Diverse regional drivers of aquatic greenhouse gas emission - management and climate drivers

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Freshwaters are a key source of natural greenhouse gas emissions to the atmosphere, owing to widespread carbon and nitrogen cycling in these systems. The magnitude of emissions can be dramatically altered by anthropogenic stressors, but our mechanistic understanding of the properties of different freshwater systems that drive emissions is a major gap for prediction. This is especially true of shallow inland waters of the prairie region, which is typified by wet-dry cycles that govern water storage in wetlands and ponds, and managed flows in many rivers. Greenhouse gas budgets are expected to be highly dynamic, and changes in climate and land use are expected to amplify this. Overlaid on this are emerging concerns regarding degraded water quality, costly flooding, and the loss of important habitat that are driving changes in policy and renewed efforts at wetland conservation and water resource management. Detailed consideration of the effects of changes in policy and practice on the greenhouse gas balance of these ecosystems is urgently required.******My program will focus on identification of the key drivers of greenhouse gas emissions from shallow surface waters in the prairie region. I will use novel approaches, including new sensors developed by my research team, to understand rates of greenhouse gas release. This will allow us to understand the importance of different release pathways for greenhouse gas budgets. I will use a local landscape approach to link prairie wetland aquatic greenhouse gas conditions to drivers including hydrology and chemistry. This will provide insight into how regional greenhouse gas emissions shift in response to natural cycles, and disturbance. Building on new work demonstrating that water level management in reservoirs can alter greenhouse gas release, I will identify the effect of human water level management on greenhouse gas emissions in managed prairie rivers including a large river impacted by flow management for electricity production, and a small sewage-dominated stream where daily water consumption patterns determine flow patterns. This research will build the foundation to help us understand current emissions from prairie aquatic ecosystems and to account for these systems in whole-farm accounting of greenhouse gas emissions. This will help us anticipate future change, and constrain estimates of regional water-atmosphere greenhouse gas exchange over multi-year periods, identifying influences of climate, land and water management.