ETBC: Teleconnections in the earth system: Nutrient subsidies and fire prone ecosystems

非洲稀树草原燃烧的频率比世界上任何其他生物群都要频繁，火灾造成的年均碳排放量约占全球总量的38%。在生物质燃烧排放的许多元素中，最令人感兴趣的两种是氮和磷，因为它们在生态系统生物地球化学循环中发挥着重要作用。然而，人们对他们在火灾后的命运知之甚少。这项研究将审查整个非洲的热源(与火有关的)养分排放、大气输送和养分沉积的模式，以探索火和输送在非洲大陆空间偏远地区之间输送养分的程度。在马里、西非对整个年度循环期间氮和磷沉积的实地测量将初步验证大气传输模型，并将用于探索非洲稀树草原生态系统中热源氮和磷沉积的潜在化学标记。还将对植被和土壤养分限制状况进行补充测量。与世界上大多数地方相比，非洲人口预计将经历全球气候变化的有害影响。这项研究将探索生态系统、土地覆盖变化和生物地球化学循环之间的相互作用，这些相互作用可能会影响现在和未来的生态系统可持续性和农业生产力。此外，这项研究的结果将为世界范围内其他易着火的生态系统提供关于火介导的营养循环的新见解。该项目还将促进与马里的国际伙伴建立新的合作关系。

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.