Collaborative Research: EAR-Climate: Ecohydrological responses to climate change: Changing flowpaths, aging groundwaters, and alterations to aquatic ecosystems

该项目将增进对气候变化导致的地下水补给减少如何影响山区地下水系统和依赖地下水的生态系统的了解。美国西部的山区含水层是地区性的短期蓄水池，为农业活动、附近的城市和受到威胁的生态社区提供稳定的供水。项目活动将在内华达山脉Sagehen实验森林(SEF)进行，包括实地水文、地球化学、泉水生态群落分析和生态系统压力指标评估。在SEF中，春季地下水年龄以前与化学风化和生态系统丰富度的增加相关。这些观测作为与现代观测相比较的水文和生态健康的重要基线。这项工作的广泛影响集中在三个领域：1)通过支持本科生研究人员和两名职业早期科学家之间的合作来加强人才培养；2)通过参与在SEF举行的年度BioBlitz活动来支持正在进行的社区科学工作；以及3)通过与沙漠研究所的Science Alive团队合作开发侧重于项目发现的“绿箱”来支持K-12 STEM教育。该项目将调查SEF降水减少和气温上升如何改变了促成泉水产生的流动路径的分布。研究计划包括在SEF进行为期两年的春季水文采样，以获取一套地球化学分析、地下水年龄示踪剂和物理泉水特征。该项目还将调查SEF中的底栖大型无脊椎动物群落(BMI)，包括特有物种和遗迹物种在过去30年中如何变化，这些变化如何与流动路径变化相关，以及更广泛的BMI群落结构如何与现代水文和地球化学特征相关。这项研究将使用BMI的生态和稳定同位素分析来揭示群落结构和食物网动态。这项研究将确定揭示山区地下水系统中常年泉流和依赖地下水的生态位即将崩溃(即水生态阈值)的指标。该奖项由水文科学和生态系统科学计划共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will advance understanding of how decreased groundwater recharge associated with climate change affects mountain groundwater systems and groundwater-dependent ecosystems. Mountain aquifers across the western United States serve as regional short-term storage reservoirs that provide a stable water supply for agricultural activities, nearby cities, and threatened ecological communities. Project activities will occur in the Sierra Nevada Sagehen Experimental Forest (SEF) and include field hydrological, geochemical, ecological community analysis of springs and an assessment of indicators of ecosystem stress. In the SEF, spring groundwater age was previously correlated with increased chemical weathering and ecosystem richness. These observations serve as an important baseline of hydrological and ecological health for comparison with modern observations. Broader impacts from this work focus on three areas: 1) strengthening personnel development by supporting undergraduate researchers and collaboration between two early career scientists; 2) supporting ongoing community science efforts through engagement with the annual BioBlitz event at the SEF; and 3) supporting K-12 STEM education through the development of a “Green Box” focused on project discoveries in collaboration with the Desert Research Institute’s Science Alive team.This project will investigate how decreased precipitation and increased temperature in the SEF have altered the distribution of contributing flowpaths to springflow generation. The research plan includes two years of spring hydrological sampling in the SEF for a suite of geochemical analytes, groundwater age tracers, and physical spring characteristics. The project will also investigate how benthic macroinvertebrate communities (BMI), including endemic and relic species, in the SEF have changed over the last 30 years, how these changes relate to flowpath changes, and how broader BMI community structures relate to modern hydrological and geochemical characteristics. The research will use ecological and stable isotopic analysis of BMI to reveal community structures and food web dynamics. This research will identify indicators that reveal impending collapse (i.e., hydroecological thresholds) of perennial springflow and groundwater-dependent ecological niches in mountain groundwater systems. This award is co-funded by the Hydrologic Sciences and Ecosystem Sciences programs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.