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dc.contributor.authorWeaver, Sophie Alden
dc.date.accessioned2020-02-14T00:13:14Z
dc.date.available2020-02-14T00:13:14Z
dc.date.issued2019-12
dc.identifier.urihttp://hdl.handle.net/11122/10913
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2019en_US
dc.description.abstractIn stream biofilms, autotrophs and heterotrophs are responsible for the majority of in stream nutrient transformations. In boreal forest catchments, discontinuous permafrost can lead to variation in nutrient and energy resources, which can control competition for nutrients between autotrophs and heterotrophs within these biofilms. I was interested in determining what resources control nutrient utilization by autotrophs and heterotrophs in headwater streams in the boreal forest of interior Alaska. I hypothesized that the outcome of competition between autotrophs and heterotrophs for inorganic nutrients would be dependent on the availability of (i) organic carbon, (ii) light, or (iii) inorganic nutrients. To measure resource limitation and competition at both patch and reach scales, I deployed nutrient diffusing substrata and conducted nutrient uptake experiments in streams along a permafrost gradient at the Caribou-Poker Creeks Research Watershed in interior Alaska. At the patch scale, autotrophs were light and nutrient limited, whereas heterotrophs were carbon and nutrient limited, and at the reach scale, light had the largest influence on nutrient uptake. Heterotrophs exhibited a larger response to nutrient enrichment when stream ambient carbon stocks were more bioavailable. Autotrophic biomass and productivity was suppressed when labile carbon was available to heterotrophs, suggesting that heterotrophs outcompete autotrophs for nutrients when a labile carbon source is introduced. The positive responses to nutrient and carbon additions suggest that the hypothesized increased nutrient and carbon exports into fluvial networks with permafrost degradation will impact biofilm structure and function, with the potential to influence nutrient export and stream ecosystem function downstream.en_US
dc.description.sponsorshipBonanza Creek Long Term Ecological Research program (NSF grants DEB-1636476 and DEB-1026415), University of Alaska Fairbanks and the Institute of Arctic Biologyen_US
dc.language.isoen_USen_US
dc.subjectbiofilmsen_US
dc.subjectAlaskaen_US
dc.subjectInterior Alaskaen_US
dc.subjectautotrophic bacteriaen_US
dc.subjectheterotrophic bacteriaen_US
dc.subjectstream ecologyen_US
dc.titleResource limitation of autotrophs and heterotrophs in boreal forest headwater streamsen_US
dc.typeThesisen_US
dc.type.degreemsen_US
dc.identifier.departmentDepartment of Biology and Wildlifeen_US
dc.contributor.chairJones, Jeremy B.
dc.contributor.committeeLeigh, Mary Beth
dc.contributor.committeeRuess, Roger W.
refterms.dateFOA2020-02-14T00:13:15Z


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