Understanding Anaerobic Carbon Cycling in Tropical and Boreal Wetland Ecosystems
| dc.contributor.advisor | Bohannan, B. J. M. | |
| dc.contributor.author | Hopple, Anya | |
| dc.date.accessioned | 2018-09-06T21:56:41Z | |
| dc.date.available | 2018-09-06T21:56:41Z | |
| dc.date.issued | 2018-09-06 | |
| dc.description.abstract | Understanding methane (CH4) cycling dynamics is of paramount importance because CH4 has 45 times the sustained-flux global warming potential of carbon dioxide (CO2) and is currently the second most important anthropogenic greenhouse gas. Wetland ecosystems emit one-third of total global CH4 emissions, making them the single largest natural CH4 source and placing them among the most important terrestrial ecosystems in the global carbon (C) cycle. Wetlands in tropical and boreal regions are drivers of recent inter-annual variation in atmospheric CH4 concentrations because they play vital roles in the global CH4 cycle by storing vast amounts of C (~31% of total soil C in boreal peatlands) and generating a significant proportion of total global wetland CH4 emissions (47-89% in tropical wetlands). However, despite the recognized importance of these ecosystems, tropical wetlands have received limited study concerning CH4 flux and, although boreal wetlands have been more thoroughly studied, significant questions remain surrounding the biogeochemical controls over CH4 dynamics in these systems. My dissertation addresses these concerns using a combination of in situ field measurements and controlled laboratory incubations across field sites in equatorial Gabon, Africa and at an experimentally-manipulated (surface and deep warming and atmospheric CO2 enrichment) peatland in northern Minnesota. Specifically, my research provides novel information about the rates and abiotic and biotic controls over methanogenesis and methanotrophy in tropical African wetland and upland habitats (Chapter II). This chapter paired functional datasets with corresponding measurements of microbial community composition, using a holistic research approach that provided unique ecological insights into tropical ecosystem CH4 cycling. In northern Minnesota, I investigated the C source fueling anaerobic C mineralization across a variety of boreal peatlands, as well as if methanogenesis was limited by labile C availability at depth (Chapter III). Finally, my dissertation includes novel results on the response of boreal peatland CH4 and CO2 production, as well as anaerobic oxidation of CH4 (AOM), to deep peat heating (Chapter IV; does not include AOM) and whole-ecosystem warming with atmospheric CO2 enrichment (Chapter V), expanding our mechanistic understanding of how climate-driven variables affect peatland C mineralization. This dissertation includes previously published and unpublished coauthored material. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/23747 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | Creative Commons BY-NC-ND 4.0-US | |
| dc.title | Understanding Anaerobic Carbon Cycling in Tropical and Boreal Wetland Ecosystems | |
| dc.type | Electronic Thesis or Dissertation | |
| thesis.degree.discipline | Department of Biology | |
| thesis.degree.grantor | University of Oregon | |
| thesis.degree.level | doctoral | |
| thesis.degree.name | Ph.D. |
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