The seawater carbon inventory at the Paleocene-Eocene Thermal Maximum
The seawater carbon inventory at the Paleocene-Eocene Thermal Maximum
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DOI：
10.1073/pnas.2003197117
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发表时间：
2020-09-29
影响因子：
11.1
通讯作者：
Honisch, Barbel
中科院分区：
文献类型：
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作者：
Haynes, Laura L.;Honisch, Barbel
古新世-始新世最高温度(PETM)(55.6Mya)是一种地质上的快速碳释放事件，被认为是最接近人为二氧化碳排放的自然模拟事件。最近的工作使用了浮游有孔虫中含硼的替代物来表征事件期间发生的表面-海洋酸化的程度。然而，海水的酸度本身对碳释放的性质和来源提供了不完全的限制。在这里，我们应用之前未描述的浮游有孔虫中B/Ca指标的培养校准，并使用它们来计算海水溶解无机碳(DIC)的相对变化，推测太平洋表层海洋DIC在PETM高峰期增加了+1,010(-646)(+1,415)µmol/kg。对PETM之前的海洋DIC清单做出合理的假设，我们提供了一个完全由数据驱动的PETM碳源估计。我们的重建产生了平均源碳增量C-13为-10ppm，海洋碳库存平均增加了+14,900 PB克碳(PGC)，表明火山二氧化碳排放是导致PETM变暖的主要碳源。
The Paleocene-Eocene Thermal Maximum (PETM) (55.6 Mya) was a geologically rapid carbon-release event that is considered the closest natural analog to anthropogenic CO2 emissions. Recent work has used boron-based proxies in planktic foraminifera to characterize the extent of surface-ocean acidification that occurred during the event. However, seawater acidity alone provides an incomplete constraint on the nature and source of carbon release. Here, we apply previously undescribed culture calibrations for the B/Ca proxy in planktic foraminifera and use them to calculate relative changes in seawater-dissolved inorganic carbon (DIC) concentration, surmising that Pacific surface-ocean DIC increased by +1,010(-646)(+1,415) mu mol/kg during the peak-PETM. Making reasonable assumptions for the prePETM oceanic DIC inventory, we provide a fully data-driven estimate of the PETM carbon source. Our reconstruction yields a mean source carbon delta C-13 of -10 parts per thousand and a mean increase in the oceanic C inventory of +14,900 petagrams of carbon (PgC), pointing to volcanic CO2 emissions as the main carbon source responsible for PETM warming.