (ECSYS) with the special attention to the infuence of different hydrographys on the distribution of picoplankton. Also we studied the variation of picoplankton in different seasons during 2000-2006 in Jiaozhou Bay. Meanwhile, to learn the biodiversiy of Synechococcus spp in the ECSYS, we isolated six strains of Synechococcus in this sea area. The phylogeny of 6 isolates were analyzed and their absorption spectra and composition of phycobiliprotein were studied at the same time. The heterotrophic bacterial abundance was about 106 cells ml-1 in the ECSYS.There was distinct spatial distribution of the bacterial abundance in the ECSYS during fall and spring. Bacterial abundance decreased with the distance far away from the coast on most of transects in fall and spring. Also, bacteria abundance decreased with the distance away from the coast in the Yellow Sea and decreased from the Changjiang River Estuary as a center to outward in the East China Sea. During spring, heterotrophic bacterial production and turnover rate was positively correlated with temperature. While it was more complicated during summer. In this season, We testified several conditions that hydrography influenced the distribution of hetertrophic bacteria much.Furthermore, our research indicated that Synechococcus was a very important contributor to the primary biomass comparing with the phytoplankton primary production in the ECSYS. The contribution of Synechococcus biomass to the total primary production ranged 4-98% (averaged 42%) and 4-93% (averaged 30%) during spring and summer. The long term investigation in Jiaozhou bay indicated that the abundance of picoplankton varied periodic during the year round. The picoplankton abundance was positivly corelated with temperature. In this typical coastal ecosystem in china, the Synechococcus contributed only approxmately 4% on the phytoplankton primary production.Six strains of Synechococcus was isolated in the ECSYS. Among them, three, which contented the Phycoerythrobilin (PE), were from the Yellow Sea. The others, two contain Phycocyanobilin (PC) and one with PEB, were from the East China Sea. The phylogeny indicated that Synechococcus was diverse in ECSYS.