Sensitivity of Holocene East Antarctic productivity to subdecadal variability set by sea ice
Sensitivity of Holocene East Antarctic productivity to subdecadal variability set by sea ice
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DOI：
10.1038/s41561-021-00816-y
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发表时间：
2021-09
影响因子：
18.3
通讯作者：
Katelyn M. Johnson;R. McKay;J. Etourneau;F. Jiménez-Espejo;Anya Albot;C. Riesselman;N. Bertler;H. Horgan;X. Crosta;J. Bendle;Kate E. Ashley;M. Yamane;Y. Yokoyama;S. Pekar;C. Escutia;R. Dunbar
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作者：
Katelyn M. Johnson;R. McKay;J. Etourneau;F. Jiménez-Espejo;Anya Albot;C. Riesselman;N. Bertler;H. Horgan;X. Crosta;J. Bendle;Kate E. Ashley;M. Yamane;Y. Yokoyama;S. Pekar;C. Escutia;R. Dunbar
南极海冰范围、初级生产力和海洋环流是相互关联的系统，构成全球碳循环的重要组成部分。亚十年到百年尺度的变率可以影响这些系统的特征和相互作用，但观测记录太短，无法评估这种变率在较长时间尺度上的影响。在这里，我们使用从综合大洋钻探计划U1357 B，近海阿德利地，东南极洲收集的170米长的沉积物芯解开海冰和近十年的气候变化对浮游植物水华频率的影响在过去的11,400年。我们应用X射线计算机断层扫描，冰代理南大洋与25个碳原子，硅藻，物理性质和地球化学分析的核心，其中包含每年解决，连续分层档案的浮游植物水华事件。在全新世的大部分时间里，水华事件每年到每两年发生一次，但在4.5 ka时，当沿海海冰加剧时，水华事件变得不那么频繁（约2-7年）。我们建议，沿海海冰加剧抑制每年海冰爆发，导致海冰动力学的敏感性增加，以subdecadal气候模式，导致一个subdecadal频率的水华事件。我们的数据表明，预计沿海海冰的损失将影响南极边缘初级生产力，改变食物网和碳循环过程在季节性时间尺度上的subdecadal变化的影响。
Antarctic sea-ice extent, primary productivity and ocean circulation represent interconnected systems that form important components of the global carbon cycle. Subdecadal to centennial-scale variability can influence the characteristics and interactions of these systems, but observational records are too short to evaluate the impacts of this variability over longer timescales. Here, we use a 170-m-long sediment core collected from Integrated Ocean Drilling Program Site U1357B, offshore Adélie Land, East Antarctica to disentangle the impacts of sea ice and subdecadal climate variability on phytoplankton bloom frequency over the last ~11,400 years. We apply X-ray computed tomography, Ice Proxy for the Southern Ocean with 25 carbon atoms, diatom, physical property and geochemical analyses to the core, which contains an annually resolved, continuously laminated archive of phytoplankton bloom events. Bloom events occurred annually to biennially through most of the Holocene, but became less frequent (~2–7 years) at ~4.5 ka when coastal sea ice intensified. We propose that coastal sea-ice intensification subdued annual sea-ice break-out, causing an increased sensitivity of sea-ice dynamics to subdecadal climate modes, leading to a subdecadal frequency of bloom events. Our data suggest that projected loss of coastal sea ice will impact the influence of subdecadal variability on Antarctic margin primary productivity, altering food webs and carbon-cycling processes at seasonal timescales.