Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak. Coastal plankton communities under elevated CO2: community barcoding results from the gene regions 18S and cox1

The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidifications on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta). Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 µatm) and those exposed to present day CO2 conditions.