How Do Eutrophication and Temperature Interact to Shape the Community Structures of Phytoplankton and Fish in Lakes?

Abstract

Freshwater ecosystems are among the systems most threatened and impacted by anthropogenic activities, but there is still a lack of knowledge on how this multi-pressure environment impacts aquatic communities in situ. In Europe, nutrient enrichment and temperature increase due to global change were identified as the two main pressures on lakes. Therefore, we investigated how the interaction of these two pressures impacts the community structure of the two extreme components of lake food webs: phytoplankton and fish. We modelled the relationship between community components (abundance, composition, size) and environmental conditions, including these two pressures. Different patterns of response were highlighted. Four metrics responded to only one pressure and one metric to the additive effect of the two pressures. Two fish metrics (average body-size and biomass ratio between perch and roach) were impacted by the interaction of temperature and eutrophication, revealing that the effect of one pressure was dependent on the magnitude of the second pressure. From a management point of view, it appears necessary to consider the type and strength of the interactions between pressures when assessing the sensitivity of communities, otherwise their vulnerability (especially to global change) could be poorly estimated.

Model‐based decomposition of environmental, spatial and species‐interaction effects on the community structure of common fish species in 772 European lakes

“…In contrast to the temperature–size rule, the average size of two cyprinids (bream, Abramis brama , and rudd, Scardinius erythrophthalmus ) was higher in warmer lakes. This is certainly attributable to the higher productivity of the warmer (and often shallow) lakes, suggesting that the higher maintenance costs at higher temperatures affect the growth rates negatively only in conditions of resource limitation and strong intra‐ and interspecific competition (Bourai et al, 2020; Fugère et al., 2018). In contrast, the size of the predator species pike declined with higher temperatures, suggesting that pike cannot cover the higher energetic costs induced by increasing temperatures by higher prey uptake rates; for example, if some of their prey species, such as bream and rudd, escape into a size refuge by higher growth rates (Mehner et al., 2016).…”

Environmental threats and conservation implications for Atlantic salmon and brown trout during their critical freshwater phases of spawning, egg development and juvenile emergence

“…The complex interactions between the stressors are not yet fully understood but are increasingly being addressed (e.g. Brook et al, 2008; Jackson et al, 2015; Bouraï et al, 2020).…”

“…For example, when pollutants exert direct effects on keystone species or induce changes in nutrient and oxygen dynamics, they may alter ecosystem functions essential for the critical life stages of Atlantic salmon and brown trout (Fleeger et al, 2003). Nutrient enrichment (eutrophication) and rise in water temperature act additively and can influence fish community dynamics (Jackson et al, 2015; Bouraï et al, 2020). A meta‐analysis conducted on net effects of cumulative impacts of multiple stressors (novel and extreme environmental changes) in freshwater ecosystems by Jackson et al (2015) revealed that the net effects of stressor pairs were frequently more antagonistic (41%) than synergistic (28%), additive (16%) or reversed (15%).…”

Life Cycle Assessment (LCA) Pengelolaan Sampah di TPA Gunung Panggung Kabupaten Tuban, Jawa Timur

“…Eutrofikasi di perairan menyebabkan kelimpahan alga yang tinggi dan menyebabkan biomassa ikan menjadi tinggi pula, terutama apabila disertai dengan suhu lingkungan yang tinggi. Dengan ini, pemanasan global menjadi satu faktor yang membuat beban lingkungan semakin tinggi (42) .…”