CAREER: Taking the hydrochemical pulse of the critical zone in small catchments of the Andes-Amazon

水的旅程-从降水到土壤和地下水再到溪流和河流-决定着这一经济和环境上必不可少的资源的数量和质量。水沿着它的路径，介导化学反应，将岩石转化为土壤，并释放养分，为生态系统提供养分。基本的科学问题仍然是水的速度有多快，以及它通过流域的路线。回答这些问题对于理解地球关键地带自然资源的生成和维持至关重要。最近开发的分析技术和理论进展有望从水携带的化学特征中获得新的见解。该项目将制定一个综合的研究和教育方案，通过对秘鲁安第斯-亚马逊河流域的五个小流域进行详细的水化学研究，提供这种见解。这个研究地点提供了一个难得的机会，获得广泛适用的机械理解，因为现有的基础设施，互补的正在进行的研究，和独特的自然地形梯度。该项目以先前在马德雷德迪奥斯河流域开展的工作为基础，重点关注从陡峭的安第斯山脉向低地亚马逊河的过渡。山区到洪泛平原的过渡是常见的水文特征，但在现有的观测站代表性很差。这项研究将确定水化学过程如何在这一过渡过程中变化，并将探索观察到的变化机制。该项目将围绕三个主题：（i）水停留时间;（ii）岩石衍生溶质的浓度-排放关系;（iii）植物水源、流域水文和岩石衍生营养素可用性之间的关系。将利用新的水文和高频水化学测量方法探讨这些主题。将从降水、河水、土壤水和地下水中采集样品，并分析溶质浓度和水同位素比。水化学研究将辅之以土壤、腐泥土和基岩中矿物分布的调查。新的数据将解释的地形，剥蚀率，植物根系和生态系统的营养数据集在该地区的其他研究的背景下。水和土壤样本收集，化学分析和数据解释将构成“关键区暑期学校”的一部分，该学校包括综合研究和教育计划的核心，并将培养高级本科生和初级研究生，他们将在这个跨学科研究领域引领下一代。该项目将通过与景观设计师的合作以及通过在美国和秘鲁开展更多的推广和教育活动，进一步扩大“临界区”概念框架的范围。

Water's journey -- from precipitation through soils and groundwater to streams and rivers -- determines the quantity and quality of this economically and environmentally essential resource. Along its path, water mediates chemical reactions that transform rock into soil and that release nutrients, providing the sustenance for ecosystems. Basic scientific questions remain about how quickly water travels and what route it takes through watersheds. Answering these questions is vital for understanding the generation and maintenance of natural resources in Earth's critical zone. Recently developed analytical techniques and theoretical advances promise new insight from the chemical signatures carried by water. This project will develop an integrated research and education program to contribute such insight through detailed hydrochemical study in five small catchments in the Andes-Amazon of Peru. This study site provides a rare opportunity to gain widely applicable mechanistic understanding because of existing infrastructure, complementary ongoing research, and unique natural topographic gradients. Building on prior work in the Madre de Dios river basin, this project will focus on the transition from the steep, mountainous Andes to the lowland Amazon. Mountain-to-floodplain transitions are common hydrologic features but are poorly represented in existing observatories. The research will identify how hydrochemical processes vary over this transition and will explore mechanisms for observed variations. The project will center around three themes: (i) water residence times; (ii) concentration-discharge relationships of rock-derived solutes; and (iii) relationships between water sources for plants, catchment hydrology, and the availability of rock-derived nutrients. These themes will be explored using new hydrometric and high-frequency hydrochemical measurements. Samples will be collected from precipitation, streamwater, soilwater, and groundwater and analyzed for solute concentrations and water isotope ratios. The hydrochemical studies will be complemented by investigations of mineral distributions in soil, saprolite, and bedrock. New data will be interpreted in the context of topographic, denudation rate, plant root, and ecosystem nutrient datasets from other studies in the region. Water and soil sample collection, chemical analyses, and data interpretation will form part of a "Critical Zone Summer School" that comprises the core of the integrated research and education plan and will train upper-level undergraduate and beginning graduate students who will lead the next generation in this cross-disciplinary research area. This project will further broaden the reach of the "critical zone" conceptual framework through collaboration with landscape architects and through additional outreach and educational activities both in the US and in Peru.