Artificial light at night not only alters the landscape, but also profoundly disrupts natural ecosystems. A recent study by the RPTU University Kaiserslautern-Landau shows that light pollution can significantly disrupt the exchange of energy and nutrients between bodies of water and their surrounding habitats—sometimes even more than non-native species. Thus, lighting along riverbanks or streams can have far-reaching ecological consequences. These results are published in Functional Ecology.