China is a country with many lakes,about one-third of which are freshwater mainly distributed in the middle and lower reaches of the Yangtze River.Currently most of the lakes are mesotrophic or eutrophic.Lake eutrophi...China is a country with many lakes,about one-third of which are freshwater mainly distributed in the middle and lower reaches of the Yangtze River.Currently most of the lakes are mesotrophic or eutrophic.Lake eutrophication has become one of the major ecological and environmental problems faced by lakes in China and can lead to a series of abnormal ecosystem responses,including extinction of submerged plants,frequent occurrence of cyanobacterial blooms,increased microbial biomass and productivity,decreased biodiversity,accelerated cycles,and a change in the efficient use of nutrients.With development of eutrophication,the whole lake ecosystem suffers decreased biodiversity,simplification of biotic community structure,instability of the ecosystem,and ultimately the clear-water,macrophyte-dominated ecosystem gradually shifts to a turbid-water,algae-dominated ecosystem.This ecosystem succession mechanism is speculated to be caused by different nutrient utilization efficiencies of macrophytes and phytoplankton.The ultimate ecosystem succession trend of seriously eutrophic lakes is that a phytoplankton-dominated autotrophic lake shifts to a heterotrophic lake dominated by micro-organisms,protozoans.展开更多
With the abundant natural grassland resources,Maqu County becomes the important stockbreeding base in the upper reaches of Yellow River.Eco environment problems,such as grassland degeneration,land desertification,wate...With the abundant natural grassland resources,Maqu County becomes the important stockbreeding base in the upper reaches of Yellow River.Eco environment problems,such as grassland degeneration,land desertification,water and soil loss,and water resource decrease were incurred by population increase and stockbreeding development.Under the trend of global warming,human factors,for example,over loading and grazing,irrational dieforestation,and low input,etc., were the direct and radical reasons to deteriorate the vulnerable ecoenvironment.Technological,legal,administrative and economic measures,such as afforestation,artificial grass planting,grassland water saving irrigation and fertilization,industrial structure,adjustment scientific and technical education,high efficient management and so on,should be taken to control eco environment synthetically in order to realize the favorable circulation of eco system and the sustainable development of regional stockbreeding.展开更多
基金supported by the National Natural Science Foundation of China (40825004,41230744,41271355 and 31270505)
文摘China is a country with many lakes,about one-third of which are freshwater mainly distributed in the middle and lower reaches of the Yangtze River.Currently most of the lakes are mesotrophic or eutrophic.Lake eutrophication has become one of the major ecological and environmental problems faced by lakes in China and can lead to a series of abnormal ecosystem responses,including extinction of submerged plants,frequent occurrence of cyanobacterial blooms,increased microbial biomass and productivity,decreased biodiversity,accelerated cycles,and a change in the efficient use of nutrients.With development of eutrophication,the whole lake ecosystem suffers decreased biodiversity,simplification of biotic community structure,instability of the ecosystem,and ultimately the clear-water,macrophyte-dominated ecosystem gradually shifts to a turbid-water,algae-dominated ecosystem.This ecosystem succession mechanism is speculated to be caused by different nutrient utilization efficiencies of macrophytes and phytoplankton.The ultimate ecosystem succession trend of seriously eutrophic lakes is that a phytoplankton-dominated autotrophic lake shifts to a heterotrophic lake dominated by micro-organisms,protozoans.
文摘With the abundant natural grassland resources,Maqu County becomes the important stockbreeding base in the upper reaches of Yellow River.Eco environment problems,such as grassland degeneration,land desertification,water and soil loss,and water resource decrease were incurred by population increase and stockbreeding development.Under the trend of global warming,human factors,for example,over loading and grazing,irrational dieforestation,and low input,etc., were the direct and radical reasons to deteriorate the vulnerable ecoenvironment.Technological,legal,administrative and economic measures,such as afforestation,artificial grass planting,grassland water saving irrigation and fertilization,industrial structure,adjustment scientific and technical education,high efficient management and so on,should be taken to control eco environment synthetically in order to realize the favorable circulation of eco system and the sustainable development of regional stockbreeding.
