title: Quantification of the effects of ocean acidification on sediment microbial communities in the environment: the importance of ecosystem approaches.
abstract: To understand how ocean acidification (OA) influences sediment microbial communities, naturally CO2-rich sites are increasingly being used as OA analogues. However, the characterization of these naturally CO2-rich sites is often limited to OA-related variables, neglecting additional environmental variables that may confound OA effects. Here, we used an extensive array of sediment and bottom water parameters to evaluate pH effects on sediment microbial communities at hydrothermal CO2 seeps in Papua New Guinea. The geochemical composition of the sediment pore water showed variations in the hydrothermal signature at seep sites with comparable pH, allowing the identification of sites that may better represent future OA scenarios. At these sites, we detected a 60% shift in the microbial community composition compared with reference sites, mostly related to increases in Chloroflexi sequences. pH was among the factors significantly, yet not mainly, explaining changes in microbial community composition. pH variation may therefore often not be the primary cause of microbial changes when sampling is done along complex environmental gradients. Thus, we recommend an ecosystem approach when assessing OA effects on sediment microbial communities under natural conditions. This will enable a more reliable quantification of OA effects via a reduction of potential confounding effects.
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany chassenr@mpi-bremen.de.
authors.forename: Christiane
authors.initials: C
authors.lastname: Hassenrück
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany.
authors.forename: Artur
authors.initials: A
authors.lastname: Fink
authors.affiliation: National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Lichtschlag
authors.affiliation: Center for Biotechnology, Bielefeld University, Universitätsstrasse 27, 33615 Bielefeld, Germany.
authors.forename: Halina E
authors.initials: HE
authors.lastname: Tegetmeyer
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: de Beer
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany Institute of Social and Preventive Medicine, Bern University, Finkenhubelweg 11, 3012 Bern, Switzerland.
authors.forename: Alban
authors.initials: A
authors.lastname: Ramette
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D002245:Carbon Dioxide / Q000032:analysis; D057894:Coral Reefs; D017753:Ecosystem; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D060086:Hydrothermal Vents / Q000382:microbiology; D010219:Papua New Guinea; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology*
chemical_list: D002245:Carbon Dioxide
keywords: microbial community composition; natural laboratories; next generation sequencing; ocean acidification; shallow-water hydrothermal vents