Like humans, many marine organisms depend on light for essential life functions. Light provides critical environmental cues, for example guiding zooplankton diel vertical migration and supporting fundamental biological processes such as photosynthesis.
However, marine light environments are increasingly being altered by human activities. Artificial Light At Night (ALAN), generated by growing marine industries such as fishing, shipping, and offshore infrastructures, can disrupt natural light cycles and therefore potentially affect marine ecosystems. At the same time, marine lightscapes are also changing through Ocean Darkening. This process causes the water column to become less transparent due to land run-off, eutrophication, and other effects related to climate change and anthropogenic activities.
Illumination and darkening are reshaping marine lightscapes in different ways, but both can impact marine life and ecosystem functioning. The ISOLUME and ALANIS projects aim to deepen scientific understanding of the underlying processes and ensuing ecological impacts.
Despite pollution being a well-established topic in both scientific research and policy frameworks, underwater light pollution still lacks adequate recognition. Marine lightscapes are just emerging as a field of research, with many fundamental concepts and definitions still under development.
Oliver Zielinski, former project coordinator of ISOLUME, further highlighted this challenge in an interview with Nature Reviews Earth & Environment. He explained that the field is still lacking fundamental understanding and structured frameworks, including a clear definition of the concept of ‘Changing Marine Lightscapes’ itself.
To showcase their progress and put lightscapes on the map, both projects presented their work at the Ocean Science Meeting 2026 in Glasgow, Scotland, where ISOLUME coordinator Dr. Bronwyn Cahil co-chaired a session on the topic.
Parallel to advancing scientific knowledge, the Changing Marine Lightscapes Joint Action is contributing to strengthening policy frameworks. Due to the current lack of comprehensive regulatory structures, ALANIS and ISOLUME experts have provided policy recommendations, in tandem response with the JPI Oceans Underwater Noise Joint Action to the European Commission’s Call for Evidence for the revision of the Marine Strategy Framework Directive (MSFD).
Descriptor 11 of the MSFD recognises marine light pollution as an energy-based pressure; however, it currently lacks clear monitoring criteria. The project experts recommend strengthening the recognition of light changes as an environmental pressure and supporting the development of monitoring and mitigation strategies for both ALAN and Ocean Darkening. In addition, both projects have been endorsed by the Mission Restore our Ocean and Waters as contributions to the Mission’s objective of protecting and restoring marine ecosystems.
With growing scientific collaboration, increasing policy attention, and strong engagement from the research community, the efforts to understand and mitigate changes in marine lightscapes are increasing and the topic is gaining momentum.
With their work funded by JPI Oceans, ISOLUME and ALANIS are helping to bring marine lightscapes into the spotlight and ensure that this emerging environmental pressure receives the scientific and policy attention it deserves.