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Iron Redox Cycling and Impacts on Phosphorus Solubility in Tundra and Boreal Ecosystems

Duroe, Kiersten A
http://rave.ohiolink.edu/etdc/view?acc_num=kent1573735336328272

Abstract Details

2019, MS, Kent State University, College of Arts and Sciences / Department of Earth Sciences.
Rapidly changing climate in high-latitude regions is altering biogeochemical cycles and potentially shifting arctic and sub-arctic ecosystems from sinks to sources of atmospheric carbon. Phosphorus (P) is an important nutrient whose availability may limit biological productivity and carbon storage in northern ecosystems. Here, we investigated the potential for phosphate adsorption to poorly-crystalline iron (Fe) oxide minerals that precipitate during drainage of anoxic, Fe-rich peat soils to limit P bioavailability in high-latitude wetlands. We compared Fe and P geochemistry in organic-rich soils collected from relatively depressed and saturated microtopographic positions to elevated and dry positions along a latitudinal gradient in northern North America, including tundra (Barrow Environmental Observatory, AK; Toolik Lake Field Station, AK) and boreal (Bonanza Creek Environmental Forest, AK; Marcell Experimental Forest, MN) ecosystems. We considered differences in soil saturation between microtopographic positions to be proxies for hydrologic changes driven by altered climate and the potential for permafrost degradation. To assess P sorption to Fe-oxides, we used phosphate sorption indices to evaluate the capacity for soils to bind phosphate and sequential extractions to quantify Fe phases, including exchangeable iron, organic-bound iron, poorly-crystalline and crystalline iron oxides, and magnetite. Our results indicate that not only does iron speciation differ amongst the four study sites, but phosphate sorption capacity differs across microtopographic gradients in patterns that may reflect the accumulation of poorly crystalline Fe-oxides at oxic-anoxic interfaces, pH, and/or influence of organic content. There was a direct correlation between poorly-crystalline iron oxides and the potential of the soil to sorb phosphate. Consequently, projected temperature increases in arctic and boreal regions may influence P availability due to increased association with poorly-crystalline Fe-oxides that precipitate as water tables lower in drying peatlands, wetlands, and polygonal landscapes.
Elizabeth Herndon (Advisor)
Lauren Kinsman-Costello (Committee Member)
David Singer (Committee Member)
100 p.
Geology
iron redox, phosphorus, climate change, nutrient cycling, phosphate sorption, iron oxides, tundra, boreal

Recommended Citations

Citations

  • Duroe, K. A. (2019). Iron Redox Cycling and Impacts on Phosphorus Solubility in Tundra and Boreal Ecosystems [Master's thesis, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1573735336328272

    APA Style (7th edition)

  • Duroe, Kiersten. Iron Redox Cycling and Impacts on Phosphorus Solubility in Tundra and Boreal Ecosystems. 2019. Kent State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1573735336328272.

    MLA Style (8th edition)

  • Duroe, Kiersten. "Iron Redox Cycling and Impacts on Phosphorus Solubility in Tundra and Boreal Ecosystems." Master's thesis, Kent State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1573735336328272

    Chicago Manual of Style (17th edition)

kent1573735336328272
346
© 2019, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.