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——决定了这一经济和环境上必不可少的资源的数量和质量。沿着它的路径，水介导化学反应，将岩石转化为土壤，并释放养分，为生态系统提供支撑。基本的科学问题仍然是关于水的流动速度和通过流域的路线。回答这些问题对于理解地球关键地带自然资源的产生和维持至关重要。最近发展的分析技术和理论的进步保证了从水携带的化学特征中获得新的见解。该项目将制定一项综合研究和教育计划，通过在秘鲁安第斯-亚马逊河流域的五个小集水区进行详细的水化学研究，为这些见解提供帮助。由于现有的基础设施、互补的正在进行的研究和独特的自然地形梯度，该研究地点提供了一个难得的机会来获得广泛应用的机制理解。在Madre de Dios河流域先前工作的基础上，该项目将重点关注从陡峭多山的安第斯山脉到亚马逊低地的过渡。山地到洪泛平原的过渡是常见的水文特征，但在现有的观测站中表现不佳。这项研究将确定水化学过程在这一转变过程中是如何变化的，并将探索观察到的变化的机制。该项目将围绕三个主题展开：(i)水停留时间；（ii）岩源溶质的富集-排出关系；（三）植物水源、流域水文和岩石营养物质可得性之间的关系。这些主题将使用新的水文测量和高频水化学测量进行探索。将从降水、水流、土壤水和地下水中收集样本，并分析溶质浓度和水同位素比率。对土壤、腐岩和基岩中矿物分布的调查将作为水化学研究的补充。新的数据将在该地区其他研究的地形、剥蚀率、植物根系和生态系统营养数据集的背景下进行解释。水和土壤样本收集、化学分析和数据解释将构成“关键区域暑期学校”的一部分，该学校是综合研究和教育计划的核心，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领导下一代。该项目将通过与景观设计师的合作，以及在美国和秘鲁的额外宣传和教育活动，进一步扩大“关键区域”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.