We thank Neal Blair at North Carolina State University for his expertise in measuring dissolved CO2 concentrations and CO2 carbon isotopic composition. Chris Martens generously donated his facilities at the University of North Carolina at Chapel Hill, and Howard Mendlovitz made the isotopic measurements of CO2 gas and methane. Anne Pimmel and Tim Bronk were indispensable in the chemistry lab aboard the Resolution, and our sampling could not been done without the rest of the Resolution's marine laboratory technicians. JOI-USSSP provided the funds for shore-based isotopic measurements.