格陵兰冰中14CH4的测量：探究末次冰期结束时CH4的来源

14CH4 measurements in Greenland ice: investigating last glacial termination CH4 sources.

作者信息

Petrenko Vasilii V, Smith Andrew M, Brook Edward J, Lowe Dave, Riedel Katja, Brailsford Gordon, Hua Quan, Schaefer Hinrich, Reeh Niels, Weiss Ray F, Etheridge David, Severinghaus Jeffrey P

机构信息

Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA.

出版信息

Science. 2009 Apr 24;324(5926):506-8. doi: 10.1126/science.1168909.

DOI:10.1126/science.1168909

PMID:19390044

Abstract

The cause of a large increase of atmospheric methane concentration during the Younger Dryas-Preboreal abrupt climatic transition (approximately 11,600 years ago) has been the subject of much debate. The carbon-14 (14C) content of methane (14CH4) should distinguish between wetland and clathrate contributions to this increase. We present measurements of 14CH4 in glacial ice, targeting this transition, performed by using ice samples obtained from an ablation site in west Greenland. Measured 14CH4 values were higher than predicted under any scenario. Sample 14CH4 appears to be elevated by direct cosmogenic 14C production in ice. 14C of CO was measured to better understand this process and correct the sample 14CH4. Corrected results suggest that wetland sources were likely responsible for the majority of the Younger Dryas-Preboreal CH4 rise.

摘要

在新仙女木期-前北方期气候突变（约11,600年前）期间，大气甲烷浓度大幅增加的原因一直是众多争论的焦点。甲烷（14CH4）中的碳-14（14C）含量应能区分湿地和天然气水合物对这一增加的贡献。我们展示了针对此次气候突变，利用从格陵兰西部一个消融地点获取的冰芯样本，对冰川冰中的14CH4进行的测量。测量得到的14CH4值高于任何情况下的预测值。样本中的14CH4似乎因冰中直接的宇宙成因14C生成而升高。对一氧化碳的14C进行了测量，以便更好地理解这一过程并校正样本中的14CH4。校正后的结果表明，湿地源可能是新仙女木期-前北方期甲烷增加的主要原因。