An int Krishna et al. 10.3389/fmars.2024.1481734these stressors can vary depending on organism type, trophic level, and trophic structure. Therefore, we identi?ed the key stressors that elicit interactive effects at the species and community levels. Temperature is, by far, the most critical stressor at the species level. One-third of the studies (33%) investigating interactive effects in individual species have identi?ed temperature as the most prominent stressor (Figure 6). However, this is not the case at the communityFrontiers in Marine Science 05level, where warming, nutrient pollution and metal contamination emerge as equally dominant stressors, followed by high turbidity, low pH, and salinity stress (all above 10%, Figure 6). While, hypoxia remains heavily understudied (<4%). At the species level, the combination of metal and nutrient pollution predominantly drives synergistic effects, whereas warming and eutrophication equally trigger both SYN and ADD responses. tagonistic and Additive effects in coastal ecosystems (across taxonomic eractive effects.FIGURE 3 Venn diagram showing the number of studies which reported Synergistic, groups). The overlaps show the number of studies reporting two or more(Figure 7A). In contrast, OA combined with other stressors appearsto invoke differential responses depending on species type, as evident by the lack of a dominant effect in stressor combinations involving OA (Figure 7A). At the community level, climate warming and ocean acidi?cation have the highest likelihood of generating synergistic responses (Figure 7B). Subsequently, we identi?ed the most studied organisms and their respective traits for the major stressor combinations. Bivalves and phytoplankton are the most studied taxonomic groups, followed by seagrass and ?sh (Figure 8). This difference could be partially attributed to research constraints arising from the complexity of studied organisms or systems. At higher body size the fraction of manipulative experiments decreases. For smaller organisms, such as phytoplankton, zooplankton, and bivalves, more than 50% of studies are performed in controlled laboratory setups, whereas this fraction falls below 50% for ?sh and decapods and below 20% for seagrass (Figure 9). Larger organisms are preferably studied in their natural and quasi-natural habitats. Likewise, in-situ experiments are preferred for studying ecosystem-level effects of multiple stressors. Metal pollution, eutrophication, and climate warming seem to be the most dominant stressor combination for phytoplankton, strongly affecting photosynthesis and growth dynamics in algal species (Figures 8, 10). For bivalves, OA and Temp are the most critical FIGURE 4 Most studied stressors, across species and communities, in coastal ecosystems (in terms of percentage), identi?ed from our review. Temp, Temperature/warming; Nut, Nutrient pollution/Eutrophication; Metal, Metal pollution; OA, Ocean acidi?cation; Sal, Salinity; DO, Dissolved oxygen; Turb, Turbidity; Dist, Physical disturbances.stressors in driving non-additive effects (Figures 8, 10). A wide range frontiersin.org