南极普里兹湾表层沉积物有机地球化学特征及其生态环境意义

摘要

Multiple biomarkers has been analyzed by gas chromatography and gas chromatography-mass spectrum on sur-face sediments collected from 5 stations in Prydz Bay,East Antarctica,and its implication on ecology and environ-ment has been discussed.The results showed that the concentration of total lipids was highest in the center area of Prydz Bay (1 193 μg·g-1 ),follow by Amery Ice Shelf area (572 μg·g-1 ),and lowest in slope area (341 μg ·g-1 ).It was significantly positive correlated with sedimentary organic carbon,total neutral monosaccharides,bi-ogenic silica,brassicasterol,and chlorophyll a concentrations in surface sea water (p<0.1 ),and indicated that organic matter preserved in surface sediment was mainly from marine phytoplankton.The significantly negative cor-relation of relative concentrations between C27 and C28 steranes showed the food chain between Euphausia crystal-lorophias and diatoms.The relative high ratio of saturated hydrocarbons:arenes (>2.5),low ratios of Pr/C17(<0.5)and Pr/Ph (<2)inferred the sedimentary organic matter was largely contributed by diatoms.Meanwhile,the double peak of saturated hydrocarbons (C17 or C18,C29)and relative high concentration of C29 steranes (35.79%) showed terrestrial vascular plants input,and it was higher in the center area of Prydz Bay (CPI=1 .60,Pr/Ph=0.69)than the slope area and Amery Ice Shelf area (CPI=1.01,Pr/Ph=0.39).The ratio of C18:2/C18:0 for fatty acids was higher in sediment collected from the center area of Prydz Bay and Amery Ice Shelf area (0.78)than that from slope area of Prydz Bay (0.23)and lower latitude regions (<0.1),and indicated that during austral sum-mer,the surface sea temperature was higher in slope area of Prydz Bay than center area of Prydz Bay and Amery Ice Shelf area.%用气相色谱和气相色谱-质谱分析法分析了南极普里兹湾5个站位表层沉积物中多种生物标志物，探讨了其生态环境指示意义。结果显示：（1）湾内中心区总类脂物含量最高（1193μg·g-1），埃默里冰架区次之（572μg· g-1），陆坡区最低（341μg·g-1），且与沉积有机碳、总糖、生物硅、菜籽甾醇、表层海水叶绿素a等参数显著正相关（p＜0．1），表明底层有机质与上层水体浮游植物密切相关；（2）C27甾烷含量与C28甾烷显著负相关（p＜0．01），指示着晶磷虾与硅藻的食物链关系；（3）相对较高的饱和烃/芳烃比值（＞2．5）、较低的Pr/C17（＜0．5）和Pr/Ph（＜2）证明沉积有机质主要来源于硅藻等浮游植物，同时饱和烃双峰群（C17或C18和C29）的存在及较高含量的C29甾烷（35．79％）指示外域有机质输入，且湾中心区的（CPI＝1．60，Pr/Ph＝0．69）要高于陆坡区和冰架区（CPI＝1．01，Pr/Ph＝0．39）；（4）湾内中心区和冰架区脂肪酸C18：2/C18：0平均比值（0．78）要高于陆坡区（0．23）和低纬度地区（＜0．1），表明南极夏季普里兹湾陆坡区的表层海水温度要高于湾中心区和冰架区。