title: The role of biophysical cohesion on subaqueous bed form size.
abstract: Biologically active, fine-grained sediment forms abundant sedimentary deposits on Earth's surface, and mixed mud-sand dominates many coasts, deltas, and estuaries. Our predictions of sediment transport and bed roughness in these environments presently rely on empirically based bed form predictors that are based exclusively on biologically inactive cohesionless silt, sand, and gravel. This approach underpins many paleoenvironmental reconstructions of sedimentary successions, which rely on analysis of cross-stratification and bounding surfaces produced by migrating bed forms. Here we present controlled laboratory experiments that identify and quantify the influence of physical and biological cohesion on equilibrium bed form morphology. The results show the profound influence of biological cohesion on bed form size and identify how cohesive bonding mechanisms in different sediment mixtures govern the relationships. The findings highlight that existing bed form predictors require reformulation for combined biophysical cohesive effects in order to improve morphodynamic model predictions and to enhance the interpretations of these environments in the geological record.
authors.affiliation: Department of Geography, Environment and Earth Sciences University of Hull Hull UK.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Parsons
authors.affiliation: Department of Geography, Environment and Earth Sciences University of Hull Hull UK; School of Marine Science and Engineering Plymouth University Plymouth UK.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schindler
authors.affiliation: School of Biology University of St Andrews Saint Andrews UK.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Hope
authors.affiliation: School of Ocean Sciences Bangor University Anglesey UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Malarkey
authors.affiliation: School of Ocean Sciences Bangor University Anglesey UK.
authors.forename: Jaco H
authors.initials: JH
authors.lastname: Baas
authors.affiliation: School of Earth and Environment University of Leeds Leeds UK.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Peakall
authors.affiliation: Department of Geography, Environment and Earth Sciences University of Hull Hull UK; School of Marine Science and Engineering Plymouth University Plymouth UK; HR Wallingford Wallingford UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Manning
authors.affiliation: Department of Geography, Environment and Earth Sciences University of Hull Hull UK.
authors.forename: Leiping
authors.initials: L
authors.lastname: Ye
authors.affiliation: Department of Geography, Environment and Earth Sciences University of Hull Hull UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Simmons
authors.affiliation: School of Biology University of St Andrews Saint Andrews UK.
authors.forename: David M
authors.initials: DM
authors.lastname: Paterson
authors.affiliation: School of Biology University of St Andrews Saint Andrews UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Aspden
authors.affiliation: School of Marine Science and Engineering Plymouth University Plymouth UK.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Bass
authors.affiliation: Centre for Applied Marine Sciences Bangor University Anglesey UK.
authors.forename: Alan G
authors.initials: AG
authors.lastname: Davies
authors.affiliation: School of Ocean Sciences Bangor University Anglesey UK; National Oceanography Centre Liverpool UK.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Lichtman
authors.affiliation: National Oceanography Centre Liverpool UK.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Thorne
keywords: bed forms; biophysical; cohesivity; roughness; sediment