Stress across aquatic systems: A meta-analysis of synergistic interactions
Environmental stressors are important forces structuring ecosystems, communities, and populations of organisms. Organisms are exposed to natural and anthropogenic stressors, such as thermal extremes, contaminants, and physical stress, in both marine and freshwater systems. Exposure to environmental stressors can result in reduced survival, growth, reproduction, and photosynthesis. Stressors often co-occur and can result in additive (synergistic) or less-than-additive effects when combined. We used meta-analytic techniques to test the hypothesis that stressors have a negative effect across aquatic (freshwater and marine) systems. Furthermore, we used meta-analytic techniques to test for differences among aquatic systems and among stressors. Finally, we tested for synergistic interactions among stressors.
Preliminary analysis showed an overall negative effect of stressors in aquatic systems (lnR = -0.274, bias-corrected CI= -0.4975 to -0.0902). Important differences between aquatic systems and stressors were observed. We found that stressors often act synergistically in these systems, and should be considered together to understand the effects of environmental stress on organisms.