Artificial light at night is a destructive form of pollution that can affect the physiological and behavioral processes of animals and plants, and can expand to the group level. Evidence from terrestrial habitats shows that its severity and type depend on the wavelength and intensity of artificial light at night. However, little is known about the impact of artificial light on marine life.
To protect wild animals, some people suggest using green or red lights instead of white lights in coastal areas. But new experiments show that exposure to red or green light at night will promote the growth of some marine algae, including some species that are known to steal oxygen from the water.
Many brightly lit cities are located in coastal areas. What effect does artificial light have on marine life? To answer this question, Sofie Spatharis and colleagues at the University of Glasgow in the UK placed a mixture of micro-marine algae collected from Scottish waters under standard white light. They also exposed the mixture to red and green lights, which have been proposed to reduce the impact on sea turtles and migratory seabirds, respectively.
In a report recently published in the British “Proceedings of the Royal Society B”, the research team found that all colors of light can promote the growth of a mixture of microalgae. The effect of red light is the most significant, doubling the number of cells produced. The proportion of species in the algae mixture has also changed: both red and green light are particularly conducive to the growth of harmful species, and they can form blooms that are fatal to fish.
According to the author, it can be seen that the use of green and red light in coastal areas should be treated with caution in order to balance the effects of red and green light on marine primary producers and other organisms.