Soil Organic Carbon Development and Turnover in Natural and Disturbed Salt Marsh Environments

TitleSoil Organic Carbon Development and Turnover in Natural and Disturbed Salt Marsh Environments
Publication TypeJournal Article
Year of Publication2021
AuthorsLuk, SY, Todd‐Brown, K, Eagle, M, McNichol, AP, Sanderman, J, Gosselin, K, Spivak, AC
JournalGeophysical Research Letters
Volume48
Issue2
Date PublishedApr-01-2023
ISSN0094-8276
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%–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 (640–9,951 years) and have the potential to inform predictions of marsh ecosystem evolution.

URLhttps://onlinelibrary.wiley.com/doi/10.1029/2020GL090287
DOI10.1029/2020GL090287