Regional patterns and temporal evolution of ocean iron fertilization and CO2 drawdown during the last glacial termination
Regional patterns and temporal evolution of ocean iron fertilization and CO2 drawdown during the last glacial termination
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DOI：
10.1016/j.epsl.2020.116675
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发表时间：
2021-01-15
影响因子：
5.3
通讯作者：
Abe-Ouchi, Ayako
中科院分区：
文献类型：
--
作者：
Lambert, Fabrice;Opazo, Natalia;Abe-Ouchi, Ayako
地球气候上一次经历地质快速全球变暖与末次冰期终止有关，当时大气中CO2浓度从末次盛冰期（LGM，26-19 kaBP）的180 ppmv上升到全新世早期（12-8 kaBP）的260 ppmv。大约四分之一的差异被认为是由于冰川时期更强的生物泵，由风成尘沉积增加驱动，因此海洋表面沃茨中的铁可用性更高。然而，尘埃供应并没有在冰消过渡期间均匀或同步变化，目前尚不清楚的是不同海洋区域的相对重要性以及这可能如何随着时间的推移而变化。使用地球系统模型的中间复杂性，我们量化的敏感性，大气中的CO2区域变化的铁供应，并测试六个不同的全球尘埃重建，以探讨过去的尘埃变化的不确定性。我们确认南大洋（>34 ° S）是对铁施肥最敏感的区域，大西洋和太平洋地区分别占全球铁施肥减少的CO2总量的41 +/- 23%和16 +/-10%。然而，北太平洋贡献了28 +/- 3%的总量，这意味着北方半球的过程中驱动冰消期CO2上升的重要作用。此外，我们的分析揭示了一个意想不到的区域时间的差异，而南半球的铁施肥影响大气中的CO2相对恒定的整个终止的影响，北方半球只发生在后期阶段的终止。(C)2020作者（S）由爱思唯尔公司出版
The last time Earth's climate experienced geologically rapid global warming was associated with the last glacial termination, when atmospheric CO2 concentrations rose from 180 ppmv during the Last Glacial Maximum (LGM, 26-19 kaBP) to similar to 260 ppmv by the early Holocene (12-8 kaBP). About one quarter of that difference is thought to be due to a stronger biological pump during glacial times, driven by increased aeolian dust deposition and hence greater iron availability in ocean surface waters. However, dust supply did not change uniformly or in synchrony over the deglacial transition and what is not known is the relative importance of different oceanic regions and how this may have changed in time. Using an Earth system model of intermediate complexity, we quantify the sensitivity of atmospheric CO2 to regional changes in iron supply, and test six different global dust reconstructions in order to explore uncertainty in past dust changes. We confirm the Southern Ocean (>34 degrees S) as the region most sensitive to iron fertilization, with the Atlantic and Pacific sectors accounting for about 41 +/- 23% and 16 +/- 10%, respectively, of the total CO2 reduction from global iron fertilization. However, the North Pacific contributes 28 +/- 3% to the total implying an important role for Northern Hemisphere processes in driving deglacial CO2 rise. In addition, our analysis reveals an unexpected regional-temporal disparity, and while Southern Hemisphere iron fertilization influences atmospheric CO2 relatively constantly throughout the termination the impact of the Northern Hemisphere only occurs during the later stages of the termination. (C) 2020 The Author(s). Published by Elsevier B.V.