Algae comprise the base of the food web in most stream ecosystems. … Algae can also be harmful. The introduction of nutrients, such as nitrogen and phosphorus, into our waterways can cause algae to grow rapidly, forming algal blooms. Too much algae in a stream, river, or lake can smother fish and other species.

What is the most likely cause of the high levels of algae in the water?

Stagnant water, high temperatures, and excessive nutrients stimulate blue-green algae growth. In summer, when the water warms up, algae can grow and spread really fast. Water reservoirs often lack circulation, therefore the water is stagnant.

What are the main causes of algal blooms?

• Runoff of Nutrients. An algal bloom is mostly caused by the presence of large amounts of nitrogen and phosphorus present in water. …
• High Temperatures. …
• Presence of Dead Organic Matter. …
• Slow-moving Water. …
• Light. …
• Turbidity.