DOI: 10.5194/cp-8-1435-2012
Scopus记录号: 2-s2.0-84866534278
论文题名: Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to Late Pliocene/Early Pleistocene climate cooling
作者: Etourneau J. ; Ehlert C. ; Frank M. ; Martinez P. ; Schneider R.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2012
卷: 8, 期: 5 起始页码: 1435
结束页码: 1445
语种: 英语
Scopus关键词: biological pump
; coastal circulation
; cooling
; diatom
; ice cover
; opal
; Pleistocene
; Pliocene
; stratification
; upwelling
; Atlantic Ocean
; Benguela Current
; Namibia
; Pacific Ocean
; Pacific Ocean (North)
; Southern Ocean
; Bacillariophyta
英文摘要: The global Late Pliocene/Early Pleistocene cooling ∼3.0-2.0 million years ago-Ma) concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela upwelling system(BUS), off Namibia, where it is known as the Matuyama Diatom Maximum (MDM). Our study focuses on a new diatom silicon isotope (λ30si) record covering the MDM in the BUS. Unexpectedly, the variations in λ30si signal follow biogenic opal content, whereby the highest λ30si values correspond to the highest biogenic opal content. We interpret the higher λ 30si values during the MDM as a result of a stronger degree of silicate utilisation in the surface waters caused by high productivity of mat-forming diatom species.This was most likely promoted by weak upwelling intensity dominating the BUS during the Late Pliocene/Early Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0-2.7Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California) during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to Late Pliocene/Early Pleistocene cooling. © Author(s) 2012. CC Attribution 3.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49562
Appears in Collections: 气候变化与战略
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Recommended Citation:
Etourneau J.,Ehlert C.,Frank M.,et al. Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to Late Pliocene/Early Pleistocene climate cooling[J]. Climate of the Past,2012-01-01,8(5)