Volume 15, issue 15 | Copyright

Special issue: Climate–carbon–cryosphere interactions in the...

Biogeosciences, 15, 4777-4779, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Peer-reviewed comment 09 Aug 2018

Peer-reviewed comment | 09 Aug 2018

Comment on “The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis” by Sapart et al. (2017)

Katy J. Sparrow and John D. Kessler Katy J. Sparrow and John D. Kessler
  • Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York, USA

Abstract. In this comment, we outline two major concerns regarding some of the key data presented in this paper. Both of these concerns are associated with the natural abundance radiocarbon-methane (14C-CH4) data. First, no systematic methodology is presented, nor previous peer-reviewed publication referenced, for how these samples were collected, prepared, and ultimately analyzed for 14C-CH4. Not only are these procedural details missing, but the critical evaluation of them using gaseous and aqueous blanks and standards was omitted although these details are essential for any reader to evaluate the quality of data and subsequent interpretations. Second, due to the lack of methodological details, the source of the sporadic anthropogenic contamination cannot be determined and thus it is premature for the authors to suggest it was in the natural environment prior to sample collection. As the natural 14C-CH4 data are necessary for the authors' stated scientific objectives of understanding the origin of methane in the East Siberian Arctic Shelf, our comment serves to highlight that the study's objectives have not been met.

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