How can regulations on fertilizer use help keep freshwater life zones clean from pollution?
(a.Helps prevent cultural eutrophication
(b.Speeds up runoff
(c.Slows algae growth
Answers
• You must prevent reaching chemical fertilizers to the lake in order to decrease the eutrophication level in the lake.
• In order to control the eutrophication, you must follow the sequence from pollution sources control, ecological restoration to catchment management. To control the internal nutrient release, physical, chemical, biological techniques, and even bionic techniques could be selected. The idea of ecological restoration for a eutrophic lake is to shift the ecosystem from phytoplankton-dominant state to macrophyte-dominant state. To realize the shift of ecosystem state, environmental condition improvement is the fundamental work
• You should do more work on environmental condition improvement than on planting of macrophytes since we are lack of the knowledge about the relationship between macrophyte and lake ecosystem. Emphasizing the macrophyte planting, therefore, has blindness at present. Because all lakes have different characteristics of environment and ecosystem, applicable lake harness techniques should be selected based on the distinct ecosystem types and environmental problems.
• Algal bloom is an extreme response of lake ecosystem to the eutrophication. Appearance of algal blooms is related to physical condition of lakes, such as underwater radiation (or transparency), temperature, and hydrodynamic conditions, or related to geochemical conditions of lakes, like concentrations of nutrients and ratio of nitrogen to phosphorus, as well as the physiological advantage of cyanobacteria such as vacuole for moving towards the radiant.