An Integrated Experimental and Modeling Approach to Predict Sediment Mixing from Benthic Burrowing Behavior

Kevin R. Roche*, Antoine F. Aubeneau, Minwei Xie, Tomás Aquino, Diogo Bolster, Aaron I. Packman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Bioturbation is the dominant mode of sediment transport in many aquatic environments and strongly influences both sediment biogeochemistry and contaminant fate. Available bioturbation models rely on highly simplified biodiffusion formulations that inadequately capture the behavior of many benthic organisms. We present a novel experimental and modeling approach that uses time-lapse imagery to directly relate burrow formation to resulting sediment mixing. We paired white-light imaging of burrow formation with fluorescence imaging of tracer particle redistribution by the oligochaete Lumbriculus variegatus. We used the observed burrow formation statistics and organism density to parametrize a parsimonious model for sediment mixing based on fundamental random walk theory. Worms burrowed over a range of times and depths, resulting in homogenization of sediments near the sediment-water interface, rapid nonlocal transport of tracer particles to deep sediments, and large areas of unperturbed sediments. Our fundamental, parsimonious random walk model captures the central features of this highly heterogeneous sediment bioturbation, including evolution of the sediment-water interface coupled with rapid near-surface mixing and anomalous late-time mixing resulting from infrequent, deep burrowing events. This approach provides a general, transferable framework for explicitly linking sediment transport to governing biophysical processes.

Original languageEnglish (US)
Pages (from-to)10047-10054
Number of pages8
JournalEnvironmental Science and Technology
Volume50
Issue number18
DOIs
StatePublished - Sep 20 2016

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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