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Diel and seasonal patterns of soil CO 2 efflux in a temperate tidal marsh.
- Source :
-
The Science of the total environment [Sci Total Environ] 2022 Jan 01; Vol. 802, pp. 149715. Date of Electronic Publication: 2021 Aug 21. - Publication Year :
- 2022
-
Abstract
- Tidal marshes store large amounts of carbon; however, little is known about the patterns, magnitudes, and biophysical drivers that regulate CO <subscript>2</subscript> efflux from these ecosystems. Due to harsh environmental conditions (e.g., flooding), it is difficult to measure continuous soil CO <subscript>2</subscript> efflux in tidal marshes. These data are necessary to inform empirical and process-based models and to better quantify carbon budgets. We performed automated (30 min) and manual (bi-monthly) soil CO <subscript>2</subscript> efflux measurements, for ~20 months, at two sites in a temperate tidal marsh: tall Spartina (TS; dominated by S. cynosuroides) and short Spartina (SS; dominated by S. alterniflora). These measurements were coupled with water quality, canopy spectral reflectance, and meteorological measurements. There were no consistent diel patterns of soil CO <subscript>2</subscript> efflux, suggesting a decoupling of soil CO <subscript>2</subscript> efflux with diel variations in temperature and tides (i.e., water level) showing a hysteresis effect. Mean soil CO <subscript>2</subscript> efflux was significantly higher at SS (2.15 ± 1.60 μmol CO <subscript>2</subscript> m <superscript>-2</superscript>  s <superscript>-1</superscript> ) than at TS (0.55 ± 0.80 μmol CO <subscript>2</subscript> m <superscript>-2</superscript>  s <superscript>-1</superscript> ), highlighting distinct biogeochemical spatial variability. At the annual scale, air temperature explained >50% of the variability in soil CO <subscript>2</subscript> efflux at both sites; and water level and salinity were secondary drivers of soil CO <subscript>2</subscript> efflux at SS and TS, respectively. Annual soil CO <subscript>2</subscript> efflux varied from 287-876 to 153-211 g C m <superscript>-2</superscript> y <superscript>-1</superscript> at SS and TS, respectively, but manual measurements underestimated the annual flux by <67% at SS and <23% at TS. These results suggest that measuring and modeling diel soil CO <subscript>2</subscript> efflux variability in tidal marshes may be more challenging than previously expected and highlight large discrepancies between manual and automated soil CO <subscript>2</subscript> efflux measurements. New technical approaches are needed to implement long-term automated measurements of soil CO <subscript>2</subscript> efflux across wetlands to properly estimate the carbon balance of these ecosystems.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Subjects :
- Carbon Dioxide analysis
Ecosystem
Seasons
Soil
Wetlands
Subjects
Details
- Language :
- English
- ISSN :
- 1879-1026
- Volume :
- 802
- Database :
- MEDLINE
- Journal :
- The Science of the total environment
- Publication Type :
- Academic Journal
- Accession number :
- 34461472
- Full Text :
- https://doi.org/10.1016/j.scitotenv.2021.149715