RAPID: Impacts of high magnitude wildfire on volcanic (lava tube) cave water chemistry, nutrient transport, activity and diversity of cave microbiome

快速：大规模野火对火山（熔岩管）洞穴水化学、营养物运输、洞穴微生物组活动和多样性的影响

• 批准号: 2203517
• 负责人: Saugata Datta
• 金额: $ 9.94万
• 依托单位: University of Texas at San Antonio
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203517&HistoricalAwards=false
• 关键词: RAPID; Impacts; magnitude; wildfire; volcanic

Wildfires of high magnitude are known to cause destruction of surface vegetation, soil sterilization, and alteration of soil chemical and hydraulic properties; whereas their effects on subsurface environments are relatively unknown. Recent Caldwell and Antelope wildfires in northern California burnt over hundreds of acres of landscape which included 97% of the area in Lava Beds National Monument (Lava Beds) that protects volcanic (lava) caves. The volcanic caves provide a unique habitat for bacteria and archaea, and morphologically diverse secondary mineral features (speleothems) in the presence of water. This study investigates the impacts of intense wildfires on volcanic cave ecosystems by sampling cave water and microbial mats, and analyzing them for detailed inorganic and organic chemistry, microbial diversity and activity. This data from fire-affected caves will be compared with pre-fire data from earlier studies, and the control caves from the unburnt areas, to quantify the changes occurred within the caves due to wildfires. This RAPID project supports one minority graduate student at the University of Texas at San Antonio, a leading Hispanic Serving Institution (HSI) and several undergraduate students (Hispanic, minorities, women and first generation). In collaboration with the National Park Service, the findings of this study will help inform protection of the sensitive natural heritage at Lava Beds National Monument, and important scientific findings will be made available to the visitors of the park. Impacts of high magnitude wildfires on surface environments are well documented such as complete destruction of vegetation, soil sterilization, and alteration of physical, chemical and hydraulic soil properties. However, their effects on subsurface environments like vadose zones, shallow aquifers, and caves are relatively understudied. The Caldwell Fire in 2020 and Antelope Fire in 2021 in northern California have affected 97% of Lava Beds National Monument (California, USA) landscape that hosts numerous volcanic (lava) caves. Volcanic (lava) caves are nutrient-poor, aphotic environments, and yet they host a rich diversity of bacteria and archaea which often utilize reduced energy sources (e.g., reduced iron, sulfur, manganese, or nitrogen compounds) available within the host rock and mineral deposits within the caves. Availability of nutrients in caves greatly depends upon the interactions between host rock (basalt) and meteoric water that infiltrates through surface soils into caves through fractured cave walls. This RAPID study will obtain water and microbial samples from volcanic caves in wildfire affected and unaffected areas at Lava Beds, during a post-fire hydrologic response time, and correlate it with chemical and molecular signatures in the samples. Post-fire changes in cave water chemistry will be quantified by measuring concentrations of cations, anions, trace metals, and dissolved organic matter, and comparing with pre-fire data from earlier studies, and from control caves. Analysis of 16S rRNA gene sequencing and ATP will be used to track changes in microbial diversity and activity within the caves during the post-fire period. One graduate student and several undergraduate students from the University of Texas at San Antonio and University of New Mexico will perform samples collection and subsequent laboratory analyses. These results will provide a key information regarding impacts of surface wildfires on subsurface ecosystems.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.

众所周知，严重的野火会导致地表植被破坏、土壤灭菌以及土壤化学和水力特性的改变；而它们对地下环境的影响相对未知。最近加利福尼亚州北部的考德威尔和羚羊野火烧毁了数百英亩的土地，其中包括保护火山（熔岩）洞穴的熔岩床国家纪念碑（熔岩床）97％的面积。火山洞穴为细菌和古细菌提供了独特的栖息地，并在有水的情况下提供了形态多样的次生矿物特征（洞穴沉积物）。本研究通过对洞穴水和微生物垫进行采样，并分析其详细的无机和有机化学、微生物多样性和活性，调查强烈野火对火山洞穴生态系统的影响。来自受火灾影响的洞穴的数据将与早期研究的火灾前数据以及未燃烧地区的对照洞穴进行比较，以量化洞穴内因野火而发生的变化。该 RAPID 项目为德克萨斯大学圣安东尼奥分校（领先的西班牙裔服务机构 (HSI)）的一名少数族裔研究生和几名本科生（西班牙裔、少数族裔、女性和第一代）提供支持。通过与国家公园管理局合作，这项研究的结果将有助于保护熔岩床国家纪念碑敏感的自然遗产，并将向公园的游客提供重要的科学发现。大规模野火对地表环境的影响已有充分记录，例如植被完全破坏、土壤消毒以及物理、化学和水力土壤特性的改变。然而，它们对包气带、浅层含水层和洞穴等地下环境的影响却相对不足。加州北部 2020 年的考德威尔火灾和 2021 年的羚羊火灾影响了熔岩床国家保护区（美国加利福尼亚州）97% 的景观，该保护区拥有众多火山（熔岩）洞穴。火山（熔岩）洞穴是营养贫乏、无光的环境，但它们却拥有丰富多样的细菌和古细菌，这些细菌和古细菌通常利用主岩中可用的还原能源（例如还原铁、硫、锰或氮化合物），并且洞穴内的矿藏。洞穴中营养物质的可用性很大程度上取决于宿主岩石（玄武岩）和大气水之间的相互作用，大气水通过破裂的洞穴壁渗透到表面土壤进入洞穴。这项 RAPID 研究将在火灾后水文响应时间内从熔岩床受野火影响和未受影响地区的火山洞穴中获取水和微生物样本，并将其与样本中的化学和分子特征相关联。通过测量阳离子、阴离子、微量金属和溶解有机物的浓度，并与早期研究和对照洞穴的火灾前数据进行比较，可以量化洞穴水化学的火灾后变化。 16S rRNA 基因测序和 ATP 分析将用于追踪火灾后时期洞穴内微生物多样性和活动的变化。来自德克萨斯大学圣安东尼奥分校和新墨西哥大学的一名研究生和几名本科生将进行样本采集和随后的实验室分析。这些结果将提供有关地表野火对地下生态系统影响的关键信息。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。