Biostimulation of microorganisms in peatlands through the weathering of atmospheric dusts at microbe-mineral interfaces

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The goal of my proposed Discovery research is to understand how microbial activity controls geochemical cycling in ombrotrophic peat in response to fertilization by atmospheric dusts and ash. Peatlands are vital ecosystems that occupy vast areas in Canada's north and around the globe, where they trap important nutrient elements and sequester CO2 in vegetation that is offset by losses from soil respiration. The impacts of increased dust deposition due to land development, increased forest fires and loss of glacial ice on element cycling are essentially unknown. This knowledge gap persists despite projected future increases in mineral and organic dusts. There are few studies on the biogeochemical processes that provide or remove nutrient and non-nutrient elements to and from Canadian peatlands and none that relate atmospheric dust inputs to both microbial responses and carbon budgets. This is a remarkable deficit. My recent investigations have centered on the relationships between nutrient elements and elements of concern that are delivered to wetlands, and the activities of native microorganisms that can chemically transform these elements. That research has raised the question of how natural peatlands, with dependence on atmospheric inputs for nutrients, mobilize chemical elements from atmospheric particulates. Such mobilization could play a critical role in supporting entire ecosystems, or conversely release elements of concern to surface water. I will answer this broad question through three distinct projects: 1) Identify current and historical inputs of atmospheric particulates to peatlands and relate these to nutrient elements and biological productivity; 2) Assess the capacity of peatland and dust-associated microbes to catalyze the weathering of atmospheric particulates for release of chemical elements 3) Relate changes in microbial activity and peatland soil C budgets to weathering of dusts and ash. The research methods to achieve these objectives span a range of approaches in geochemistry and microbiology that is highly interdisciplinary. Three PhD students, two MSc students and six undergraduates will participate in the research. The HQP will be recruited from all gender and ethnic groups, and will be trained to approach their research collaboratively with each other and with other scientists. Projects 2 and 3, by building on fundamental knowledge gained from P1, will provide the first assessment of element mobilization from dusts in peat under simulated field conditions, including weathering rates; investigations of mineral deposition on peatland biogeochemical cycling are rare, and investigations of ash are novel. The research will also provide new insights on C cycling to develop more accurate C budgets for peatlands and will open a new area of investigation that relates microbial geochemistry to peatland productivity.