反射光谱技术:研究南极企鹅古生态演化的一种新方法

为探求快速、廉价、无损和同步的光谱技术在南极生态环境研究中的可能性,本文利用南极阿德雷岛的四根企鹅粪土沉积柱样品的反射光谱,通过逐步多元线性回归和主成分回归两种数学运算方法,建立了反射光谱数据与企鹅粪九种标型元素浓度之间的关系,并探讨了南极企鹅粪土沉积物光谱数据的古生态意义。结果表明:南极粪土沉积样品反射率光谱与企鹅粪九种标型元素(P、Ca、Cu、F、Ba、S、Zn、Sr、Se)含量之间存在良好的相关性,预测值与实测值之间的相关系数R都达到了0.9以上,在深度剖面上预测浓度与实测浓度具有非常一致的变化趋势;南极粪土沉积物光谱数据包含有明确的古生态变化信息,可利用主成分分析快速恢复历史时期企鹅数量演化过程。本研究结果为在偏远的南极地区开展古生态环境研究提供了一种新的快捷方法和技术途径。

REFLECTANCE SPECTROSCOPY:A NEW METHOD FOR THE RECONSTRUCTION OF PENGUIN PALAEOECOLOGICAL PROCESS IN ANTARCTIC ORNITHOGENIC SEDIMENTS

Rapid,non-destructive and simultaneous method such as diffuse reflectance infrared spectroscopy provides potentially useful alternative to time-consuming chemical methods of soil or sediment elemental analysis.To assess the utility of near-infrared reflectance spectroscopy(NIRS) for the determination of elemental concentrations in the ornithogenic sediments and penguin palaeoecological reconstruction,four sediment cores(Y2,Y2-4,Y4,AD3) on the Ardley Island in the maritime Antarctic were analyzed by both chemical and spectroscopic methods.All these sediment cores have been proven to be influenced by penguin droppings in our previous studies.Stepwise multiple linear regression and principal component regression approaches were used to develop calibration models for predicting the concentrations of nine bio-elements including P,Ca,Cu,Zn,Se,Sr,Ba,F and S. The results showed that the correlation coefficients between optimal spectra-predicted and chemically analyzed concentrations of these nine bio-elements were quite high(more than 0.90),and the predicated concentration-versus-depth profiles were very consistent with those from actual chemical analysis.Furthermore,in order to infer the palaeoecological significance of spectra data,principal component analysis(PCA) was used to reconstruct the fluctuation of historical penguin population.Compared with the change pattern of penguin size inferred from the concentration variations of nine bio-elements,they had a very similar trend.Overall,this study demonstrated that using reflectance spectroscopy to infer palaeoecological information recorded in Antarctic ornithogenic sediments is feasible.