title: Modelling the transport of environmental DNA through a porous substrate using continuous flow-through column experiments.
abstract: Detecting environmental DNA (eDNA) in water samples is a powerful tool in determining the presence of rare aquatic species. However, many open questions remain as to how biological and physical conditions in flowing waters influence eDNA. Motivated by what one might find in a stream/river benthos we conducted experiments in continuous flow columns packed with porous substrates to explore eDNA transport and ask whether substrate type and the presence of colonized biofilms plays an important role for eDNA retention. To interpret our data, and for modelling purposes, we began with the assumption that eDNA could be treated as a classical tracer. Comparing our experimental data with traditional transport models, we found that eDNA behaves anomalously, displaying characteristics of a heterogeneous, polydisperse substance with particle-like behaviour that can be filtered by the substrate. Columns were quickly flushed of suspended eDNA particles while a significant amount of particles never made it through and were retained in the column, as calculated from a mass balance. Suspended eDNA was exported through the column, regardless of biofilm colonization. Our results indicate that the variable particle size of eDNA results in stochastic retention, release and transport, which may influence the interpretation eDNA detection in biological systems.
authors.affiliation: Department of Biological Sciences, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA ashogren@nd.edu.
authors.forename: Arial J
authors.identifier: 0000-0002-1284-3836
authors.initials: AJ
authors.lastname: Shogren
authors.affiliation: Department of Biological Sciences, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Tank
authors.affiliation: Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Andruszkiewicz
authors.affiliation: Department of Biological Sciences, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA Oceanic Institute of Hawai'i Pacific University, Waimanalo, HI, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: Olds
authors.affiliation: Department of Biological Sciences, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA Biology Department, Aquatic Ecosystems Analysis Laboratory, University of Nevada, Reno, NV, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Jerde
authors.affiliation: Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA.
authors.forename: Diogo
authors.initials: D
authors.lastname: Bolster
mesh_terms: D000818:Animals; D004247:DNA / Q000032:analysis* / Q000737:chemistry*; D008956:Models, Chemical; D010473:Perciformes; D045483:Rivers
chemical_list: D004247:DNA
keywords: anomalous transport; eDNA; porous media