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dc.contributor.advisorHelgason, Bobbien_US
dc.contributor.advisorBedard-Haughn, Angelaen_US
dc.creatorKonschuh, Hannahen_US
dc.date.accessioned2013-09-16T19:50:48Z
dc.date.available2013-09-16T19:50:48Z
dc.date.created2013-06en_US
dc.date.issued2013-06-24en_US
dc.date.submittedJune 2013en_US
dc.identifier.urihttp://hdl.handle.net/10388/ETD-2013-06-1059en_US
dc.description.abstractRecent work has demonstrated that vast amounts of soil organic carbon (SOC) are redistributed and buried within Canadian croplands; however, the effects of redistribution on SOC dynamics and biological properties of the soil environment remain unknown. Because soil microorganisms are drivers of carbon (C) turnover in soil, the effects of such processes on microbial community dynamics are important in assessing the overall effects of redistribution and the stability of displaced C. This is particularly important in the face of future climate change scenarios and potential disturbances. The objectives of this study were to examine microbial community dynamics with depth and among landscape positions in an eroded landscape, and to assess C mineralization response between surface and subsurface soil layers in a depositional position. Microbial abundance was highly influenced by SOC redistribution. This was most evident in the buried backslope position where substantial soil and SOC deposition had occurred, creating a very thick A horizon (ca. 80 cm). Phospholipid fatty acid (PLFA) analysis revealed substantial concentrations of microbial biomass located at depth (30-60 cm), which was greater than PLFA concentration at the soil surface and correlated with SOC concentration. Community structure analysis demonstrated the strong influence of landscape position and depth in structuring microbial communities near the soil surface (0-20 cm). Communities in positions that were predominantly erosional were the most different from those in the depositional position, accounting for the largest amount of variation (60%) in the overall analysis. The existence of distinct microbial communities found in depositional material (0-25 cm) and within the buried A horizon (30-80 cm) in the buried backslope position indicate a strong influence of depth and redistribution in structuring microbial communities. The existence of significant viable biomass in the buried A horizon of the depositional position leads to question the persistence of highly concentrated, buried SOC over many decades. When soils from surface (0-5 and 20-25 cm) and subsurface (40-45 and 65-70 cm) depths were incubated in surface-like conditions, greater mineralization response in surface relative to subsurface soils, despite relatively similar SOC concentration, suggests that redistribution protects buried C from decomposition. Distinct microbial communities found at the onset and completion of the mineralization study between surface and subsurface soil layers may indicate the influence of microbial community structure on mineralization response. Depth was the largest source of variation in microbial community structure, and although a shift occurred after exposure to incubation conditions, the effect of depth remained the strongest influence. This work indicates that SOC redistribution strongly influences microbial abundance and community structure development, primarily driven by altered substrate gradients occurring with depth, and suggests that C is less susceptible to decomposition once buried in depositional positions.en_US
dc.language.isoengen_US
dc.subjectErosionen_US
dc.subjectredistributionen_US
dc.subjecteroded landscapeen_US
dc.subjectsoil organic carbonen_US
dc.subjectburied carbonen_US
dc.subjectcarbon mineralizationen_US
dc.subjectmicrobial community structureen_US
dc.subjectphospholipid fatty acid analysisen_US
dc.titleAsessing microbial community dynamics and carbon mineralization with depth across an eroded agricultural landscape at St. Denis National Wildlife Areaen_US
thesis.degree.departmentSoil Scienceen_US
thesis.degree.disciplineSoil Scienceen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M.Sc.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberSchoenau, Jeffen_US
dc.contributor.committeeMemberWalley, Franen_US


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