Changes in microbial communities in coastal sediments along natural CO 2 gradients at a volcanic vent in Papua New Guinea

• Published in: Environmental Microbiology
• Main Authors: Raulf, Felix F., Fabricius, Katharina, Uthicke, Sven, de Beer, Dirk, Abed, Raeid M. M., Ramette, Alban
• Other Authors: Australian Institute of Marine Science (AIMS), Deutsche Forschungsgemeinschaft, Federal Ministry of Education and Research (BMBF), Max Planck Society
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: Ocean acidification
• Online Access: http://dx.doi.org/10.1111/1462-2920.12729; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2F1462-2920.12729; http://onlinelibrary.wiley.com/wol1/doi/10.1111/1462-2920.12729/fullpdf

Summary Natural CO 2 venting systems can mimic conditions that resemble intermediate to high p CO 2 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 p CO 2 levels, we examined the composition and diversity of microbial communities in oxic sandy sediments along a natural CO 2 gradient. Increasing p CO 2 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 CO 2 concentrations close to today's conditions had different structures than those of sites with elevated CO 2 levels. We also observed increasing sequence abundance of several organic matter degrading types of F lavobacteriaceae and R hodobacteraceae , which paralleled concurrent shifts in benthic cover and enhanced primary productivity. With increasing p CO 2 , sequences related to bacterial nitrifying organisms such as N itrosococcus and N itrospirales decreased, and sequences affiliated to the archaeal ammonia‐oxidizing T haumarchaeota N itrosopumilus 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 CO 2 exposure to levels predicted for the end of the century.