@article {2942, title = {Soil Organic Carbon Development and Turnover in Natural and Disturbed Salt Marsh Environments}, journal = {Geophysical Research Letters}, volume = {48}, year = {2021}, month = {Apr-01-2023}, abstract = {Salt marsh survival with sea-level rise (SLR) increasingly relies on soil organic carbon (SOC) accumulation and preservation. Using a novel combination of geochemical approaches, we characterized fine SOC (<=1 mm) supporting marsh elevation maintenance. Overlaying thermal reactivity, source (δ13C), and age (F14C) information demonstrates several processes contributing to soil development: marsh grass production, redeposition of eroded material, and microbial reworking. Redeposition of old carbon, likely from creekbanks, represented \~{}9\%{\textendash}17\% of shallow SOC (<=26 cm). Soils stored marsh grass-derived compounds with a range of reactivities that were reworked over centuries-to-millennia. Decomposition decreases SOC thermal reactivity throughout the soil column while the decades-long disturbance of ponding accelerated this shift in surface horizons. Empirically derived estimates of SOC turnover based on geochemical composition spanned a wide range (640{\textendash}9,951 years) and have the potential to inform predictions of marsh ecosystem evolution.}, issn = {0094-8276}, doi = {10.1029/2020GL090287}, url = {https://onlinelibrary.wiley.com/doi/10.1029/2020GL090287}, author = {Luk, Sheron Y. and Todd-Brown, Katherine and Eagle, Meagan and McNichol, Ann P. and Sanderman, Jonathan and Gosselin, Kelsey and Spivak, Amanda C.} }