Ecologist Dr Thomas Davies from the University of Plymouth has been driving the strategy for marine light pollution research and mobilising policy action since he published the first paper on the topic in 2014. He co-founded the Global Ocean Artificial Light at Night Network (GOALANN), endorsed by the United Nations Ocean Decade of Ocean Science for Sustainable Development as an Ocean Decade Action.
Now, Dr Davies reflects on the challenges of tackling artificial light at night in our coastal and marine waters, and what action is needed from policy makers, industry and coastal communities to ensure the future health of our seas.
Navigating the challenges of marine light pollution
By Dr Thomas Davies, Associate Professor of Marine Conservation
It has long been understood that artificial light at night (ALAN) has a negative impact on insects, birds and mammals, and also interferes with our own sleep and circadian rhythms. Many of us watched the plight of the hawksbill turtle hatchlings on Sir David Attenborough’s Planet Earth II who instead of using the moon as their compass to find safety in the sea, moved towards the bright light of the coastal town. In terms of the impact on marine and coastal life, what we saw on the Barbadian beach on Planet Earth II is just a drop in the ocean…
ALAN is a growing concern as a pollutant to our seas and threatens coastal marine systems. It disrupts the natural patterns and biological processes of marine life, including those that support critical ecosystem services. This includes animals’ ability to see their environment – to hunt, hide, communicate, navigate, grow, time important events and reproduce.
Almost a third of UK coastlines are exposed to light pollution from coastal towns, cities and offshore infrastructure, and together they form artificial skyglow that can expand the impact of light pollution to hundreds of kilometres offshore.
Seeing blue
The lighting technologies of the early 20th century impacted the first ten metres of our oceans. However, with the exponential rise in the use of energy-efficient LED lighting – seen as environmentally friendly – more blue light is actually entering our oceans. And this blue light can penetrate below 100 metres!
With coastal human populations set to at least double by 2060, its effects are only going to increase.
Only in the last ten years has our understanding of marine light pollution developed. Now, over 200 scientific papers document the impacts of light pollution on marine species, from fish to coral, from the tropics to the poles.
At the University of Plymouth, our evidence has demonstrated that it can suppress zooplankton migration, which effects the delicate food change and carbon sequestration. It disrupts coral spawning that reduces marine habitats and upsets the ‘lunar compass’ of coastal species, threatening the sandhopper and the vital ecosystem it supports.
The need for policy action
Light emissions into the sea are unregulated by our national policy – there is currently no UK legislation that aims to set the criteria for Good Environmental Status of light pollution at sea.
We recommend that light pollution is both considered under descriptor 11 of the UK marine strategy, and a legal requirement to consider and mitigate for the ecological impacts of light pollution on the marine environment in offshore and onshore planning processes.
As policy makers, local councils, industry, and communities alike, when looking into lighting our coastal towns, cities and offshore infrastructure, the very health of our seas depends on how we answer the following questions.
- Is the light necessary or for purely aesthetic purposes?
- How much light is needed?
- Where is the light needed?
- Can the colour of lights be tailored to reduce ecological impacts?
Dr Thomas Davies will be attending the upcoming Coastal Futures 2025 conference on 29–30 January. Visit the University of Plymouth stand at the conference to find out more about our research on marine light pollution.