Multiple stressors and pollutants
Freshwaters are used intensively by humans, meaning that they are exposed to a number of stressors. We explore the complex interrelations and impacts of the different stressors: How do nutrients and contaminants enter our surface waters, which factors play a central role in this process, and where are rivers and lakes in a particularly poor state? Nutrient inputs of nitrogen and phosphate, for example, may affect water quality, leading to algal blooms. It is often impossible to completely remove pharmaceuticals and biocides during wastewater treatment. They then end up in rivers and lakes, where they may affect the hormonal metabolism of fish and amphibians. Mining may lead to the contamination of adjacent freshwaters with potash and sulphate. Land use change, urbanisation, water control structures and the increasing use of artificial lighting at night (light pollution) exert additional pressure on our freshwaters. In our research, we acknowledge that use by humans is an important part of reality – only then can future-oriented solutions be developed.
Misbalance of thyroid hormones after two weeks of exposure to artificial light at night in Eurasian perch Perca fluviatilis
In a lab study it was tested if light pollution affects thyroid hormones in Eurasian perch. The results show first signs of endocrine disruption in thyroid metabolism after a relatively short exposure of two weeks under high-intensity streetlight conditions. Misbalanced thyroidal status can have serious implications for metabolic rates as well as developmental and reproductive processes.
Many contaminants affect organismal behavior and subsequent ecological outcomes. To improve understanding of the challenges and opportunities for behavioral ecotoxicology within regulatory toxicology/risk assessment, the authors formulated perspectives and recommendations, which promise to serve as a roadmap to advance interfaces among basic and translational sciences, and regulatory practices.
The authors suggest that lunar illuminated fraction should, in general, never be used in biological studies, as alternative variables such as horizontal illuminance better represent moonlight exposure, and therefore offer a greater chance of detecting the effects of moonlight. They provide a brief explanation of how moonlight varies with season and time of night.
Nanosilver impacts on aquatic microbial decomposers and litter decomposition assessed as pollution-induced community tolerance (PICT)
The authors have shown that shifts in microbial communities triggered by chronic exposure to low concentrations of silver nanoparticles increases the community tolerance to silver, as described in the pollution-induced community tolerance (PICT) concept, with consequences for leaf litter decomposition, a pivotal process in forest streams.
Uptake and physiological effects of the neonicotinoid imidacloprid and its commercial formulation Confidor® in a widespread freshwater oligochaete
The neonicotinoid imidacloprid (IMI) is one of the most extensively applied neuro-active insecticides worldwide and continues to enter surface waters in many countries despite a recent ban for outdoor use in the EU. The study assessed the effects of pure IMI and its commercial formulation Confidor® on the aquatic oligochaete Lumbriculus variegatus, a key species in freshwater sediments.