Collaborative Research: Coupled Biogeochemistry and Geomorphology in Three Tropical Forest Ecosystems

地球化学中的一个主要范例是，由于岩石破裂所提供的养分长期耗尽，古老的土壤是贫瘠的。 据推测，营养物质的耗竭，特别是磷的耗竭，在热带低地普遍存在，那里缺乏历史上的冰川作用，这表明土壤比许多温带地区更古老。 然而，这种假设几乎肯定是过于简单化了。热带地貌是一个动态系统，在不同的地质和气候背景下，基岩转化为土壤以及土壤因侵蚀而流失的速度不同。 因此，绘制热带地区磷消耗的程度需要解决一个基本的和很少承认的问题，这是这个项目的重点，什么是磷在热带地区的停留时间，他们是足够的磷消耗发生？ 这个问题将在一项多学科、多地点的研究中得到解决，该研究将是第一个将土壤肥力评估与有助于量化土壤停留时间的新技术相结合的研究。该项目将把地球化学和地貌学结合起来，回答有关土壤肥力和养分循环的基本问题，并将促进量化热带地区肥力差异的迫切需要的努力。它将支持几个机构的国际研究，并让每个地点的当地科学家和学生参与。 除了培养研究生和博士后学者外，该项目还将为综合热带生态学、地球化学和地貌学的实地课程确定地点。

One of the dominant paradigms in biogeochemistry is that old soils are infertile as a result of the long term depletion of nutrients supplied through the breakdown of rocks. Nutrient depletion, particularly of phosphorus, is postulated to be widespread in tropical lowlands where the lack of historic glaciation suggests that soils are older than in many temperate regions. This assumption, however, is almost certainly an oversimplification. Tropical landscapes are dynamic systems in which the conversion of bedrock to soil and the removal of soil through erosion occur at different rates in different geologic and climatic settings. Thus mapping the extent of phosphorus depletion in the tropics requires addressing a fundamental and little acknowledged question that is the focus of this project, what are phosphorus residence times in the tropics and are they sufficient for phosphorus depletion to occur? This question will be addressed in a multidisciplinary, multisite study that will be the first to integrate assessments of soil fertility with new technologies that can help quantify soil residence times. This project will integrate biogeochemistry and geomorphology to answer fundamental questions about soil fertility and nutrient cycling and will promote a much needed effort to quantify differences in fertility in the tropics. It will support international research at several institutions and involve local scientists and students at each location. In addition to training graduate students and postdoctoral scholars, this project will establish site locations for a field course that integrates tropical ecology, biogeochemistry, and geomorphology.