设为首页 | 英文网站 | 中文网站
2020年 当前位置: 首页 >> 科学研究 >> 科研论文 >> 2020年 >> 正文
El Niño/Southern Oscillation during the 4.2 ka event recorded by growth rates of corals from the North South China Sea
作者:  点击数: 时间:2020/01/12 11:30:09

Abstract

The 4.2 ka event that occurred during the period from 4 500–3 900 a BP was characterized by cold and dry climates and resulted in the collapse of civilizations around the world. The cause of this climatic event, however, has been under debate. We collected four corals (Porites lutea) from Yongxing Island, Xisha Islands, South China Sea, dated them with the U-series method, and measured the annual coral growth rates using X-ray technology. The dating results showed that the coral growth ages were from 4 500–3 900 a BP, which coincide well with the period of the 4.2 ka event. We then reconstructed annual sea surface temperature anomaly (SSTA) variations based on the coral growth rates. The growth rate-based SSTA results showed that the interdecadal SSTA from 4 500–3 900 a BP was lower than that during modern times (1961–2008 AD). A spectral analysis showed that the SSTA variations from 4 500–3 900 a BP were under the influence of El Niño-Southern Oscillation (ENSO) activities. From 4 500–4 100 a BP, the climate exhibited La Niña-like conditions with weak ENSO intensity and relatively stable and lower SSTA amplitudes. From 4 100–3 900 a BP, the climate underwent a complicated period of ENSO variability and showed alternating El Niño- or La Niña-like conditions at interdecadal time scales and large SSTA amplitudes. We speculate that during the early and middle stages of the 4.2 ka event, the cold climate caused by weak ENSO activities largely weakened social productivity. Then, during the end stages of the 4.2 ka event, the repeated fluctuations in the ENSO intensity caused frequent extreme weather events, resulting in the collapse of civilizations worldwide. Thus, the new evidence obtained from our coral records suggests that the 4.2 ka event aswell as the related collapse of civilizations were very likely driven by ENSO variability.

Key words: 4.2 ka event, ENSO variability, SSTA, coral growth rate, Xisha Islands

 

上一条:Latitudinal variation in reef coral tissue thickness in the South China Sea:Potential linkage with coral tolerance to environmental stress 下一条:Antibiotics in coral reef fishes from the South China Sea: Occurrence,distribution, bioaccumulation, and dietary exposure risk to human

关闭

广西大学珊瑚礁研究中心 版权所有
地址:广西南宁市大学东路100号 邮编:530004 电话:0771-3227133 3227522 3227855