Freshwater lakes are rich ecosystems that provide habitat and food sources for numerous species. Aquatic plants in lakes provide shelter and habitat for aquatic animals, while plankton and fish form the basis of food chains.

The lake is also a migratory and breeding ground for many migratory and waterfowl. Protecting freshwater lakes helps to maintain ecological balance, protect species diversity and the health of biomes. Freshwater lakes are important sources of water storage and supply.

Lakes can store large amounts of fresh water, providing an important replenishment of water supplies in nearby areas. Lakes can also balance the supply and demand of water resources by storing water and regulating water flow, helping to solve hydrological problems such as drought and floods.

Fish stocks in freshwater lakes are critical to fisheries and economic development. Fishing in lakes can provide employment and economic income. Fishing communities around lakes often depend on fishing for their livelihoods and support the local economy through the capture and farming of fish.

Freshwater lakes are formed by a variety of factors and processes. The general process of forming a freshwater lake is as follows:

1. Geological structure: The formation of freshwater lakes is usually related to the movement of the earth's crust and geological structure. Geological processes such as uplift, subsidence, fracture, and uplift of the Earth's crust can lead to the formation of lakes. For example, the subsidence of the Earth's crust may form a basin, which then fills with water to form a lake.

2. Rivers and the water cycle: As a river flows through an area, it may form lakes in low-lying places. When a river flows into a low-lying area, the flow slows down and the water accumulates, forming a lake. In addition, evaporation and precipitation during the water cycle can also provide water for lakes.

3. Glaciation: Glaciers are another important factor in the formation of lakes. The water released when glaciers melt can fill low-lying areas, forming glacial lakes. Lakes form when glaciers melt faster than the lake drains.

4. Volcanic activity: When a volcano erupts, the eruption can block rivers or streams, causing water to accumulate to form a volcanic lake. Volcanic activity can also form crater lakes by uplifting the Earth's crust.

5. Human activities: Human activities can also lead to the formation of freshwater lakes. For example, man-made dams and dikes can block rivers and create artificial lakes. These lakes can be used for irrigation, power generation, water supply, or other purposes.

These are some of the common processes and factors that form freshwater lakes. In fact, the mechanisms and conditions under which lakes form are very diverse, and each lake may have its own unique way of forming.

The biodiversity surrounding the freshwater lake is very rich, including plants and animals. Here are some common freshwater lake organisms:

1. Aquatic plants: Various aquatic plants grow in freshwater lakes, such as floating leaf plants (such as lotus and duckweed), submerged plants (such as algae and water onions), and lake bottom plants (such as cattails and rushes). These plants form complex ecosystems in lakes, providing shelter and food sources for other organisms.

2. Plankton: Freshwater lakes are rich in plankton, including phytoplankton (such as algae and planktonic bacteria) and zooplankton (such as planktonic crustaceans and planktonic insects). They are an important part of the lake food chain, providing a food source for many aquatic organisms.

3. Fish: There are all kinds of fish in freshwater lakes, including freshwater fish and migratory fish. There are many types of freshwater fish including carp, trout, eel, salmon, perch, and more. These fish find food and breed in lakes.

4. Aquatic insects: There are a large number of aquatic insects in freshwater lakes, such as water mosquitoes, water beetles, and water fleas. They are an important link in the lake food chain, providing food for many fish and other aquatic animals.

5. Waterfowl: The freshwater lake is the habitat of many waterfowl, such as ducks, swans, cranes, and herons. They depend on the plants and small animals in the lake for food and nest around the lake to reproduce.

In addition, freshwater lakes can accommodate other animals such as turtles, snakes, frogs, aquatic mammals such as beavers and water rats, and terrestrial animals surrounding the lakes such as deer, wild boars, and squirrels.

These organisms form part of the freshwater lake ecosystem, interdependent and interacting to form a complex network of biodiversity.