Rotating disk electrodes to assess river biofilm thickness and elasticity

WATER RESEARCH

卷:45

Article

Bouletreau, Stephanie^1,2  Charcosset, Jean-Yves^1,2  Gamby, Jean⁴  Lyautey, Emilie^1,2  Mastrorillo, Sylvain^1,2  Azemar, Frederic^1,2  Moulin, Frederic³  Tribollet, Bernard⁴  Garabetian, Frederic⁵ 

[1] Univ Toulouse, INP, UPS, EcoLab Lab Ecol Fonct, F-31062 Toulouse, France

[2] CNRS, EcoLab, F-31062 Toulouse, France

[3] Inst Mecan Fluides Toulouse, UMR 5502, F-31400 Toulouse, France

[4] Univ Paris 06, CNRS, Lab Interfaces & Syst Electrochim LISE, UPR 15, F-75252 Paris 05, France

[5] Univ Bordeaux, EPOC OASU, Stn Marine Arcachon, UMR 5805, F-33120 Arcachon, France

关键词: Epilithon;    Periphyton;    Biofilm architecture;    Biofilm deformation;    Voltammetry;    Electrochemistry;   

DOI  :  10.1016/j.watres.2010.10.016

来源: Elsevier

【 摘 要 】

The present study examined the relevance of an electrochemical method based on a rotating disk electrode (RDE) to assess river biofilm thickness and elasticity. An in situ colonisation experiment in the River Garonne (France) in August 2009 sought to obtain natural river biofilms exhibiting differentiated architecture. A constricted pipe providing two contrasted flow conditions (about 0.1 and 0.45 m s(-1) in inflow and constricted sections respectively) and containing 24 RDE was immersed in the river for 21 days. Biofilm thickness and elasticity were quantified using an electrochemical assay on 7 and 21 days old RDE-grown biofilms (t(7) and t(21), respectively). Biofilm thickness was affected by colonisation length and flow conditions and ranged from 36 +/- 15 mu m (mean +/- standard deviation, n = 6) in the fast flow section at t(7) to 340 +/- 140 mu m (n = 3) in the slow flow section at t(21). Comparing the electrochemical signal to stereomicroscopic estimates of biofilms thickness indicated that the method consistently allowed (i) to detect early biofilm colonisation in the river and (ii) to measure biofilm thickness of up to a few hundred mu m. Biofilm elasticity, i.e. biofilm squeeze by hydrodynamic constraint, was significantly higher in the slow (1300 +/- 480 mu m rpm(1/2), n = 8) than in the fast flow sections (790 +/- 350 mu m rpm(1/2), n = 11). Diatom and bacterial density, and biofilm-covered RDE surface analyses (i) confirmed that microbial accrual resulted in biofilm formation on the RDE surface, and (ii) indicated that thickness and elasticity represent useful integrative parameters of biofilm architecture that could be measured on natural river assemblages using the proposed electrochemical method. 2010 Elsevier Ltd. All rights reserved.

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