CAREER: What sets the CO2 thermostat? Insights from the global geochemical cycles of Ca, Mg, and K

地球气候、全球碳循环和海水组成之间的反馈构成了在地球40亿年历史的大部分时间里维持地球上宜居条件的主要机制之一。这个项目试图为我们理解海洋过程提供一个新的基础，海洋过程在随着时间的推移调节地球化学循环方面发挥着重要但没有得到重视的作用。这一职业奖的研究部分将涉及开发和应用新的分析方法和工具，以调查一些最鲜为人知的维持海洋化学平衡的方式。职业奖励也旨在支持特别强有力的教育努力和研究与教育的融合。为此，希金斯与社区发展组织Isles，Inc.合作，在新泽西州特伦顿提出了一个城市自来水教育监测计划。该项目将由Isles，Inc.员工、社区志愿者、特伦顿学生、普林斯顿本科生、首席研究员和一名博士后研究员组成的团队进行。学生们将通过调查自来水的化学成分来学习科学方法的步骤，接触到科学工作背后的细节，并培养对科学如何赋予个人权力和影响社区的欣赏。PI建议通过使用多收集器电感耦合等离子体质谱(MC ICP-MS)对镁(26 mg/24 mg)、钙(44Ca/42Ca)和钾(41K/39K)的稳定同位素比率进行高精度的高通量测量，来研究影响阳离子、碱度和二氧化碳通过海洋-大气系统的海洋过程。将开展的具体研究课题包括：1)自生海洋粘土中的镁和钾的全球汇；2)与浅水碳酸盐沉积物成岩作用有关的镁和钙的全球通量；以及3)低温海底热液系统中的镁和钙的全球通量。方法包括实验室实验以及沉积物和孔隙流体样品的分析。

Feedbacks between Earth's climate, the global carbon cycle, and the composition of seawater constitute one of the primary mechanisms invoked for maintaining habitable conditions on our planet over much of its 4 billion year history. This project seeks to provide a new foundation for our understanding of the marine processes that play a significant but underappreciated role in moderating Earth's chemical cycles through time. The research component of this CAREER award would involve the development and application of new analytical methods and tools to investigate some of the most poorly understood ways in which the chemical balance of the oceans is maintained. CAREER awards are also designed to support particularly strong educational efforts and the integration of research and education. To this end, Higgins proposes an educational monitoring program of urban tap water in Trenton, NJ in collaboration with Isles, Inc., a community development organization. This project would be carried out by teams consisting of Isles, Inc. employees, community volunteers, Trenton students, Princeton undergraduates, the lead investigator, and a postdoctoral investigator. Students would learn the steps of the scientific method through an investigation of the chemistry of their home tap water, get exposure to the nuts-and-bolts behind how science works, and develop an appreciation for how science can empower an individual and impact a community. The PI proposes to investigate marine processes that affect the flow of cations, alkalinity, and CO2 through the ocean-atmosphere system with the targeted application of high-precision high-throughput measurements of stable isotope ratios of magnesium (26Mg/24Mg), calcium (44Ca/42Ca), and potassium (41K/39K) by multi-collector inductively coupled plasma mass spectrometry (MC ICP-MS). Specific research topics that will be pursued are 1) Global sinks of Mg and K in authigenic marine clays, 2) Global fluxes of Mg and Ca associated with diagenesis of shallow-water carbonate sediments, and 3) Global fluxes of Mg and Ca in low temperature seafloor hydrothermal systems. Approaches include laboratory experiments as well as analysis of sediment and pore-fluid samples.