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

人类在无意中对地球气候系统进行了一项实验，导致大气中的碳含量增加到人类从未经历过的水平。气候系统正在以明显的方式作出反应，而触发正反馈将加速变化，对整个生物圈，特别是人类构成巨大风险。越来越多的人担心潜在的失控效应，这促使人们开始谈论有意利用地球工程来稳定地球的温度和巨大的冰盖。一种经常讨论的方法是太阳辐射管理（SRM），即故意注入大气气溶胶来模拟由爆炸性火山活动自然引起的行星遮阳。然而，这种行动的意外后果仍然未知，可能会对生物圈造成更大的破坏。这个项目的目标是地球历史上类似于今天的一段时间——一个有大片大陆冰盖和大量大气尘埃的时期，随后是“温室”变暖——探索地球气候和生物圈系统是如何对持续的爆炸性火山活动做出反应的。这项研究将测试一些假设，这些假设的中心思想是，大约3亿年前，赤道盘古超大陆上频繁的爆炸性火山活动增加了大气尘埃中微量营养素（如铁）的输送，导致植物生长加快，并导致海洋生态系统中广泛缺氧的发展。最近的研究记录了大约300万年前大量的尘埃沉积，这些尘埃的微量营养素含量显著升高，但令人费解，以及丰富的爆炸性火山活动，特别是在赤道纬度。火山活动、大气粉尘和养分反应性的共同作用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。如果社会开始有意地进行地球工程，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来揭示气候系统的行为外，该项目还将帮助一些学生和早期职业研究人员为STEM劳动力做好准备，提高国家的科学和教育能力。这项工作以两种方式探索了气候系统行为的新方面：1 -重复的、高频的爆炸性火山活动在直接影响地球气候方面的作用；2 -爆炸性火山活动与矿物粉尘中增加的养分释放以及随之而来的影响碳循环的生态系统施肥之间的联系。为了验证这一点，野外和实验室工作将在古赤道盘古大陆一个巨大火山活动中心的火山岩剖面上进行；将收集有关火山复发间隔和硫负荷的数据，以及同期矿物粉尘的营养丰富度的数据。这些数据将使模拟火山活动如何通过以下两种方式影响气候成为可能：1 .直接“遮蔽”地球；2 .改变大气酸度，刺激尘埃的微量营养素含量，从而使海洋生态系统肥沃。俄勒冈州立大学地球科学与科学教育学院将为俄克拉荷马州的教师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。

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.