Quantifying the effect of sediment microbial activity in facilitating silica sequestration during early diagenesis (QUALIFIED)

反向风化是通过涉及生物产生的二氧化硅的反应形成粘土矿物的过程。二氧化碳是逆风化的副产品，也是一种重要的温室气体。因此，逆风化被认为是在地球自然历史上调节全球气候的一个重要过程。以前的研究只关注非生物因素(即不受生物学影响的因素)。这项研究是第一次考察微生物对反向风化反应的影响。该项目包括对特征良好的微生物菌株进行实验室实验。这些实验将提供对受控环境中这一复杂过程的理解。在科学小组领导的两次实地活动期间，将在墨西哥湾北部进行后续实验和调查。该项目在多个层面上为科学教育和发展做出了贡献。本科生和研究生将学习跨学科的方法，并与一位国际专家合作进行反向风化研究。来自当地社区学院的本科生将获得带薪实习机会。该项目通过与Dauphin Island海洋实验室探索大厅计划的伙伴关系，支持高中海洋科学教育。参与这项研究的科学家还将与阿拉巴马州伯明翰的一个非营利性组织合作，为服务不足和代表性不足的3-8年级学生提供教育机会。逆风化作用影响着海洋中的许多生物地球化学循环。RW现在被认为占全球海洋硅质埋藏的40%左右。这种由RW驱动的埋藏限制了溶解的二氧化硅返回水柱的运动，在那里它可以促进硅藻的生长(消耗二氧化碳)，并有可能将硅藻碳输送到深海，在那里它可以被隔离几个世纪。RW也可能是Li、Al、K、Fe、Ge海洋循环中的一个主要但鲜为人知的汇术语，并可能在沿海海洋酸化中发挥作用。来自密西西比河羽流的初步现场数据直接证明了沉积物微生物在RW早期阶段的作用。鉴于这些试点实验的生物设计简单，二氧化硅循环和沉积物微生物学专家之间的合作对于更好地了解微生物在可再生水中的作用是必要的。通过这项研究，科学团队将解决一个一般性的问题：在RW过程中，哪些因素决定了微生物是促进还是阻碍了早期成岩二氧化硅产品的形成？该项目支持多个层次的科学教育，包括：(1)由Dauphin Island海洋实验室探索馆项目为K-12学生提供的项目，(2)为社区大学生提供的STEM研究经验，(3)研究生和博士后培训，以及(4)国际合作。该项目由海洋科学部的化学海洋学和生物海洋学项目资助。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。

Reverse weathering is the process that forms clay minerals through reactions that involve biologically produced silica. Carbon dioxide is a byproduct of reverse weathering and an important greenhouse gas. As a result, reverse weathering is considered an important process that has regulated global climate over the earth’s natural history. Prior studies that have examined reverse weathering have focused only on abiotic factors (i.e., factors not affected by biology). This research is the first to examine microbial effects on reverse weathering reactions. The project includes laboratory experiments with well-characterized microbial strains. These experiments will provide understanding of this complicated process in a controlled environment. Follow-up experiments and surveys will be conducted in the northern Gulf of Mexico during two field campaigns led by the scientific team. This project contributes to scientific education and development at many levels. The graduate and postgraduate personnel will learn interdisciplinary approaches and collaborate with an international expert in reverse weathering research. Undergraduate trainees from local community colleges will receive paid internships. The project supports high school education in marine science through a partnership with the Dauphin Island Sea Lab Discovery Hall Program. Scientists involved in this study will also work with a non-profit in Birmingham, Alabama, that brings educational opportunities to underserved and underrepresented students in grades 3-8. Reverse weathering (RW) affects many biogeochemical cycles in the ocean. RW is now recognized to represent ~40% of global oceanic silica burial. Such RW-driven burial restricts movement of dissolved silica back into the water column where it can fuel diatom growth (consuming carbon dioxide) and potentially transport diatom carbon to the deep ocean where it can be sequestered for centuries. RW also is likely to be a major, but poorly understood, sink term in the oceanic cycles of Li, Al, K, Fe, Ge and may play a role in coastal ocean acidification. Preliminary field data from the Mississippi River plume directly demonstrates a role for sediment microbes in the early phases of RW. Given the simplicity in the biological design of these pilot experiments, collaboration between experts in silica cycling and sediment microbiology is necessary to better understand the role of microbes in RW. Through this research, the scientific team will address the general question: What factors determine whether microbes facilitate or impede formation of early diagenetic silica products within the process of RW? This project supports science education across many levels including: (1) programs for K-12 students offered by the Dauphin Island Sea Lab Discovery Hall Program, (2) STEM research experiences for community college students, (3) graduate student and postdoctoral training and (4) international collaboration.This project is funded by the Chemical Oceanography and Biological Oceanography Programs in the Division of Ocean Sciences.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.