After water storage in the Three Gorges Reservoir Region,there are no outbreaks of algal blooms in the main stream of the reservoir region,but the density of algae increases obviously. Outbreaks of algal blooms mainly...After water storage in the Three Gorges Reservoir Region,there are no outbreaks of algal blooms in the main stream of the reservoir region,but the density of algae increases obviously. Outbreaks of algal blooms mainly appeared in the tributaries of the reservoir region such as the Xiangxi River,Daning River,Shennong River and Xiaojiang River,but they did not occur every year. The reasons for outbreaks of algal blooms in the tributaries are shown as follows: the existence of sources of algae(blue-green algae) in the Three Gorges Reservoir is the root cause,and the sources include sources existing and being produced in the reservoir and sources from upstream main stream and its tributaries and other related lakes and reservoirs,of which the sources are mainly from the Dianchi Lake; slight or moderate eutrophication of water is the basic condition;hydrologic and hydrodynamic conditions and suitable temperature are conducive to proliferation and aggregation of algae(blue-green algae) after the operation of the Three Gorges Reservoir until outbreaks of algal blooms appear. Outbreaks of algal blooms in the tributaries of the Three Gorges Reservoir Region mainly appear in backwater reaches; they mainly occur in the tributaries in the north of the reservoir region and near to the dam;they mainly appear from March to July; the dominant species of algae( blue-green algae) in the Three Gorges Reservoir are Pyrrophyta,Bacillariophyta and Chlorophyta,but they tend to change into blue-green algae and other algae. To control outbreaks of algal blooms in the tributaries of the Three Gorges Reservoir Region,it is needed to prevent water containing blue-green algae collected from the Dianchi Lake and other lakes and reservoirs from being input into the lower reaches,reduce pollution load flowing into the Three Gorges Reservoir,use enclosures to change hydrodynamic conditions of backwater reaches of the tributaries appropriately,and adopt biological measures such as culturing fish and planting plants to improve ecosystem of the tributaries and other measures to inhibit and eliminate algae and decrease eutrophication level.展开更多
Harmful Algal Blooms (HAB) were investigated to prevent the outbreak of HAB in both freshwater and seawater. Parameters inducing HAB were volcanic eruption, sunlight, aeolian dust, environmental factors (current, pH, ...Harmful Algal Blooms (HAB) were investigated to prevent the outbreak of HAB in both freshwater and seawater. Parameters inducing HAB were volcanic eruption, sunlight, aeolian dust, environmental factors (current, pH, dissolved oxygen, food web, turbulence, growth phase), enzyme, iron, nutrients (carbon, nitrogen, phosphorus, sulfur, silicon, minerals) while the critical growth parameter for the outbreak of HAB was iron (Fe). HAB development was halted in freshwater and seawater due to the sulfur compounds (H2S, sulfates) inducing the deficiency of the dissolved Fe in the water. The atomic ratio of N/P is commonly known to be 16/1 in freshwater and 176/1 in seawater for HAB. Therefore, nitrogen can be a relatively limiting factor in seawater while phosphorus in freshwater. HAB could be prevented by control of growth parameters such as pH, temperature, sunlight, turbulence, nitrogen, phosphorus, iron, and sulfur compounds prior to reaching the early exponential phase of algal growth.展开更多
文摘After water storage in the Three Gorges Reservoir Region,there are no outbreaks of algal blooms in the main stream of the reservoir region,but the density of algae increases obviously. Outbreaks of algal blooms mainly appeared in the tributaries of the reservoir region such as the Xiangxi River,Daning River,Shennong River and Xiaojiang River,but they did not occur every year. The reasons for outbreaks of algal blooms in the tributaries are shown as follows: the existence of sources of algae(blue-green algae) in the Three Gorges Reservoir is the root cause,and the sources include sources existing and being produced in the reservoir and sources from upstream main stream and its tributaries and other related lakes and reservoirs,of which the sources are mainly from the Dianchi Lake; slight or moderate eutrophication of water is the basic condition;hydrologic and hydrodynamic conditions and suitable temperature are conducive to proliferation and aggregation of algae(blue-green algae) after the operation of the Three Gorges Reservoir until outbreaks of algal blooms appear. Outbreaks of algal blooms in the tributaries of the Three Gorges Reservoir Region mainly appear in backwater reaches; they mainly occur in the tributaries in the north of the reservoir region and near to the dam;they mainly appear from March to July; the dominant species of algae( blue-green algae) in the Three Gorges Reservoir are Pyrrophyta,Bacillariophyta and Chlorophyta,but they tend to change into blue-green algae and other algae. To control outbreaks of algal blooms in the tributaries of the Three Gorges Reservoir Region,it is needed to prevent water containing blue-green algae collected from the Dianchi Lake and other lakes and reservoirs from being input into the lower reaches,reduce pollution load flowing into the Three Gorges Reservoir,use enclosures to change hydrodynamic conditions of backwater reaches of the tributaries appropriately,and adopt biological measures such as culturing fish and planting plants to improve ecosystem of the tributaries and other measures to inhibit and eliminate algae and decrease eutrophication level.
文摘Harmful Algal Blooms (HAB) were investigated to prevent the outbreak of HAB in both freshwater and seawater. Parameters inducing HAB were volcanic eruption, sunlight, aeolian dust, environmental factors (current, pH, dissolved oxygen, food web, turbulence, growth phase), enzyme, iron, nutrients (carbon, nitrogen, phosphorus, sulfur, silicon, minerals) while the critical growth parameter for the outbreak of HAB was iron (Fe). HAB development was halted in freshwater and seawater due to the sulfur compounds (H2S, sulfates) inducing the deficiency of the dissolved Fe in the water. The atomic ratio of N/P is commonly known to be 16/1 in freshwater and 176/1 in seawater for HAB. Therefore, nitrogen can be a relatively limiting factor in seawater while phosphorus in freshwater. HAB could be prevented by control of growth parameters such as pH, temperature, sunlight, turbulence, nitrogen, phosphorus, iron, and sulfur compounds prior to reaching the early exponential phase of algal growth.
