Electric lights cause coral ecosystems to lose their day-night rhythms

Light pollution of corals affects their reproduction

Coral reefs are made up of marine organisms which reproduce externally by releasing their reproductive cells, namely sperm and eggs, into the water at the same time. The reproductive process is dependent upon the natural rhythms of daytime and night-time and other environmental and biological factors which allows the process to be synchronised.

Light pollution of corals affects their reproduction

Light pollution of corals affects their reproduction. Picture in public domain.

Coral reefs next to coastal regions are subject to electric light from buildings, roadways and other human-made constructions. These artificial light sources are often on all night which negatively impacts the marine organisms of coral reefs, which in turn affects their reproduction.

It is another area of interference by humans of the environment and wildlife in the environment. We know that global warming is bleaching coral reefs such as the Great Barrier Reef, which is being severely damaged and now we have this secondary, negative impact.

The research was done by transporting a piece of naturally occurring coral reef into the laboratory where part of it was exposed to artificial light while exposing another part, the control, to natural daytime and night-time only.

Both key coral species were affected by light pollution. Only corals exposed to natural light cycle succeeded in spawning synchronisation. Prof Levy.

The findings were published in the Current Biology journal. As the human population grows including at coastal regions the damage done to coral reefs will get worse. It is possible, however, that some corals may be resistant to light pollution.