5-1 Centennial Scale Carbon Burial and Storage in the Nearshore zone of Connecticut

Session: Nearshore and Estuarine Research: Dynamics and Future Resiliency in the Coastal Zone (Posters)

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Abstract:

In the coastal zone, carbon productivity and burial studies have predominantly focused on vegetated salt marsh environments, leaving subaqueous nearshore systems comparatively understudied and poorly quantified despite their large spatial extent and capacity for sediment accumulation. Subaqueous nearshore environments form a dynamic transition zone between terrestrial, estuarine, and shelf systems, where carbon accumulation is primarily driven by sediment influx and hydrodynamic processes rather than biological productivity. Consequently, the mechanisms governing organic carbon preservation in these settings remain poorly constrained.

In this study, we investigate centennial-scale carbon accumulation within subaqueous nearshore sediments along the Connecticut coast using sediment cores, age–depth models, and organic carbon analyses. Carbon inventories from ~180 sites are presented in relation to depositional settings to assess how physical processes regulate carbon preservation over time. Preliminary results indicate that carbon accumulation rates and burial efficiency vary systematically across subaqueous nearshore landforms, with enhanced preservation observed in low-energy, sediment-focusing environments relative to more hydrodynamically active settings. Evidence of rapid sediment accumulation, particularly in upstream river estuary locations, suggests that event-driven sediment delivery may contribute disproportionately to long-term carbon burial.

Overall, these findings suggest that subaqueous nearshore sediments function as physically influenced, long-term carbon reservoirs whose storage capacity is tightly coupled to geomorphic stability and sediment supply. Incorporating subaqueous nearshore environments into coastal carbon frameworks is therefore critical for improving regional carbon budgets and evaluating the resilience of coastal carbon storage under changing environmental conditions.

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