摘要
沉积物生物膜通过分泌胞外聚合物(EPS)影响其理化特性及生态功能。明确不同类型沉积物中生物膜的形成特征,对于精准评估污染物的生态毒性与修复潜力具有重要意义。本文对比研究了2种不同质地的人工沉积物——砂质黏质粉砂(ASC)和砂质粉砂(ASS,其黏粒含量比ASC低10%),与天然湖泊沉积物(NS)在孵育45 d期间的生物膜形成特征,重点关注EPS增长特征及微生物群落脂肪酸组成动态。结果表明,人工沉积物中EPS含量显著增长,主要组分为胞外蛋白(47.0%~98.9%),孵育约3周后趋于稳定,达1000μg·g^(-1),而胞外多糖的含量在15~25μg·g^(-1)。根据Logistic生长模型,ASC和ASS蛋白含量的平均增长速率分别为0.302 d^(-1)和0.335 d^(-1),粗质沉积物中ASS增长更快。微生物脂肪酸甲酯图谱分析显示,人工沉积物与NS的微生物群落结构相似性超过90%,其主要差异体现在好氧真核类群的相对丰度;随孵育时间延长,ASC与ASS组间生物膜群落组成差异增大,尤其是ASS中好氧与厌氧功能微生物的比值更高(2.7 vs.2.5)。生物膜增长稳定后,人工沉积物的总有机质含量和渗透系数也趋于稳定,含水率则呈稳定上升趋势;而NS的总EPS含量无显著增长,为(254±43)μg·g^(-1),尽管其初始含水率和总有机质含量水平更高,但均呈下降趋势。该结果表明,生物膜的生长阶段(如增长期或稳定期)将直接影响沉积物的理化特性。本研究初步揭示了人工与天然沉积物间生物膜形成特征的差异,并为探究生态修复中沉积物生物膜作用的室内模拟实验设计提供方法参考。
Sediment biofilms modify the physicochemical properties and ecological functions of sediments by secreting extracellular polymers(EPS).Understanding biofilm formation characteristics across different sediment types is essential for accurate assessment of pollutant ecotoxicity and remediation potential.This study compared the biofilm formation process of two types of artificial sediments with different textures,sandy clayey silt(ASC)and sandy silt(ASS,with 10%lower clay content than ASC),and natural lake sediments(NS)over a 45-day i ncubation period,focusing on EPS growth and the dynamics of microbial community fatty acid composition.The results showed a significant increase in EPS content in artificial sediments,with extracellular protein as the major component(47.0%-98.9%),stabilizing after about three weeks and reaching 1000μg·g^(-1),while extracellular polysaccharide content ranged from 15 to 25μg·g^(-1).According to the Logistic growth model,the average growth rates of protein in ASC and ASS were 0.302 d^(-1)and 0.335 d^(-1),respectively,with the coarser-textured ASS s howing faster growth.Microbial fatty acid methyl ester profiles showed over 90%similarity in community s tructure between artificial and natural sediment,mainly differing in the relative abundance of aerobic eukaryotic group.Over time,biofilm community composition further diverged between ASC and ASS,particularly in the ratio of aerobic to anaerobic functional groups,which was higher in ASS(2.7 vs.2.5).Once biofilm growth stabilized,the total organic matter(TOM)content and hydraulic conductivity of the artificial sediments also stabilized,while water content increased steadily.In contrast,the EPS content in NS did not grow significantly,remaining at(254±43)μg·g^(-1),although NS initially had higher water content and TOM levels,both of which showed a decreasing trend.These results indicate that the growth stage of biofilms(whether growing or stabilizing)directly affects the physicochemical properties of sediments.This study provides preliminary insights into the differences in biofilm formation between artificial and natural sediments,and offers a methodological reference for designing lab-scale simulation experiments to explore the role of sediment biofilms in bioremediation.
作者
唐金灿
梁莉莉
王亚芬
TANG Jincan;LIANG Lili;WANG Yafen(School of Environmental Studies,China University of Geosciences,Wuhan 430078,China;Hubei Provincial Engineering Research Center of Systematic Water Pollution Control,Wuhan 430078,China)
出处
《生态毒理学报》
北大核心
2025年第3期424-436,共13页
Asian Journal of Ecotoxicology
基金
国家自然科学基金资助项目(41977362)
湖北省生态环境厅环保科研项目(2022HB-04)
中央高校基本科研业务费(122-G1323522145)。
