NSF Postdoctoral Fellowship in Biology FY 2020: Controls on the formation and persistence of mineral-associated organic matter

本行动资助美国国家科学基金会2020年度生物学博士后研究奖学金，利用生物馆藏进行研究。该奖学金支持将以创新的方式利用生物收集的研究员的研究和培训。该项目将确定最能支持美国森林长期土壤碳储存的环境条件。土壤是一个巨大的碳库，将有机物质困在地下，减缓大气中二氧化碳的积累。因此，土壤是缓解进一步环境变化的重要资源。然而，对土壤所能吸收的碳量的了解仍在不断发展。本研究将探讨植被类型、土壤微生物群落和土壤矿物质的物理结构如何影响生态系统长期有效储存碳的能力。该研究员将使用从美国国家生态观测站网络（NEON）运营的美国各地收集的土壤来测试这些想法。该研究员还将参加一个K-12教师培训课程和几个学生拓展项目，以提高科学素养。通过这项工作产生的数据将用于分析和解释环境数据的实践课程。从13个森林NEON站点的样本档案中提取的矿物土壤将使用顺序密度分馏法将其分为矿物相关有机质（MAOM）和其他有机质池。利用NEON数据门户网站的现有植被和微生物数据，研究员将评估树种、微生物群落和土壤矿物学的变化如何影响作为MAOM在站点内和跨站点水平上储存的土壤碳的比例。此外，研究员将使用标记有13C和15N同位素的有机物来研究MAOM的稳定性。模拟的根际条件将在试验性中生态系统中产生，使用一种带有合成有机酸根渗出液的流动系统。双标记的MAOM将受到这些条件的影响，矿物表面的不稳定将用同位素比质谱法进行量化。剩余的材料将用先进的成像技术进行可视化，以识别抵抗解吸的特定有机-矿物键。该研究员将与数据金块项目一起创建一个在线课程计划，向高中生传授分析生态数据的过程。该研究员将在一个针对当地高中生的暑期研究项目中与科学界代表性不足的群体合作，并将参加一个K-12教师培训课程，为气候变化教学设计有效的策略。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。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2020, Research Using Biological Collections. The fellowship supports research and training of the Fellow that will utilize biological collections in innovative ways. The project will identify the environmental conditions that best support long term soil carbon storage in forests across the U.S. Soils act as an enormous reservoir of carbon, trapping organic matter below ground and slowing the accumulation of carbon dioxide in the atmosphere. Soil is therefore an important resource for mitigating further environmental change. However, the understanding of the amount of carbon that soil can sequester is continually evolving. This research will explore how the vegetation type, soil microbial communities, and physical structure of soil minerals affect the ability of ecosystems to effectively store carbon over long time periods. The Fellow will test these ideas using soil collected from sites across the U.S. operated by the National Ecological Observatory Network (NEON). The Fellow will also participate in a K-12 teacher training course and several student-outreach programs to advance scientific literacy. Data generated through this work will be used for hands-on lessons about analyzing and interpreting environmental data.Mineral soil from the sample archives of thirteen forested NEON sites will be separated into mineral-associated organic matter (MAOM) and other organic matter pools using sequential density fractionation. Using existing vegetation and microbial data from the NEON data portal, the Fellow will assess how variation in tree species, microbial communities, and soil mineralogy influence the proportion of soil carbon stored as MAOM at both the within-site and across-site levels. Further, the Fellow will investigate MAOM stability using organic matter labeled with both 13C and 15N isotopes. Simulated rhizosphere conditions will be generated in experimental mesocosms using a flow-through system with a synthetic root exudate solution of organic acids. Dual-labeled MAOM will be subjected to these conditions and destabilization from mineral surfaces will be quantified with isotope ratio mass spectrometry. The remaining material will be visualized with advanced imaging techniques to identify the particular organo-mineral bonds that resist desorption. The Fellow will create an online lesson plan with the Data Nuggets program to teach high school students about the process of analyzing ecological data. The Fellow will work with underrepresented groups in science during a summer research program for local high school students, and will participate in a K-12 teacher training course designing effective strategies for teaching about climate change.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.