How Does Temperature Affect Dissolved Oxygen?

Writer： admin Time：2023-12-21 10:05:11 Browse：673℃

What is Dissolved Oxygen (DO)？

Dissolved oxygen (DO) refers to oxygen content in water, which aquatic organisms rely on for survival. This free oxygen, not bonded to other elements, is crucial for the respiration of fish, invertebrates, and microorganisms living in water.

Why is Dissolved Oxygen So Important?

Aquatic Respiration: Just as land animals need oxygen in the air to breathe, aquatic organisms extract this dissolved oxygen from the water. Low levels can lead to stress or even fatalities in these organisms.

Ecosystem Indicator: The level of dissolved oxygen is a vital parameter of water quality. High DO levels generally signify healthy water bodies, while low levels can indicate pollution, excessive organic decay, or eutrophication.

Wastewater and Drinking Water: In industries like wastewater treatment and drinking water purification, monitoring dissolved oxygen helps ensure that treatment processes are effective and that the water meets safety standards.

Sources of Dissolved Oxygen

They are two main sources of dissolved oxygen in water: Atmospheric Diffusion and Photosynthesis by Aquatic Plants.

Atmospheric Diffusion

The air surrounding us is composed of about 21% oxygen, which gradually seeps into the water through a process called diffusion. This happens when oxygen molecules move from the air into the water, balancing the concentration on both sides.

Natural Aeration: This occurs through wind action, which helps mix the air and water, enhancing oxygen diffusion.

Human-Induced Aeration: Practices such as using waterwheels, pumps, and dams can also increase the amount of oxygen that penetrates the water.

Photosynthesis by Aquatic Plants

Aquatic plants, including phytoplankton and algae, play a pivotal role in oxygenating water. Through photosynthesis, these plants convert sunlight into energy, releasing oxygen as a byproduct. This oxygen dissolves directly into the water, adding to its overall oxygen content.

However, this dissolved oxygen doesn't stay indefinitely. It's consumed through processes like:

Chemical Oxidation: Interactions involving dissolved substances in the water.

Respiration: Conducted by fish and other aquatic organisms.

Decomposition: Breakdown of organic materials, which uses up oxygen.

Factors affecting dissolved oxygen (DO) in water

The amount of dissolved oxygen in water is related to both the partial pressure of oxygen in the air and the temperature of the water.

① Barometric pressure. The relationship between dissolved oxygen and barometric pressure is directly proportional. So how do you go about determining barometric pressure? Do you read the weather forecast every day? Of course not, it is not that troublesome to judge the barometric pressure. The simplest way is when we feel very boring weather, that is, low air pressure, the pond is easy to lack of oxygen, we should pay attention to the oxygen, open the aerator.

② Temperature and salinity. Dissolved oxygen is inversely proportional to these two factors, the lower the water temperature, the higher the content of dissolved oxygen in the water. The higher the salinity, the lower the content of dissolved oxygen in the water. Freshwater generally has higher dissolved oxygen than seawater.

③ Sunlight. The level of dissolved oxygen is directly proportional to the intensity of sunlight (within a certain intensity range), mainly because the stronger the sunlight, the more oxygen produced by photosynthesis.

④ Breeding density. Dissolved oxygen is inversely proportional to culture density. If the breeding density of a pond is too high, the more serious the oxygen depletion is, the less dissolved oxygen will be in the pond relatively speaking.

⑤ Transparency. Dissolved oxygen is inversely proportional to transparency (within a relative range).

⑥ Substrate (organic matter). Dissolved oxygen is inversely proportional to organic matter. If there is too much organic matter in the pond, the more severe the oxygen depletion. The lower the relative DO content.

How Does Temperature Affect Dissolved Oxygen?

How to Measure Temperature and Dissolved Oxygen in Water?

To Measure Dissolved Oxygen (DO)

Usually, we use optical dissolved oxygen probes to detect the dissolved oxygen content in water. Yosemitech Optical Do Sensors use high-efficiency fluorescent membranes, don't consume oxygen, no flow limit. Built-in temperature sensors, automatic temperature compensation. It has excellent accuracy and stability.

https://e.yosemitech.com/DO/Y504-A.html

To Measure Temperature?

Temperature sensors are recommended to accurately measure temperature levels in the water. Temperature probes work by providing readings via electrical signals.