河流原位自生古菌对四醚脂类古温度代用指标的影响  

Effect from in-situ archaeal membrane lipids in rivers on tetraether-based paleothermometer

作　　者：郑平波 张虎才 孙惠玲[1] ZHENG Ping-bo;ZHANG Hu-cai;SUN Hui-ling(Yunnan Key Laboratory of Plateau Geographic Processes and Environment Change,Faculty of Geography,Yunnan Normal University,Kunming 650500,Yunnan,China;Institute for Ecological Research and Pollution Control of Plateau Lakes,School of Ecology and Environmental Science,Yunnan University,Kunming 650504,Yunnan,China)

机构地区：[1]云南师范大学地理学部,云南省高原地理过程与环境变化重点实验室,云南昆明650500 [2]云南大学生态与环境科学学院,高原湖泊生态与污染治理研究院,云南昆明650500

出　　处：《云南大学学报（自然科学版）》2023年第3期741-750,共10页Journal of Yunnan University(Natural Sciences Edition)

基　　金：国家自然科学基金(41971115,41761044);云南师范大学研究生科研创新基金(YJSJJ22-13107).

摘　　要：河流作为内陆环境中地表径流的重要环节,是陆相土壤生成的甘油二烷基甘油四醚(isoGDGTs)输入湖泊环境的重要载体.围绕河流相原位自生的isoGDGTs在输送过程中如何影响湖相环境中isoGDGTs衍生的四醚指数(TEX_(86))指标的问题,以中国西南地区抚仙湖流域为研究对象,展开对抚仙湖流域表层土壤、河流表层沉积物、季节性湖泊表层水悬浮颗粒物(SPM)的isoGDGTs来源及分布特征的分析和讨论.结果表明,抚仙湖表层水体SPM和流域表层土壤中的isoGDGTs分别主要由奇古菌(Thaumarchaeota)中的Group I.1a和Group I.1b类群构成.入湖河流的表层沉积物中富含原位自生的厌氧产甲烷古菌(Methanonatronarchaeia).并且,指示河流表层沉积物中原位自生的厌氧产甲烷古菌丰度的Archaeol质量浓度与isoGDGTs中的GDGT-1组分的质量浓度显著正相关.这表明抚仙湖流域河流原位自生的厌氧产甲烷古菌主要通过贡献更多的GDGT-1组分来干扰湖相环境中的TEX86指标,进而导致TEX86重建温度异常偏低.不过,这种河流相原位自生的isoGDGTs组分对湖泊isoGDGTs组分的影响仅在降水丰沛时期得以展现.As a part of surface runoff under terrestrial conditions,rivers could not only carry the terrestrial-derived isoprenoid glycerol dialkyl glycerol tetraethers(isoGDGTs),but also in-situ produced isoGDGTs to the lake.The features of isoGDGTs which come from in-situ archaea in the river were investigated to find out their potential impact on the application of the TEX_(86) index of isoGDGTs in lacustrine environment.We took the Lake Fuxian basin in Southwest China as the research object and analyzed various samples collected around the lake,including surface soils,surface river sediments and year-round suspended particulate matters(SPM)in surface water.The results showed that isoGDGTs in SPM and soils were mainly originated from the cluster of Group I.1a Thaumarchaeota and Group I.1b Thaumarchaeota,respectively.The surface river sediments held a significant characteristic of in-situ anaerobic methanogenic archaea(e.g.,Methanonatronarchaeia).Moreover,the abundance of archaeol in surface river sediments was significantly positively correlated with GDGT-1 abundance.It meant the anaerobic methanogenic archaea could contribute a higher abundance of GDGT-1 to distort the TEX_(86) signal,further,which might result in the TEX86 value of surface river sediments being apparently lower than that of soil.Furthermore,the above effects only occurred during the rainy season.

关 键 词：抚仙湖 河流 厌氧产甲烷古菌 甘油二烷基甘油四醚 四醚指数 

分 类 号：X524[环境科学与工程—环境工程]