摘要
微生物能够通过改变细胞膜脂类成分而灵敏地响应地质环境条件的变化,使得人们建立了一系列微生物的古环境代用指标。应用比较广泛的古温度定量化指标包括藻类的长链烯酮U_(37)~k、古菌甘油二烷基甘油四醚的TEX_(86),以及细菌甘油二烷基甘油四醚的MBT/CBT等。然而,由于缺乏生理学和生态学分析,人们在应用微生物的环境代用指标时不断发现适用性问题。论文重点从微生物对环境响应的化学过程、生理范围和生态效应这三方面分析了一些环境代用指标在应用时需要考虑的多指标相互验证、线性范围和灵敏度,以及地区性差异等问题。微生物通过脂类响应环境变化有多种化学方式和途径可以实现,使得许多代用指标可以相互验证。微生物对地质环境的生理响应是有线性范围的,这决定了微生物脂类的环境代用指标的灵敏度大小。而微生物对环境因子的生态响应则决定了代用指标的应用存在地区性差异。某种环境的微生物活动往往受到一些限制性因子控制,相应地一些微生物脂类的环境代用指标也主要响应这些限制性环境因子的变化。微生物的古环境代用指标的应用不仅需要了解微生物通过脂类响应环境变化的化学机理,更要了解相应微生物的生理学和生态学原理。
Objectives： Microbes can show sensitive response to environmental change via the variation of cell membrane lipids. This enables the proposal and establishment of a series of molecular proxies for paleoenvionmental conditions. k Among them, Uk 37 of algal unsaturated long-chained ketones, TEX86 of archaeal tetraethers, and the MBT/CBT of bacterial tetraethers are the most widely-used proxies in paleoenvironmental reconstruction. However, the proxies were found difficult in practical application in some cases, which awaits the systematic analysis on the microbial physiology and ecology.
Methods： Molecular data of a variety of proxies were compiled from different microbes in different regions with various environmental conditions in modern soils in the world. Comparison was made among the molecular data published, which enables us to investigate the biogeochemieal, physiological, and ecological differences in microbial responses to the ambient environmental conditions.
Results： Three aspects related to the application of proxies were proposed to he deciphered, including the cross-check of multiple proxies due to the various hiogeochemical processes, the sensitivity and the linear range of the proxies resulting from physiological responses, and the spatial heterogeneity of the proxies arising from the ecological difference. Biogeochemieally, microbes can show responses to the ambient environmental conditions via several molecular patterns and pathways, providing a unique chance for the cross-check of multiple proxies. Physiologically, microbes are found to show a linear response to the environmental conditions only in certain range. The linear physiological response thus determines the sensitivity of the proxies for paleoenvironmental reconstruction. Ecologically, microbes might show responses to different environmental factors in different regions. The heterogeneity of ecological responses could affect the proxies used in different regions. Microbial activities in a specific environment might be restric
出处
《地质论评》
CAS
CSCD
北大核心
2018年第1期183-189,共7页
Geological Review
基金
国家重点研发计划项目(编号:2016YFA0601104)
国家自然科学基金重点项目(编号:41330103)的成果~~
