Autotrophic organism: a kind of nutrition with carbon dioxide in the atmosphere or carbonate in the environment as carbon nutrition.

For example, green plants and a few bacteria are autotrophic, and they can synthesize simple inorganic carbon dioxide or carbonate into complex organic matter for life activities.

Autotrophic organisms can be divided into: photoautotrophic and chemoautotrophic.

Photoautotrophic organisms: cells contain photosynthetic pigments, which can convert sunlight energy into chemical energy and supply life activities.

Chemotactic autotrophs: obtain energy by oxidizing some inorganic substances, such as nitrifying bacteria and ammonia oxides (NH3); Sulfurized bacteria obtain energy through sulfur oxide or hydrogen sulfide (H2S).

Heterotrophs: You can't synthesize inorganic substances into organic substances by yourself. You can only maintain your metabolism by ingesting organic substances.

The fundamental difference between autotrophs and heterotrophs lies in whether inorganic matter can synthesize organic matter by itself.

Extended data

Nitrification use

Nitrifying bacteria preparation is a kind of treatment agent used to control the concentration of autogenous ammonia in aquaculture pond water. It is not only convenient to use, but also immediate, so it is more and more popular among fish friends. When in use, the agent can be directly dispersed in the pool, and the effect of ammonia removal can be quickly exerted.

Commercial nitrobacteria preparations can be divided into living bacteria and dormant bacteria, and fishermen can choose to use them according to their own needs. The former is made of living bacteria, and their activities can be seen under the microscope. The latter is made of dormant bacteria, but they can't be seen under the microscope.

The advantage of selecting live bacteria is that the ammonia removal effect is fast, which is most suitable for emergency situations with high ammonia concentration.

However, living bacteria have strict requirements for oxygen, especially nitrifying bacteria, which can only survive under the condition of sufficient oxygen, so it is often difficult to preserve living bacteria and make products. Therefore, when buying such products, we should pay special attention to their effective service life. If we use expired products, it is inefficient from the point of view of ammonia removal.

The advantage of choosing dormant bacteria is that they can be preserved for a long time without worrying about failure. However, because the activation time from dormant bacteria to live bacteria may take several days, it can not be used for emergency treatment, but only for daily water quality management.

Generally speaking, the shelf life of dormant bacteria is about 1 ~ 2 years, so we should still pay attention to the service life marked on the goods to avoid expiration. In addition, this product can only be made into preparations by bacteria belonging to nitrite genus, so after use, there may be redundant intermediate no2- accumulated in water, which makes the concentration of nitrite suddenly increase temporarily, but it will not have obvious influence on water quality.

Baidu Encyclopedia: Nitrifying Bacteria