African savannas burn more frequently than any other biome worldwide, with average annual carbon emissions from fires representing ~38% of the global total. Of the many elements emitted in biomass burning, two of the most interesting are nitrogen and phosphorus because of their important role in ecosystem biogeochemical cycles. However, their fate following fires is poorly understood. This research will examine patterns of pyrogenic (fire-related) nutrient emissions, atmospheric transport and nutrient deposition across Africa to explore the extent to which fires and transport move nutrients among spatially remote regions of the continent. Field measurements in Mali, West Africa of nitrogen and phosphorous deposition during a full annual cycle will provide initial validation of an atmospheric transport model, and will be used to explore potential chemical markers for pyrogenic nitrogen and phosphorous deposition in African savanna ecosystems. Complementary measurements of vegetation and soil nutrient limitation status will also be made.
More than in most places around the world, the human populations of Africa are expected to experience deleterious effects from global climate change. This research will explore interactions between ecosystems, land-cover changes and biogeochemical cycles that may impact ecosystem sustainability and agricultural productivity now, and into the future. Further, the results of this research will provide new insights on fire-mediated nutrient cycling for other fire-prone ecosystems worldwide. The project will also foster new collaborative relationships with international partners in Mali.
