Answer:Algae bloom occurs when algae either multicellular seaweeds or microscopic blue green algae,become abundant in a body of water and form a floating mass.Normally,algae are autotrophs and make up large proportion of food in the marine habitats and are also producers of oxygen.when the growth of algae becomes excessively,it causes water pollution.the water produces unpleasant odour and colourations due to the algae pigments.they obstruct effective light from penetrating into the occean.the algae blooms produces toxin which may harm fishes and consequently the animals that feed on fishes.
Humans activities causes algae bloom as run off waters from farms and agricultural settings are high in nitrogen and phosphorus ,due to improper use of chemicals and these nutrients promotes algae bloom
