Description
TitleControls affecting methane fluxes in restored and natural tidal wetlands
Date Created2014
Other Date2014-10 (degree)
Extent1 online resource (xi, 115 p. : ill.)
DescriptionNatural wetlands emit one third of global methane (CH4), the second most important greenhouse gas after carbon dioxide (CO2). However, there is a huge uncertainty about regional and global CH4 emission estimates, because of the estimation of CH4 emissions for large areas based on the CH4 flux measurement made in highly heterogeneous, poorly mapped small areas. But, within a small area of wetland, there can be a huge spatial variation in CH4 flux due to spatial heterogeneity. Therefore, for better understanding of CH4 dynamics of a wetland, CH4 flux measurement should be made in a variety of microsites of a wetland covering different scales, vegetation, and heterogeneity of the sites. Our two-year CH4 flux measurements from two microsites from each of three wetlands of New Jersey Meadowlands will help to refine CH4 budget of low salinity marshes, which have a large uncertainty about their CH4 budget. The annual CH4 flux in a restored high marsh site varied from 1.8 (Spartina patens marsh) - 26.6 (Phragmites australis marsh) g CH4 m-2 yr-1. The S. alterniflora marsh and mud flat area of another restored low marsh, emitted 15.6 and 7.5 g CH4 m-2 yr-1, respectively. The annual emission of CH4 for a S. patens marsh and a P. australis marsh at a natural high marsh site were 2.7 and 12.6 g CH4 m-2 yr-1, respectively. We also investigated relationships between CH4 flux and various physical factors including air and soil temperature, net radiation, and vapor pressure deficit (VPD). Presence of most of the belowground biomasses close to the soil surface suggests that most of the effect of belowground biomass on CH4 dynamics occurs close to soil and atmosphere interface. Investigations of belowground biomass distribution, root and rhizome characteristics as well as leaf area index (LAI), in this study aid modeling CH4 and other greenhouse gas transport. There was higher CH4 emission during incoming tide than during outgoing tide in a mud flat microsite; however, we did not find a relationship between tidal water depth difference and CH4 flux in vegetated areas. The weak, but positive relationship between CH4 flux and VPD in vegetated areas suggest stomatal control on CH4 flux.
NotePh.D.
NoteIncludes bibliographical references
NoteIncludes vita
Noteby Rajan Tripathee
Genretheses, ETD doctoral
Languageeng
CollectionGraduate School - Newark Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.
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