Complex coupled metabolic and prokaryotic community responses to increasing temperatures in anaerobic marine sediments: critical temperatures and substrate changes

• Published in: FEMS microbiology ecology Vol. 91; no. 8; p. fiv084
• Main Authors: Roussel, Erwan G., Cragg, Barry A., Webster, Gordon, Sass, Henrik, Tang, Xiaohong, Williams, Angharad S., Gorra, Roberta, Weightman, Andrew J., Parkes, R. John
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.08.2015
• Series: Editor's choice
• Subjects: Acetic acid; Anaerobic processes; Anaerobiosis - physiology; Archaea; Bacteria; Bacteria - genetics; Bacteria - metabolism; Biogeochemistry; Chemoautotrophic Growth - physiology; Critical temperature; Ecology; Environmental aspects; Euryarchaeota - genetics; Euryarchaeota - metabolism; Eutrophication; Geologic Sediments - microbiology; Marine sediments; Metabolism; Methane - metabolism; Methanogenesis; Methylamine; Microbial colonies; Microbiology; Organic matter; Oxidation; Oxidation-Reduction; Phylogeny; Physiological aspects; Prokaryotes; RNA, Ribosomal, 16S - genetics; Sediments; Slurries; Substrates; Substrates (Biochemistry); Sulfate reduction; Sulfate-reducing bacteria; Sulfates; Sulfates - metabolism; Temperature; Temperature effects; Tidal flats; United Kingdom; anaerobic processes; acetogenesis; chemolithotrophic; mineralisation; temperature; chemoorganotrophic; sulphate reduction; methanogenesis; sediment
• ISSN: 1574-6941; 0168-6496; 1574-6941
• DOI: 10.1093/femsec/fiv084

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. Temperature increases had a non-linear effect on biogeochemistry and prokaryotes in marine sediments, with rapid changes over small temperature intervals which are relevant to climate change and the deep biosphere.