Effects of mixing processes on microbial degradation and the distribution of microorganisms in stationary and non-stationary contaminant plumes

混合过程对微生物降解以及微生物在固定和非固定污染物羽流中分布的影响

• 批准号: 5419180
• 负责人: Professor Dr. Christian Griebler
• 金额: --
• 依托单位: Department für Funktionelle und Evolutionäre Ökologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2004
• 资助国家: 德国
• 起止时间: 2003-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5419180?language=en
• 关键词: Effects; mixing; processes; microbial; degradation

In the proposed project we want to study the effects of mixing processes and changing groundwater flow regimes on the microbial degradation potential in contaminated aquifers. Microbial degradation activities will be quantified by compound-specific isotope analysis (CSIA), i.e. the stable isotope fractionation of 13C/12C and D/H in the residual, not yet degraded contaminant fraction. In laboratory tank experiments artificial contaminant plumes (e.g. toluene) will be produced under stationary or transient flow conditions. The augmentation of the tank system with well defined bacterial cultures and the supply of mixtures of deuterated and non-deuterated contaminants will allow to quantify microbial degradation at a high resolution (mm-scale). Because of extremely different fractionation properties of aerobic and anaerobic strains we will be able to differentiate between the respective contributions of the two to the overall degradation processes. Furthermore, the effects of stationary and non-stationary flow conditions on the introduced microorganisms will be investigated. Here the overall question is how tolerant and/or flexible are microorganisms which are confronted with frequently changing environmental conditions (e.g. oxic-anoxic) and how long after a disturbance it might take to initiate and resuscitate a pronounced degradation. The concept will also be investigated in the field where a cross section through a contamination plume with a 50 x 50 cm resolution of the sampling spots will be sampled. CSIA will provide information on the spatial distribution of biodegradation activities in situ. By means of molecular methods the field samples will also be analysed for the presence of different groups (e.g. sulfate-reducing and iron-reducing bacteria) and individual strains of microorganisms (the ones we isolated from the actual site). Comparisons of results from laboratory and field investigations should reveal general insights into the effect of mixing and non-stationary flow conditions on natural attenuation processes in contaminated aquifers.

在拟议的项目中，我们希望研究混合过程和地下水流动状况变化对受污染含水层中微生物降解潜力的影响。微生物降解活动将通过特定化合物同位素分析（CSIA）进行量化，即残留的、尚未降解的污染物部分中13 C/12 C和D/H的稳定同位素分馏。在实验室水槽实验中，人造污染物羽流（如甲苯）将在静止或瞬态流动条件下产生。通过使用明确的细菌培养物来增强罐系统以及供应氘化和非氘化污染物的混合物，将能够以高分辨率（毫米级）量化微生物降解。由于需氧和厌氧菌株的分离特性极其不同，我们将能够区分两者对整个降解过程的各自贡献。此外，将研究稳态和非稳态流动条件对引入的微生物的影响。在这里，总的问题是如何容忍和/或灵活的微生物面临着频繁变化的环境条件（如缺氧-缺氧），以及多久后的干扰，它可能需要启动和恢复明显的降解。还将在实地对这一概念进行研究，对污染羽流的横截面进行采样，采样点的分辨率为50 x 50厘米。CSIA将提供关于现场生物降解活动空间分布的信息。还将通过分子方法分析现场样品中是否存在不同的微生物群体（例如硫酸盐还原菌和铁还原菌）和单个微生物菌株（我们从实际现场分离的菌株）。实验室和实地调查结果的比较应揭示混合和非稳定流动条件对受污染含水层自然衰减过程的影响的一般性见解。