%0 journal article
%@ 0094-8276
%A Macovei, V., Petersen, W., Brix, H., Voynova, Y.

%D 2021
%J Geophysical Research Letters
%N 11
%P e2021GL092645 
%R doi:10.1029/2021GL092645
%T Reduced Ocean Carbon Sink in the South and Central North Sea (2014–2018) Revealed From FerryBox Observations
%U https://doi.org/10.1029/2021GL092645
11 
%X Surface seawater carbon dioxide partial pressure (pCO2) in the south-central North Sea was measured between 2014 and 2018 using FerryBox-integrated membrane sensors on ships-of-opportunity. Average annual pCO2 variability was biologically controlled, with thermal effects modulating its amplitude. Deseasonalized winter trends of seawater pCO2 were positive (4.4 ± 2.0–8.4 ± 2.9 µatm yr−1), biogeochemically driven, stronger than the atmospheric pCO2 trend, and more pronounced than previous analyses. The trends calculated including all deseasonalized monthly averages were even higher (9.7 ± 2.8–12.2 ± 1.4 µatm yr−1). During our investigation, the southern study area became a stronger source and the northern part became a weaker sink for atmospheric carbon. Overall, average sea-air CO2 flux in our study area, from the Skagerrak to the Southern Bight (53°N), changed from −0.75 ± 0.61 mmol m−2 day−1 in 2014 to +0.20 ± 0.96 mmol m−2 day−1 in 2018.