Changes in diatom productivity and upwelling intensity off Peru since the Last Glacial Maximum: Response to basin-scale atmospheric and oceanic forcing
Changes in diatom productivity and upwelling intensity off Peru since the Last Glacial Maximum: Response to basin-scale atmospheric and oceanic forcing
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DOI：
10.1002/2016pa002936
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发表时间：
2016-10-01
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影响因子：
--
通讯作者：
Schneider, Ralph
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文献类型：
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作者：
Doering, Kristin;Erdem, Zeynep;Schneider, Ralph
稳定硅同位素（Si-30）的新记录，以及来自秘鲁中部（南纬9度）和北方（南纬5度）的生物蛋白石和有机碳的浓度，揭示了过去2万年硅藻生产力和营养利用的变化。研究结果是基于一种新的方法，利用小（11-32 μ m）和大（>150 μ m）硅藻组分（Si-30（Coscino-bSi））的Si-30特征之间的差异，结合硅藻组合的方差，重建过去的上升流强度。结合我们的记录与两个先前公布的记录从南部上升流区关闭秘鲁（12-15度S）显示了一般脱钩的环境条件在中部和南部大陆架主要由北移的主要上升流细胞从其现代位置（12-15度S）向9度S在终端1。在这个时候，只有温和的上升流强度和生产力水平占主导地位的9度和12度之间的S解释了一个更偏北的位置，南西风和南太平洋副热带高压。此外，在海因里希体育场1期间，南纬12-15度的生产力显着下降，与赤道东太平洋生物蛋白石产量的增加相吻合，这是由热带辐合带南移和东北信风增强引起的。现代条件是在全新世开始时才建立起来的。到达秘鲁上升流系统的地下沃茨的预先形成的Si-30签名的过去的变化没有显着影响保存的Si-30签名。
New records of stable silicon isotope signatures (Si-30) together with concentrations of biogenic opal and organic carbon from the central (9 degrees S) and northern (5 degrees S) Peruvian margin reveal changes in diatom productivity and nutrient utilization during the past 20,000years. The findings are based on a new approach using the difference between the Si-30 signatures of small (11-32 mu m) and large (>150 mu m) diatom fractions (Si-30(Coscino-bSi)) in combination with the variance in diatom assemblages for reconstruction of past upwelling intensity. Combination of our records with two previously published records from the southern upwelling area off Peru (12-15 degrees S) shows a general decoupling of the environmental conditions at the central and southern shelf mainly caused by a northward shift of the main upwelling cell from its modern position (12-15 degrees S) toward 9 degrees S during Termination 1. At this time only moderate upwelling intensity and productivity levels prevailed between 9 degrees S and 12 degrees S interpreted by a more northerly position of Southern Westerly Winds and the South Pacific Subtropical High. Furthermore, a marked decrease in productivity at 12-15 degrees S during Heinrich Stadial 1 coincided with enhanced biogenic opal production in the Eastern Equatorial Pacific, which was induced by a southward shift of the Intertropical Convergence Zone and enhanced northeasterly trade winds. Modern conditions were only established at the onset of the Holocene. Past changes in preformed Si-30 signatures of subsurface waters reaching the Peruvian Upwelling System did not significantly affect the preserved Si-30 signatures.