Multiple Stressors in Aquatic Ecosystems: Sublethal Effects of Temperature, Dissolved Organic Matter, Light and a Neonicotinoid Insecticide on Gammarids

Abstract

Whether and to which extent the effects of chemicals in the environment interact with other factors remains a scientific challenge. Here we assess the combined effects of temperature (16 vs. 20°C), light conditions (darkness vs. 400 lx), dissolved organic matter (DOM; 0 vs. 6 mg/L) and the model insecticide thiacloprid (0 vs. 3 µg/L) in a full-factorial experiment on molting and leaf consumption of Gammarus fossarum. Thiacloprid was the only factor significantly affecting gammarids’ molting. While DOM had low effects on leaf consumption, temperature, light and thiacloprid significantly affected this response variable. The various interactions among these factors were not significant suggesting additivity. Only the interaction of the factors temperature and thiacloprid suggested a tendency for antagonism. As most stressors interacted additively, their joint effects may be predictable with available models. However, synergistic interactions are difficult to capture while being central for securing ecosystem integrity.

Neurotoxicity in Marine Invertebrates: An Update

“…The environmental risk assessment is currently based on laboratory, mesocosms, and in the field researches, while taking in account that each single chemical introduced in the environment can undergo degradation or interact with other chemicals, or natural factors (biotic/abiotic), leading to synergistic or antagonistic effects [ 3 , 9 , 10 ]. Although growing evidence points to the importance of considering interactions between stressors in the environment, insufficient literature has been produced so far [ 2 , 10 , 11 , 12 ].…”