Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the ...Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the largest freshwater lake in China and one of two lakes connected to the Changjiang （Yangtze） River, were investigated from February 2008 to May 2009. Mussels were sampled in hydrologically and geographically distinct sampling areas. A total of 42 species and 13 genera were identified, of which 32 species were endemic to China. Two species, Unio douglasiae and Lamprotula caveata, dominated all sampling areas. The number of genera and species, and the number of species within each genus, differed significantly among sampling areas. Freshwater mussels were very abundant, with an overall density of 0.28±0.22 ind./m-＇ and biomass of 4.08±3.96 g/m^2. Significant variation observed among sampling areas and among genera was probably due to the variety of habitats among the areas sampled and to the adaptability of different freshwater mussels to environments. This study suggests that Poyang Lake and other freshwater lakes in the region are important sites of freshwater mussel biodiversity and conservation.展开更多
Virioplankton dynamics at seven sample sites(from two freshwater lakes) with different trophic states were monitored over the period of a year.Water was sampled monthly from August 2004 to July 2005,and the abundances...Virioplankton dynamics at seven sample sites(from two freshwater lakes) with different trophic states were monitored over the period of a year.Water was sampled monthly from August 2004 to July 2005,and the abundances of viruses and bacteria were measured using direct epifluorescence microscopy counting.Results indicated that both natural and anthropogenic factors could influence the distribution of virioplankton.Temporally,viral abundance was significantly correlated to bacterial density and water temperature.Spatially,viral abundance was significantly correlated to trophic state.This in turn indicated that viral abundance was directly dependant on host abundance in eutrophic lakes,while trophic state and temperature could drive the distribution of virioplankton.The virus-bacteria ratio was significantly lower in less productive water-bodies.The result implied that the control of virioplankton on their hosts may change according to the host density.展开更多
基金Supported by the National Natural Science Foundation of China(No. 30860045)
文摘Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the largest freshwater lake in China and one of two lakes connected to the Changjiang （Yangtze） River, were investigated from February 2008 to May 2009. Mussels were sampled in hydrologically and geographically distinct sampling areas. A total of 42 species and 13 genera were identified, of which 32 species were endemic to China. Two species, Unio douglasiae and Lamprotula caveata, dominated all sampling areas. The number of genera and species, and the number of species within each genus, differed significantly among sampling areas. Freshwater mussels were very abundant, with an overall density of 0.28±0.22 ind./m-＇ and biomass of 4.08±3.96 g/m^2. Significant variation observed among sampling areas and among genera was probably due to the variety of habitats among the areas sampled and to the adaptability of different freshwater mussels to environments. This study suggests that Poyang Lake and other freshwater lakes in the region are important sites of freshwater mussel biodiversity and conservation.
基金Supported by the National Natural Science Foundation of China(No.30470344and30670088)Key Technology Project of Hubei Province(No.2006AA305A04)Commonweal Project of State Oceanic Administration of China(No.200705014)
文摘Virioplankton dynamics at seven sample sites(from two freshwater lakes) with different trophic states were monitored over the period of a year.Water was sampled monthly from August 2004 to July 2005,and the abundances of viruses and bacteria were measured using direct epifluorescence microscopy counting.Results indicated that both natural and anthropogenic factors could influence the distribution of virioplankton.Temporally,viral abundance was significantly correlated to bacterial density and water temperature.Spatially,viral abundance was significantly correlated to trophic state.This in turn indicated that viral abundance was directly dependant on host abundance in eutrophic lakes,while trophic state and temperature could drive the distribution of virioplankton.The virus-bacteria ratio was significantly lower in less productive water-bodies.The result implied that the control of virioplankton on their hosts may change according to the host density.
