Updated publication reference for PubMed record(s): 31562384. Updated publication reference for PubMed record(s): 31562384. Bathymodiolus childressi is a species of deep-sea mussels found predominantly in the Gulf of Mexico. It colonizes cold seeps such as brine pool and oil seeps. The success of these animals in such environment is thought to be due to the symbiotic association of the mussel host with several species of bacteria. The aim of this study is to understand the role of the different partners involved in the symbiotic system using various “-omics” approaches. In addition to protein identification we used the mass spectrometry data generated and submitted with this project to derive the stable carbon isotope ratios for the different members of the symbiosis using the direct Protein-SIF method. The respective isotope pattern file and SIF computation files are included with this submission.