This causes microscopic algae and cyanobacteria to bloom, and then animals eat the phytoplankton.

With the canopy gone, sunlight causes algae to grow, which feeds insects.

Interrupting the carbon dioxide supply can cause algae to flocculate on its own, which is called "autoflocculation".

As the land around the springs developed, fertilizer and septic tank runoff carrying nitrate polution has caused brown algae to cloud the springs, reducing visibility and fish populations.

An algae scrubber filters water by moving water rapidly over a rough, highly illuminated surface, which causes algae to start growing in large amounts.

This was causing unwanted algae to grow and destroying the bass fishing for which the lake was noted.

Water gets polluted by nitrogen and phosphorus which causes algae to grow proliferously causing the oxygen concentrations to decline rapidly, life is no longer supported in this habitat.

Therefore, even low concentrations of nutrients can cause plant life and algae to grow quickly, obscuring the sunlight needed for their growth, leading to a loss of oxygen in the water.

In excessive quantities phosphorus acts as a fertilizer and causes algae to flourish or "bloom".

Plus pet waste can cause algae and weeds.