often even more adverse (Skei et al., 2000; Cloern, 2001; Marcus, 2004; different stressor combinations at the level of individual species (A) and at community-level (B). Krishna et al. 10.3389/fmars.2024.1481734Church et al., 2006; Lin et al., 2020). For example, several sites in the Bohai Sea (China) have been identi?ed as high-risk areas for autotrophs, crustacean, ?sh and bivalves due to the compounding effects of the elevated nutrient and metal concentrations (Lin et al., 2020). For phytoplankton, the metal/nutrient stressor combination appears to be most critical and is discussed below. 4.2 Phytoplankton A full range of physiological effects can result from the interaction of eutrophication and metal pollution in phytoplankton, rangingland that strongly in?uence coastal environments (Sandifer and Sutton-Grier, 2014; He and Silliman, 2019). Warming, eutrophication and metal pollution negatively affect the ecological health of coastal systems in isolation and their interactive effects areFrontiers in Marine Science 07from acute toxicity to sub-lethal or positive effects. In addition, shifts in community structure have been observed (Solan and Whiteley, 2016). Toxic metals have inhibitory effects on the germination of phytoplankton in eutrophic coastal waters (Lu et al., 2017). It has been reported that the combined effect of metal and nutrient stressors results in signi?cant changes in phytoplankton community structure leading to a shift from bigger diatoms to smaller and harmful cyanobacteria and dino?agellates (Riedel et al., 2003; Song et al., 2022). Metals, such as copper and cadmium, inhibit the growth of large algal species (e.g. diatom), even in nutrient-replete conditions, by suppressing the uptake of enzymes and causing cell leakage. The shift to harmful algal species results in a reduction of food quality for secondary producers and thereby affects the trophodynamics in the coastal food web. Nutrient enrichment in many coastal waters can considerably enhance trace metal uptake in phytoplankton, which leads to bioaccumulation of metals at the higher trophic levels (Wang and Dei, 2001). Likewise, eutrophication-mediated increase inFIGURE 7 The above ternary plots show the percentage score for the reported interactive effect (Synergistic, Antagonistic, Additive) corresponding to theFIGURE 8 Illustration of relationships between stressor combinations, taxonomic groups, and traits. The lines highlight stressor combinations impacting different organisms and traits consequently affected. Colors of lines correspond to the organisms and their widths represent the frequency of studies reporting each speci?c connection, highlighting the most frequently observed relationships.frontiersin.org