DISSERTATION RESEARCH: Leaf litter leachate and the fate of phosphorus in seasonal lowland tropical forests

磷是植物生长的关键元素，因此土壤中磷的有效性对世界粮食生产和陆地生态系统的碳循环至关重要。然而，对磷循环的控制还没有被很好地理解，这些控制预计会随着全球气候变化和持续的土地利用转换而改变。了解低地热带地区的磷循环尤其重要，因为该地区的许多土壤含有严重阻碍这种养分移动的矿物质成分。这项研究的目的是提高我们对凋落物渗滤液(衰老叶片的水提取物)如何影响季节性低地热带森林中磷循环的理解。这项研究将评估叶凋落物渗滤液对养分回归土壤是否重要，以及根据凋落物的结构和化学特征是否可以预测淋溶潜力。研究人员还将调查垃圾渗滤液在多大程度上控制植物-土壤-微生物环境中的磷循环。这项研究的更广泛影响包括它有助于我们理解凋落物淋溶和降雨模式之间的关系，以及这些结果在预测和减轻气候变化影响方面的应用。更好地理解自然系统如何循环磷也可以在管理系统中应用于提高产量，而不需要大量投入化肥。在这项研究的过程中，学生将通过巴拿马史密森热带研究所主办的课程和佛罗里达大学的本科生参与这项研究来指导本科生。

Phosphorus is a key element for plant growth, so phosphorus availability in the soil is critical for world food production and carbon cycling by terrestrial ecosystems. Yet the controls on phosphorus cycling are not well understood, and these controls are expected to change with global climate change and continued land-use conversion. Understanding phosphorus cycling in the lowland tropics is especially critical because many soils of this region have mineral constituents that greatly hinder the mobility of this nutrient. The goal of this study is to improve our understanding of how leaf litter leachate (water extracts of senesced leaves) affects phosphorus cycling in seasonal lowland tropical forests. This study will evaluate whether leaf litter leachate is important for the return of nutrients to the soil, and if leaching potential can be predicted from structural and chemical characteristics of litter. The researchers will also investigate the extent to which litter leachate controls phosphorus cycling within the plant-soil-microbe environment. The broader impacts of this research include its contribution to our understanding of the relationships between litter leaching and rainfall patterns, and the applications of these results for predicting and mitigating the effects of climate change. An improved understanding of how natural systems cycle phosphorus could also have applications for improving production in managed systems, without high inputs of fertilizer. During the course of this research, the student will mentor undergraduate students through coursework hosted by the Smithsonian Tropical Research Institute in Panama, and by engaging University of Florida undergraduates in this research.