title: Diuron tolerance and potential degradation by pelagic microbiomes in the Great Barrier Reef lagoon.
abstract: Diuron is a herbicide commonly used in agricultural areas where excess application causes it to leach into rivers, reach sensitive marine environments like the Great Barrier Reef (GBR) lagoon and pose risks to marine life. To investigate the impact of diuron on whole prokaryotic communities that underpin the marine food web and are integral to coral reef health, GBR lagoon water was incubated with diuron at environmentally-relevant concentration (8 µg/L), and sequenced at specific time points over the following year. 16S rRNA gene amplicon profiling revealed no significant short- or long-term effect of diuron on microbiome structure. The relative abundance of prokaryotic phototrophs was not significantly altered by diuron, which suggests that they were largely tolerant at this concentration. Assembly of a metagenome derived from waters sampled at a similar location in the GBR lagoon did not reveal the presence of mutations in the cyanobacterial photosystem that could explain diuron tolerance. However, resident phages displayed several variants of this gene and could potentially play a role in tolerance acquisition. Slow biodegradation of diuron was reported in the incubation flasks, but no correlation with the relative abundance of heterotrophs was evident. Analysis of metagenomic reads supports the hypothesis that previously uncharacterized hydrolases carried by low-abundance species may mediate herbicide degradation in the GBR lagoon. Overall, this study offers evidence that pelagic phototrophs of the GBR lagoon may be more tolerant of diuron than other tropical organisms, and that heterotrophs in the microbial seed bank may have the potential to degrade diuron and alleviate local anthropogenic stresses to inshore GBR ecosystems.
authors.affiliation: Australian Centre for Ecogenomics, The University of Queensland , St Lucia, Queensland , Australia.
authors.forename: Florent E
authors.initials: FE
authors.lastname: Angly
authors.affiliation: Australian Centre for Ecogenomics, The University of Queensland, St Lucia, Queensland, Australia; Global Change Institute, The University of Queensland, St Lucia, Queensland, Australia.
authors.forename: Olga
authors.initials: O
authors.lastname: Pantos
authors.affiliation: Australian Centre for Ecogenomics, The University of Queensland , St Lucia, Queensland , Australia.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Morgan
authors.affiliation: Department of Soil, Water and Environmental Science, The University of Arizona, Tucson, AZ, United States of America; Microbiology Department, The Ohio State University, Columbus, OH, United States of America.
authors.forename: Virginia
authors.initials: V
authors.lastname: Rich
authors.affiliation: Australian Institute of Marine Science , Townsville, Queensland , Australia.
authors.forename: Hemerson
authors.initials: H
authors.lastname: Tonin
authors.affiliation: Australian Institute of Marine Science , Townsville, Queensland , Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Bourne
authors.affiliation: Australian Institute of Marine Science, Townsville, Queensland, Australia; National Research Centre for Environmental Toxicology, The University of Queensland, Coopers Plains, Queensland, Australia.
authors.forename: Philip
authors.initials: P
authors.lastname: Mercurio
authors.affiliation: Australian Institute of Marine Science , Townsville, Queensland , Australia.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Negri
authors.affiliation: Australian Centre for Ecogenomics, The University of Queensland , St Lucia, Queensland , Australia.
authors.forename: Gene W
authors.initials: GW
authors.lastname: Tyson
keywords: Amplicon profiling; Diuron; Great barrier reef; Herbicide; Incubation; Metagenomics