Distribution Of Virioplankton In Freshwater Wetland

We investigated the spatial distribution of virioplankton in 15 wetlands in with different trophic environments. Epifluorescence microscopy was used to detect the abundance of virioplankton. Water transparency, water temperature, pH, total nitrogen concentration, total phosphorus concentration, COD, chlorophyll a and viable bacteria concentration were also recorded. Our results indicated that viral abundance was not only correlated to bacterial density and chlorophyll a concentration (P<0.05), but also closely correlated to COD and water temperature (P<0.01) . This in turn suggested that organic substance and water temperature should be the key factors to influence the spatial and temporal distribution of virioplankton respectively. Moreover, viral abundance was more closely correlated to bacterial density (P<0.05) than to chl a concentration (P>0.05) in eutrophic freshwater wetlands, which indicated that it was bacteriophage (but not phytoplankton virus) the dominant species of virioplankton in eutrophic freshwater wetlands.From November 10th to November 25th in 2007, we did the transfer-light-film experiment in two small enclosures in Fubao Bay Dianchi Lake, a test group and a control group, measuring the physical and chemical indicators of water bodies (TN, TP, CHLa, SD, T, DO), Epifluorescence microscopy was used to detect the abundance of virioplankton, bacteria. Our conclusion is that under natural conditions, the the dominant species is phagocyte, and under the shading conditions, the dominant species is cyanophage. And through the further regression analysis, virus can not be effectively controlled planktonalage and bacteriaplankt, UV inactivation is not the main reason of the virus mortality.On January 26th, March 28th, July 25th, November 20th 2007, In this study, we carried out a large-spatial-scale study on the distribution of virioplankton, bacterioplankton and environmental factors parameters (TN, TP, T, pH, COD, CHLa, DO) in Dianchi Lake. The range abundance of the virus is 6×10⁷～7×10⁸VLPs*L^-1, abundance of bacteria 3×10⁷～3×10⁹BLPs*L^-1.We found the highest abundance of the virioplankton is in summer, lowest in spring. Our conclusion is that the host of virioplankton in Dianchi Lake(mainly planktonic bacteria, followed by the planktonic algae) influence the dynamic viriation of virioplankton, nutrition levels can not affect the abundance of virioplankton, but influence the host of virioplankton, and further influence the virioplankton.