NSF Postdoctoral Fellowship in Biology FY 2019: Characterizing the Microbial Consortia Capable of Degrading Complex Carbon in Salt Marsh Sediments using RNA-SIP

这一行动为NSF 2019财年生物学博士后研究奖学金提供资金，扩大了生物学领域代表性不足群体的参与。该奖学金支持一项针对该研究员的研究和培训计划，该计划将增加生物学中代表性不足的群体的参与。盐沼是沿海湿地，提供几项重要的生态系统服务，包括风暴潮保护、养分清除和碳固存。它们作为高效碳汇的潜力在很大程度上是由微生物调节的，这些微生物利用有机物为呼吸提供燃料，从而控制分解和长期储存碳之间的平衡。尽管它们很重要，但人们对生活在这些沼泽沉积物中的微生物、它们的分布以及不同微生物群可以利用的碳形式知之甚少。此外，氮素生产和化肥径流的增加以未知的方式极大地改变了这些沿海湿地系统，特别是关于栖息在其中的微生物的类型和活动。这项研究将提供关于有助于长期碳储存的微生物群体的新信息，这是一种有价值的生态系统服务，以及对盐沼如何应对环境变化的有价值的洞察。该研究员旨在通过组织和实施专门为社区大学学生开发的虚拟导师计划来扩大对科学的参与。盐沼是一种非同寻常的、但特征不佳的微生物类群的宿主。这项研究的目的是使用RNA稳定同位素探测(RNA-SIP)对能够降解复杂有机物的目标微生物群进行深度测序，从而能够表征优先结合标记底物的生物。当与基因组测序结合使用时，RNA-SIP提供了一个独特的机会来1)检查微生物沿深度梯度的结构和分布；2)评估在硝酸盐浓度升高的条件下这些微生物组的变化(如果有的话)，这些变化已被证明通过提供一个能量上有利的电子受体来刺激复杂有机物的分解；以及3)利用元转录组学研究基因表达的模式，特别是与碳降解有关的分解代谢基因。总体而言，这项研究将为控制深层盐沼沉积物中长期碳储存的微生物群体提供洞察力。除了这项研究，该研究员的目标是通过组织和实施专门为社区大学学生开发的虚拟导师计划来扩大对科学的参与。社区大学为美国近一半的本科生提供服务，然而传统的STEM培训计划往往忽视了这些庞大的人才库。因此，这个虚拟社区大学STEM网络旨在增加参与度，从而提高多样性、包容性和留住来自所有背景的科学家。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。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2019, Broadening Participation of Groups Under-represented in Biology. The fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. Salt marshes are coastal wetlands that provide several important ecosystem services, including storm surge protection, nutrient removal, and carbon sequestration. Their potential as an efficient carbon sink is largely mediated by microbes that use organic matter to fuel respiration, and as a result, control the balance between decomposition and long term storage of carbon. Despite their importance, very little is known about the microbes living within these marsh sediments, their distribution, and what forms of carbon different microbial groups can use. Further, increased nitrogen production and fertilizer runoff has drastically altered these coastal wetland systems in unknown ways, particularly with regard to the type and activity of microbes inhabiting them. This research will provide new information on microbial groups contributing to long term carbon storage, a valuable ecosystem service, as well as valuable insight into how salt marshes respond to environmental change. The fellow aims to broaden participation in science by organizing and implementing a virtual mentorship program developed specifically for community college students. Salt marshes are host to a remarkable, but poorly characterized, diversity of microbial taxa. This research aims to deeply sequence targeted groups of microbes capable of degrading complex organic matter using RNA Stable Isotope Probing (RNA-SIP), which allows for characterization of organisms that preferentially incorporate labeled substrate. When coupled with genomic sequencing, RNA-SIP provides a unique opportunity to 1) examine the structure and distribution of microbes along a depth gradient; 2) assess changes, if any, to these microbial groups under elevated nitrate conditions, which have been shown to stimulate decomposition of complex organic matter by providing an energetically favorable electron acceptor; and 3) investigate patterns in gene expression, particularly catabolic genes associated with carbon degradation, using metatranscriptomics. Overall, this research will offer insight into the microbial consortia responsible for controlling long term carbon storage in deep salt marsh sediments. In addition to this research, the fellow aims to broaden participation in science by organizing and implementing a virtual mentorship program developed specifically for community college students. Community colleges serve nearly half of the undergraduate population in the United States, however traditional STEM training programs tend to overlook these massive talent pools. This virtual community college STEM network therefore aims to increase engagement, and thus improve diversity, inclusivity, and retention of scientists from all backgrounds.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.