细菌色素在水体环境中的指示作用与意义

Indicative role and significance of bacterial pigments in aquatic environments

细菌色素(Bchl)作为厌氧光合细菌(APB)的主要色素,其在沉积物中的信息是研究古环境变化的重要生物标志物.系统总结了细菌色素的来源、APB的分布、色素分析测定方法及其在指示古海洋、古湖泊以及现代水生环境的水文条件、极地冰盖变化和水体缺氧事件发生中的应用.细菌色素主要来源于水体化变层处的绿硫细菌(GSB)和紫硫细菌(PSB)等厌氧光合细菌;PSB的碳同位素分馏较GSB的高.因APB独特的生存环境,产生的色素能够指示湖泊的化变层深度变化及半混合历史.目前针对细菌色素的分析方法主要有光谱法、色谱法及色谱-质谱联用法,其中色谱-质谱联用法在色素定性和定量上有绝对优势.细菌色素在水体和沉积物中的保存易受到物理、化学、生物等因素的干扰,其稳定性还存在不确定性,且其分析方法还在摸索中,需进一步深入探究和优化测定方法和降解保存机制,以便将其广泛运用到古环境、古气候研究中.

Bacterialchlorophyll(Bchl),as the main pigment of anaerobic photosynthetic bacteria(APB),serves as an important biomarker for studying paleoenvironmental changes in sediment.This paper provides a comprehensive review of the sources of bacterial pigments,distribution of APB,analytical methods for bacterial pigments,and its applications in indicating hydrological conditions in modern and ancient aquatic environments,polar ice cover changes,occurrence of hypoxia events and primary production.Bacterial pigments primarily originates from APB such as green sulfur bacteria(GSB)and purple sulfur bacteria(PSB)at the chemocline.PSB exhibits a higher carbon isotope fractionation compared to GSB.Due to the unique living environmental conditions of APB,the produced pigments can indicate changes in the depth of chemocline and the meromixis history of lakes.Currently,spectroscopy,chromatography and chromatography-mass spectrometry are the main analytical methods for bacterial pigments,with chromatography-mass spectrometry demonstrating advantages in bacterial pigment identification and quantification.The preservation of bacterial pigments in water and sediment is susceptible to physical,chemical and biological disturbances,and its stability is still uncertain.The analytical methods,and degradation and preservation mechanisms require further exploration and optimization to facilitate the widespread application of bacterial pigments in paleoenvironmental and paleoclimate reseaerch.