Spatial and temporal dynamics of biogeochemical processes in the Fraser River, Canada : a coupled organic-inorganic perspective Voss, Britta M.
dc.coverage.spatial Fraser River, Canada
dc.coverage.spatial Southwestern Canada 2014-10-28T14:18:06Z 2014-10-28T14:18:06Z 2014-09
dc.description Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2014 en_US
dc.description.abstract The great geologic and climatic diversity of the Fraser River basin in southwestern Canada render it an excellent location for understanding biogeochemical cycling of sediments and terrigenous organic carbon in a relatively pristine, large, temperate watershed. Sediments delivered by all tributaries have the potential to reach the ocean due to a lack of main stem lakes or impoundments, a unique feature for a river of its size. This study documents the concentrations of a suite of dissolved and particulate organic and inorganic constituents, which elucidate spatial and temporal variations in chemical weathering (including carbonate weathering in certain areas) as well as organic carbon mobilization, export, and biogeochemical transformation. Radiogenic strontium isotopes are employed as a tracer of sediment provenance based on the wide variation in bedrock age and lithology in the Fraser basin. The influence of sediments derived from the headwaters is detectable at the river mouth, however more downstream sediment sources predominate, particularly during high discharge conditions. Bulk radiocarbon analyses are used to quantify terrestrial storage timescales of organic carbon and distinguish between petrogenic and biospheric organic carbon, which is critical to assessing the role of rivers in long-term atmospheric CO2 consumption. The estimated terrestrial residence time of biospheric organic carbon in the Fraser basin is 650 years, which is relatively short compared to other larger rivers (Amazon, Ganges-Brahmaputra) in which this assessment has been performed, and is likely related to the limited floodplain storage capacity and non-steady-state post-glacial erosion state of the Fraser River. A large portion of the dissolved inorganic carbon load of the Fraser River (>80%) is estimated to derive from remineralization of dissolved organic carbon, particularly during the annual spring freshet when organic carbon concentrations increase rapidly. This thesis establishes a baseline for carbon cycling in a largely unperturbed modern mid-latitude river system and establishes a framework for future process studies on the mechanisms of organic carbon turnover and organic matter-mineral associations in river systems. en_US
dc.description.sponsorship Principle funding for this thesis was provided by grants from the National Science Foundation (OCE-0851015, OCE-0851101, and EAR-1226818). Financial support for field and analytical work was also provided by the WHOI Ocean Ventures Fund, James and Jane Orr, the WHOI Deep Ocean Exploration Institute for supporting the 2011 Geodynamics Program study tour, the MIT Student Assistance Fund, NSF grant OCE-0928582, the LightHawk organization, the WHOI Coastal Ocean Institute, the MIT PAOC Houghton Fund, the Friends of Switzerland Stratton Fellowship, and the WHOI Academic Programs Office. en_US
dc.format.mimetype application/pdf
dc.identifier.citation Voss, B. M. (2014). Spatial and temporal dynamics of biogeochemical processes in the Fraser River, Canada : A coupled organic-inorganic perspective [Doctoral thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution]. Woods Hole Open Access Server.
dc.identifier.doi 10.1575/1912/6919
dc.language.iso en_US en_US
dc.publisher Massachusetts Institute of Technology and Woods Hole Oceanographic Institution en_US
dc.relation.ispartofseries WHOI Theses en_US
dc.subject Biogeochemical cycles
dc.subject Organic compounds
dc.title Spatial and temporal dynamics of biogeochemical processes in the Fraser River, Canada : a coupled organic-inorganic perspective en_US
dc.type Thesis en_US
dspace.entity.type Publication
relation.isAuthorOfPublication 4adaa54e-db40-4d69-8211-3d8da084af25
relation.isAuthorOfPublication.latestForDiscovery 4adaa54e-db40-4d69-8211-3d8da084af25
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