Aquatic organisms in aquatic ecosystem mainly include aquatic plants such as emergent plants, floating plants and submerged plants, aquatic animals such as fish and benthos, and other lower aquatic organisms such as zooplankton and microorganisms.
Emergent plants have both ecological function and ornamental value, and are usually located on hillside and waterfront. They can provide habitats, spawning and hiding places for birds, fish and other animals, increase the diversity and stability of ecosystems, and also provide a good root zone environment for microorganisms and increase their activity and biomass. Emergent plants have developed roots, which can transport oxygen to sediments, improve redox conditions, reduce the release of phosphorus and other nutrients in sediments, and increase the purification ability of water bodies. Their roots can also fix wetland sediments, maintain soil and water, maintain lake morphology, form a natural ecological buffer zone in the waterfront, and reduce the pollution load of surface runoff into the lake. Its leaves, flowers and stems also have a strong wetland beautification function. Common emergent plants are: pear blossom, iris, canna, Arundo donax, calamus, cattail, catalpa, Sagittarius, Alisma orientalis and onion.
Floating plants are an important part of aquatic plants, and their leaves float on the water for photosynthesis, so the transparency of water body is low. They are often pioneers in the construction of aquatic plants in eutrophic water bodies, which can reduce the light radiation on the water surface, limit the proliferation of phytoplankton, improve the transparency of water bodies, and absorb various nutrients and heavy metal elements in water, thus creating conditions for the recovery of other aquatic plants. Compared with submerged plants, the leaves and flowers of floating plants float on the water surface, mainly for ornamental purposes. By matching floating plants with different colors, we can create a colorful water landscape and enhance the interaction and entertainment of water. Common floating-leaf plants mainly include: water lily, peach blossom, shepherd's purse, water chestnut and other plants.
Submerged plants, as the main producers of aquatic ecosystem, are the key links to maintain the healthy operation of aquatic ecosystem. Submerged plants can play an important role in absorbing nutrients, inhibiting algae growth, increasing dissolved oxygen, adsorbing suspended solids and providing necessary conditions for aquatic animals to survive. Therefore, the restoration of submerged plants is also an important measure in the water ecological management and restoration project. Submerged plants should be planted at different depths according to the biological characteristics of different kinds of light compensation depth, growth type and other parameters, combined with the underwater topography and constant water level elevation of the lake, and finally form a patchwork "underwater forest" landscape. The common submerged plants are Vallissima, Ceratophyllum, Myriophyllum, Kuroshio, Potamogeton crispus, Potamogeton, etc.
Aquatic animals are an important part of aquatic ecosystem and play an important role in the ecosystem. Fish can control the biomass of other biological populations through downward effect, and transmit it along the food chain and food web, affecting all links in the food chain and accelerating the material and energy cycle of the system; The feeding activities of fish can affect the resuspension of lake sediments, increase the turbidity of water, reduce the transparency of water, and affect the growth of aquatic plants. Grazing activities can directly destroy the roots of aquatic plants. The excretion of fish will also increase the endogenous load flux. Classical biological manipulation technology and non-classical biological manipulation technology with fish as the main carrier have been widely used in cyanobacteria bloom control. Benthic animals mainly feed on bacteria, algae, zooplankton and organic debris in water, which can effectively reduce suspended solids in water and improve its transparency. Reasonable species ratio can prolong the food chain of ecosystem, improve the effect of biological purification, and have great influence on the structure, function and evolution of lake ecosystem. Common aquatic animals are: silver carp, bighead carp, snakehead, Siniperca chuatsi, Pelteobagrus fulvidraco and other fish, as well as benthic animals such as snails, mussels and Corbicula fluminea.
At present, most lakes and rivers are eutrophic or eutrophic water bodies, and the structure and function of aquatic ecosystem are unbalanced and in an unhealthy state. Cyanobacteria bloom frequently, and the black and smelly water body stinks. People who may not know or pay attention to it feel that it has no impact at all, but for residents along the river and lake, it has a great impact on the quality of daily life. Respond to the call of the country that "clear water and green mountains are priceless", protect lakes and rivers, do not throw garbage into the water, and do not illegally fish and breed. A healthy living environment needs everyone to improve and maintain.