Oceanography Seminar

November 10, 3:00pm - 4:00pm
Mānoa Campus, MSB 100 Add to Calendar

Sam Wilson
C-MORE Postdoctoral Scholar
University of Hawaii, Manoa

“Hydrogen production associated with nitrogen fixation: from the laboratory to the open ocean”

Abstract: In the surface waters of the tropical and subtropical environment, dissolved H2 concentrations are supersaturated with respect to atmospheric equilibrium. This phenomenon is most commonly attributed to the biological fixation of N2 as the production of H2 is inherent to the functioning of the nitrogenase enzyme. Therefore, wherever N2 fixation occurs, H2 is leaked to the ambient environment providing a source of potential energy to the wider microbial community. Understanding how the rates of H2 production vary between N2 fixing microorganisms is essential to understanding the cycling of H2 in the marine environment.

The relationship between N2 fixation, H2 production, and photosynthesis was examined in various marine cyanobacteria including Trichodesmium and Crocosphaera. The ratio of H2 produced:N2 fixed was found to vary over 2 orders of magnitude between different cyanobacteria and correlated with the metabolic strategy of the organism to fix N2. The laboratory studies have been complemented with a series of oceanographic cruises in the North Pacific Subtropical Gyre to examine the relationship between measured rates of N2 fixation and H2 concentrations, and investigate how the community composition of diazotrophs affects H2 cycling in the open ocean.


Ticket Information
Free

Event Sponsor
Oceanography, Mānoa Campus

More Information
Ocean Student, 956-7633, ocean@soest.hawaii.edu

Share by email