Studies On Plankton Community Structure And Its Variation In Recycling Water Aquaculture Ponds

The wastewater pond not only affects the quality of aquatic products, and may cause pollution on the environment, but also affects Plankton population structure and its variation in water body. In order to solve this problem, we constructed a fish-rice compound ecosystem. The main idea is that transporting nutrients from the water body of the pond into rice- field and providing rice with a part of nutrients, which was purified and absorbed by rice, and then was returned to the pond, so as to increase full utilization of nutrients and improve breeding efficiency, which can reduce the pollution of the surrounding environment. It is mainly studied on plankton community structure and its variation in recycling and non-recycling aquaculture ponds. The purpose of constructing an eco-model, which provides a scientific basis for the sustainable development of aquaculture. the main research results are as follows:1. Structure of the phytoplanktonic communities(1) The phytoplankton were identified belonging to 93 species,47 genera,6 phyla from the recycling water aquaculture pond. The phytoplankton identified belonging 100 species,48 genera,6 phyla from the control pond. Chlorophyta ranked first in species richness of the two ponds (40.86% and 42% of the total record taxa, respectively).(2) Chlorophyta ranked first in the dominant population of the recycling water aquaculture pond and the control pond. Chlorella,Scenedesmus,Closterium in Chlorophyta. Cyclotella,Synedra in Bacillariophyta. In addition, The dominant species of the control pond the following:Melosira,Diploneis,Closteriu,Navicul in Bacillariophyta. Netrium in Cyanophyta and Spirulina,Merismopedia,Microcystis in Chlorophyta.(3) The Shannon-Wiener diversity index of Phytoplankton were 1.39～1.62 and 1.16～1.48 in the recycling water aquaculture pond and control pond, respectively.(4) The density and biomass of the Phytoplankton, which of the recycling water aquaculture pond were significant lower than the control pond in the experiment period (P<0.05). The density of the Phytoplankton were 247.68～1133.31 (×104ind/L) and 511.68～1773.3 (×104ind/L) the recycling water aquaculture pond and control pond, respectively, the biomass were 3.07～10.83 (mg/L) and 4.48～17.34 (mg/L) the recycling water aquaculture pond and control pond, respectively. 2. Structure of the zooplanktonic communities(1) The Zooplankton were identified belonging to 42 species,33 gena and 88 species,68 gena from the recycling water aquaculture pond and control pond, respectively, The dominant species of zooplankton which were mainly consisted of Protozoa and Rotifer. The order of all species were Protozoa> Rotifer> Cladocera and Copepoda. Protozoa and Rotifer in the recycling water aquaculture pond, which represented 33.34% and 52.38%, respectively. But Protozoa and Rotifer in the control pond, which represented 48.86% and 42.05%, respectively.(2) The dominant species of the zooplankton were Cyphoderia,D.balbianii,B. angularis,B. diversicornis,P. trigla,L.patella,Nauplius,D. drachyurum in the recycling water aquaculture pond; in addition, there were D.bacillarum,D.corona,A.discoides,B.calyciflorus,A.multiceps in the control pond.(3) The Shannon-Wiener indexes of Zooplankton were 0.51～1.95 and 1.08～1.45 in the recycling water aquaculture pond and control pond, respectively.(4) The density and biomass of the Zooplankton, which of the recycling water aquaculture pond were significant higher than the control pond in the experiment period(P< 0.05). The density of the Zooplankton were 72～708.11 (ind/L) and 152.9-208.20 (ind/L) the recycling water aquaculture pond and control pond, respectively; the biomass were 0.41～1.69 (mg/L) and 0.26～0.46(mg/L) the recycling water aquaculture pond and control pond respectively.