Spatial and temporal variability in carbon dioxide and methane exchange at three coastal marshes along a salinity gradient in a northern Gulf of Mexico estuary

Verfasser / Beitragende:
[Benjamin Wilson, Behzad Mortazavi, Ronald Kiene]
Ort, Verlag, Jahr:
2015
Enthalten in:
Biogeochemistry, 123/3(2015-04-01), 329-347
Format:
Artikel (online)
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024 7 0 |a 10.1007/s10533-015-0085-4  |2 doi 
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245 0 0 |a Spatial and temporal variability in carbon dioxide and methane exchange at three coastal marshes along a salinity gradient in a northern Gulf of Mexico estuary  |h [Elektronische Daten]  |c [Benjamin Wilson, Behzad Mortazavi, Ronald Kiene] 
520 3 |a Carbon gas fluxes in tidal marshes vary spatially and temporally because of vegetation cover, subsurface biogeochemical processes, and environmental forcing. The objective of this study was to examine how ecosystem carbon gas exchange changes along an estuarine salinity gradient. We measured carbon dioxide (CO2) and methane (CH4) gas fluxes from three marshes representing a salinity gradient (0-32ppt) in the Mobile Bay estuary, Alabama, USA. CH4 flux was relatively small with no significant differences across sites despite salinity differences. Interestingly, sediment porewater CH4 concentrations were significantly higher at the high salinity salt marsh and decreased with decreasing salinity. Midday net ecosystem exchange (where a positive rate indicates net carbon assimilated through photosynthesis) was greatest at the most fresh site (4.8±0.3µmol CO2 m−2s−1), followed by the saline (2.8±1.0µmol CO2 m−2s−1) and brackish (1.4±0.6µmol CO2 m−2s−1) sites. However, net ecosystem exchange integrated diurnally revealed each marsh to be a net CO2 source to the atmosphere as a result of high ecosystem respiration with the freshwater marsh emitting more CO2 (−893.4±187.9g C m−2year−1) than the brackish (−517.8±85.2g C m−2year−1) and salt marsh (−410.2±98.2g C m−2year−1). This finding leads to the conclusion that either the marshes are losing carbon or that they receive a subsidy of respirable carbon, possibly via tidal deposition. The extent to which sedimentation from tidal deposition contributes carbon to these ecosystems, however, remains unknown. Without such a subsidy, marshes in the study area will not be able to keep up with sea level rise. 
540 |a Springer International Publishing Switzerland, 2015 
690 7 |a Carbon dioxide  |2 nationallicence 
690 7 |a Methane  |2 nationallicence 
690 7 |a Climate change  |2 nationallicence 
690 7 |a Primary production  |2 nationallicence 
690 7 |a Ecosystem respiration  |2 nationallicence 
690 7 |a Mobile Bay Alabama  |2 nationallicence 
700 1 |a Wilson  |D Benjamin  |u Department of Biological Sciences, University of Alabama, Box 870344, 35487, Tuscaloosa, AL, USA  |4 aut 
700 1 |a Mortazavi  |D Behzad  |u Department of Biological Sciences, University of Alabama, Box 870344, 35487, Tuscaloosa, AL, USA  |4 aut 
700 1 |a Kiene  |D Ronald  |u Department of Marine Sciences, University of South Alabama, 36688, Mobile, AL, USA  |4 aut 
773 0 |t Biogeochemistry  |d Springer International Publishing  |g 123/3(2015-04-01), 329-347  |x 0168-2563  |q 123:3<329  |1 2015  |2 123  |o 10533 
856 4 0 |u https://doi.org/10.1007/s10533-015-0085-4  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s10533-015-0085-4  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Wilson  |D Benjamin  |u Department of Biological Sciences, University of Alabama, Box 870344, 35487, Tuscaloosa, AL, USA  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Mortazavi  |D Behzad  |u Department of Biological Sciences, University of Alabama, Box 870344, 35487, Tuscaloosa, AL, USA  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Kiene  |D Ronald  |u Department of Marine Sciences, University of South Alabama, 36688, Mobile, AL, USA  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Biogeochemistry  |d Springer International Publishing  |g 123/3(2015-04-01), 329-347  |x 0168-2563  |q 123:3<329  |1 2015  |2 123  |o 10533