Open Accessδ 13 C methane source signatures from tropical wetland and rice field emissions
Author(s) -
James L. France,
Rebecca E. Fisher,
David Lowry,
Grant Allen,
Marcos Andrade,
Stéphane Bauguitte,
Keith Bower,
Timothy J. Broderick,
M. C. Daly,
G. Forster,
Mangaliso J. Gondwe,
Carole Helfter,
Alison M. Hoyt,
A. E. Jones,
Mathias Lanoisellé,
Isabel Moreno,
P. B. R. NisbetJones,
D. E. Oram,
Dominika Pasternak,
Joseph Pitt,
Ute Skiba,
Mark Stephens,
Shona Wilde,
E. G. Nisbet
Publication year - 2021
Publication title -
philosophical transactions - royal society. mathematical, physical and engineering sciences/philosophical transactions - royal society. mathematical, physical and engineering sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.074
H-Index - 169
eISSN - 1471-2962
pISSN - 1364-503X
DOI - 10.1098/rsta.2020.0449
Subject(s) - wetland , environmental science , methane , tropics , global warming , atmospheric sciences , range (aeronautics) , atmosphere (unit) , atmospheric methane , climate change , greenhouse gas , ecology , geography , meteorology , oceanography , geology , materials science , composite material , biology
The atmospheric methane (CH4 ) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH4 emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of newδ 13 CCH4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring ofδ 13 CCH4 in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH4 sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH4 to the atmosphere during periods of reduced wetland extent. This new data expands the geographical extent and range of measurements of tropical wetland and riceδ 13 CCH4 sources and hints at significant seasonal variation in tropical wetlandδ 13 CCH4 signatures which may be important to capture in future global and regional models.This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.