Simply Science 02
A green scum on the surface of a body of water is often due to an overgrowth of algae. Algae are simple, photosynthetic organisms that can thrive in aquatic environments under certain conditions.
Algae need nutrients to grow, mainly nitrogen and phosphorus. If there is an excess of these nutrients, often due to agricultural runoff, sewage discharge, or the use of fertilizers in the surrounding area, it can promote algae growth.
Algae thrive in warm water, so if your reservoir is experiencing higher-than-usual temperatures, it can encourage algae growth.
Lack of water circulation can create stagnant conditions that favour algae growth. Reservoirs with low water turnover rates are more susceptible to this issue.
Algae photosynthesise and require sunlight to grow. If your reservoir receives ample sunlight, it can encourage algae to flourish on the surface.
Pollution from various sources, such as industrial discharges, sewage, or agricultural runoff from surrounding farmland, can introduce chemicals into the water that promote algae blooms.
Consumers of algae, such as zooplankton and certain fish species, can help keep algae populations in check. If these organisms are absent, algae can multiply rapidly.
The overgrowth of algae can not only be unsightly but can also have very negative ecological consequences. Some types of algae, for example, can produce toxins that are harmful to aquatic life and can affect the water's quality.