What atmospheric oxygen measurements can tell us about the global carbon cycle

Authors

Ralph F. Keeling
Raymond P. Najjar
Michael L. Bender, University of Rhode Island
Pieter P. Tans, University of Rhode Island

Document Type

Article

Date of Original Version

1993

Department

Oceanography

Abstract

This paper explores the role that measurements of changes in atmospheric oxygen, detected through changes in the O₂/N₂ ratio of air, can play in improving our understanding of the global carbon cycle. Simple conceptual models are presented in order to clarify the biological and physical controls on the exchanges of O₂, CO₂, N₂, and Ar across the air‐sea interface and in order to clarify the relationships between biologically mediated fluxes of oxygen across the air‐sea interface and the cycles of organic carbon in the ocean. Predictions of large‐scale seasonal variations and gradients in atmospheric oxygen are presented. A two‐dimensional model is used to relate changes in the O₂/N₂ ratio of air to the sources of oxygen from terrestrial and marine ecosystems, the thermal ingassing and outgassing of seawater, and the burning of fossil fuel. The analysis indicates that measurements of seasonal variations in atmospheric oxygen can place new constraints on the large‐scale marine biological productivity. Measurements of the north‐south gradient and depletion rate of atmospheric oxygen can help determine the rates and geographical distribution of the net storage of carbon in terrestrial ecosystems.

Citation/Publisher Attribution

Keeling, R. F., Najjar, R. P., Bender, M. L., & Tans, P. P. (1993). What atmospheric oxygen measurements can tell us about the global carbon cycle. Global Biogeochemical Cycles, 7(1), 37-67. doi:10.1029/92GB02733

Available at: https://doi.org/10.1029/92GB02733