湛江湖光岩玛珥湖中长链烷基二醇类化合物的检出及可能的环境意义

Identification and potential environmental implication of long-chain alkyl diols in Huguangyan maar Lake

通过对湛江湖光岩玛珥湖现代环境介质(水体和表层沉积物)中的长链烷基二醇类化合物的定性和定量分析,检测出了一系列的长链烷基二醇化合物,包括1,13-C28、1,13-C30、1,14-C30、1,15-C30和1,15-C32。表层水体中1,14-C30相对含量最高,中层水体中1,15-C30相对含量最高,而底层水体中1,13-C30相对含量最高。推测1,14-C30主要来源于硅藻,但也不排除异鞭藻来源。1,13-C28可能同时具有黄绿藻和硅藻来源。1,13-C30、1,15-C30和1,15-C32长链化合物主要来源于黄绿藻(Eustigmatophytes),但也存在其他藻类来源。表层沉积物中长链烷基二醇化合物的分布与中层水体颗粒物各二醇类化合物的分布相似,表明湖光岩玛珥湖沉积物中长链烷基二醇类化合物主要来源于浮游藻类。湖泊水体颗粒物中二醇指数(DIX)同实测的湖泊水体温度具有很强的线性相关性,而表层沉积物中DIX一致,表明湖光岩玛珥湖中二醇指数能够用来作为水体温度的替代性指标。此研究结果为长链烷基二醇类化合物在湖泊古环境重建应用中提供了现代过程证据。

Long-chain alkyl diols, including 1,13-C28, 1,13-C30, 1,14-C30, 1,15-C30 and 1,15-C32 diol, are identified in suspended particulate matter （SPM） at different water depths and surface sediments from the Huguangyan maar Lake. The highest percentage of diol is 1,14-C30 in the SPM of surface water. The highest percentage of diol is 1,15-C30 in the SPM of mid-depth water, and the highest percentage of diol is 1,13-C30 in the SPM of bottom water. It can be deduced that 1,14-C30 diol is mainly derived from diatom, and some possibly derived from Dictyochophyceae, 1,13-C28 diol from Eustigmatophytes and diatom, and 1,13-C30, 1,15-C30 and 1,15-C32 diols from Eustigmatophytes in the Huguangyan maar Lake. The distribution of diols in the surface sediments is similar to that in the SPM of mid-depth water, suggesting that the long-chain alkyl diols in sediments are derived from phytoplankton algae in the Hguangyan maar Lake. The significant positive relationship between measured water temperature and Diol Isomer Index （DIX） of the SPM in water, and the consistency of DIX in the surface sediments suggest that DIX can be used as a palaeotemperature proxy in the Hugaungyan maar Lake.