The role of dissolved oxygen in water

Posted by Binda on May 17th, 2024

The role of dissolved oxygen in water is mainly in the following aspects:

Maintaining the survival of aquatic organisms

Dissolved oxygen in water is necessary for the survival of aquatic organisms such as fish and other aquatic animals. They maintain life by breathing dissolved oxygen in water through their gills.

Promoting self-purification of water bodies

In the natural environment, microorganisms in the water body purify the water by utilizing dissolved oxygen for biochemical decomposition, converting organic matter and nutrients into simple inorganic substances.

Affecting the quality of water bodies

The level of dissolved oxygen is an important indicator of the self-purification capacity of a water body and an important parameter for evaluating water quality. Low dissolved oxygen levels usually mean that the water body is polluted or has a reduced self-purification capacity.

Promote plant growth

Plants in water produce dissolved oxygen through photosynthesis, and an increase in dissolved oxygen facilitates plant growth and reproduction.

Affects industrial processes

In industry, dissolved oxygen is used in oxidative reactions such as redox and photochemical reactions, which play an important role in the production and use of chemicals.

Medical Applications

In the medical field, dissolved oxygen is used in the treatment of various diseases such as hypoxia and altitude sickness.

In addition, the content of dissolved oxygen has an important influence on the ecological balance of water bodies, aquaculture and the quality of drinking water. For example, in aquaculture, dissolved oxygen levels need to be maintained at a certain level to support the growth and health of aquatic organisms. In drinking water treatment, maintaining proper DO levels is essential to ensure safe and palatable water quality.

Determination of dissolved oxygen

Determination methods

Dissolved oxygen in water can be determined by chemical or instrumental methods. The classical chemical method is iodometric method, which is highly accurate and is also used to check the reliability of other methods. The iodometric method requires the preparation of a variety of reagent solutions, and the measurement steps are cumbersome and time-consuming, so it is mostly used in the laboratory, and is inconvenient to be applied in the actual aquaculture production conditions.

Instrumental method is a simple operation, reliable results of the rapid determination method. Breeding site can use portable dissolved oxygen meter, as long as the dissolved oxygen probe placed in the water body to be measured and gently shake, the results will soon be displayed in the form of digital. However, as the degree of intensification of farming and management level rises, it can be expected that in the near future, portable dissolved oxygen meter will become the main measurement instrument on the farm site.

Measuring time and frequency

Before the middle period of the general determination of 2 times can be, the determination of time to choose the early morning or evening, so that you can know the lowest and highest dissolved oxygen level in the pond in a day, to help determine whether the dissolved oxygen in the water body is in the appropriate range, in particular, to help prevent the "flood pond" and other serious hypoxia events, the late period of time to choose the determination of time in the early morning, evening, as well as Midnight. For ponds that have just been treated with disinfection, algaecide and aerobic microbial amendments, and ponds with frequent DO problems, the frequency of measurements should be increased as much as possible.

Measurement location

Measurements should be made at representative locations, and the results should reflect the dissolved oxygen status of the environment in which most of the farmed animals are located, so it is not advisable to make measurements only at the surface of the water or near the oxygenator. In any case, the measurement of dissolved oxygen at the bottom of the central pool is a very useful reference for understanding the dissolved oxygen status of the water body and taking corresponding measures.

Oxygenation measures

In aquaculture production, dissolved oxygen management is essentially through the adoption of a variety of direct or indirect measures to increase oxygen, not only to ensure that breeding animals in a good dissolved oxygen environment, to achieve the best production efficiency, but also not to over-oxygenation leading to waste of costs. In terms of the whole breeding process and link, it can be started from the following aspects.