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dc.date.accessioned2013-08-01T10:29:21Z
dc.date.available2013-08-01T10:29:21Z
dc.date.issued2012en_US
dc.date.submitted2012-10-04en_US
dc.identifier.citationGundersen, Cathrine Brecke. Biodegradation and Characterization of Dissolved Organic Matter (DOM) along the Flowpath of a N-saturated Subtropical Forested Catchment in China. Masteroppgave, University of Oslo, 2012en_US
dc.identifier.urihttp://hdl.handle.net/10852/33997
dc.description.abstractExcessive input of anthropogenic reactive nitrogen (Nr) to forested ecosystems is associated with increased rates of denitrification and possible emission of the potentially harmful greenhouse gas nitrous oxide (N 2 O). Denitrification is performed by heterotrophic bacteria, and Dissolved Organic Matter (DOM) is thus required for the process to proceed. Only a fraction of DOM is however assumed to be readily available for the bacteria. In a N- saturated subtropical forest in South China (Tie Shan Ping) potential denitrification rates and growth potential have been investigated in the framework of a study on N 2 O emissions. Spatial variations were found, displaying higher denitrification rates at the unsaturated hill slope (recharge zone) as compared to the more hydromorphic groundwater discharge zone. These findings were explained by the denitrifiers being C - limited, which was especially evident at the groundwater discharge zone. It was hypothesized that the reduced transport of DOM from the densely vegetated hill slope to the groundwater discharge zone was attributed to rapid mineralization along the flow pat h. This would result in only the more recalcitrant fraction of DOM remaining in solution for transportation to the groundwater discharge zone. The objective of this present study was to test this hypothesis by investigating differences in chemical characteristics and biodegradability of the DOM between the hill slope and the groundwater discharge zone. Soil-water samples collected along a topographic gradient, using suction lysimeters, were subject to both biological-, chemical-, and structural analyses. Measured biodegradability, using a batch experimental setup, suggested that the DOM from the groundwater discharge zone was far more biodegradable than the DOM from the hill slope. This was further corroborated with the structural characterization, using UV - Vis Absorbency and Fluorescence Spectroscopy, indicating small amount of more aromatic, and alow ratio of Humic to Fulvic acids in the DOM from the groundwater discharge zone as compared to the samples from the hill slope. This would imply that the attenuation of DOM along the flow path in Tie Shan Ping could not be attributed to mineralization. Instead, the loss of less biodegradable DOM is suggested to be explained by selective adsorption of the more aromatic, higher molecular weight, hydrophobic constituents of DOM to the clay-rich and organic-poor soils of the hill slope.eng
dc.language.isoengen_US
dc.titleBiodegradation and Characterization of Dissolved Organic Matter (DOM) along the Flowpath of a N-saturated Subtropical Forested Catchment in Chinaen_US
dc.typeMaster thesisen_US
dc.date.updated2013-07-10en_US
dc.creator.authorGundersen, Cathrine Breckeen_US
dc.subject.nsiVDP::440en_US
dc.identifier.bibliographiccitationinfo:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft.au=Gundersen, Cathrine Brecke&rft.title=Biodegradation and Characterization of Dissolved Organic Matter (DOM) along the Flowpath of a N-saturated Subtropical Forested Catchment in China&rft.inst=University of Oslo&rft.date=2012&rft.degree=Masteroppgaveen_US
dc.identifier.urnURN:NBN:no-32876en_US
dc.type.documentMasteroppgaveen_US
dc.identifier.duo169739en_US
dc.contributor.supervisorRolf D. Vogt, Jan Mulderen_US
dc.identifier.bibsys132328925en_US
dc.identifier.fulltextFulltext https://www.duo.uio.no/bitstream/handle/10852/33997/1/Cathrine-Gundersen-2012r.pdf
dc.identifier.fulltextFulltext https://www.duo.uio.no/bitstream/handle/10852/33997/2/Cathrine-Gundersen-2012reviced%5B1%5D.pdf


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