Source-sink dynamics of coastal blue carbon: a review of mechanisms and drivers

The race to understand Earth's carbon cycle has long focused on forests and atmospheric processes, but a growing body of research reminds us that some of the most efficient carbon sinks on the planet lie beneath the surface of coastal waters. Mangroves, salt marshes, seagrass meadows, and macroalgae forests collectively store vast quantities of carbon in their sediments and biomass, yet their role in climate mitigation remains inadequately quantified. A new synthesis published in the scientific literature addresses this gap directly, examining the source-sink dynamics of coastal blue carbon ecosystems with a critical eye toward the methodological inconsistencies and geographic biases that have long hampered reliable assessment. As marine climate data becomes increasingly integral to artificial intelligence-driven monitoring systems—raising questions about governance and cooperation that we have explored elsewhere—the urgency of accurate blue carbon accounting takes on even greater significance. Equally, the broader stressors facing coastal marine systems, including ocean acidification and warming, underscore why understanding carbon sequestration pathways matters not only for climate predictions but for anticipating compounding ecological impacts.

The editorial significance of this review lies in its refusal to treat blue carbon as a monolithic solution. By examining carbon storage capacity, sequestration pathways, and spatial heterogeneity across ecosystem types, the authors move beyond simplistic narratives that characterize coastal wetlands as unambiguous climate assets. The emphasis on biogeochemical processes—sedimentation, tidal dynamics, and microbial mediation—reveals the complex, context-dependent nature of blue carbon dynamics. This nuance matters because policymakers and investors increasingly seek nature-based solutions, and oversimplified messaging risks overstating mitigation potential in ways that could undermine scientific credibility. The review's candid assessment of how methodological inconsistencies distort our understanding is therefore not merely an academic concern; it is a matter of ensuring that climate action rests on validated, measurable foundations.

Perhaps the most consequential element of the synthesis is its examination of anthropogenic disturbances. Coastal development, land-use change, pollution, and ecosystem degradation do not merely reduce carbon sequestration—they can transform thriving sinks into sources, releasing stored carbon back into the atmosphere. This reversal represents a threat that demands integrated monitoring across scales, yet the review rightly identifies critical knowledge gaps, particularly in quantifying lateral carbon fluxes and microbial carbon stabilization mechanisms. These gaps are not minor technical details; they are fundamental uncertainties that affect our ability to model climate trajectories and design effective intervention strategies. Without robust, standardized approaches to measuring blue carbon dynamics under both pristine and disturbed conditions, our mitigation efforts remain建立在不完整的数据之上.

The path forward requires what the authors describe as integrated, multi-scale monitoring—a call that aligns with the broader imperative for data openness and collaborative frameworks in marine science. As the volume of ocean data grows through satellite observations, in situ sensors, and AI-assisted analysis, the challenge shifts from data collection to synthesis and shared access. The question that lingers is whether the scientific community and policymakers can mobilize the resources and coordination needed to close these knowledge gaps before accelerating coastal development and climate change further degrade the very ecosystems we depend upon for carbon sequestration. The answer will shape not only the future of blue carbon science but the feasibility of nature-based climate mitigation at meaningful scales.