[Chlorophyll-a concentration and phytoplankton size-fractionated composition in Jiaozhou Bay].

An investigation was made on the chlorophyll-a (Chla) concentration and phytoplankton size-fractionated composition in Jiaozhou Bay and its adjacent waters in February, May, August, and November 2008. The average annual Chla concentrations inside and outside the Bay was 4.90 mg x m(-3) and 2.03 mg x m(-3), respectively. The Chla concentration presented a decreasing trend from the northeast and near-shore to the central, south, and outside of the Bay, and had an obvious double-peak seasonal variation, being higher in summer and winter. The phytoplankton in the Bay was dominated by nanophytoplankton, accounting for 60.9% of the total Chla concentration, followed by microphytoplankton, and picophytoplankton, which was consistent with the phytoplankton size-fractionated composition in coastal waters of China. Comparing with historical data, the proportion of nanophytoplankton in the Bay had some increase, while that of picophytoplankton decreased to some extent.