The Relationships Between The Seasonal Variations And The Environmental Factors Were Studied By Canonical Correspondence Analysis(CCA) In Hyriopsis Schlegeli Breeding Pools

Hyriopsis schlegeli, originated from BIWA Lake of Japanese, was introduced to China in1997, it was proved that it's powerful pearl breeding ability and superior quality, has already been bred and spread throughout the country. To understand the food and living environment provided by different ways of spreading manure, nine times of water specimen collection, carried out from May of2010to March of2011. We also have preliminary study about Hyriopsis schlegeli on eating habit. Main research results are as follows:1.103categories of phytoplankton were detected all the year around. The density range of phytoplankton between different ways on spreading manure respectively is:the pool without spreading manure had an abundance ranging from1.8×105to289.5×105cells/L;the pool with spreading fermentation organic manure including probiotic bacteria had the abundance ranging from12.9×105to705×105cells/L; the pool with spreading fermentation chicken manure owned the range from5.4×105to481.6×105cells/L.The abundance of phytoplankton in the pools without spreading manure conspicuously lower than the pools spread with manure. There were no significant differences between phytoplankton abundance of varying manure pools.2. The phytoplankton community composition of the three kinds of pools was similar. Green alga was dominated among May to July. From August to October phytoplankton community was dominated by Green alga, Cyanophyta has a high biomass in this stage only. Cryptophyta was dominant in November, December and March. Data collected in a limnological survey, carried out among pools breeding Hyriopsis schlegeli of varying manure state, were ordinated using CANOCO3.1to generalise the way in which the structure of phytoplankton assemblage is conditioned by both physical and chemical variables. In this paper, among the varying manure pools, an attempt to clarify the role played by environmental variables in modulating the structure of phytoplankton assemblages is presented. The results indicate that water temperature is one of the key regulatory factors for phytoplankton abundance. What's more, seasonal variations of phytoplankton were also influenced by soluble nutrients, such as in winter and early spring. However, in later spring and early summer, COD and DO are playing central roles in regulating the phytoplankton abundance. According to cases ordination by CCA, Hyriopsis schlegeli breeding pools, in Fuzhou Jiangxi province is characterized by not clear seasons that spring is short and winter is long. IN autumn phytoplankton community is dominated by Cyanophyta and Bacillariophyta. And Bacillariophyta is mainly distributed in the winter.3. Hyriopsis schlegeli mainly feed on algae, which depend on seasonal dominant phytoplankton. There are different food choice of Hyriopsis schlegeli which come from pools with different fertilization modes. Although the categories of phytoplankton which three kinds of ages Hyriopsis schlegeli feed on are the same, the more algae the four age Hyriopsis schlegeli eating one time than others.