EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recent FerryBox observations reveal a strong increase in surface seawater pCO2 in the North Sea

Vlad Macovei, Yoana Voynova, Holger Brix, and Wilhelm Petersen
Vlad Macovei et al.
  • Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Germany (

Surface seawater carbon dioxide partial pressure (pCO2) in the North Sea, a large temperate shelf sea, was measured between 2014 and 2018 using FerryBox-integrated membrane sensors on ships of opportunity. The use of commercial vessels ensured a high spatio-temporal resolution, with data available year-round in areas belonging to all the stratification regime types found in the North Sea. Average annual cycles revealed a dominant biological control on pCO2 variability, with thermal effects modulating its amplitude. In the regions of freshwater influence, the biogeochemical characteristics of the riverine end-member also influenced the pCO2 measured near shore. Deseasonalized winter trends of seawater pCO2 were positive (ranging from 4.4 ± 2.0 µatm yr-1 to 8.4 ± 2.9 µatm yr-1 depending on the region), while the trends calculated including all deseasonalized monthly averages were even higher (ranging from 9.7 ± 2.8 µatm yr-1 to 12.2 ± 1.4 µatm yr-1). All these trends were stronger than the atmospheric pCO2 trend. Consequently, during our study period, the southern North Sea became a stronger source and the northern North Sea became a weaker sink for atmospheric carbon with implications for the Northwestern European Shelf carbon uptake capacity.

How to cite: Macovei, V., Voynova, Y., Brix, H., and Petersen, W.: Recent FerryBox observations reveal a strong increase in surface seawater pCO2 in the North Sea, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5692,, 2021.


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