Question

What happens in an algal bloom? Why are they harmful?

Answer 1

Harmful effects. As algal blooms grow, they deplete the oxygen in the water and block sunlight from reaching fish and plants. ... And when the algae eventually die off, the microbes which decompose the dead algae use up even more oxygen, which in turn causes more fish to die or leave the area.

Answer 2

As algal blooms grow the deplete oxygen in the water and block out sunlight from fish and plants. When the algae die off, the microbes which decompose the dead algae use up even more oxygen which make the fish die or leave that area.

Step-by-step explanation: