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Medientyp:
E-Artikel
Titel:
Ice Record of δ 13 C for Atmospheric CH 4 Across the Younger Dryas-Preboreal Transition
Beteiligte:
Schaefer, Hinrich;
Whiticar, Michael J.;
Brook, Edward J.;
Petrenko, Vasilii V.;
Ferretti, Dominic F.;
Severinghaus, Jeffrey P.
Erschienen:
American Association for the Advancement of Science (AAAS), 2006
Erschienen in:
Science, 313 (2006) 5790, Seite 1109-1112
Sprache:
Englisch
DOI:
10.1126/science.1126562
ISSN:
0036-8075;
1095-9203
Entstehung:
Anmerkungen:
Beschreibung:
<jats:p>
We report atmospheric methane carbon isotope ratios (δ
<jats:sup>13</jats:sup>
CH
<jats:sub>4</jats:sub>
) from the Western Greenland ice margin spanning the Younger Dryas–to–Preboreal (YD-PB) transition. Over the recorded ∼800 years, δ
<jats:sup>13</jats:sup>
CH
<jats:sub>4</jats:sub>
was around –46 per mil (‰); that is, ∼1‰ higher than in the modern atmosphere and ∼5.5‰ higher than would be expected from budgets without
<jats:sup>13</jats:sup>
C-rich anthropogenic emissions. This requires higher natural
<jats:sup>13</jats:sup>
C-rich emissions or stronger sink fractionation than conventionally assumed. Constant δ
<jats:sup>13</jats:sup>
CH
<jats:sub>4</jats:sub>
during the rise in methane concentration at the YD-PB transition is consistent with additional emissions from tropical wetlands, or aerobic plant CH
<jats:sub>4</jats:sub>
production, or with a multisource scenario. A marine clathrate source is unlikely.
</jats:p>