Guest Seminar: Marine particulate respiration quotient: linking oxygen and biogeochemical cycles

Speaker

Dr. Allison Moreno
Postdoctoral Scholar
University of California, Los Angeles

Abstract

The loss of ocean oxygen, deoxygenation, caused by anthropogenic warming could lead to major declines in animal habitats. However, current Earth System Models strongly vary in their projections of global ocean oxygen. To bridge our understanding, I will demonstrate that marine oxygen concentrations are strongly modulated by a rarely considered quantity known as the respiration quotient, specifically how much oxygen is consumed per mole of organic carbon respired. We find that relatively small changes in the respiration quotient produce large changes of oxygen concentration within oxygen minimum zones and have strong feedbacks on primary productivity through the nitrogen cycle. Because the respiration quotient has rarely been measured in the ocean, this result conveys that future deoxygenation in response to warming will be more intense than previously anticipated.