Abstract
Humans first began using artificial light at night (ALAN) during the industrialrevolution 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 clock that most organisms use for their timings of foraging, reproduction, and sleep. Whether all intertidal organisms possess phenotypic plasticity to effectively adapt to increasing and changing artificial light pollution is not yet known, but ideas are suggested in this thesis. I begin by summarising the published research that has investigated the biological effects of light pollution among many different species, from marine to terrestrial, including some novel thoughts on polarised light pollution. Following this, behavioural experiments, and movement analysis of shore crabs, Carcinus maenas, have shown that exposure to ALAN increases their activity levels and disrupts their circadian rhythms, with no evidence of short-term adaptation. This has consequences for organism fitness by increasing stress and causing the animals to become more vulnerable to environmental stimuli, such as predation, and altering the timing of important behaviours such as mating which may have negative consequences on population size. Mitigation strategies, such as changing the spectra of artificial light sources via coloured filters, and important areas of future work are discussed.
| Date of Award | 2 Dec 2021 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Martin J How (Supervisor) & Andy Wakefield (Supervisor) |