The impact of artificial light on arctic marine organisms and ecosystems during the polar night

At any given moment, half of the Earth’s surface is in darkness. While darkness prevails, biological processes regulated by the sun have generally been assumed to cease. But darkness is also the preferred ‘habitat’ for the many nocturnal organisms that remain active at night. For many of these, the moon, stars and aurora borealis may provide important cues to guide behaviours and interaction with other organisms. This is not the least true for the Arctic polar night. Unfortunately, with a changing climate and increased human activities in the Arctic, these natural light sources will in many places be more or less invisible due to the much stronger illumination from artificial light. This project will explore the potential effects of artificial light on organisms that remain active in one of the last undisturbed and pristine dark habitats on the planet – the Arctic polar night. The project include a wide use of autonomous platforms that can be operated without artificial light. One of the key tasks have been to carry out experiments regarding how fish and zooplankton are affected by light of different colours and intensity. Results sop for indicate that all colours, including red, is having a great effect.

Recent advances in the study of Arctic marine ecosystems have caused a radical shift regarding how we perceive their seasonality and function. Instead of an ecosystem that enters a resting state during the polar night, we now recognize a system in which most trophic levels and taxonomic groups remain active. And importantly, a system for which light, even at the dead of night, is the regulative factor. In such a system where organisms remain active and are adapted to detect and respond to extremely low levels of natural light, we hypothesize that their susceptibility towards light pollution is likely to be high. With a continued warming and reduction of Arctic sea ice, human presence in the region is likely to increase. Inevitably, so will light pollution. Moreover, we have carried out a pilot study in the Arctic polar night which showed that the entire pelagic community - fish and zooplankton, alike – avoid the faint light from a research vessel down to at least 200m depth. This has triggered new and innovative hypotheses and research questions that form the foundation of Deep Impact: Can we reliably carry out biological surveys in the dark from vessels illuminated by artificial light? A quantification and assessment of the potential bias introduced from a lit-ship on any measurement, sampling, bio-acoustical surveys and stock assessments of commercial and non-commercial species, holds great potential for providing ground-breaking discoveries relevant for the Arctic region itself and beyond. The Arctic polar night, however, provides the perfect test site from which this may be tested. As such, Deep Impact is highly relevant for the call: (1) it focus on the influence on polar marine ecosystems from the combined effects of climate change and increased human activity, (2) it is based on new and innovative hypotheses and (3) it utilizes the natural advantages of working in Svalbard while at the same time exploring the relevance for lower latitudes.