Changes in benthic ecosystems and ocean circulation in the Southeast Atlantic across Eocene Thermal Maximum 2
Changes in benthic ecosystems and ocean circulation in the Southeast Atlantic across Eocene Thermal Maximum 2
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始新世热最大值 2 期间东南大西洋底栖生态系统和海洋环流的变化
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
A. Ridgwell
中科院分区：
文献类型：
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作者：
Suzanne M Jennions;Ellen Thomas;D. Schmidt;D. Lunt;A. Ridgwell
始新世最大温度2出现在古新世-始新世温度最大值之后约1.8MYR，与始新世温度最大值一样，具有碳同位素负漂移和增温的特征。我们结合了东南大西洋1263(1500 m古深度)和1262(3600 m古深度)站点的底栖有孔虫和沉积学记录，表明在ETM2高峰期，底栖有孔虫多样性和累积率在较浅的站点下降得更快和更严重。由于两个地点距离很近，地表生产力的差异不可能导致这种不同的影响。相反，我们推断，通过ETM2的海洋环流的变化可能在中等深度产生了更明显的变暖(站点1263)。变暖的影响包括代谢率增加、有效食物供应减少和脱氧增加，因此可能解释了1263地点更严重的海底影响。相应地，1263号站位的生物扰动可能比1262号站位的生物扰动减少得更多，这对整体碳酸盐记录产生了不同的影响。我们使用沉积物驱动的地球系统模型来测试生物扰动的减少和/或通风较差的水域碳酸盐饱和度的可能降低是否可以解释1263点大量δ13C的更极端的漂移和wt%CaCO_3的更剧烈的转变。我们发现，在ETM2峰值期间，既需要加强酸化，也需要减少生物扰动，以解释观察到的特征。我们的生态和模型分析相结合说明了海洋环流变化在放大当地环境变化和推动海底生物多样性和丰富度暂时但严重丧失方面的潜在作用。
Eocene Thermal Maximum 2 (ETM2) occurred ~1.8 Myr after the Paleocene-Eocene Thermal Maximum (PETM) and, like the PETM, was characterized by a negative carbon isotope excursion and warming. We combined benthic foraminiferal and sedimentological records for Southeast Atlantic Sites 1263 (1500 m paleodepth) and 1262 (3600 m paleodepth) to show that benthic foraminiferal diversity and accumulation rates declined more precipitously and severely at the shallower site during peak ETM2. As the sites are in close proximity, differences in surface productivity cannot have caused this differential effect. Instead, we infer that changes in ocean circulation across ETM2 may have produced more pronounced warming at intermediate depths (Site 1263). The effects of warming include increased metabolic rates, a decrease in effective food supply and increased deoxygenation, thus potentially explaining the more severe benthic impacts at Site 1263. In response, bioturbation may have decreased more at Site 1263 than at Site 1262, differentially affecting bulk carbonate records. We use a sediment-enabled Earth system model to test whether a reduction in bioturbation and/or the likely reduced carbonate saturation of more poorly ventilated waters can explain the more extreme excursion in bulk δ13C and sharper transition in wt % CaCO3 at Site 1263. We find that both enhanced acidification and reduced bioturbation during the ETM2 peak are needed to account for the observed features. Our combined ecological and modeling analysis illustrates the potential role of ocean circulation changes in amplifying local environmental changes and driving temporary, but drastic, loss of benthic biodiversity and abundance.
影响因子：
5.8
作者：
D. Lunt;P. Valdes;T. Jones;A. Ridgwell;A. Haywood;D. Schmidt;R. Marsh;M. Maslin
通讯作者：
D. Lunt;P. Valdes;T. Jones;A. Ridgwell;A. Haywood;D. Schmidt;R. Marsh;M. Maslin
影响因子：
18.3
作者：
Ridgwell, Andy;Schmidt, Daniela N.
通讯作者：
Schmidt, Daniela N.
影响因子：
3.7
作者：
H. McCarren;Ellen Thomas;Takashi Hasegawa;U. Röhl;J. Zachos
通讯作者：
H. McCarren;Ellen Thomas;Takashi Hasegawa;U. Röhl;J. Zachos