楚科奇海和白令海沉积物中的生物标志物及其生态环境响应

BIOMARKERS IN SEDIMENTS IN THE ARCTIC AREAS AND ECOLOGICAL ENVIRONMENTAL RESPONSE

采用210Pb方法对北极C8和B2-9岩心样进行了定年和沉积速率研究,获得分辨率约为10a的100年以来(1880—1999,1889—1999年)连续的海洋沉积环境序列。该岩心样中检出众多的生物标志物(正构烷烃、类异戊二烯、脂肪酸、甾醇等),利用这些精细分子组合特征∑nC22+/∑nC21-、TABHC、CPI、CPIA、∑C20:0-/nC20:0+、C18:2/C18:0并结合甾醇C27、C28、C29的含量特征变化,认为海域沉积物中有机质主要来自陆源碎屑物质以及海洋自生源(硅质生物)组成。研究还表明,白令海沉积地层(3～0cm)中生物标志物记录对应时间段约为1980—1999年,保存着北极增暖的强烈信号。北极的温室效应被放大,进一步证实了极地海洋生物学过程对气候变化有响应。

Core samples C8 and B2-9 from the seafloor of the Arctic were dated with ^210Fb to obtain a consecutive sequence of oceanic sedimentary environments at the interval of a decade during 1880-1999 and 1889- 1999. A variety of biomarkers were detected, including n-alkane, isoprenoid, fatty acid, sterol, etc. According to the characteristics of their molecular indices （∑nC22^＋/∑nC21^-、TABHC、CPI、CPIA、∑C20：0^-/nC20：0^＋、C18：2/C18：0） and in consideration of the variation of sterols content （C27, C28, and C29 sterols）,the 100-year variation history of subarctic sea paleoenvironment was reestablished. Composition of organic matter indicates that substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results also suggest that the record of biomarkers from the surface sediments （3-0 cm）in the Bering Sea represents a period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments. The fact that Arctic greenhouse effect was multiplied has further proved the response of marine biological process in the polar region to the climate change.