Effects of artificial light at night (ALAN) In Chironomus riparius

• Autor(a) principal: Silva, Bruna Soares da
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/35667
• topic: Light pollution; Circadian rhythms; Melatonin; Aquatic insects; Life cycle; Physiology; Urbanization

Ever since the invention of light, our society was changed, and alterations on light intensity and spectrum patterns were observed. Artificial light at night (ALAN) is considered an emergent anthropogenic pressure, linked to urbanization, that is affecting biodiversity. It is reported that ALAN has the capacity to interfere with the circadian rhythms and to suppress melatonin synthesis, leading to behavioral and physiological changes in organisms exposed this stressor. Effects of ALAN in terrestrial and marine ecosystems have been documented in the last years, however freshwater systems and freshwater species remain understudied. Therefore, and aiming to better understand what happens in freshwater systems, Chironomus riparius larvae were exposed to two light intensities (1 and 10 lux, during nighttime using LED lamps), and one exogenous melatonin concentration (1 μM) to assess possible effects on lifehistory traits and on biochemical endpoints. Results showed that exposure to ALAN induced a delay in emergence for C. riparius, and a reduction in size of male imagoes. Short-term exposures to ALAN caused oxidative stress and damage on C. riparius larvae, and also altered their energy metabolism. Added exogenous melatonin, despite being known for its pleiotropic effects and antioxidative actions, could only partially mediate effects caused by ALAN. To summarize, these results suggest that low intensity levels of ALAN can affect C. riparius life-history and physiology, with potential population level effects, revealing the need for studies on ecological effects of ALAN. More studies need to, for instance, estimate effects on fertility and fecundity, and evaluate multigenerational consequences. Given the central role of melatonin, its physiological action should also be studied to unravel the mechanisms of action in invertebrates. This research will allow to evaluate light pollution thus contributing to a better management and conservation of urban aquatic ecosystems.