Unraveling Nonlinear Interactions: A DPSIR-Based Conceptual Model for Synergistic Impacts of Climate Change and Human Activities on Coastal Blue Carbon Ecosystems

Coastal blue carbon ecosystems (BCEs) face accelerating degradation from synergistic climate-human pressures, threatening their carbon sink function. This review synthesizes nonlinear interactions governing BCE carbon cycles by developing a novel DPSIR (Drivers-Pressures-State-Impacts-Responses) conceptual model. Our framework integrates biogeochemical processes (e.g., photosynthesis, carbonate dynamics) and physical transport mechanisms (e.g., lateral carbon fluxes) to elucidate multi-factor couplings—such as nutrient pollution, hydrological alteration, and species interactions—that drive spatiotemporal variability in carbon storage. Crucially, we identify how anthropogenic drivers amplify biogeochemical feedback loops that destabilize carbon sequestration, while restoration strategies can rebuild resilience. To enhance monitoring efficacy, greenhouse gas flux periodicity and CO₂/CH₄ emission ratios are proposed as diagnostic indicators for BCE health assessment. The analysis reveals persistent knowledge gaps in quantifying inorganic carbon cycling, microbial responses under warming, and cross-system carbon fluxes. We emphasize that effective conservation requires integrated policies balancing blue economy development with science-based management, such as payment for ecosystem services and bioremediation. This DPSIR model advances a holistic understanding of BCE carbon-climate feedbacks, providing a foundation for safeguarding these critical ecosystems under global change.