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| DOI | 10.1029/2023PA004776 |
| Millennial-Scale Carbon Flux Variability in the Subantarctic Pacific During Marine Isotope Stage 3 (57-29 ka) | |
| 发表日期 | 2024 |
| ISSN | 2572-4517 |
| EISSN | 2572-4525 |
| 起始页码 | 39 |
| 结束页码 | 3 |
| 卷号 | 39期号:3 |
| 英文摘要 | Antarctic ice cores reveal a glacial climate state during Marine Isotope Stage 3 (MIS-3; 57-29 ka) punctuated by millennial-scale warming events and pulses of CO2. This study further explores how changes in Southern Ocean carbon cycling contributed to these millennial-scale fluctuations in climate. Evidence from South Atlantic sediment cores suggests that warming events were associated with decreased dust-borne iron flux, reduced export production, and increased upwelling from the deep Southern Ocean (SO). These processes are considered to have contributed to rising atmospheric CO2 during periods of rapid warming. Here we investigate whether the same processes occurred in the southwest Pacific sector of the SO at TAN1106-28. We show that reduced New Zealand glaciation and localized iron limitation in the southwest Pacific led to reduced export production during millennial-scale warming events. Decreases in foraminifera-bound delta 15N during all MIS-3 warming events may reflect increased nutrient supply by upwelling. Increased calcium carbonate flux during MIS-3 warming events likely reflects coccolithophore production in response to sea surface temperatures, which, would increase carbonate counter pump strength and reduce CO2 sequestration. Concomitant decreases in bottom water oxygen, inferred from redox-sensitive U and Mn sediment concentrations, and increases in the 14C age of deep waters, suggest that old, nutrient-rich waters influenced southwest Pacific middepth waters during warming events. This signature may reflect an expansion of Pacific Deep Water into the SO during warming. Taken together, our multi-proxy data set reveals that the southwest subantarctic Pacific acted as a source of CO2 during millennial-scale warming events of MIS-3. Antarctic ice cores have provided evidence of episodes of warming and cooling of the Southern Hemisphere that took place over hundreds to thousands of years between 57,000 and 29,000 years ago. During warming events, the Southern Ocean is thought to have played a role in the increasing concentration of CO2 in the atmosphere. Here we use a sediment core from the southwest Pacific Southern Ocean to show that decreased iron input to the surface ocean reduced biological productivity during warming events, which hampered CO2 sequestration in the region. While in the deep ocean, proxies for the concentration of oxygen and the relative age of deep waters suggest that conditions may have become favorable for a release of CO2 from the ocean interior to the atmosphere during episodic warming. These findings support the theory that the Southern Ocean played an important role in the past carbon cycle by modulating the exchange of CO2 between the deep ocean and the atmosphere during periods of rapid climate change. Decreased iron from New Zealand limits subantarctic Pacific export production during MIS-3 warming events Decreases in foraminifera bound-delta 15N during MIS-3 warming events are likely due to increased nutrient supply and reduced utilisation Decreases in bottom water O2 during MIS-3 warming events may result from increased Pacific Deep Water influence |
| 英文关键词 | Marine Isotope Stage 3; carbon cycle; biogeochemistry; paleoceanography; iron limitation; AMOC |
| 语种 | 英语 |
| WOS研究方向 | Geology ; Oceanography ; Paleontology |
| WOS类目 | Geosciences, Multidisciplinary ; Oceanography ; Paleontology |
| WOS记录号 | WOS:001188170800001 |
| 来源期刊 | PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/306813 |
| 作者单位 | University of Tasmania; University of Queensland; National Institute of Water & Atmospheric Research (NIWA) - New Zealand; University of Southampton; NERC National Oceanography Centre; Victoria University Wellington; National Taiwan University; Australian Nuclear Science & Technology Organisation |
| 推荐引用方式 GB/T 7714 | . Millennial-Scale Carbon Flux Variability in the Subantarctic Pacific During Marine Isotope Stage 3 (57-29 ka)[J],2024,39(3). |
| APA | (2024).Millennial-Scale Carbon Flux Variability in the Subantarctic Pacific During Marine Isotope Stage 3 (57-29 ka).PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY,39(3). |
| MLA | "Millennial-Scale Carbon Flux Variability in the Subantarctic Pacific During Marine Isotope Stage 3 (57-29 ka)".PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 39.3(2024). |
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