FAQ

How Does Temperature Affect Dissolved Oxygen?

Writer： admin Time：2023-12-21 10:05:11 Browse：171℃

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.

Factors affecting dissolved oxygen (DO) in 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?

Saturated dissolved oxygen concentration in water and its corresponding temperature
temperature		DO（ppm or mg/L）	temperature		DO（ppm or mg/L）
℉	℃	DO（ppm or mg/L）	℉	℃	DO（ppm or mg/L）
32	0	14.6	74	23.3	8.5
34	1.1	14.1	76	24.4	8.3
36	2.2	13.7	78	25.6	8.2
38	3.3	13.3	80	26.7	8.0
40	4.4	12.9	82	27.8	7.8
42	5.6	12.2	84	28.9	7.7
44	6.7	11.9	86	30	7.5
46	7.8	11.6	88	31.1	7.4
48	8.9	11.3	90	32.2	7.3
50	10	11.0	92	33.3	7.1
52	11.1	10.7	94	34.4	7.0
54	12.2	10.4	96	35.6	6.9
56	13.3	10.2	98	36.7	6.8
58	14.4	9.9	100	37.8	6.6
60	15.6	9.7	102	38.9	6.5
62	16.7	9.5	104	40	6.4
64	17.8	9.3	106	41.1	6.3
66	18.9	9.1	108	42.2	6.2
68	20	8.9	110	43.3	6.1
70	21.1	8.7	112	44.4	6.0
72	22.2		114	45.6	5.9

Dissolved oxygen in water at standard atmospheric pressure as a function of temperature and salinity (dissolved oxygen mg/L)
Temp (℃)	Salinity
Temp (℃)	0	5	10	15	20	25	30	35	40
20	9.1	8.8	8.7	8.3	8.1	7.9	7.7	7.4	7.2
22	8.7	8.5	8.2	8	7.8	7.6	7.3	7.1	6.9
24	8.4	8.1	7.9	7.7	7.5	7.3	7.1	6.9	6.7
26	8.1	7.8	7.6	7.4	7.2	7	6.8	6.6	6.4
28	7.8	7.6	7.4	7.2	7	6.8	6.6	6.4	6.2
30	7.5	7.3	7.1	6.9	6.7	6.5	6.3	6.2	6
32	7.3	7.1	6.8	6.7	6.5	6.3	6.1	6	5.8
34	7.0	6.8	6.6	6.4	6.3	6.1	5.9	5.8	5.6
36	6.8	6.6	6.4	6.2	6.1	5.8	5.7	5.6	5.4
38	6.5	6.3	6.2	6	5.8	5.7	5.5	5.4	5.2
40	6.3	6.2	5.9	5.8	5.6	5.7	5.3	5.2	5