Salinity, depth, current, temperature, oxygen, carbon dioxide (CO2), radon (222Rn), pH and chlorophyll hourly variation during a complete neap to spring tidal cycle in 2 mangrove creeks in Brazil: Paraty (23°18'06.2S 44°38'53.6W) and Florianópolis (27°38'55.6S 48°33'11.2W). Sea level and current velocities were measured every 2 minutes using a ADCP (Nortek ECO) deployed in the mouth of each tidal creek. Salinity and temperature (Solinst Levelogger 5), dissolved oxygen (PME miniDOT) and pH (Onset HOBO pH logger) probes were attached to the vessel at 0.5 m depth and set to record every minute. Chlorophyll was also recorded every minute using a YSI EXO2. A submergible water pump was installed from the vessel at 0.5 m depth to continuously transport (3 L min-1) surface mangrove creek water into a RAD AQUA DURRIDGE showerhead gas equilibrator. The headspace air was pumped to a Drierite® desiccant and then to an automated radon (222Rn) detector (RAD7, DURRIDGE) coupled with a CO2 trace gas analyzer (LI-COR 7810). The gas equilibrator and detectors were connected in series in a closed air loop . The 222Rn activities (measured each 30 min) and pCO2 (1 min frequency) in air were converted to dissolved in seawater using their partitioning and solubility coefficients. The time series data were integrated using moving averages every hour to allow comparison across the different variables and time scales.