5 Conclusion Publisher’s note Krishna et al. 10.3389/fmars.2024.1481734In our review analysis, we identi?ed climate warming, eutrophication, ocean acidi?cation, and metal pollution, or combinations thereof, as the most critical stressors triggering non- additive responses in coastal ecosystems. Thus, from a management perspective, particular attention should be placed on mitigating these stressors in coastal systems. Phytoplankton and bivalves are the most studied taxonomic groups in multi-stressor experiments and observations. They are, however, sensitive to different stressor combinations. Simultaneous exposure to metal pollution and high nutrient concentrations invokes synergistic responses in phytoplankton, often with negative effects on their physiology. For bivalves, climate warming and ocean acidi?cation appear to be the most critical stressor combination, with adverse effects on physiological and morphological traits. Organisms at different trophic levels, or belonging to different ecosystem components (such as micro- and macrobenthos), are sensitive to different stressor combinations. Consequently, interactive effects could induce radical changes in trophodynamics and food web structure as climate and human- induced changes in coastal ecosystems continue to intensify. For a holistic understanding of the cumulative effects of multiple stressors in coastal ecosystems, however, we suggest that more research focus should be placed on studying community and ecosystem-level responses. This can be achieved by combining in-situ observations (e.g. mesocosm experiments) with modelling approaches. In addition, other relevant taxonomic groups such as zooplankton, ?sh and benthic polychaetes demand more research.polychaetes and those who did mostly reported synergistic effects (having negative consequences) in response to multiple stressors. Benthic polychaetes are powerful ecosystem engineers as they contribute to nutrient recycling, carbon storage and oxygenation of sediments (Meadows et al., 2012; Grif?ths et al., 2017). Thus, the holistic understanding of how coastal ecosystems will evolve with ongoing changes requires knowledge of how different trophic levels will respond to multiple stressors. Therefore, it is important to diversify the target taxonomic group in multi-stressor studies or experiments. Our review also disclosed that relevant stressors such as hypoxia, turbidity, and invasive species, are understudied. Hypoxia has been identi?ed as one of the most critical stressors for coastal ecosystems, negatively affecting pelagic and benthic organisms (Howarth et al., 2011). Other stressors such as warming, eutrophication and ocean acidi?cation create feedback loops with hypoxia and together they intensify the stress on coastal food webs (Conley et al., 2009; Carstensen et al., 2014). Hypoxia, particularly, increases respiratory stress in benthic fauna (such as arthropods and bivalves) and in ?sh, which can trigger cascading effects (Grantham et al., 2004; Bograd et al., 2008; Hughes et al., 2015). Likewise, ?shing, introduction of invasive species and turbidity have been reported to alter trophodynamics (Scheffer et al., 2005; Lehtiniemi et al., 2005; Bruno and Cardinale, 2008). Thus, more experimental and modelling efforts should be put together to investigate the non-additive effects of these stressors at species and community levels in coastal ecosystems.Frontiers in Marine Science 10All claims expressed in this article are solely those of the authors and do not necessarily represent those of their af?liated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.Data availability statement The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author. Author contributions SK: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing. CL: Data curation, Writing – review & editing. SÖ: Data curation, Visualization, Writing – review & editing. JR: Data curation, Writing – review & editing. JP: Data curation, Writing – review & editing. MM: Data curation, Writing – review & editing. MP: Data curation, Writing – review & editing. SH: Data curation, Writing – review & editing. HP: Data curation, Writing – review & editing. MH: Data curation, Writing – review & editing. JS: Data curation, Writing – review & editing. KW: Data curation, Writing – review & editing. Funding The author(s) declare ?nancial support was received for the research, authorship, and/or publication of this article. The funding for this study comes from the projects: Multiple Stressors onNorth Sea Life (MuSSeL) funded by German Federal Ministry of Education and Research BMBF (grant number: 03F0862A at Hereon, 03F0862B at BSH, 03F0862C at Hochschule Bremerhaven, 03F0862D at Thu?nen- Institut, 03F0862E at University of Hamburg), and CALIPSO (grant number: P11701-01) and BIOcean5D (grant number: P11370) at NOC, Southampton. Acknowledgments We are grateful to Cedric Meunier and Ingrid Kroencke for their valuable input in the development of this paper. Con?ict of interest Authors CL, MM, HP, and KW were employed by company Helmholtz-Zentrum Hereon. Author JP was employed by company Electricité de France. The remaining authors declare that the research was conducted in the absence of any commercial or ?nancial relationships that could be construed as a potential con?ict of interest.frontiersin.org