在古海洋学研究中,常用浮游有孔虫来恢复表层海水温度(SST),然而基于浮游有孔虫恢复SST的这些方法之间存在一定的差异。为了说明各方法的特点,在浮游有孔虫鉴定和浮游有孔虫表层种Globigerinoides ruberMg/Ca比值测试的基础上,分别利用转换函数FP12-E,现代类比(Modern Analog Technique,MAT)和Mg/Ca比值法对西北太平洋北赤道流分叉处MD06-3054孔中记录的末次冰期以来的SST进行了估算。分析发现:(1)转换函数FP12-E不适用于该孔;(2)该孔中MAT法估算的末次冰期到冰后期SST的变化小于Mg/Ca比值法得到的结果;(3)考虑到浮游有孔虫产量的季节变化,Mg/Ca比值法得到的SSTMg/Ca末次冰期到冰后期的变化可能偏大。尽管如此,相对于MAT等古生态学方法,Mg/Ca比值法受到的影响因素更少,若能对浮游有孔虫的季节产量等方面加以校正,将会得到更准确的结果。
In paleoceanographic research,sea surface temperature(SST) is usually reconstructed with planktonic foraminifera.Results from different methods are diverse.In order to better understand the difference of these methods,the authors reconstructed the SST since the last glacial using the methods of transfer function FP12-E,Modern Analog Technique(MAT),and Mg/Ca ratios with samples from the core MD06-3054,which is located at the bifurcation of North Equatorial Current in the northwestern Pacific.The SST was recovered by counting planktonic foraminiferal fauna and measuring the Mg/Ca ratios of surface dweller Globigerinoides ruber(white,G.ruber in short).It is found that(1) the method of transfer function FP-12E is not applicative in this case;(2) the rising of SST from the last glacial to the post glacial stage reconstructed with MAT is smaller than that reconstructed from the Mg/Ca ratios in core MD06-3054;(3) take into consideration the production change of planktonic foraminifera tests with seasons,the increasing of the SSTMg/Ca calculated from Mg/Ca ratios may larger than the changes in SSTA.Even so,comparing with the palaeoecological methods(such as MAT),the geochemical method of Mg/Ca ratios has fewer affecting factors and may provide more accurate data if calibration is made for seasonal productivity change of planktonic foraminifera.