Biofilm plays a vital role in nutrients and toxic contaminants cycling in aquatic environments.  In order to evaluate the initial stages of biofilm formation on different substrata, iron oxide (goethite and hematite) coated slides and silica slides in a sampling device were lowered in the Flint River.  Carbohydrate and protein, the predominant constituents of biofilm extracellular polymeric substances (EPS) were measured by spectrophotometry during the first 6h-14 days.  Increasing amounts of carbohydrate and protein accumulated on all the surfaces during the period of immersion, however, hematite surfaces (days 6-14) showed decreasing values.  The carbohydrate to protein ratio for water extractable biofilm EPS (free) and EPS extracted by sonication (surface bound) on 6h slides were highly variable. Scanning electron microscopy revealed initial patchiness structure of biofilm, and at day 14 surfaces colonized with bacteria cells and diatoms. Surface composition of substrata can impact polysaccharide to protein ratio during initial biofilm formation.

Initial stages of biofilm formation on different substrata in the Flint River

239th National Meeting (2010)

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