This dataset contains carbon dioxide (CO2) system data collected by scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) to investigate the effects of Mercuric chloride (HgCl2) on low salinity, organic-rich estuarine water samples acquired from the Tampa Bay estuary located in west central Florida. Discrete water samples were collected using two, 30-liter (30L) Niskin bottles to capture surficial waters from the lower Hillsborough River. Filtered water ...