Preliminary Studies On Selective Grazing Of Zooplankton On Phytoplankton In Jiaozhou Bay

Dilution method and microscopic method were preformed to measure the selective grazing of microzooplankton on phytoplankton at three typical stations, inside, outside and inner the harbor area of the Jiaozhou Bay from October 2004 to June 2005. Based on these experiments, the phytoplankton community constructure and species succession, the grazing rates on phytoplankton species of microzooplankton, the intrinsic growth of phytoplankton, the grazing pressure on phytoplankton standing stocks, and the grazing pressure on potential primary productivity were measured.Phytoplankton is free floating flora, which convert inorganic compounds into complex organic compounds. This process of primary productivity supports the pelagic food-chain. The grazing link between phytoplankton and zooplankton played an important role in marine energy flow. Dilution method, a most popular method to research the grazing of microzooplankton, was used intensively. In this case, the chlorophyll a is measured to represent the biomass, however, chlorophyll a is affected easily by many factors. Moreover, we can't get the result of selectively grazing. In this paper, we combined dilution method and microscopic counting to examine the selective grazing of microzooplankton on specific phytoplankton in the Jiaozhou Bay.More than 90 phytoplankton were found in the Jiaozhou Bay, which mainly were composed of diatom. The horizontal distribution of the phytoplankton in the Jiaozhou Bay was different according to the variation of months. The seasonal variation of phytoplankton in the Jiaozhou Bay was a typical double period's type. The highest peaks appeared in January and July, and the lowest peaks appeared in June and November separately. The dominant microzooplankton species were Stromdinium sp., Tintinnopsis beroidea , Codonellopsis mobilis and so on.In station A, the grazing rates on Thalassiosira nordenski?ldi, Amphiprora lineatum , Prococentrum gracile, Chaetoceros affinis, Chaetoceros curvisetusis and Thalassionema nitzchioides are biggest according to the variation of months, they...