Does the body/biological clock help with sleep stages?

YES

Explanation:

Understanding your body's internal clock—or circadian rhythm—is the first step to better sleep. Your circadian rhythm (also known as your sleep/wake cycle or body clock) is a natural, internal system that's designed to regulate feelings of sleepiness and wakefulness over a 24-hour period.

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.