Collaborative Research: Probing Causal Links Among Volcanism, Dust, and Carbon Burial in the Permian - a Harbinger of the Future?

人类对地球气候系统进行了一次无意的实验，导致大气中的碳增加到人类从未经历过的水平。气候系统目前正在以明显的方式作出反应，触发正反馈将加速变化，对整个生物圈、特别是人类群体构成巨大风险。对潜在失控效应的担忧与日俱增，这引发了人们对有意通过地球工程来稳定地球温度及其巨大冰盖的讨论。一种普遍讨论的方法是太阳辐射管理(SRM)，即故意注入大气气溶胶，以模拟火山喷发自然造成的行星阴影。然而，这种行动的意外后果仍然未知，并可能引发更大的生物圈破坏。这个项目的目标是类似于今天的地球历史--一个拥有大片大陆冰盖和大量大气尘埃的时期，然后是“温室”变暖的时期--以探索地球的气候和生物圈系统如何对持续的火山爆发做出反应。这项研究将检验一些假设，这些假设的核心是大约3亿年前赤道盘古超大陆上频繁的火山爆发增加了大气尘埃中的微量营养素(如铁)的输送，导致海洋生态系统中植物生长和普遍缺氧的发展。最近的研究记录了大量的尘埃堆积，大约300 Mya，这些尘埃的微量营养素含量显著增加，但令人费解，以及大量的喷发火山作用，特别是在赤道纬度。火山作用、大气灰尘和营养物质的反应性的交汇被认为极大地影响了地球的碳循环，从而影响了气候和生物圈。如果社会开始进行有意的地球工程，就必须从地球的过去中学习，以了解潜在的未来后果。除了通过出版和传播结果揭示气候系统的行为外，该项目还将帮助几名学生和职业生涯早期的研究人员为STEM劳动力做准备，提高国家的科学和教育能力。这项工作从两个方面探索气候系统行为的新方面：1-重复的高频火山活动在直接影响地球气候方面的作用；2-将火山爆发与矿物粉尘增加养分释放和随之而来的影响碳循环的生态系统施肥联系在一起。为了验证这一点，将在代表古赤道盘古大陆巨大火山活动中心的一段暴露良好的火山岩上进行野外和实验室工作；将收集关于火山复发间隔和硫负荷的数据，以及同时代矿物粉尘的营养丰富程度的数据。这些数据将能够模拟火山活动是如何影响气候的，1--直接“遮蔽”地球，2--改变大气酸度，刺激尘埃中的微量营养素含量，从而使海洋生态系统肥沃。俄克拉何马州地球科学和科学教育学院将为俄克拉荷马州的教师准备和提供长期的专业发展，以提高中学生的气候科学素养。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。

Humanity has undertaken an unintentional experiment on Earth’s climate system, causing atmospheric carbon to increase to levels never before experienced by humans. The climate system is now responding in palpable ways, and the triggering of positive feedbacks will accelerate changes, posing large risks to the biosphere in general and human populations in particular. Increasing concerns of potential runaway effects have spurred talk of intentional geoengineering to stabilize Earth’s temperatures, and its large ice sheets. A commonly discussed approach is solar radiation management (SRM), the intentional injection of atmospheric aerosols to mimic the planetary shading induced naturally by explosive volcanism. However, the unintended consequences of such action remain unknown, and could initiate even larger disruptions of the biosphere. This project targets an interval of Earth history analogous to today— a time with large continental ice sheets and abundant atmospheric dust followed by “greenhouse” warming— to explore how Earth’s climate and biospheric systems responded to sustained explosive volcanism. This research will test a number of hypotheses centered on the idea that frequent, explosive volcanism over the equatorial Pangean supercontinent ~300 million years ago increased delivery of micronutrients (e.g. iron) from atmospheric dust, leading to enhanced plant growth and development of widespread anoxia in marine ecosystems. Recent research documents large accumulations of dust deposits ~300 Mya, a remarkably elevated but enigmatic micronutrient content of these dusts, and abundant explosive volcanism, especially at equatorial latitudes. The confluence of volcanism, atmospheric dustiness, and nutrient reactivity is posited to have greatly affected Earth’s carbon cycle, and thus climate and biosphere. If society embarks upon intentional geoengineering, it is imperative to learn from Earth’s past to understand potential future consequences. In addition to shedding light on behavior of the climate system through publication and dissemination of results, this project will help prepare several students and early-career researchers for the STEM workforce, enhancing the nation’s capabilities in science and education.This work explores novel aspects of climate-system behavior in two ways: 1— the role of repeated, high-frequency explosive volcanism in affecting Earth’s climate directly, and 2— linkages that tie explosive volcanism to enhanced nutrient release from mineral dusts and consequent ecosystem fertilization that affects the carbon cycle. To test this, field and laboratory work will be done on a well-exposed section of volcanic rocks representative of a vast center of volcanism in paleoequatorial Pangea; data will be collected on volcanic recurrence intervals and sulfur loading, and on the nutrient richness of coeval mineral dusts. These data will enable modeling of how this volcanism affected climate by both 1— direct “shading” of the planet, and 2— altering atmospheric acidity, stimulating micronutrient content of dust and thus fertilizing marine ecosystems. OU Geosciences and Science Education faculty will prepare and deliver long-term professional development for Oklahoma teachers, to increase climate science literacy amongst secondary school students.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.