摘要
细菌能够沿着液相中和固相上污染物的浓度梯度进行运动,进而达到降解污染物的目的,其中细菌在固相上的运动称为趋触效应,对污染土壤的生物修复至关重要。而土壤胶体则会通过影响有机污染物的固液分配比例影响趋触效应。本研究选取对萘具有化学响应的假单胞菌5RL(Pf5RL)为目标细菌,以其残体为土壤胶体代表,通过迁移实验探究细菌残体对趋触效应作用下Pf5RL迁移行为的影响。结果表明:细菌残体在石英砂中可稳定存在,Pf5RL及萘均对其迁移行为无影响,其最大穿出相对浓度(max C/C_(0))均约为0.6;细菌残体的存在却会阻碍Pf5RL迁移,使max C/C_(0)由0.97±0.02降低至0.75±0.01;主要是因为细菌残体提高了静电引力,增加了Pf5RL在细菌残体上的附着;萘也会阻碍Pf5RL迁移,主要是因为石英砂对萘的吸附产生了近表面趋化性及趋触性,使max C/C_(0)由0.97±0.02降低至0.75±0.04;在萘存在的情况下,细菌残体则会通过增加萘的吸附位点增强近表面趋化性及趋触性,从而进一步阻碍Pf5RL迁移,使max C/C_(0)由0.75±0.04进一步降低至0.50±0.03。细菌残体在有机污染物介导的趋触和趋化效应上有很重要的作用,是影响原位细菌降解动物粪便和再生水带来的土壤有机污染物的重要影响因素。
Bacteria can move along pollutant concentration gradients under both liquid and solid phases,facilitating the degradation of contaminants.Migration toward concentrated contaminants along immobilized solid surface is called heptotaxis,which plays a crucial role in the bioremediation of contaminated soils.Soil colloids can influence heptotaxis by affecting the solid⁃liquid distribution of organic contaminants.In this study,we investigated the effect of soil colloids on bacterial transport mediated by heptotaxis with Pseudomonas fluorescens 5RL(Pf5RL),a bacteri⁃um chemically responsive to naphthalene and its necromass as model bacteria and soil colloids.The results showed that the necromass remained stable in quartz sand,and that neither Pf5RL nor naphthalene affected its transport behavior,with a maximum breakthrough relative concentration(max C/C_(0))of~0.6.However,the presence of necromass could hinder the transport of Pf5RL,decreasing the max C/C_(0)from 0.97±0.02 to 0.75±0.01.This is pri⁃marily attributed to the increased electrostatic attraction which enhanced the attachment of Pf5RL on the necromass.The presence of naphthalene impeded Pf5RL transport due to the adsorption of naphthalene on sand,resulting in near⁃surface chemotaxis and heptotaxis effects,accompanied by a declining max C/C_(0)of Pf5RL from 0.97±0.02 to 0.75±0.04.Under the presence of naphthalene,the necromass further hindered Pf5RL transport by increasing the adsorption sites for naphthalene,which strengthened near⁃surface chemotaxis and heptotaxis effects,leading to a further decrease in max C/C_(0)of Pf5RL from 0.75±0.04 to 0.50±0.03.Our results highlight the significant role of necromass in the heptotaxis and chemotactic effects mediated by organic contaminants.It is suggested that necro⁃mass may be a crucial factor influencing the in⁃situ degradation of organic contaminants brought into soils by appli⁃cation of animal manure and reclaimed water.
作者
卢恩
陈希娟
石亚楠
杨新瑶
杨立琼
LU En;CHEN Xijuan;SHI Yanan;YANG Xinyao;YANG Liqiong(Shenyang University,Key Lab for Ecorestoration of Regional Contaminated Environment,Ministry of Education,Shenyang 110044,China;Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2024年第9期2908-2916,共9页
Chinese Journal of Ecology
基金
国家自然科学基金面上项目(52379051,42177406)资助。
关键词
细菌
细菌残体
趋触效应
近表面趋化性
迁移
bacteria
necromass
heptotaxis
near⁃surface chemotaxis
transport
