Microorganisms in the capillary fringe, rapidly changing environment

毛细边缘（CF）中悬浮或固定的生物膜形成微生物对物理行为的影响将与水化学家合作，研究土壤-水-气界面的生物或地球化学变化（例如水力参数的变化、CF的范围、含水量）（Frimmel/Abbt-Braun）、地质学家（Grathwohl）、（土壤）物理学家（Vogel/Geistlinger）和数学家（Bastian/Ippisch）对实验数据进行建模。实验室工作将包括短期和长期实验，以阐明生物膜形成的孔径变化（生物堵塞），矿物/有机表面的毛细吸力，存在/不存在胞外聚合物（EPS）或生物表面活性剂和细菌运动的土壤含水量变化。将开发一种通过利用荧光底物和天然或修饰的荧光细菌与非侵入性技术来可视化和估计（量化）细菌分布、活性和生物膜形成的技术。将研究CF中悬浮或固定的细菌对氧运输过程以及生化反应的影响，并将使用数据来模拟和预测水位波动和不同营养水平下污染物的命运。当硝酸盐作为电子受体，随后的氮气形成过程中发生反硝化和气泡的形成和消失对运输过程的影响将进行研究。

The influence of suspended or immobilized, biofilms forming microorganisms in capillary fringes (CF´s) on the physical behaviour (e.g. changes of hydraulic parameters, extent of the CF, water content) and changes of bio- or geochemistry in the soil-water-gas-interphase will be investigated in cooperation with water chemists (Frimmel/Abbt-Braun), geologists (Grathwohl), (soil) physicists (Vogel/Geistlinger) and mathematicians (Bastian/Ippisch) for modeling of experimental data. The lab work will include short term and long term experiments to elucidate pore size changes (bioclogging) by biofilm formation, capillary suction at mineralic/organic surfaces, changes in soil water content in the presence/absence of extracellular polymeric substances (EPS) or biosurfactants and bacterial movement. A technique to visualize and estimate (quantify) the bacterial distribution, activity and biofilm formation in a variably saturated porous medium (CF) by utilization of fluorescent substrates and natural or modified fluorescent bacteria with non-invasive techniques will be developed. The influence of suspended or immobilized bacteria in the CF on transport processes of oxygen coupled with biochemical reactions will be investigated and data will be used to model and predict the fate of a pollutant at fluctuating water tables and under different nutrition levels. When nitrate is used as electron acceptor subsequent nitrogen gas formation occurs during denitrification and the influence of gas bubble formation and disappearance on transport processes will be investigated.