A year-long survey of some physical parameters （water temperature, dissolved oxygen, pH, turbidity）, chemical parameters （Biological Oxygen Demand ＂BOD＂, Chemical Oxygen Demand ＂COD＂, nitrate, ammonia, orthopho...A year-long survey of some physical parameters （water temperature, dissolved oxygen, pH, turbidity）, chemical parameters （Biological Oxygen Demand ＂BOD＂, Chemical Oxygen Demand ＂COD＂, nitrate, ammonia, orthophosphate） and some biological （zooplankton） and microbiological （total bacteria, indicator bacteria, pathogenic bacteria） components in Domat AI-Gandal Lake was conducted. Water samples were collected seasonally from spring 2004 to winter 2005. Four locations on the Lake were sampled in order to evaluate the condition of the Lake. To investigate the possible effect of zooplankton in controlling the presence of faecal indicator bacteria, a 24 hour experiment was carried out to examine this hypothesis as well as the grazing pressure of zooplankton on the bacterial community of the Lake. The results showed that variations in season temperature affected the zooplankton and density of bacteria in the Lake. Zooplankton was composed by Protozoa 75%, Rotifera 20.6%, Cladocera 3% and Copepoda 2%. The reduction rates for the tested faecal pollution indicators in presence of zooplankton predators were remarkable （up to 99%）. In conclusion zooplankton, especially protozoa, was found to play an important role as biological control against bacterial indicators of faecal pollution.展开更多
文摘A year-long survey of some physical parameters （water temperature, dissolved oxygen, pH, turbidity）, chemical parameters （Biological Oxygen Demand ＂BOD＂, Chemical Oxygen Demand ＂COD＂, nitrate, ammonia, orthophosphate） and some biological （zooplankton） and microbiological （total bacteria, indicator bacteria, pathogenic bacteria） components in Domat AI-Gandal Lake was conducted. Water samples were collected seasonally from spring 2004 to winter 2005. Four locations on the Lake were sampled in order to evaluate the condition of the Lake. To investigate the possible effect of zooplankton in controlling the presence of faecal indicator bacteria, a 24 hour experiment was carried out to examine this hypothesis as well as the grazing pressure of zooplankton on the bacterial community of the Lake. The results showed that variations in season temperature affected the zooplankton and density of bacteria in the Lake. Zooplankton was composed by Protozoa 75%, Rotifera 20.6%, Cladocera 3% and Copepoda 2%. The reduction rates for the tested faecal pollution indicators in presence of zooplankton predators were remarkable （up to 99%）. In conclusion zooplankton, especially protozoa, was found to play an important role as biological control against bacterial indicators of faecal pollution.
