What happens to the amount of dissolved oxygen in waterways due to pollution?

The amount of dissolved oxygen in waterways typically lessens due to pollution. This reduction occurs because various pollutants, such as organic matter, nutrients, and chemicals, can lead to increased biological activity in the water. When organic matter decomposes, microorganisms consume oxygen in the process, leading to a decrease in the levels of dissolved oxygen available for aquatic life. Additionally, pollution can produce substances that create harmful conditions, further depleting oxygen levels.

Maintaining optimal dissolved oxygen levels is crucial for the survival of fish and other aquatic organisms, as they rely on this oxygen for respiration. When pollution enters a waterway, the delicate balance of the ecosystem shifts, ultimately harming the biodiversity and health of the aquatic environment.