Abstract
Background: Marine ecosystems face unprecedented threats from accelerating ocean acidification (OA) and warming (OW), driving them towards critical transitions that can lead to abrupt ecosystem shifts and biodiversity loss (Hoegh-Guldberg et al., 2017; Samanth, 2024). Identifying early warning signals (EWS) is crucial for proactive management, especially in complex systems where multiple stressors interact (George et al., 2023; Lade & Gross, 2012). This study investigates the potential for EWS to predict such transitions in marine ecosystems under combined OA and OW. Methods: We synthesized existing experimental and observational data from diverse marine taxa, focusing on physiological and ecological responses to OA and OW. A meta-analysis approach was employed to identify common patterns in response variables indicative of system state changes. We applied established EWS metrics, including increased variance and autocorrelation (Liu et al., 2015; Neijnens et al., 2021), to simulated time-series data derived from these observed responses under accelerating stress scenarios. Results: Our analysis revealed that several key biological indicators, such as calcification rates in corals (Bove et al., 2020) and larval development in fish (Villalobos et al., 2020), exhibit clear EWS signatures under simulated stress. Increased temporal variance and lag-1 autocorrelation were consistently observed in metrics approaching critical thresholds. The combined effects of OA and OW often exacerbated these signals, suggesting synergistic rather than merely additive impacts on ecosystem stability (Agostini et al., 2021). Conclusions: This study provides compelling evidence for the utility of EWS in forecasting critical transitions in marine ecosystems under accelerating OA and OW. The findings underscore the urgency for continuous monitoring of specific biological indicators and the development of adaptive management strategies based on these predictive tools. Further research is needed to validate these signals in diverse field settings and integrate them into comprehensive risk assessments for marine biodiversity (Oostdijk et al., 2021).
Keywords
Ocean acidification, Ocean warming, Early warning signals, Critical transitions, Marine ecosystems, Ecosystem stability, Climate change, Ecological tipping points