Production mechanism and global budget of N<sub>2</sub>O inferred from its isotopomers in the western North Pacific

GEOPHYSICAL RESEARCH LETTERS, VOL. 29, NO. 3, 10.1029/2001GL014311, 2002

Production mechanism and global budget of N₂O inferred from its isotopomers in the western North Pacific

Sakae Toyoda and Naohiro Yoshida

Interdisciplinary Graduate School of Science and Engineering,
Tokyo Institute of Technology,
Japan

Also at CREST Project, Japan Science and Technology Corporation (JST), Kawaguchi, Japan

Tatsuya Miwa

Interdisciplinary Graduate School of Science and Engineering,
Tokyo Institute of Technology,
Japan

Now at Toyota Motor Corporation, Toyota, Japan

Yohei Matsui and Hiroaki Yamagishi

Interdisciplinary Graduate School of Science and Engineering,
Tokyo Institute of Technology,
Japan

Urumu Tsunogai

Interdisciplinary Graduate School of Science and Engineering,
Tokyo Institute of Technology,
Japan

Now at Division of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan

Yukihiro Nojiri

National Institute for Environmental Studies,
Japan

Nobuo Tsurushima

National Institute of Advanced Industrial Science and Technology,
Japan

Abstract

[1] We measured the intramolecular distribution of ¹⁵N as well as conventional nitrogen and oxygen isotope ratios in oceanic nitrous oxide (N₂O) in the western North Pacific for the first time. In contrast to a nearly homogeneous vertical distribution of a bulk nitrogen isotope ratio, a wide variation in site preference for intramolecular ¹⁵N distribution was found, suggesting the subsurface and deep source mixing and the production mechanism in the ocean. The oceanic composition of N₂O isotopomers quantitatively outlines the ocean as the most significant source after the terrestrial one.

Received 2 November 2001; revised 27 December 2001; accepted 28 December 2001; published 15 February 2002.

Index Terms: 0312 Atmospheric Composition and Structure: Air/sea constituents fluxes (3339, 4504); 1615 Global Change: Biogeochemical Processes (4805); 4820 Oceanography Biological and Chemical: Gases; 4870 Oceanography Biological and Chemical: Stable isotopes; 9355 Information Related to Geographic Region: Pacific Ocean.

Citation: Toyoda, S., N. Yoshida, T. Miwa, Y. Matsui, H. Yamagishi, U. Tsunogai, Y. Nojiri, and N. Tsurushima, Production mechanism and global budget of N₂O inferred from its isotopomers in the western North Pacific, Geophys. Res. Lett., 29(3), 10.1029/2001GL014311, 2002.