COLLABORATIVE RESEARCH: Investigating the link between modern spring activity and associated paleospring mounds in Death Valley, NP

在未来的几十年里，气候变化预计会减少旱地地区和美国西南部已经缺水的地区的可用水量。为了实施可持续的水资源政策，对区域气候历史的全面了解是必不可少的。pi将调查先前未被描述的陆地石灰岩，这些石灰岩是由Keane Wonder spring (KWST), Death Valley， National Park的春季活动（石灰华）形成的，以重建过去潮湿事件的时间。石灰华沉积物除了作为该地区过去水文气候记录者的潜力之外，还有助于更好地了解栖息在泉水和相关沉积物中的微生物群落如何成为化石记录的一部分，从而为解释地球上最早的生命记录提供信息。这项研究的结果将有助于阐明该地区过去的水文气候变化，并有助于我们了解控制微生物石化的途径。本研究将支持三所院校（其中两所为少数民族院校）的三名职业生涯早期至中期的教师、两名研究生和五名本科生。学生培训和课堂实地考察将为本科生提供独特的研究机会，包括实地调查和实验室处理方法。最近总结全球石灰华沉积趋势的工作表明，沉积高峰与当地高降水或潮湿条件的时间相对应。石灰华矿床在死亡谷很常见，但其作为水文气候档案的可靠性尚未经过多次气候转变的全面审查，需要与校准良好的近端水文气候记录进行比较。除了具有古气候档案的潜力外，石灰华矿床是微生物群落与其环境相互作用的敏感记录者，使石灰华成为评估微生物化石形态和功能的目标设置。pi将使用一套地球化学和微生物学分析，对现代泉水和相关的现代石灰华生长进行分析，并沿着泉水流动样带的不同相类型揭示活跃的石灰华增生记录和保存微生物、地球化学和水文特征的程度。pi将分析KWST的第四纪石灰华矿床，并使用一套地球化学和地质年代学分析来确定该地区水文气候变化的时间。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In the coming decades, climate change is projected to reduce water availability in dryland regions and the already water-stressed regions of the southwestern United States. In order to implement sustainable water resource policies, a thorough understanding of regional climate history is essential. The PIs will investigate previously undescribed terrestrial limestone rocks that form from spring activity (travertine) from Keane Wonder Spring (KWST), Death Valley, National Park to reconstruct the timing of past wet events. In addition to their potential as past recorders of the regions’ hydroclimate, travertine deposits serve to better understand how microbial communities that inhabit the spring water and associated sediment become part of the fossil record, thus informing the interpretation of the earliest records of life on Earth. Results from this research will help elucidate past changes in the regions’ hydroclimate and help inform our understanding of the pathways that govern microbial fossilization. This study will support three early to mid-career faculty, two graduate students and five undergraduate students at three institutions (two of which are minority-serving institutions). Training for students and class field trips will provide unique research opportunities for undergraduates including field surveys and lab processing methods. Recent work summarizing global trends in travertine deposits indicates that peaks in deposition correspond with local times of high precipitation or wet conditions. Travertine deposits are common in Death Valley, but their reliability as hydroclimate archives has not been fully vetted across multiple climate transitions and necessitates comparison with well-calibrated, proximal hydroclimate records. In addition to their paleoclimate archive potential, travertine deposits are sensitive recorders of interactions between microbial communities and their environment, making travertine a target setting to assess the morphology and function of fossilized microorganisms. The PIs will use a suite of geochemical and microbiological analyses of modern spring water and associated modern travertine growth along distinct facies types of a spring flow transect to reveal the extent to which active travertine accretion records and preserves microbiological, geochemical, and hydrologic signatures. The PIs will analyze Quaternary travertine deposits at KWST and use a suite of geochemical and geochronological analyses to establish the timing of hydroclimatic changes in the region.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.