Question

With the rising water temperature, dissolved oxygen
(a) Remain unchanged
(b) Increase in amount (c) Decrease in the amount
(d) Is more available to aquatic organisms.

Answer 1

In cold water, the water molecules are close together, which means they are more tightly packed, they have lower kinetic energy and therefore less space for movement between molecules which makes it harder for the oxygen to escape.

Complete step by step answer:
Oxygen naturally dissolves in water when comes in contact and its solubility is strongly dependent and decreases at a higher temperature. Temperature affects the dissolved oxygen in the water in two ways: - Diffusion through a membrane
- The ability of water to dissolve oxygen
Thus, warmer water cannot dissolve as much oxygen as colder water.
So, the correct answer is, ‘decrease in amount.’

Additional information:
- Dissolved oxygen refers to the level of free, non- compound oxygen present in the water or other liquid. It is an important parameter of its influence on the organism living within a body of water.
- Importance of dissolved oxygen:
It is necessary for many aquatic animals as they use oxygen in respiration.
The microbes and fungi also require dissolved oxygen to decompose organic material at the bottom of the body of water.
- Uses of dissolved oxygen analysis:
Determine the health or cleanliness of a lake or stream.
Determine the amount and type of biomass a freshwater system can support.
Determine the amount of decomposition occurring in the lake or stream.

Note: Different methods of analysis of dissolved oxygen:
Optical sensor method
Electrochemical dissolved oxygen sensor
Colorimetric method
Titrimetric method
- Factor affect dissolved oxygen in water:
Temperature
Salinity
Barometric pressure