δ13C methane source signatures from tropical wetlands and rice field emissions. / France, James; Fisher, Rebecca; Lowry, David; Allen, Grant; Andrade, Marcos; Bauguitte, Stephane; Bower, Keith; Broderick, T J; Daly, Michael; Forster, Grant; Gondwe, Mangaliso ; Helfter, Carole; Hoyt, A.M.; Jones, Anna; Lanoiselle, Mathias; Moreno, Isabel; Nisbet-Jones, Peter; Oram, D E ; Pasternak, Dominika; Pitt, Joseph ; Skiba, Ute; stephens, mark; Wilde, Shona; Nisbet, Euan.

In: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 27.08.2021.

Research output: Contribution to journalArticlepeer-review

Forthcoming
  • Grant Allen
  • Marcos Andrade
  • Stephane Bauguitte
  • Keith Bower
  • T J Broderick
  • Michael Daly
  • Grant Forster
  • Mangaliso Gondwe
  • Carole Helfter
  • A.M. Hoyt
  • Anna Jones
  • Isabel Moreno
  • D E Oram
  • Dominika Pasternak
  • Joseph Pitt
  • Ute Skiba
  • mark stephens
  • Shona Wilde

Abstract

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 new δ13CCH4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. In summary, tropical wetland δ13CCH4 generally range between -62 and -52 ‰ and rice paddies between -59 and -57 ‰. Long-term monitoring of δ13CCH4 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 rice δ13CCH4 sources and hints at significant seasonal variation in tropical wetland δ13CCH4 signatures which may be important to capture in future global and regional models.
Original languageEnglish
JournalPhilosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences
Publication statusAccepted/In press - 27 Aug 2021

ID: 43400771