Question

As compared to fresh river water, sea water contains .........

• A. 10% more oxygen
• B. 20% more oxygen
• C. 10% less oxygen
• D. 20% less oxygen

Hint:

Dissolved oxygen decreases with increasing salinity and temperature. Freshwater generally supports more oxygen than seawater at the same temperature and atmospheric pressure.

Answer 1

The Correct Option is D

Dissolved oxygen (DO) is the amount of oxygen that is present in water, and it is crucial for the survival of aquatic organisms. The solubility of oxygen in water depends on several factors, including temperature, pressure, and salinity. Sea water contains a higher concentration of dissolved salts than fresh river water, leading to a reduction in the ability of water to hold gases such as oxygen. This is because the salts in sea water take up space and reduce the solubility of oxygen. As a result, sea water typically contains about 20% less dissolved oxygen compared to fresh water under the same conditions. This reduction in dissolved oxygen has important ecological implications, as marine life must adapt to these lower oxygen levels. This is why many marine organisms have specialized respiratory adaptations to extract oxygen efficiently.