This dataset provides carbonate chemistry and hydrological measurements supporting the analysis of the stability of alkalinity and carbon transport potential in the Elbe Estuary, northern Germany. It includes (1) results from laboratory incubation experiments using water samples from the Elbe conducted in 2023, (2) historical water chemistry monitoring records from multiple stations, and (3) daily flow discharge measurements from the Neu Darchau gauging station. Experimental data were collected from the experiments varying salinity and seasonal conditions, and parameters measured include pH, temperature, and total alkalinity. Major ion concentrations (Na+, K+, Ca2+, Mg2+, Cl-, SO42-) were reconstructed from stoichiometry. The saturation states of calcite and aragonite, as well as pCO2, were calculated using the phreeqpython geochemical package. Historical data, covering carbonate chemistry and major ions at several stations and over multiple years, were collected from digitized sources and FGG Elbe. Together, this dataset facilitates the investigation of long-term trends in the carbonate system and carbon transport in the land ocean transition zone of the Elbe River.

The study was additionally supported by the Ocean Alkalinity Enhancement (OAE) R&D Program (https://www.carbontosea.org/).