Stanford University

*** Ph.D. Thesis/ Oral Defense ***

Mixed Signals: How Stable Isotopes Provide Insights into the Cycling and Transport of Nitrous Oxide in the Pacific Ocean 

Noah Gluschankoff

Monday, March 3,  9:00 AM

Hewlett 102

Zoom link

Department of Earth System Science

Advisor: Dr. Karen Casciotti

Abstract: Nitrous oxide (N2O) is a powerful greenhouse gas and a leading agent of stratospheric ozone depletion. Up to 30% of all N2O in the atmosphere comes from natural microbial processes in the ocean. Despite knowing the overall contribution of ocean derived N2O to the atmosphere, significant questions remain regarding what shapes the distribution of N2O in the ocean. Additionally, the sensitivity of N2O to environmental change remains fully unresolved. In my dissertation, I use the isotopes of nitrogen (N) and oxygen (O) of N2O and its substrates to investigate how N2O is produced, consumed, and transported in the eastern Pacific Ocean. In the first part of my talk, I will demonstrate new isotopic tools I developed to understand the cycling and transport of N2O in the tropical South Pacific Ocean. In the second half of my talk, I explore how these tools can be used to understand N2O transport in the California Current System and then discuss the sensitivity of N2O to changing environmental conditions in the eastern tropical South Pacific during El Niño and La Niña events. Overall, this work serves as an advancement in the tools used to understand N2O distributions in the ocean and our understanding of how N2O cycling and emissions may change in past, present, and future climate scenarios.