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Reduced Ocean Carbon Sink in the South and Central North Sea (2014–2018) Revealed From FerryBox Observations
Author(s) -
Macovei V. A.,
Petersen W.,
Brix H.,
Voynova Y. G.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl092645
Subject(s) - seawater , carbon dioxide , sink (geography) , environmental science , oceanography , carbon sink , climatology , sea surface temperature , atmospheric sciences , carbon cycle , climate change , geology , geography , ecology , biology , cartography , ecosystem
Surface seawater carbon dioxide partial pressure ( p CO 2 ) in the south‐central North Sea was measured between 2014 and 2018 using FerryBox‐integrated membrane sensors on ships‐of‐opportunity. Average annual p CO 2 variability was biologically controlled, with thermal effects modulating its amplitude. Deseasonalized winter trends of seawater p CO 2 were positive (4.4 ± 2.0–8.4 ± 2.9 µatm yr −1 ), biogeochemically driven, stronger than the atmospheric p CO 2 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 CO 2 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.