Scripps Institution of Oceanography at UC San Diego presents the Tsaihwa "James" Chow Lecture series September 23 and 24, 2024. Join us as American oceanographer, biogeochemist and microbiologist Bess Ward presents two lectures:
Monday, September 23, 2024 | Scripps Seaside Forum | Nitrous Oxide in the Ocean - No laughing matter
Talk at 3:00 p.m. with dessert reception to follow
The ocean is a major source of nitrous oxide (N2O) to the atmosphere, where it acts as a powerful greenhouse gas and ozone destroying agent. Microbes are largely responsible for the production and consumption of N2O in the ocean and other natural systems. In the context of the marine nitrogen cycle, we will explore environmental/physiological controls on two of the microbial pathways involved in N2O production and consumption. Nitrification (which requires oxygen) is the source of most of the N2O flux to the atmosphere, but denitrification (which occurs only in the absence of oxygen) is responsible for “hotspots” of N2O production. Episodic large fluxes of N2O to the atmosphere are linked to regions where denitrification occurs in subsurface waters.
Tuesday, September 24, 2024 | Hubbs 4500 | Nitrous oxide production and consumption in surface ocean waters
Talk at 12:00 p.m. with lunch to follow
Nitrous oxide (N2O), a potent greenhouse gas and ozone destroying agent, is produced and consumed by microbial processes in seawater. Production in surface waters is attributed mostly to nitrification, which is considered an obligately aerobic process, but there are no known consumption processes that occur under oxygenated conditions. Nevertheless, we are able to measure nitrous oxide consumption and to detect the presence and expression of genes that encode the nitrous oxide reduction reaction in surface waters. Experimental results from open ocean and coastal environments will be presented, to document and characterize this consumption term and the microbes responsible for it. The widespread occurrence of surface ocean N2O consumption challenges our understanding of conventional microbial physiologies and the regulation of net N2O exchange between ocean and atmosphere.
Ward is the William J. Sinclair Professor of Geosciences and The High Meadows Environmental Institute at Princeton University. Learn more about Bess Ward: https://geosciences.princeton.edu/people/bess-b-ward
Dr. Tsaihwa J. Chow was a geochemist with a long association with Scripps Institution of Oceanography at the University of California, San Diego.