Ocean Acidification

Highlights

• Thermal stress was the most studied natural driver of seagrass decline.
• Study frequency reflects research effort, not ecological importance.
• Most multi-stressor studies assessed only two interacting drivers.
• Warming–acidification effects varied among species and exposure contexts.
• Indonesia remains underrepresented in long-term seagrass research.

Abstract

Seagrass ecosystems are exposed to natural environmental variability and climate-modulated extremes that can interact with anthropogenic pressures and accelerate ecological decline. This systematic review synthesized 60 peer-reviewed publications published between 2010 and 2025 to examine how temperature and marine heatwaves, ocean acidification and pH, salinity, drought and flooding, hydrodynamics, sea-level change, turbidity and light limitation, sediment conditions, and oxygen availability affect seagrass ecosystems. Thermal variables were the most frequently investigated category; however, publication frequency was treated as an indicator of research effort rather than a ranking of ecological importance. Experimental and field evidence showed that warming and marine heatwaves often reduce growth, photosynthetic performance, biomass, and recovery, although outcomes depend on species, exposure duration, light, nutrients, and prior stress history. Evidence for warming–acidification interactions was contrasting: acidification impaired plant performance during thermal stress in some studies, whereas enhanced inorganic carbon availability supported biomass or carbon metabolism in others. Most multi-stressor experiments evaluated only two drivers, and relatively few examined three or more simultaneous or successive stressors. The most commonly reported ecosystem consequences included habitat contraction, canopy and biomass loss, physiological impairment, altered carbon and nutrient cycling, sediment destabilization, community reorganization, and reduced resilience. Geographic evidence remained concentrated in Europe, the Mediterranean, Australia, China, and North America. Indonesia and much of Southeast Asia were comparatively underrepresented despite high seagrass diversity and documented declines associated with interacting environmental change. Future research should prioritize standardized long-term monitoring and multifactorial experiments that distinguish research frequency from ecological effect and support regionally calibrated risk assessment.

Muhlis, Halide H. & Ambo-Rappe R., 2026. Natural environmental drivers of seagrass degradation: a global systematic review with implications for Indonesia. Continental Shelf Research 302: 105768. doi: 10.1016/j.csr.2026.105768. Article (subscription required).