LTREB: Evaluation of Geothermally-modified Runoff and Nutrient Cycling in a Lowland Tropical Stream

9528434普林格尔以前的研究集中在地热引入的溶质和流生态之间的联系在低地雨林的哥斯达黎加。结果表明，富磷河流与贫磷河流“并存”。高磷的来源是地热改性的地下水，它在水流溶质化学中产生了很高的空间变异性。这些发现代表了中美洲火山脊大部分地区的河流模式。这项研究将建立在这些先前的发现。目前的项目将评价河流溶质化学，并纳入与哥斯达黎加两个主要河流流域沿着当地流域径流和地热输入有关的重要地貌特征。有待检验的假设是，地表水和地下水溶质化学的时空格局与火山地貌的三个主要地貌特征有关。 在其中一个研究排水系统中进行的过程导向研究将使河流溶质化学和运输与生态系统和生态系统级过程联系起来。实验和流监测将测试的假设，即在营养限制藻类生长和落叶分解在表面沃茨的空间和时间模式控制的存在或不存在的地热引入磷，沿着与物理/水文特性的流通道。 该项目的成果将包括关于中美洲主要是低地热带雨林的溪流溶质化学的唯一长期数据集。河流溶质化学和面向过程的数据对于科学家们寻求了解和管理热带森林以及预测区域环境变化对这些受威胁的生态系统的影响至关重要。

9528434 Pringle Previous research focused on the linkage between geothermally-introduced solutes and stream ecology in lowland rain forests of Costa Rica. Results indicated that phosphorus-rich streams exist 'side-by-side' with phosphorus poor streams. The source of the high phosphorus is geothermally-modified groundwater that creates a high spatial variability in stream solute chemistry. These findings represent patterns among streams draining much of the volcanic spine of Central America. This research will build on these previous findings. The current project will evaluate stream solute chemistry and incorporate important geomorphic features associated with local watershed runoff and geothermal inputs along two major stream drainages in Costa Rica. The hypothesis to be tested states that spatial and temporal patterns in solute chemistry of surface- and ground-water are related to three major geomorphic features of the volcanic landscape. Process oriented studies in one of the study drainages will allow the linkage of stream solute chemistry and transport to ecosystem- and landscape-level processes. Experiments and stream monitoring will test the hypothesis that spatial and temporal patterns in nutrient limitation of algal growth and leaf litter decomposition in surface waters are controlled by the presence or absence of geothermally-introduced phosphorus, along with physical/hydrological characteristics of the stream channel. Results from this project will comprise the only long-term data set on stream solute chemistry for primarily lowland tropical rainforest in Central America. Stream solute chemistry and process-oriented data are of fundamental importance to scientists seeking to understand and manage tropical forests and to predict the effects of regional environmental change on these threatened ecosystems.