title: Diverse, rare microbial taxa responded to the Deepwater Horizon deep-sea hydrocarbon plume.
abstract: The Deepwater Horizon (DWH) oil well blowout generated an enormous plume of dispersed hydrocarbons that substantially altered the Gulf of Mexico's deep-sea microbial community. A significant enrichment of distinct microbial populations was observed, yet, little is known about the abundance and richness of specific microbial ecotypes involved in gas, oil and dispersant biodegradation in the wake of oil spills. Here, we document a previously unrecognized diversity of closely related taxa affiliating with Cycloclasticus, Colwellia and Oceanospirillaceae and describe their spatio-temporal distribution in the Gulf's deepwater, in close proximity to the discharge site and at increasing distance from it, before, during and after the discharge. A highly sensitive, computational method (oligotyping) applied to a data set generated from 454-tag pyrosequencing of bacterial 16S ribosomal RNA gene V4-V6 regions, enabled the detection of population dynamics at the sub-operational taxonomic unit level (0.2% sequence similarity). The biogeochemical signature of the deep-sea samples was assessed via total cell counts, concentrations of short-chain alkanes (C1-C5), nutrients, (colored) dissolved organic and inorganic carbon, as well as methane oxidation rates. Statistical analysis elucidated environmental factors that shaped ecologically relevant dynamics of oligotypes, which likely represent distinct ecotypes. Major hydrocarbon degraders, adapted to the slow-diffusive natural hydrocarbon seepage in the Gulf of Mexico, appeared unable to cope with the conditions encountered during the DWH spill or were outcompeted. In contrast, diverse, rare taxa increased rapidly in abundance, underscoring the importance of specialized sub-populations and potential ecotypes during massive deep-sea oil discharges and perhaps other large-scale perturbations.
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA, USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Kleindienst
authors.affiliation: Josephine Bay Paul Center, Marine Biological Laboratory, Woods Hole, MA, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Grim
authors.affiliation: Josephine Bay Paul Center, Marine Biological Laboratory, Woods Hole, MA, USA.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Sogin
authors.affiliation: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Bracco
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA, USA.
authors.forename: Melitza
authors.initials: M
authors.lastname: Crespo-Medina
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA, USA.
authors.forename: Samantha B
authors.initials: SB
authors.lastname: Joye
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044822:Biodiversity; D006838:Hydrocarbons / Q000378:metabolism*; D008800:Mexico; D008969:Molecular Sequence Data; D000066388:Oil and Gas Industry; D059392:Petroleum Pollution; D010802:Phylogeny; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D006838:Hydrocarbons