Preliminary Study On The Community Characteristics Of Microzooplankton In Jiaozhou Bay

The community characteristics of microzooplankton in Jiaozhou Bay was studied by field investigations from December 2000 toDecember 2001. The main results are as follows:1 The main species consisted of Tintinnopsis beroide, T. directa, T. lohmanni, T. brevicollis, T. aperta, T. radix, T. urnula, T. kofoidi, Leprotintinnus nordqvisti, Codonellopsis sp., Stenosemella sp., Favella campanula, Amphorellopsis acuta, Amphorella brandti, Helicostomella longa, Trichocerca sp., Synchaeta sp., Paracalanus parvus and Oikopleura sp, including as well copepod nauplius and larvae of polychaeta. Among them, Tintinnopsis beroide, T. urnula, T. brevicollis and copepod nauplius were dominant.2 Microzooplankton of Jiaozhou Bay were composed chiefly of neritic warm-temperate and estuarine low-salinity species. Eurythermic and euryhaline species were sparse. Cold-water, oceanic hypersaline and tropical warm-water species were not found during the study period.3 Abundance of microzooplankton hi Jiaozhou Bay varied significantly among sampling stations during the survey period. In general, high densities of microzooplankton appeared in water bodies of the inner bay, low densities were recorded at estuary and outer part of the bay. The highest annual average densities was recorded at Station 3 ( 346.45 ind./L), the lowest at Station 10 (55.54 ind./L). Abundance differences of microzooplankton hi different water layers were not evident. Mean densities of microzooplankton were higher markedly in February (300.32 ind./L) and May (324.17 ind./L) than that hi August (99.06 ind./L) and November (88.71 ind./L).4 In coastal waters of Jiaozhou bay, annual average densities of microzooplankton decreased hi the order of sampling sites of Daguhe Estuary (997.49 ind./L), Hongdao (677.26 ind./L), Haibohe Estuary (425.44 ind./L ), Tuandao (293.95 ind./L), Huangdao (283.7 ind./L) and Nautical School (107.23 ind./L).5 At the Nautical School Sampling Station (24 hour monitoring station), the highest average density of microzooplankton was recorded at sunset (154.91 ind./L), successively, at sunrise (146.63 ind./L) and noon (93.09 ind./L), the lowest was at midnight (77.31 ind./L).6 Protozoa and copepod nauplius were the most dominant groups , comprising more than 90% of the total abundance of microzooplankton.7 In comparison with other gulf waters in the world, densities of microzooplankton and loricate ciliates in Jiaozhou Bay were at intermediate level.