Microorganisms are tiny critters. These days we hear a lot about their impact on our health. The microorganisms that inhabit your gut, for example, help you extract nutrients from your food and defend your body against pathogens. But microorganisms play a big role in geological environments too, where among other things, their reactions can cause minerals to precipitate or dissolve, mobilize hazardous trace elements, metabolize hydrocarbons, and drive cycling of carbon, nitrogen, sulfur, iron, and most other elements in global cycles.
A newly funded NSF project led by Dr. Kirk is focused on two microbial reactions in particular, iron reduction and methanogenesis. During iron reduction, microorganisms respire ferric iron, the form of iron in rust. During methanogenesis, microorganisms make methane, the primary component of natural gas and a potent greenhouse gas. Some iron reducers and methanogens, the microbes that drive the reactions, can cooperate with one another by sharing energy resources. However, most predictive models assume that methanogens and iron reducers do not coexist, due to competition for energy sources, and only allow methane generation where ferric minerals have been depleted. Failure to account for both cooperative and competitive interactions may introduce error in process-based estimates of methane production. Moreover, environmental drivers of cooperation between each group have not been identified, limiting the ability of models to predict how methane fluxes vary with environmental conditions.
This study will use experiments and biogeochemical modeling to create a new model for methanogenesis – one that links competitive and cooperative interactions. The model will improve the ability to predict methane generation and manage carbon budgets in natural and engineered systems including soils, aquifers, landfills, and wastewater treatment systems. The study will also provide interdisciplinary training to undergraduate and graduate students and increase involvement of underrepresented groups in science through participation in the Kansas Louis Stokes Alliance for Minority Participation summer research program and summer outreach events for middle-school girls.