Marine CO2 system data from Tempelfjorden, Svalbard, 2015-2017

Marine CO2 system data (total alkalinity and pH on the total scale) were collected from three to five stations in a tidewater-glacier fjord, Tempelfjorden. The fjord is part of the larger Isfjorden system, which is located on the west coast of Spitsbergen. Samples were collected between August 2015 and December 2017. The seawater samples were collected using a Niskin bottle following standard procedures and analyzed at UNIS (Longyearbyen, Norway). Total alkalinity was determined using a non-purged open cell potentiometric titration (Metrohm© Titrando system, Switzerland), with a precision typically about ± 2 µmol kg-1. The accuracy was set by the use of Certified Reference Materials (purchased from A. Dickson, Scripps Institution of Oceanography, USA). pH was determined using a diode-array spectrophotometer and the unpurified indicator dye m-cresol purple (mCP) following the method of Clayton and Byrne (1993). The perturbation of the sample pH due to the addition of the indicator dye was corrected for according to Chierici et al. (1999). The precision was generally around ± 0.001. Description of the analytical methods can be found as a summary in the data file. The fieldwork was funded by the Norwegian Research Council under Arctic Field Grant (RiS #: 10662), with additional fieldwork support from the University Centre in Svalbard (UNIS) and the Ocean Acidification flagship program within the FRAM- High North Centre for Climate and the Environment, Norway (A. Fransson, M. Chierici).