Biogeography of symbionts associated with adult hydrothermal shrimps Rimicaris exoculata and Rimicaris chacei revealed by 16S rRNA gene metabarcoding, based on samples collected during the MoMARdream-Naut 2007, BioBaz 2013, and BICOSE 2014 cruises, within the framework of the Ifremer REMIMA project (20142029).

We aimed to study the symbiosis of R. exoculata and R. chacei adult specimens from four vent sites along the MAR: TAG, Snake Pit Rainbow and Lucky Strike. We used 16S (V3-V5) metabarcode sequencing on the MiSeq platform to identify the presence of symbiotic lineages of specific symbiotic organs (cephalothoracic cavity and midgut tube) and to compare their diversity according to the site and species. Nineteen shrimps collected during three different oceanographic cruises were analyzed in this study. Specimens were sampled using either the PERISCOP device or the suction sampler of the ROV Victor 6000 (Remotely Operated Vehicle), operated from the research vessel. Among these 19 individuals, three R. chacei and three R. exoculata were collected at the TAG vent field (BICOSE 2014 cruise), three R. chacei and three R. exoculata at the Snake Pit vent field (BICOSE 2014 cruise), three R. chacei (MoMARdream-Naut 2007 and BioBaz 2013 cruises) and three R. exoculata (BioBaz 2013 cruise) at the Rainbow vent field, and one R. chacei at the Lucky Strike vent field (BioBaz 2013 cruise). DNA extractions from symbiotic tissues were performed using the NucleoSpin Soil kit (Macherey-Nagel), yielding a total of 32 DNA extracts: 19 from the scaphognathite and 13 from the midgut tube. Each extract was amplified in triplicate, resulting in 95 sequencing libraries.