金佛山不同高程岩溶泉初春时期溶解态脂类生物标志物研究

为探究金佛山不同高程的表层岩溶泉入春时期溶解有机质的来源和转化特点,于2017年1、2和4月分别在水房泉(2045 m)和碧潭泉(730 m)进行采样,利用气相色谱-质谱联用仪(GC-MS)对样品中脂类生物标志物(溶解态正构烷烃、脂肪酸)的组分进行定量分析.结果表明,水房泉和碧潭泉溶解态正构烷烃(T-ALK)含量变化范围分别为1546~19314 ng·L~(-1)和1089~12234 ng·L~(-1),平均含量分别为8036、5553ng·L~(-1);脂肪酸变化范围分别为4163~13048 ng·L~(-1)和5519~10079 ng·L~(-1),平均含量分别为8039和8421 ng·L~(-1).由于春季气温回升和降水增多,正构烷烃和脂肪酸含量总体均处于上升趋势.同时,基于正构烷烃分子参数CPI、OEP、TAR、L/H发现,溶解态正构烷烃以细菌源为主,高等植物源输入逐月升高,以低海拔处的碧潭泉变化更为显著.溶解态脂肪酸1、2月以细菌源为主,4月以真菌源和高等植物源脂肪酸为主,细菌源比重依然较高,且因不同海拔的生境不同导致碧潭泉的水生生物输入较水房泉更稳定.

Sources analysis and characteristics of dissolved lipid biomarkers of Karst springs from different elevations in Jinfo Mountain in early spring

In order to explore the sources and transport of dissolved organic matter in epi-Karst springs during the transition from winter to spring, samples containing lipid biomarkers (dissolved n-alkanes and fatty acids) were collected from Shuifang spring (high altitude) and Bitan spring (low altitude) at different elevations in Jinfo mountain in January, February and April 2017. The composition of lipid biomarkers was quantitatively analyzed using the gas chromatography-mass spectrometer (GC-MS). The results showed that the total contents of dissolved n-alkanes in Shuifang spring and Bitan spring ranged from 1546 to 19314 ng·L^-1 and from 1089 to 12234 ng·L^-1, respectively. The average contents of n-alkanes were 8036 and 555 ng·L^-1. Fatty acids ranged from 4163 to 13048 ng·L^-1 and from 5519 to 10079 ng·L^-1, respectively. The average contents of fatty acids were 8039 and 8421 ng·L^-1, respectively. In a word, the contents of n-alkanes and fatty acids were on the rise, responding to the increased air temperature and precipitation in spring. It shows that the n-alkanes were mainly from bacteria, and the input of terrigenous higher plants increased month by month, especially in Bitan spring based on the calculation of n-alkane molecular parameters (CPI, OEP, TAR and L/H). In January and February, dissolved fatty acids mainly originated from bacteria. In April, the main sources of fatty acids came from fungus and terrigenous higher plants, while the contribution from bacterial sources was still high. The aquatic biogenic fatty acids in Bitan spring were more stable than those in Shuifang spring as a result of different altitude habitats.