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

我提出的探索研究的目标是了解微生物活动如何控制近营养型泥炭的地球化学循环，以响应大气尘埃和灰烬的施肥。泥炭地是重要的生态系统，占据了加拿大北部和全球的大片地区，在那里它们捕获了重要的营养元素，并将二氧化碳封存在植被中，这些二氧化碳被土壤呼吸损失所抵消。由于土地开发而增加的粉尘沉积、森林火灾的增加和冰川冰的损失对元素循环的影响基本上是未知的。尽管预计未来矿物和有机粉尘会增加，但这种知识差距仍然存在。关于向加拿大泥炭地提供或去除营养和非营养元素的生物地球化学过程的研究很少，也没有将大气尘埃输入与微生物反应和碳收支联系起来的研究。这是一个显著的赤字。我最近的研究集中在营养元素和被输送到湿地的关注元素之间的关系，以及能够化学转化这些元素的本地微生物的活动。这项研究提出了一个问题：依赖于大气养分输入的天然泥炭地是如何从大气颗粒物中调动化学元素的。这种动员可以在支持整个生态系统方面发挥关键作用，或者反过来向地表水释放令人关切的元素。我将通过三个不同的项目来回答这个广泛的问题：1)确定当前和历史上大气颗粒物对泥炭地的输入，并将其与营养元素和生物生产力联系起来；2)评估泥炭地和粉尘相关微生物催化大气颗粒物风化释放化学元素的能力3)将微生物活动和泥炭地土壤碳收支的变化与灰尘和灰烬的风化联系起来。实现这些目标的研究方法跨越了地球化学和微生物学的一系列方法，是高度跨学科的。3名博士生、2名硕士生和6名本科生将参与研究。HQP将从所有性别和种族群体中招募人员，并将接受培训，以便彼此合作并与其他科学家合作开展研究。项目2和项目3将以从P1获得的基本知识为基础，首次评估模拟野外条件下泥炭粉尘中的元素调动情况，包括风化率；泥炭地生物地球化学循环中矿物沉积的研究较少，而对灰分的研究则较为新颖。该研究还将提供关于碳循环的新见解，以开发更准确的泥炭地碳预算，并将开辟一个新的研究领域，将微生物地球化学与泥炭地生产力联系起来。

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.