Soil organic carbon development and turnover in natural and disturbed salt marsh environments

Geophysical Research Letters
By: , and 

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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), indicating that this process may become increasingly important with SLR. 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 future predictions of marsh ecosystem evolution.

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Publication type Article
Publication Subtype Journal Article
Title Soil organic carbon development and turnover in natural and disturbed salt marsh environments
Series title Geophysical Research Letters
DOI 10.1029/2020GL090287
Volume 48
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description e2020GL090287, 11 p.
Country United States
State Massachusetts
Other Geospatial Plum Island
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