The natural sources of water pollution are algae blooms.
Answer: Option C
Explanation:
The natural form of water pollution is due to water erosion, the composition of minerals, leaves, human/animal droppings, etc. Algae blooms are the development of phytoplankton (a tiny floating plants in fresh and salt water).
Algae bloom also causes problems in the aquatic ecosystem. The excessive algae can block sun rays and hence affect important aquatic habitats.
This can also be seen in the fish gills and inhibit their breathing. When a significant bloom of algae dies, they can damage the available oxygen in the water and make it uninhabitable for other life forms.