Distribution characteristics and indicative significance of fecal sterols in dif-ferent species in Nagri Prefecture of Qinghai-Xizang Plateau
This study took the Xiada Co Basin in Nagri Prefecture on Qinghai-Xizang Plateau as the research area,and the fecal samples of human,donkeys,foxes,rabbits,horses,wolves,birds,sheep and cattle around the lake were collected.Subsequently,the 9 sterol compounds in the fecal samples were detected by gas chromato-graphy-mass spectrometry to analyze its distribution characteristics and indicative significance.The results showed that coprostanol and epicoprostanol were the major sterols in human faeces,accounting for more than 60％of the total sterol concentration(the sum of the 9 sterols in faeces)in human faeces,but these 2 com-pounds only accounted for 0.66％～10.04％of the total sterol concentration in faeces of the other species,and the concentration of(coprostanol+epicoprostanol)in human feces was more than twice as high as as the sum of the concentrations of these 2 compounds in the faeces of the other 8 species.Therefore,coprostanol and epi-coprostanol could be used as tracers for human activities in Xiada Co Basin.Cholesterol accounted for more than 50％of the total sterols in the feces of carnivores such as foxes and wolves,but less than 7％in other spe-cies,implying that this sterol could be used to trace carnivores.Sitosterol accounted for more than 85％of total sterols in bird feces,much higher than its share of total fecal sterols in other species,suggesting that it could be used to identify plant-feeding birds.Sitosterol,stigmasterol,24-ethylcoprostanol and sitostanol were the dom-inant sterols in plant-feeding mammal feces.Thus,these sterols could be used to identify plant-feeding mam-mals.In addition,the fecal sterol compound ratio was also effective in identifying human feces in the Xiada Co Basin.Furthermore,the relative contents of C27 and C29 sterols could reflect the dietary composition of the an-imals,and the human fecal sterol data indicated that the people's dietary pattern was meat predominantly.Changes in the population size of humans and other animals will lead to changes in the amount of fecal sterols in lake sediments,which are transported to the lake and deposited.Therefore,by analyzing the steroidal bio-markers in lake sediment cores,we can obtain records of past changes in human population size and dietary habits.Combined with climate and environmental indicators in the same core,we can further explore the rela-tionship between past human activities and climate change.This study has constructed a scientific basis for re-constructing the relationship between past human activity and paleoenvironment in the Xiada Co Basin on the western Qinghai-Xizang Plateau.
万方数据
维普
