The Biological Effects of Light Pollution on Terrestrial and Marine Organisms

Humans first began using artificial light at night (ALAN) during the industrial revolution and sources of light have diversified and intensified considerably over the last century. Light pollution has previously been defined under two separate branches,“ecological light pollution” where the natural light patterns are altered in marine and terrestrial environments, and “astronomical light pollution” where the view of the night sky is reduced. Natural light is vital for the regulation of animal behaviour and interactions. Surprisingly, this environmental stressor did not become a worldwide concern until 2009. Since then, research into this subject has substantially increased, with studies highlighting the detrimental effects of ALAN. These effects can be serious for many organisms and include the disruption of the essential circadian rhythms that most organisms use to time important behaviours such as foraging, reproduction, and sleep. Whether all organisms possess phenotypic plasticity to effectively adapt to increasing and changing artificial light pollution is not yet known. Here, we summarise the effects of light pollution among many different species, from marine to terrestrial, with a focus on the areas that require further research to enhance our knowledge of this subject. The aim of this review is to raise awareness and enhance understanding about this little-discussed environmental concern, including some novel ideas on camouflage and polarised light pollution, hopefully encouraging future research into the effects of light pollution on organism behaviour.