Coastal systems respond to changing tides in ways that directly affect carbon burial. Tidal range amplification increases the vertical and horizontal reach of the tide, altering inundation patterns, sediment transport, plant productivity, and decomposition. These processes interact to determine whether more organic matter is deposited and preserved or whether stored carbon is lost through erosion and enhanced respiration.
Physical drivers and sediment dynamics
Matthew L. Kirwan at the Virginia Institute of Marine Science has shown that marsh accretion and carbon accumulation depend on the balance between sediment supply, plant productivity, and inundation frequency. When tidal range grows, increased tidal prism can deliver more suspended sediment to intertidal habitats, potentially raising marsh elevation capital and promoting burial of organic matter. This positive outcome requires adequate upstream sediment sources and relatively low wave energy. In contrast, amplified tides can increase currents and shear stress on exposed margins, enhancing erosion and exporting previously buried carbon to the estuary or ocean where it may remineralize.
Biological responses and preservation conditions
Carlos M. Duarte at King Abdullah University of Science and Technology has documented how coastal vegetated habitats such as seagrass meadows and salt marshes are major long-term carbon sinks whose efficiency depends on both biomass production and anoxic sediment conditions that slow decomposition. Tidal changes that lengthen inundation may boost productivity in some systems by providing nutrients and reducing desiccation stress, increasing organic input for burial. Conversely, more frequent oxygenation through stronger tidal flushing or increased wave energy can accelerate microbial breakdown of organic matter, reducing long-term burial efficiency. Local species composition and soil structure modulate these outcomes.
Human and cultural dimensions mediate these physical and biological pathways. Coastal engineering, land reclamation, and wetland drainage often reduce natural accommodation space for marsh migration, intensifying coastal squeeze and undermining carbon storage despite tidal changes. Communities dependent on fisheries and shoreline protection feel direct consequences when erosion alters habitat extent and carbon services. Environmentally, loss of buried carbon can create feedbacks to regional greenhouse gas budgets and weaken nature-based climate mitigation strategies.
Overall, tidal range amplification has a mixed influence on coastal carbon burial: it can enhance burial where sediment supply, vegetation response, and protective geomorphology align, or it can promote erosion and decomposition where energy increases, sediment is limited, or human constraints prevent habitat adjustment. Managing sediment pathways, protecting habitat migration corridors, and reducing hard infrastructure in sensitive zones are critical to sustaining blue carbon benefits as tidal regimes change.