NCNF

Nitrogen (N) is an important element in the ocean that limits the growth of the microscopic marine plants, phytoplankton. Estimates suggest N inputs and losses may not be balanced in the modern ocean, and thus an underestimation of N inputs may explain this imbalance. The conversion of gaseous N2 to biologically available N (N2 fixation) is the largest source of new N to the ocean. It is possible that the ?missing? N can be explained by identifying new sources of N2 fixation. N2 fixation relies on a group of microorganisms, termed ?diazotrophs,? that utilize N2 for growth, unlike other marine microorganisms. Diazotrophs fall into two groups, cyanobacterial diazotrophs, which are able to derive energy through photosynthesis, and non-cyanobacterial diazotrophs (NCDs), which require a non-light-based energy source. Next to nothing is known about the ecology and biology of NCDs, except that they are ubiquitous in the ocean and contain the nitrogen fixing gene, but no direct measurements of their N2 fixation activity exist. Recent molecular advances for studying organisms at the single cell level now makes the measurement of N2 fixation by NCDs possible. This study is focused on determining whether marine NCDs are actually fixing N2 in the environment and understanding how their N2 fixation is modulated. Determining if NCD activity is an important missing N source in the global oceans has the potential to fill a critical gap in our understanding of the marine N cycle. This project supports early career STEM researchers including a graduate student and a postdoctoral scientist, as well as undergraduate students through several programs including UCSC?s California Alliance for Minority Participation (CAMP).