Consequences of nitrogen fertilization and soil acidification from acid rain on dissolved carbon and nitrogen stability in the unglaciated Appalachian Mountains

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dc.contributor.authorTaylor, Philip Grahamen
dc.contributor.committeechairValett, H. Mauriceen
dc.contributor.committeememberBurger, James A.en
dc.contributor.committeememberJones, Robert H.en
dc.contributor.departmentBiologyen
dc.date.accessioned2014-03-14T20:39:06Zen
dc.date.adate2008-09-05en
dc.date.available2014-03-14T20:39:06Zen
dc.date.issued2008-02-04en
dc.date.rdate2008-09-05en
dc.date.sdate2008-05-31en
dc.description.abstractThe expansion and proliferation of reactive nitrogen (N) sources, predominantly fertilizer application and fossil fuel combustion, has enriched the earth with N and acidified ecosystems. Acid rain is a primary vector of both N fertilization and acidification, initiating a cascade of consequences that alter biogeochemical cycling and global biological structure and function. Studies on N and acid influences are however rarely linked despite their common source. We used a wide, chronic gradient of N deposition (5.5 – 31 kg N ha⁻¹ yr-1) to explore patterns in carbon (C) and N cycling in light of recognized biogeochemical responses to acidic deposition. Specifically, we examined the response of key controls on dissolved C and N stability because soluble pools are involved in decomposition and nutrient recycling, the formation of soil organic matter (SOM), and the translation of elements through the biogeochemical continuum from atmospheric to soil to water. Results suggest that N deposition led to reduced organic matter C/N, enhanced net nitrification, and greater DON generation; and, these patterns were associated with changes in C composition. Conversely, physiochemical processes in the mineral soil seemed to control organic matter dynamics, with effects on N processing. Moreover, pH dependent controls on DOC stability were evidenced by changes in DOC concentration, chemical complexity and recalcitrance. These horizon-specific, differential responses to acid rain indicate that changes in the forest floor N economy were responsible for increased surface water NO3-N concentrations, whereas enhanced organomineral stability of DOC caused a significant increase in DOM concentrations in export.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-05312008-124241en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05312008-124241/en
dc.identifier.urihttp://hdl.handle.net/10919/33362en
dc.publisherVirginia Techen
dc.relation.haspartPhilipTaylor.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectbiogeochemistryen
dc.subjecttemperate ecosystemsen
dc.subjectcarbonen
dc.subjectnutrient cyclingen
dc.subjectNitrogenen
dc.subjectdissolved organic matteren
dc.subjectNitrogen depositionen
dc.subjectAppalachian Mountainsen
dc.titleConsequences of nitrogen fertilization and soil acidification from acid rain on dissolved carbon and nitrogen stability in the unglaciated Appalachian Mountainsen
dc.typeThesisen
thesis.degree.disciplineBiologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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