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

Bulseco-Mckim, Ashley N, Woods Hole MA

Investigators

Abstract

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.