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McCabe.Samantha_MSthesis_2020_FINAL.pdf (7.39 MB)

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Permafrost Thaw Drives Changes in Plant Community Characteristics and Nutrient Stoichiometry, with Increases in the Magnitude of C-cycling in an Arctic Peatland

McCabe, Samantha J
http://orcid.org/0000-0002-3256-6813
http://rave.ohiolink.edu/etdc/view?acc_num=osu1577999303124241

Abstract Details

2020, Master of Science, Ohio State University, Environmental Science.
In the arctic region, permafrost exists as a deep, frozen layer of soil, some of which formed during cold glacial periods thousands of years ago. This freeze effectively trapped carbon and other nutrients from decomposing and/or cycling into the ecosystem. However, due to climate warming, this frozen layer is thawing, releasing long-storage carbon stocks and transforming the landscape as ground sinks to fill space left by ice. This consequently drives shifts in hydrology (i.e., water-levels) and in plant communities, with their own impacts on carbon balance. My master’s thesis work examines arctic wetland plants under climate change, as part of an interdisciplinary US Department of Energy-funded exploration of carbon cycling of these wetland systems that spans microbiology to models, and via which I get to actively and regularly engage with project colleagues from 13 institutions across 3 continents (The IsoGenie Project). A major goal of this work is to better understand and predict changing carbon budgets in the Arctic, and the magnitude of their climate feedbacks, thereby directly informing climate mitigation and adaptation efforts. The IsoGenie Project has been studying this phenomenon at Stordalen Mire, a northern peatland in Sweden, which is actively thawing. This active thaw allows us to observe three unmistakable habitat-types in one location, each with their own distinct hydrology and plant community. After thaw-associated inundation, the Stordalen Mire dwarf-shrub dominated palsa experiences an intermediate shift to moss dominated (Sphagnum sp.) bog and finally into a graminoid dominated (Eriophorum sp.) fen. We refer to this linear progression of habitat and vegetation changes as the thaw gradient. Prior studies have supported that post-thaw shifts in community composition, coupled with shifts in environmental conditions, will influence the vegetation’s role in rate of C and nutrient cycling after thaw. My thesis research asks how permafrost thaw changes community composition, nutrient concentrations, and the quality and quantity of decomposable tissue input (i.e., leaf litter) of arctic wetland plants. Percent cover of an area, per species, was collected to show community changes. Carbon and other nutrient contents were assessed in leaf tissues to show variation by species. Last, species were measured for biomass (tissue weight), seasonal growth (May to October), and leaf litter input to characterize the growth-to-decomposition cycle. Insights provided by these parameters will improve our understanding of controls on, and prediction of, greenhouse gas emissions in thawing permafrost peatland systems.
Virginia Rich (Advisor)
Gil Bohrer (Committee Member)
Scott Saleska (Committee Member)
Mark Dilley (Committee Member)
106 p.
Climate Change; Environmental Studies; Freshwater Ecology; Plant Biology
permafrost; thaw; peatland; bog; fen; arctic; wetland; plants; vegetation; leaf; litter; climate change; carbon; stock; cycle; biomass; nutrient stoichiometry;

Recommended Citations

Citations

  • McCabe, S. J. (2020). Permafrost Thaw Drives Changes in Plant Community Characteristics and Nutrient Stoichiometry, with Increases in the Magnitude of C-cycling in an Arctic Peatland [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1577999303124241

    APA Style (7th edition)

  • McCabe, Samantha. Permafrost Thaw Drives Changes in Plant Community Characteristics and Nutrient Stoichiometry, with Increases in the Magnitude of C-cycling in an Arctic Peatland. 2020. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1577999303124241.

    MLA Style (8th edition)

  • McCabe, Samantha. "Permafrost Thaw Drives Changes in Plant Community Characteristics and Nutrient Stoichiometry, with Increases in the Magnitude of C-cycling in an Arctic Peatland." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1577999303124241

    Chicago Manual of Style (17th edition)

osu1577999303124241
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