Why do algal blooms form and what do they ultimately cause?

Algae Blooms

Explanation:

Algae bloom is a rapid accumulation proteins and amino acids that creates the generation of algae in freshwater or marine water ecosystem as a result the discoloration of the water takes place. The blooming can influence animals and sea creatures in harmful ways as they tend to block the sunlight and deplete the oxygen levels and excessive blooming can be seen as an example of Red tides caused by pigmented algae.

answer; (d) melting of sea ice;