Many national and international investigators contributed their observations to this database. ORNL gratefully acknowledges the efforts of investigators and supporting staff at sea and on land. Richard A. Feely [Pacific Marine Environmental Laboratory/National Oceanographic and Atmospheric Administration (PMEL/NOAA)] and Rik Wanninkhof [Atlantic Oceanographic and Meteorological Laboratory (AOML) /NOAA] offered encouragement in this task; this was appreciated. . We gratefully acknowledge that the continued support from the Office of Global Programs of the National Oceanic and Atmospheric Administration has made this compilation possible. The field study of T. Takahashi and his associates have been supported by the National Science Foundation and Department of Energy.