TY - JOUR A1 - Fonvielle, Jeremy A1 - Bistarelli, Lukas Thuile A1 - Tao, Yile A1 - Woodhouse, Jason N. A1 - Shatwell, Tom A1 - Villalba, Luis A. A1 - Berger, Stella A. A1 - Kyba, Christopher C. M. A1 - Nejstgaard, Jens C. A1 - Jechow, Andreas A1 - Kupprat, Franziska A1 - Stephan, Susanne A1 - Walles, Tim J. W. A1 - Wollrab, Sabine A1 - Hoelker, Franz A1 - Dittmar, Thorsten A1 - Gessner, Mark O. A1 - Singer, Gabriel A. A1 - Grossart, Hans-Peter T1 - Skyglow increases cyanobacteria abundance and organic matter cycling in lakes JF - Water Research N2 - Artificial light propagating towards the night sky can be scattered back to Earth and reach ecosystems tens of kilometres away from the original light source. This phenomenon is known as artificial skyglow. Its consequences on freshwaters are largely unknown. In a large-scale lake enclosure experiment, we found that skyglow at levels of 0.06 and 6 lux increased the abundance of anoxygenic aerobic phototrophs and cyanobacteria by 32 (+/- 22) times. An ecosystem metabolome analysis revealed that skyglow increased the production of algal-derived metabolites, which appeared to stimulate heterotrophic activities as well. Furthermore, we found evidence that skyglow decreased the number of bacteria-bacteria interactions. Effects of skyglow were more pronounced at night, suggesting that responses to skyglow can occur on short time scales. Overall, our results call for considering skyglow as a reality of increasing importance for microbial communities and carbon cycling in lake ecosystems. Y1 - 2025 U6 - https://doi.org/10.1016/j.watres.2025.123315 SP - 1 EP - 11 PB - Elsevier ER -