Which two water characteristics are inversely related to dissolved oxygen levels?

Which two water characteristics are inversely related to dissolved oxygen levels?

• A. Temperature
• B. Salinity
• C. Temperature and salinity
• D. pH

Answer: (C)

Dissolved oxygen is governed by how much gas water can hold under given conditions, which is strongly affected by temperature and salinity. Warmer water cannot hold as much oxygen, so DO levels drop as temperature rises. Likewise, higher salinity makes water less capable of keeping dissolved oxygen, so increasing salt content lowers DO even at the same temperature. Because both factors push DO in the opposite direction, they are the two water characteristics inversely related to dissolved oxygen. pH doesn’t have a direct, consistent inverse relationship with DO in the same way.

Dissolved oxygen is governed by how much gas water can hold under given conditions, which is strongly affected by temperature and salinity. Warmer water cannot hold as much oxygen, so DO levels drop as temperature rises. Likewise, higher salinity makes water less capable of keeping dissolved oxygen, so increasing salt content lowers DO even at the same temperature. Because both factors push DO in the opposite direction, they are the two water characteristics inversely related to dissolved oxygen. pH doesn’t have a direct, consistent inverse relationship with DO in the same way.