RUI: SG: Field and Laboratory Tests of Pyrogenic Organic Compounds in Australian Stalagmites as a Novel, High-Resolution Paleofire Proxy

RUI：SG：澳大利亚石笋中热原有机化合物作为新型高分辨率古火代理的现场和实验室测试

基本信息

批准号：
2147186
负责人：
Rhawn Denniston
金额：
$ 19.98万
依托单位：
Cornell College
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2025-07-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2147186&HistoricalAwards=false
关键词：
RUI SG Field Laboratory Tests

项目摘要

The massive fires that burned across many parts of Australia in 2019-2020 are part of a global trend. Rising temperatures, coupled in some cases with prolonged droughts and fire suppression efforts, have created conditions conducive to unusually intense and widespread fires, including across many parts of the western United States. While exceptional for the century, it is unclear how unusual this fire activity is over long-term Earth history. In order to better place modern fire activity into a longer-term context, it is necessary to develop reconstructions of burning that occurred prior to the satellite era (1979-present). Records of ancient fire have been developed from burn scars on tree rings, from charcoal in lake sediments, and from fire-derived compounds deposited on and stored in glacial ice. In tropical Northwest Australia, it is not possible to recover such data. The goal of this project is to develop methods to recover fire-derived compounds from stalagmites in caves in that region. Results are expected to provide a clearer understanding of the utility of stalagmites as a novel record of past burning, and allow its application to other fire-prone regions, including the western United States. The project will also provide opportunities for undergraduate student training.Fire plays a critical role in the ecology of the tropics, but fuel loads, sources of ignition, and background climate conditions are often markedly different now than they were a century or more ago. Addressing the extent to which fire regimes are changing is complicated by the sparsity of high-resolution, long-term records of fire frequency and intensity spanning far beyond the instrumental era. Understanding the frequency and intensity of fire activity prior to the arrival of European pastoralists and during intervals of climate distinct from the modern era (e.g, the Little Ice Age: CE 1450- 1850) is critically important for managing current fires, estimating cascading effects of fires on plant and animal diversity, and maintaining ecosystem resiliency. This study aims to refine a novel paleofire proxy capable of addressing these limitations: pyrogenic organic compounds (including polycyclic aromatic hydrocarbons, PAHs) in stalagmites. Previous research by the PI and collaborators has revealed that stalagmites from a tropical Australian cave preserve changes in the type and abundance of pyrogenic compounds over time, with these shifts consistent with recent fire activity proximal to the cave. Burning of biomass produces PAHs, which are then transported into the underlying cave by monsoon rains, and incorporated into stalagmites as they crystallize from dripwater. While these results are extremely promising, the biochemical and hydrological mechanics of the cave system need to be further scrutinized before this method can be applied more widely. Toward that end, the PI and collaborators will perform field and laboratory experiments: (i) measurements of organic compounds such as PAHs in soil and cave dripwater prior to, immediately following, and a year after a prescribed burn over the cave site, (ii) replication of pyrogenic organic compound distributions in a coeval stalagmite sample, and (iii) comparison of the paleofire signals in a 20th century stalagmite to remote sensing data and records of fire derived from historical documents. This work will also provide training to several undergraduates at Cornell College in field and laboratory methods, a critical step in advancing their careers as scientists.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.

2019 - 2020年澳大利亚许多地区燃烧的大火是全球趋势的一部分。在某些情况下，随着干旱和火灾抑制作用的长期加速，温度的升高已经创造了有利于异常激烈和广泛的大火的条件，包括美国西部许多地区。虽然在本世纪异常，但尚不清楚这种火灾活动在长期地球历史上是多么不寻常。为了更好地将现代火灾活动置于长期的环境中，有必要发展卫星时代之前发生的燃烧的重建（1979年至今）。从树环上的燃烧伤痕，湖中的木炭以及沉积在冰川冰上存放的消防化合物，从树环上的燃烧疤痕，燃烧的疤痕中得出了古老的火记录。在澳大利亚热带西北地区，不可能恢复此类数据。该项目的目的是开发从该地区洞穴中的Stalagmites恢复源自火的化合物的方法。预计结果有望更清楚地了解Stalagmites作为过去燃烧的新记录，并允许其在包括美国西部在内的其他容易发生的地区。该项目还将为本科生培训提供机会。FIRE在热带地区的生态中起着至关重要的作用，但是燃料负载，点火源和背景气候条件现在通常与一个世纪或以前的情况明显不同。通过高分辨率的稀疏性，火灾频率和强度的长期记录越来越远远超出了器乐时代，因此解决火灾状况的变化程度变得复杂。在欧洲牧民到达之前以及在与现代时代不同的气候间隔（例如，小冰河时代：CE 1450-1850）的气候间隔内了解火灾活动的频率和强度至关重要在动植物的多样性上发火，并保持生态系统的弹性。这项研究旨在完善能够解决这些局限性的新型古发代理：天生的有机化合物（包括多环芳族烃，PAHS）。 PI和合作者的先前研究表明，来自热带澳大利亚洞穴的石塔米木伴随着热带洞穴的变化，随着时间的流逝，热源化合物的类型和丰富度变化，这些变化与最近靠近洞穴的火灾活动一致。生物量的燃烧会产生PAH，然后由季风降雨将其转运到下面的洞穴中，并从滴水器结晶时掺入石塔木米。尽管这些结果非常有前途，但需要对洞穴系统的生化和水文力学进行进一步审查，然后才能更广泛地应用这种方法。为此，PI和合作者将执行现场和实验室实验：（i）测量有机化合物，例如土壤和洞穴滴水器中的PAH，紧随其后的是，以及在处方烧毁洞穴的燃烧后一年（ii）（ii）（ii））复制辅助石质岩样品中的热源有机化合物分布，以及（iii）20世纪石岩中古射线信号与遥感数据和源自历史文档的火记录的比较。这项工作还将为康奈尔学院（Cornell College of Field）和实验室方法的几位大学生提供培训，这是科学家作为科学家的职业发展的关键步骤。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛的评估来支持的。影响审查标准。