Artificial light at night on the coast of Liguria with light pollution in sea water

Artificial light at night

Two million square kilometres of the world's oceans and 22% of coastlines are exposed to light pollution from offshore infrastructure and coastal towns and cities – together they form artificial skyglow that can expand the impact of light pollution to hundreds of kilometres offshore.
Artificial light at night (ALAN) is of growing concern as a pollutant to our seas. 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.
The impacts of light pollution on the night sky, astronomy and land-based ecosystems are well studied – but until just over 10 years ago, the full extent of ALAN in our coastal waters, seas and oceans was unknown.

Skyglow is the most geographically widespread form of light pollution. Surveys have shown it can currently be detected above 23% of the world's coasts nightly and, with coastal human populations set to at least double by 2060, its effects are only going to increase.

Our results show it is already having demonstrable impacts on biological processes that are guided by celestial light cues. 

Thomas DaviesDr Thomas Davies
Associate Professor of Marine Conservation

Introducing the issue, driving the strategy

Ecologist Dr Thomas Davies, Associate Professor of Marine Conservation at the ̽»¨ÊÓÆµ, 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.
More recently, working in partnership with Professor Tim Smyth at ̽»¨ÊÓÆµ Marine Laboratory, this research is now combining laboratory and field experiments with remote sensing to deliver insights into how changing lightscapes impact marine organisms and ecosystems.
As a co-founder of the UN Ocean Decade endorsed , the University has been instrumental in providing the first central resource for the understanding and managing of marine light pollution through policy technology and behaviour.

Seeing blue

The lighting technologies of the early 20th century impacted the first 10 metres of our oceans. However, with the more recent introduction of blue wavelength LEDs, artificial light can now penetrate below 100 metres.
LEDs make up more than 80% of the global lighting market and, in the UK alone, have been rolled out across coastal cities and offshore infrastructure without consideration of the impacts on the marine environment.
Exponential growth in their use has resulted in more blue wavelength light that penetrates deeper into seawater.

Global Ocean Artificial Light at Night Network (GOALANN)

Endorsed by the United Nations Decade of Ocean Science for Sustainable Development as an Ocean Decade Action.
GOALANN is an international network of the world's leading experts in marine light pollution whose mission is to conserve the oceans by improving knowledge and awareness of marine light pollution, its ecological and societal impacts, and management options.
The initiative unifies research groups from around the world to provide a central resource of marine light pollution expertise, projects and tools for policy makers, environmental managers, maritime industries, the media and the public.
Underwater view of light on water surface

Documenting the impact

In the last decade, over 200 scientific papers have been published documenting the impacts of light pollution on marine species, from fish to coral and from the tropics to the poles.
Marine light pollution has been proven to:
  • Suppress zooplankton migration, which negatively affects the food chain and carbon sequestration;
  • Disrupt coral spawning, which subsequently reduces marine habitats;
  • Upset the 'lunar compass' of coastal species, threatening the health of the sandhopper and the wider ecosystem it supports.
Dr Thomas Davies, Lecturer in Marine Conservation at the UN Ocean Decade Conference in Barcelona 2024
Dr Thomas Davies launches GOALANN at the UN Ocean Decade Conference, Barcelona 2024

Track the progress of our research and engagement

News

A map of the world showing changes in the ocean identified through this project - red areas indicate regions where oceans are getting darker, while blues indicate regions where oceans are getting lighter
Is the ocean getting darker?

New research found 21% of the global ocean experienced a reduction in the depth of its photic zones, home to 90% of all marine life

27 May 2025
 
 

Ocean darkening

Dr Thomas Davies and Professor Tim Smyth at ̽»¨ÊÓÆµ Marine Laboratory are advancing the scientific boundaries of coastal darkening research, evolving toward a globally contextualized understanding of ocean darkening. Their collaboration has evidenced the scale of ocean darkening, and they are now looking at its drivers and ecological impacts.
The implications of ocean darkening for marine ecology and the ecosystem services provided by the surface oceans are currently unknown but likely to be severe.
Dark silty ocean water with a glimpse of light
Applications are currently open for the following PhD studentships:
Drivers and impacts of darkening in the global ocean
Sustainable lighting for coastal cities

For more information on our marine light pollution research, please contact Dr Thomas Davies .