Version History for data release: Moore, C.S., Byrne, R.H., and Yates, K.K., 2023, CO2 system measurements in Hillsborough River, Florida (ver. 2.0, July 2024): U.S. Geological Survey data release, https://doi.org/10.5066/P9J9IYFD. ________________________________________________________ Version 1.0 posted online January 12, 2023 ________________________________________________________ Version 2.0 revised and reposted online July 1, 2024 Changes in Version 2.0 1. Added 24 additional data columns to the CO2_System_Laboratory_Measurements_in_Hillsborough_River_Florida data files (.csv and .xlsx) with new calculations from previously published data in the data release. 2. Updated the metadata (.txt and .xml) with new version and attribute information from the data file additions.