Oceanic pCO2 from East and West Greenland fjords, August 2018 and 2016

The oceans play an essential role in mitigating climate change by sequestering approximately 25% of annually emitted anthropogenic carbon dioxide (CO2). High-latitude oceans, especially Arctic continental shelves, represent large atmospheric CO2 sinks due to their unique conditions. However, retreating glaciers and increasing meltwater supply are changing fjord circulation and biogeochemistry, which may impact future carbon uptake. Indeed, Arctic coastal shelves are heterogeneous regions that remain inadequately sampled and therefore poorly understood, hindering accurate assessments of carbon uptake in this region. This study investigates variation in pCO2 levels during August in the Greenland coastal ocean. Here we present the first-ever large-scale measurements of oceanic pCO2 in Greenlandic fjords., by combining datasets from two August cruises. HDMS Lauge Koch and RV Sanna cruises sampled on the East and West coast of Greenland in August 2018 and 2016 respectively. This dataset consists of 112 sample sites where pCO2 was measured throughout the upper water column. Fjord pCO2 profiles were measured using a Contros Hydro-C CO2 sensor. The HydroC sensor was equilibrated for 5-10 min until a stable reading was acquired at 8 depths between 1–60m. Environmental variables recorded by CTD instruments are available for cruises from the West and East coasts respectively at the following DOIs: https://doi.org/10.5281/zenodo.4062024  and https://doi.org/10.5281/zenodo.5572329. Carbonate chemistry and δ18O-H2O from both cruises can be found at: https://doi.org/10.5281/zenodo.6759882  We would like to thank the crew on board the HDMS Lauge Koch and RV Sanna for their collaboration. The Cruises were funded by Danish Centre for Marine Science (Grants: 2016-05 and 2017-06) and by the EU Horizon2020 funded project INTAROS (grant no. 727890) and the Danish Cooperation for Environment in the Arctic. This dataset is a contribution the project FACE-IT (The Future of Arctic Coastal Ecosystems – Identifying Transitions in Fjord Systems and Adjacent Coastal Areas). FACE-IT has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 869154.