title: Complex coupled metabolic and prokaryotic community responses to increasing temperatures in anaerobic marine sediments: critical temperatures and substrate changes.
abstract: The impact of temperature (0-80°C) on anaerobic biogeochemical processes and prokaryotic communities in marine sediments (tidal flat) was investigated in slurries for up to 100 days. Temperature had a non-linear effect on biogeochemistry and prokaryotes with rapid changes over small temperature intervals. Some activities (e.g. methanogenesis) had multiple 'windows' within a large temperature range (∼10 to 80°C). Others, including acetate oxidation, had maximum activities within a temperature zone, which varied with electron acceptor [metal oxide (up to ∼34°C) and sulphate (up to ∼50°C)]. Substrates for sulphate reduction changed from predominantly acetate below, and H2 above, a 43°C critical temperature, along with changes in activation energies and types of sulphate-reducing Bacteria. Above ∼43°C, methylamine metabolism ceased with changes in methanogen types and increased acetate concentrations (>1 mM). Abundances of uncultured Archaea, characteristic of deep marine sediments (e.g. MBGD Euryarchaeota, 'Bathyarchaeota') changed, indicating their possible metabolic activity and temperature range. Bacterial cell numbers were consistently higher than archaeal cells and both decreased above ∼15°C. Substrate addition stimulated activities, widened some activity temperature ranges (methanogenesis) and increased bacterial (×10) more than archaeal cell numbers. Hence, additional organic matter input from climate-related eutrophication may amplify the impact of temperature increases on sedimentary biogeochemistry.
authors.affiliation: School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Erwan G
authors.initials: EG
authors.lastname: Roussel
authors.affiliation: School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Cragg
authors.affiliation: School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK Cardiff School of Biosciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Gordon
authors.initials: G
authors.lastname: Webster
authors.affiliation: School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Henrik
authors.initials: H
authors.lastname: Sass
authors.affiliation: School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Tang
authors.affiliation: Cardiff School of Biosciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Angharad S
authors.initials: AS
authors.lastname: Williams
authors.affiliation: DISAFA, University of Turin, Largo P. Baccini 2, 10095 Grugliasco, TO, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Gorra
authors.affiliation: Cardiff School of Biosciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Weightman
authors.affiliation: School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK parkesrj@cardiff.ac.uk.
authors.forename: R John
authors.initials: RJ
authors.lastname: Parkes
mesh_terms: D000693:Anaerobiosis / Q000502:physiology; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D052837:Chemoautotrophic Growth / Q000502:physiology*; D019605:Euryarchaeota / Q000235:genetics / Q000378:metabolism*; D005068:Eutrophication; D019015:Geologic Sediments / Q000382:microbiology*; D008697:Methane / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013431:Sulfates / Q000378:metabolism; D013696:Temperature
chemical_list: D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D008697:Methane
keywords: acetogenesis; anaerobic processes; chemolithotrophic; chemoorganotrophic; methanogenesis; mineralisation; sediment; sulphate reduction; temperature