Invited Speaker Seminar Series Summer 2020

On Monday July 13th, Bennett James Kapili from Anne Dekas lab at Stanford University will share his research with us.

A brief summary of Bennett's research:

Nitrogen-fixing organisms (i.e., diazotrophs) play a key role in determining ecosystem productivity by alleviating nitrogen limitation. However, we know little about the identity and activity of diazotrophs in deep-sea sediments (>200 m water depth), a habitat covering nearly two-thirds of the planet. In this talk, I will present our recent study that identifies candidate diazotrophs from Pacific Ocean sediments collected at 2,893 m water depth using 15N-DNA stable isotope probing and a novel pipeline for nifH sequence analysis. Our results indicate that the Deltaproteobacteria, predominately members of the Desulfobacterales and Desulfuromonadales, are abundant and active diazotrophs. In addition, we detect an unexpectedly diverse assemblage of low-abundance candidate diazotrophs, including members from the Acidobacteria, a phylum not previously shown to fix nitrogen. The candidate diazotrophs appear catabolically diverse, particularly with respect to possible terminal electron acceptors, which bears implications for the stability of this fixed nitrogen source over geologic timescales.