Distinct distribution revealing multiple bacterial sources for 1-Omonoalkyl glycerol ethers in terrestrial and lake environments  

作　　者：YANG Huan ZHENG FengFeng XIAO WenJie XIE ShuCheng 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences [2]State Key Laboratory of Marine Geology, Tongji University

出　　处：《Science China Earth Sciences》2015年第6期1005-1017,共13页中国科学（地球科学英文版）

基　　金：supported by the National Basic Research Program of China(Grant No.2011CB808800);the National Natural Science Foundation of China(Grant No.41330103);the"111"Project(Grant No.B08030)

摘　　要：The 1-O-monoalkyl glycerol ethers （MAGEs） were initially viewed as the biomarkers for sulfate-reducing bacteria （SRB） me- diating anaerobic oxidation of methane in the marine environments. However, limited information is known about their distri- bution in terrestrial and other aquatic settings including soils, fresh water lakes, and cave sediments, which may obscure our understanding of their biological sources. Here we found that MAGEs were ubiquitous but differed obviously in distributional pattern among those environments. The surface soils are dominated generally by iC15：0-MAGE, followed by nCI6：o-MAGE whereas the lake sediments show the opposite, resulting in significantly higher iC15：0/nC16：0 ratios in soils than in lake sedi- ments. The cave deposits are characterized by considerably higher proportions of branched MAGEs than the former two envi- ronments. The logarithm of iC15：0/aC15：0 ratio shows a significant negative correlation with soil pH, likely reflecting an adapta- tion of microbial cell membrane to change in the ambient proton concentration. The MAGE profiles in cultured bacteria cannot fully explain the MAGE distribution in all the samples analyzed. Therefore, MAGEs in soil, lake sediments, and cave deposits likely have additional biological source（s） other than SRB and cultured MAGE-producing bacteria. The difference in MAGE pattern among environments is likely to be attributed to change in microbial communities.The 1-O-monoalkyl glycerol ethers(MAGEs) were initially viewed as the biomarkers for sulfate-reducing bacteria(SRB) mediating anaerobic oxidation of methane in the marine environments. However, limited information is known about their distribution in terrestrial and other aquatic settings including soils, fresh water lakes, and cave sediments, which may obscure our understanding of their biological sources. Here we found that MAGEs were ubiquitous but differed obviously in distributional pattern among those environments. The surface soils are dominated generally by i C15:0-MAGE, followed by n C16:0-MAGE whereas the lake sediments show the opposite, resulting in significantly higher i C15:0/n C16:0 ratios in soils than in lake sediments. The cave deposits are characterized by considerably higher proportions of branched MAGEs than the former two environments. The logarithm of i C15:0/a C15:0 ratio shows a significant negative correlation with soil p H, likely reflecting an adaptation of microbial cell membrane to change in the ambient proton concentration. The MAGE profiles in cultured bacteria cannot fully explain the MAGE distribution in all the samples analyzed. Therefore, MAGEs in soil, lake sediments, and cave deposits likely have additional biological source(s) other than SRB and cultured MAGE-producing bacteria. The difference in MAGE pattern among environments is likely to be attributed to change in microbial communities.

关 键 词：1-O-monoalkyl glycerol ethers soil lake sediments cave deposits biological sources 

分 类 号：Q938[生物学—微生物学]