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10月20日:The stable isotope records of vermetid from the Mediterranean basins during the past two millennia

时间:2017-10-18浏览:97


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报告题目:The stable isotope records of vermetid from the Mediterranean basins during the past two millennia


报告时间:20171020 1530-1700

报告地点:海洋楼一楼报告厅


报告人:Prof.Aldo Shemesh

The Weizmann Institute of Science, Rehovot, Israel


报告内容简介:

High-resolution δ18O and δ13C records obtained from cores drilled from ledges of the reef builder gastropod Dendropoma petraeum were used to calibrate the isotopic signals and to reconstruct variations of sea surface temperature, hydrology and productivity during the past 2000 years in the Levantine, Central and Western basins of the Mediterranean. The δ18O of the aragonite shell of living vermetids indicates that skeletal deposition occurs under isotopic equilibrium and faithfully records the temperature and surface water δ18O during spring and summer. The vermetid δ13C is strongly related to δ13C of dissolved inorganic carbon and to the primary productivity of the surface water. Data will be presented from cores drilled along the coasts of Israel, Crete, Sicily, Tunisia and Spain. The mean down core δ18O record clearly captures global and local climatic events, such as the Little Ice Age (LIA) and the recent warming of surface waters in the Eastern Mediterranean. The δ18O records of the three basins are synchronous between 600 and 1750 AD but decouple at around 1750. While the Eastern Mediterranean shows a clear warming trend the Central and the Western basins show a different thermal behavior. On the other hand, the carbon isotopic composition of the 3 basins is similar, showing δ13C depletion during the last century which is mostly related to the increased anthropogenic emissions of 13C depleted carbon dioxide and to a certain decrease in primary production. The data indicate that D. petraeum isotopic signatures are unique proxies for the last two millennia for high-resolution reconstruction of paleo-oceanographic environments in the Mediterranean and the sub-tropical Atlantic regions.

  

邀请人:王汝建 教授

  

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