Benthic biofilm controls on fine particle dynamics in streams

K. R. Roche*, J. D. Drummond, F. Boano, A. I. Packman, T. J. Battin, W. R. Hunter

*Corresponding author for this work

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Benthic (streambed) biofilms metabolize a substantial fraction of particulate organic matter and nutrient inputs to streams. These microbial communities comprise a significant proportion of overall biomass in headwater streams, and they present a primary control on the transformation and export of labile organic carbon. Biofilm growth has been linked to enhanced fine particle deposition and retention, a feedback that confers a distinct advantage for the acquisition and utilization of energy sources. We quantified the influence of biofilm structure on fine particle deposition and resuspension in experimental stream mesocosms. Biofilms were grown in identical 3 m recirculating flumes over periods of 18–47 days to obtain a range of biofilm characteristics. Fluorescent, 8 µm particles were introduced to each flume, and their concentrations in the water column were monitored over a 30 min period. We measured particle concentrations using a flow cytometer and mesoscale (10 µm to 1 cm) biofilm structure using optical coherence tomography. Particle deposition-resuspension dynamics were determined by fitting results to a stochastic mobile-immobile model, which showed that retention timescales for particles within the biofilm-covered streambeds followed a power-law residence time distribution. Particle retention times increased with biofilm areal coverage, biofilm roughness, and mean biofilm height. Our findings suggest that biofilm structural parameters are key predictors of particle retention in streams and rivers.

Original languageEnglish (US)
Pages (from-to)222-236
Number of pages15
JournalWater Resources Research
Volume53
Issue number1
DOIs
StatePublished - Jan 1 2017

Keywords

  • benthic biofilm
  • fine particles
  • microbial biofilm
  • optical coherence tomography
  • stochastic model
  • streams

ASJC Scopus subject areas

  • Water Science and Technology

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    Roche, K. R., Drummond, J. D., Boano, F., Packman, A. I., Battin, T. J., & Hunter, W. R. (2017). Benthic biofilm controls on fine particle dynamics in streams. Water Resources Research, 53(1), 222-236. https://doi.org/10.1002/2016WR019041