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Title: Carbon Dioxide and Methane Emissions From A Temperate Salt Marsh Tidal Creek
Abstract

Coastal salt marshes store large amounts of carbon but the magnitude and patterns of greenhouse gas (GHG; i.e., carbon dioxide (CO2) and methane (CH4)) fluxes are unclear. Information about GHG fluxes from these ecosystems comes from studies of sediments or at the ecosystem‐scale (eddy covariance) but fluxes from tidal creeks are unknown. We measured GHG concentrations in water, water quality, meteorological parameters, sediment CO2efflux, ecosystem‐scale GHG fluxes, and plant phenology; all at half‐hour intervals over 1 year. Manual creek GHG flux measurements were used to calculate gas transfer velocity (k) and parameterize a model of water‐to‐atmosphere GHG fluxes. The creek was a source of GHGs to the atmosphere where tidal patterns controlled diel variability. Dissolved oxygen and wind speed were negatively correlated with creek CH4efflux. Despite lacking a seasonal pattern, creek CO2efflux was correlated with drivers such as turbidity across phenological phases. Overall, nighttime creek CO2efflux (3.6 ± 0.63 μmol/m2/s) was at least 2 times higher than nighttime marsh sediment CO2efflux (1.5 ± 1.23 μmol/m2/s). Creek CH4efflux (17.5 ± 6.9 nmol/m2/s) was 4 times lower than ecosystem‐scale CH4fluxes (68.1 ± 52.3 nmol/m2/s) across the year. These results suggest that tidal creeks are potential hotspots for CO2emissions and could contribute to lateral transport of CH4to the coastal ocean due to supersaturation of CH4(>6,000 μmol/mol) in water. This study provides insights for modeling GHG efflux from tidal creeks and suggests that changes in tide stage overshadow water temperature in determining magnitudes of fluxes.

 
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Award ID(s):
1652594 1759879
NSF-PAR ID:
10455091
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Journal of Geophysical Research: Biogeosciences
Volume:
125
Issue:
8
ISSN:
2169-8953
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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    This dataset includes GHG concentrations in water, water quality, meteorology, sediment CO2 efflux, ecosystem-scale GHG fluxes, and plant phenology; all at half-hour time-steps over one year.

    This study was carried out in the St. Jones Reserve, a component of the Delaware National Estuarine Research Reserve in Dover, Delaware, U.S.A. The study site is part of the following networks:

    - AmeriFlux (https://ameriflux.lbl.gov/sites/siteinfo/US-StJ)
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    Main reference:

    Trifunovic, B., Vázquez‐Lule, A., Capooci, M., Seyfferth, A. L., Moffat, C., & Vargas, R. (2020). Carbon dioxide and methane emissions from a temperate salt marsh tidal creek. Journal of Geophysical Research: Biogeosciences, 125, e2019JG005558. https://doi.org/ 10.1029/2019JG005558


     
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