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Title: Vegetation and hydrology stratification as proxies to estimate methane emission from tidal marshes
Abstract

Direct measurement of methane emissions is cost-prohibitive for greenhouse gas offset projects, necessitating the development of alternative accounting methods such as proxies. Salinity is a useful proxy for tidal marsh CH4emissions when comparing across a wide range of salinity regimes but does not adequately explain variation in brackish and freshwater regimes, where variation in emissions is large. We sought to improve upon the salinity proxy in a marsh complex on Deal Island Peninsula, Maryland, USA by comparing emissions from four strata differing in hydrology and plant community composition. Mean CH4chamber-collected emissions measured as mg CH4m−2 h−1ranked asS. alterniflora(1.2 ± 0.3) ≫ High-elevationJ. roemerianus(0.4 ± 0.06) > Low-elevationJ. roemerianus(0.3 ± 0.07) = S. patens(0.1 ± 0.01). Sulfate depletion generally reflected the same pattern with significantly greater depletion in theS. alterniflorastratum (61 ± 4%) than in theS. patensstratum (1 ± 9%) with theJ. roemerianusstrata falling in between. We attribute the high CH4emissions in theS. alterniflorastratum to sulfate depletion likely driven by limited connectivity to tidal waters. Low CH4emissions in theS. patensstratum are attributed to lower water levels, higher levels of ferric iron, and shallow rooting depth. Moderate CH4emissions from theJ. roemerianusstrata were likely due to plant traits that favor CH4oxidation over CH4production. Hydrology and plant community composition have significant potential as proxies to estimate CH4emissions at the site scale.

 
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Award ID(s):
2051343
NSF-PAR ID:
10361190
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Springer Science + Business Media
Date Published:
Journal Name:
Biogeochemistry
Volume:
157
Issue:
2
ISSN:
0168-2563
Page Range / eLocation ID:
p. 227-243
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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