Babila Tali L, Penman Donald E, Standish Christopher D, Doubrawa Monika, Bralower Timothy J, Robinson Marci M, Self-Trail Jean M, Speijer Robert P, Stassen Peter, Foster Gavin L, Zachos James C
School of Ocean and Earth Science, University of Southampton Waterfront Campus, National Oceanography Centre, Southampton, UK.
Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.
Sci Adv. 2022 Mar 18;8(11):eabg1025. doi: 10.1126/sciadv.abg1025. Epub 2022 Mar 16.
The Paleocene-Eocene Thermal Maximum (PETM) is recognized by a major negative carbon isotope (δC) excursion (CIE) signifying an injection of isotopically light carbon into exogenic reservoirs, the mass, source, and tempo of which continue to be debated. Evidence of a transient precursor carbon release(s) has been identified in a few localities, although it remains equivocal whether there is a global signal. Here, we present foraminiferal δC records from a marine continental margin section, which reveal a 1.0 to 1.5‰ negative pre-onset excursion (POE), and concomitant rise in sea surface temperature of at least 2°C and a decline in ocean pH. The recovery of both δC and pH before the CIE onset and apparent absence of a POE in deep-sea records suggests a rapid (< ocean mixing time scales) carbon release, followed by recovery driven by deep-sea mixing. Carbon released during the POE is therefore likely more similar to ongoing anthropogenic emissions in mass and rate than the main CIE.
古新世-始新世极热事件（PETM）以一次重大的负碳同位素（δC）偏移（CIE）为特征，这表明有同位素较轻的碳注入到外生储库中，其质量、来源和速度仍存在争议。尽管全球信号是否存在仍不明确，但在一些地方已发现了短暂的前期碳释放证据。在此，我们展示了来自一个海洋大陆边缘剖面的有孔虫δC记录，该记录显示在事件开始前有1.0至1.5‰的负偏移（POE），同时海面温度至少升高2°C，海洋pH值下降。在CIE开始之前δC和pH值的恢复以及深海记录中明显不存在POE，这表明碳释放迅速（<海洋混合时间尺度），随后由深海混合驱动恢复。因此，POE期间释放的碳在质量和速率上可能比主要的CIE更类似于当前的人为排放。
