Stanford University

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ESS-Seminar Speaker Series: Dr. Kenneth Johnson, Senior Scientist at the Monterey Bay Aquarium.

Wednesday, Oct 21, 2020 11:30 AM
Via Zoom
More Info:
ESS-Seminar Speaker Series: Dr. Kenneth Johnson, Senior Scientist at the Monter…
Department of Earth System Science

Please join us for next week's Virtual Fall Quarter Seminar Series with Guest Speaker, Kenneth Johnson, Ph.D. A special thanks to Karen Casciotti for bringing us this speaker for you. Also, Morgan O'Neill and Jamie Jones for co-instructing and running this Virtual Seminar Series This Fall by bringing you experts in the fields as we learn from them. For virtual connection information, please go to:

Join from PC, Mac, Linux, iOS or Android:

Password: 916773

Talk Title: "Observing the dynamics of the nitrogen cycle in situ with chemical sensors on profiling floats"

Abstract: Denitrification in the Oxygen Deficient Zones (ODZ) of the world ocean exerts a major control on the global nitrogen cycle. However, there is little information on temporal variability of oxygen, nitrate, or nitrite in these systems. Here, I’ll present results for chemical variability in the Eastern Tropical North Pacific, Arabian Sea, and the Bay of Bengal over time scales from weeks to years. The data sets were collected with chemical sensors on profiling floats that have operated for as long as 5 years in these systems. The observations imply that fixed nitrogen loss occurs in all 3 ODZs as a slow conversion of nitrate to nitrite, which accumulates to elevated concentration, followed by episodic events of rapid nitrite loss.

Dr. Kenneth Johnson is a Senior Scientist at the Monterey Bay Aquarium Research Institute in Moss Landing. His research focuses on the development of novel chemical sensors which can be deployed for extended periods (years) in the ocean. Much of the focus in his laboratory is on the implementation of Biogeochemical-Argo, a global observing system using these sensors on profiling floats.

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