Linking biofilm spatial structure to real-time microscopic oxygen decay imaging |
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Authors: | S Rubol A Freixa X Sanchez-Vila A M Romaní |
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Institution: | 1. Department of Energy Resources Engineering, Stanford University, Stanford, CA, USA;2. Catalan Institute for Water Research (ICRA), Girona, Spain;3. Hydrogeology Group, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, UPC, Barcelona, Spain;4. Institute of Aquatic Ecology, University of Girona, Girona, Spain |
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Abstract: | Two non-destructive techniques, confocal laser scanning microscopy (CLSM) and planar optode (VisiSens imaging), were combined to relate the fine-scale spatial structure of biofilm components to real-time images of oxygen decay in aquatic biofilms. Both techniques were applied to biofilms grown for seven days at contrasting light and temperature (10/20°C) conditions. The geo-statistical analyses of CLSM images indicated that biofilm structures consisted of small (~100 μm) and middle sized (~101 μm) irregular aggregates. Cyanobacteria and EPS (extracellular polymeric substances) showed larger aggregate sizes in dark grown biofilms while, for algae, aggregates were larger in light-20°C conditions. Light-20°C biofilms were most dense while 10°C biofilms showed a sparser structure and lower respiration rates. There was a positive relationship between the number of pixels occupied and the oxygen decay rate. The combination of optodes and CLMS, taking advantage of geo-statistics, is a promising way to relate biofilm architecture and metabolism at the micrometric scale. |
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Keywords: | Confocal laser scanning microscopy real-time images of oxygen concentration biofilm growth planar optodes biofilm respiration geostatistics |
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