古大气CO_2浓度重建方法技术研究现状

On Methods and Technologies for Reconstruction of Paleoatmospheric CO_2 Concentration

温室气候引起的全球气候变暖越来越引起人们的关注,大气中不断上升的CO2浓度被认为是导致气候变暖的主要因素。地史时期大气CO2浓度变化与温室气候可能存在类似的关系,可提供参考,因而古大气CO2浓度重建是首要任务。总结近年来古大气CO2浓度重建的进展,重点介绍GEOCARB模型模拟、植物叶片气孔参数和同位素指针的方法和技术。GEOCARB模型是反映全球古大气CO2浓度长期变化的碳相关模型;气孔参数方法是使用气孔比例来估计古大气CO2浓度;同位素指针包括成壤碳酸盐、浮游植物有机质生物标记物、钙质浮游有孔虫、古苔藓植物等,其中成壤碳酸盐碳同位素方法使用最为广泛。国内只是在叶片参数研究方面有一些进展,古大气CO2浓度重建工作任重而道远。

It has been more and more paid attention to the globalclimate change caused by the warming greenhouse effect.And the increasing of atmospheric CO2 concentration is thought to be the main factor of global warming.There could be a similar linkage of CO2 concentration and greenhouse climate between modern and ancient analogues,for which the estimate of paleoatmospheric CO2 concentration is a first task to reconstruct ancient climate.Then,this paper aims to summarize the main methods and technologies of paleoatmospheric CO2 concentration estimate at the arts of states by analyses and synthetization of recent published references.So far,there are three main methods to reconstruct ancient atmospheric CO2 concentration.They are GEOCARB model,stomatal parameters of fossil plant,and isotopes proxy indicators.The GEOCARB model is an extremely carbon-model relevant,and has been established by Berner（1990s-2000s）,showing a long tendency for changes of ancient atmospheric CO2 concentration.The method of stomatal parameter of fossil plant is used to estimate the CO2 concentration by stomatal ratio,which is often influenced by lack of fossil cuticle.The method of isotopes proxy indicator has been focused on pedogenic carbonate in soil,calcareous phytoplankton,planktonic foraminifera,and fossil bryophytes,in which carbon isotope proxy is the mostly applicable one that could be constrained by distinguishing of primary and secondary calcite.These works have not been carried out except for a few in stomatal parameters,stimulating the further research of Chinese geo-scientists.