Winter Phytoplankton Assemblages of Coastal Yellow Sea Connected to Jiaozhou Bay,China

I Introduction Phytoplankton play an important role in the primary production of ocean (Ning et al., 1995). They are impor-tant biological mediators of carbon turnover in seawater ecosystems (Zhu et al., 1993). Phytoplankton in Jiaozhou Bay have been preliminarily studied on the subjects of community structure, primary productivity and carbon budget (Qian et al., 1983; Guo et al., 1992; Jiao et al., 1994). It has been found that seasonal variation of phytoplankton cell abundance presents w…

Winter phytoplankton assemblages of coastal Yellow Sea connected to Jiaozhou Bay, China

The daily species variation of phytoplankton assemblage of coastal Yellow Sea connected to Jiaozhou Bay in the seawater around the Xiaoqingdao Island was studied for the three months of winter, 2003. A total of 79 taxa from four phyla, Bacillariophyta (52 species), Pyrrophyta (25 species), Chrysophyta (1 species), and Cyanophyta (1species) were determined. In general, the most important groups were Bacillariophyta and Pyrrophyta on cell abundance and species richness. In January, the dominant species was mainly composed of cosmopolitan species such as Skeletonema costatum, then it changed to cosmopolitan species Thalassiosira nordenskiodii in February, and finally, it recovered to Skeletonema costatum again in March. Cell abundance ranged from 1.02 to 130.71 × 10³ cells L⁻¹ with a single peak on 6th Feb., and the average abundance was 28.11 ± 26.01 × 10³ cells L⁻¹ (n=90) during the winter time. The trends of Shannon-Weiner diversity index and Pielou’s evenness index were contrary to cell abundance, whereas the species diversity and evenness were the lowest in February. Temperature and salinity were closely correlated to phytoplankton species composition and cell abundance. According to the variations of temperature and salinity, species sequence was obvious at the studied site. This implies that the phytoplankton community of inner Jiaozhou Bay would be influenced heavily by the coastal Yellow Sea phytoplankton assemblages.