Variations Of Plankton In Artificial Reef Area Of Haizhou Bay

The deployment of artificial reefs will change tide motion characteristics of reef area,and produce upwelling and eddy current.Under the effect of these currents, nutrients in sediment will be released into the water,and then the nutrients structure will be optimized.These changes of nutrients will eventually impact fishery resources through the food chain by promoting the growth and reproduction of food oganisms. According to the survey of plankton and environmental factors, this paper studied the community structure of plankton and the relationship between phytoplankton species and its environmental factors to discuss the effect of artificial reef on ecological environment. results are as follows:1. The phytoplankton species number was no significant difference between reef area and control area,while the species similarity index was significant difference between reef area and control area.So,we can indicate that the species composition of phytoplankton was different in these two areas.2. The phytoplankton biomass of reef area was 1.39 times comparied with control area after the deployment of artificial reef. Seasonal variation of Phytoplankton biomass showed a same trend:summer>autumn> spring.3. Dominance of the main dominant species were higher in reef area than in control area,which led to the Shannon-Wiener index and Pielou evenness index of phytoplankton were slightly lower in reef area than in control area.While the Margalef index of reef area were higher than control area,there were more species in reef area as a whole.4.Based on the survey data of 2008,by using canonical correspondence analysis(CCA),this paper studied the relationship between phytoplankton species and its environmental factors. The result showed that total inorganic nitrogen, water temperature and transparency were the most important factors influencing the distribution of phytoplankton species. The distribution of main dominant phytoplankton species Chaetoceros muelleri and Eucompia zoodiacus correlated strongly with phosphate.5. The result of gray relational analysis,According to the survey data of spring and summer 2009,showed that the main environmental factors affecting the phytoplankton abundance in spring were dissolved inorganic nitrogen (DIN), BOD5,suspended solids,while those in summer were active Silicate,active phosphate,and BOD5.6. Every years's species number of zooplankton were higher in reef area than in control area except 2008; zooplankton abundance of control area was 1.28 times of reef area,the distribution of zooplankton was different from phytoplankton may be caused by these two follwed reasons: the reproduction,growth,development of copepods are inhibited by the diatoms have been considered as the principal food source for copepods;fish grazing pressure on zoopalnkton in reef area was stronger than in control area.Seasonal variation of zooplankton abundance after and before the deployment of artificial reef showed a same trend:spring>summer> autumn.7. The same as phytoplankton, the Shannon-Wiener index and Pielou evenness index of zooplankton were slightly lower in reef area than in control area,so it was easier to form dominant species in reef area.While the Margalef index of reef area were higher than control area,there were more species in reef area.