title: Changes in microbial communities in coastal sediments along natural CO2 gradients at a volcanic vent in Papua New Guinea.
abstract: Natural CO2 venting systems can mimic conditions that resemble intermediate to high pCO2 levels as predicted for our future oceans. They represent ideal sites to investigate potential long-term effects of ocean acidification on marine life. To test whether microbes are affected by prolonged exposure to pCO2 levels, we examined the composition and diversity of microbial communities in oxic sandy sediments along a natural CO2 gradient. Increasing pCO2 was accompanied by higher bacterial richness and by a strong increase in rare members in both bacterial and archaeal communities. Microbial communities from sites with CO2 concentrations close to today's conditions had different structures than those of sites with elevated CO2 levels. We also observed increasing sequence abundance of several organic matter degrading types of Flavobacteriaceae and Rhodobacteraceae, which paralleled concurrent shifts in benthic cover and enhanced primary productivity. With increasing pCO2 , sequences related to bacterial nitrifying organisms such as Nitrosococcus and Nitrospirales decreased, and sequences affiliated to the archaeal ammonia-oxidizing Thaumarchaeota Nitrosopumilus maritimus increased. Our study suggests that microbial community structure and diversity, and likely key ecosystem functions, may be altered in coastal sediments by long-term CO2 exposure to levels predicted for the end of the century.
authors.affiliation: HGF-MPG Joint Research Group on Deep Sea Ecology and Technology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors.forename: Felix F
authors.identifier: http://orcid.org/0000-0002-3605-9288
authors.initials: FF
authors.lastname: Raulf
authors.affiliation: Water Quality and Ecosystem Health, Australian Institute of Marine Science, Townsville, Australia.
authors.forename: Katharina
authors.initials: K
authors.lastname: Fabricius
authors.affiliation: Water Quality and Ecosystem Health, Australian Institute of Marine Science, Townsville, Australia.
authors.forename: Sven
authors.initials: S
authors.lastname: Uthicke
authors.affiliation: Microsensor Group, Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: de Beer
authors.affiliation: Department of Biology, Sultan Qaboos University, Muscat, Oman.
authors.forename: Raeid M M
authors.initials: RM
authors.lastname: Abed
authors.affiliation: HGF-MPG Joint Research Group on Deep Sea Ecology and Technology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors.forename: Alban
authors.initials: A
authors.lastname: Ramette
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001105:Archaea / Q000145:classification / Q000378:metabolism; D002245:Carbon Dioxide / Q000032:analysis*; D004259:DNA-Directed DNA Polymerase; D017753:Ecosystem; D041965:Flavobacteriaceae / Q000145:classification; D019015:Geologic Sediments / Q000382:microbiology*; D059013:Microbial Consortia; D058465:Nitrification / Q000502:physiology; D058458:Nitrogen Cycle / Q000502:physiology*; D009792:Oceans and Seas; D010219:Papua New Guinea; D041902:Rhodobacteraceae / Q000145:classification; D012623:Seawater / Q000382:microbiology*; D018707:Volcanic Eruptions
chemical_list: D002245:Carbon Dioxide; D000641:Ammonia; C070331:Tli polymerase; D004259:DNA-Directed DNA Polymerase