Chinese sturgeon is on the verge of extinction. The principle of artificial propagation of ACIPENSER sinensis fry by using the ecological culture pond of ACIPENSER sinensis is as follows: the ammonia nitrogen produced by ACIPENSER sinensis is absorbed by plants; plant (1) According to the meaning of the question, "the ammonia nitrogen produced by sturgeon is absorbed by plants; Oxygen released by plants forms an "oxygen bar" in a closed workshop for sturgeon to survive; It shows that the products produced by one organism can be used by other organisms, and the ecosystem follows the principle of material circulation. The ecological culture pond of Chinese sturgeon only needs a small amount of evaporation water every day, without changing water. The bottom of the pond is clean, and all creatures live normally without artificial evolution, which shows that the ecosystem has the ability of self-regulation.

(2) Silver carp mainly eats zooplankton such as rotifers and copepods, saying that silver carp is a consumer; As can be seen from the picture, Hualien can use the feces of Chinese sturgeon, and Hualien is the decomposer.

(3) Because producers have photosynthesis, consumers at all levels have respiration and microorganisms have decomposition, the diagram can be expressed as:

(4) Biological information transmission is divided into physical information, chemical information and behavioral information. External factors such as water temperature and salinity belong to physical information. It provides and improves the living environment of Chinese sturgeon, and makes the population growth optimal, so the population cannot exceed the environmental capacity. From the ecological point of view, the Chinese sturgeon is on the verge of extinction. Protecting the Chinese sturgeon now reflects the protection of biodiversity.

So the answer is:

(1) Material recovery? homemade

(2) Consumers and decomposers

(3)

(4) Physical information? Environmental capacity (quantity)? biodiversity