Rapid decline of the CO2 buffering capacity in the North Sea and implications for the North Atlantic Ocean
Article first published online: 6 OCT 2007
Copyright 2007 by the American Geophysical Union.
Global Biogeochemical Cycles
Volume 21, Issue 4, December 2007
How to Cite
2007), Rapid decline of the CO2 buffering capacity in the North Sea and implications for the North Atlantic Ocean, Global Biogeochem. Cycles, 21, GB4001, doi:10.1029/2006GB002825., et al. (
- Issue published online: 6 OCT 2007
- Article first published online: 6 OCT 2007
- Manuscript Accepted: 22 MAY 2007
- Manuscript Revised: 3 MAY 2007
- Manuscript Received: 23 AUG 2006
- anthropogenic CO2;
- Revelle factor;
- North Sea
 New observations from the North Sea, a NW European shelf sea, show that between 2001 and 2005 the CO2 partial pressure (pCO2) in surface waters rose by 22 μatm, thus faster than atmospheric pCO2, which in the same period rose approximately 11 μatm. The surprisingly rapid decline in air-sea partial pressure difference (ΔpCO2) is primarily a response to an elevated water column inventory of dissolved inorganic carbon (DIC), which, in turn, reflects mostly anthropogenic CO2 input rather than natural interannual variability. The resulting decline in the buffering capacity of the inorganic carbonate system (increasing Revelle factor) sets up a theoretically predicted feedback loop whereby the invasion of anthropogenic CO2 reduces the ocean's ability to uptake additional CO2. Model simulations for the North Atlantic Ocean and thermodynamic principles reveal that this feedback should be stronger, at present, in colder midlatitude and subpolar waters because of the lower present-day buffer capacity and elevated DIC levels driven either by northward advected surface water and/or excess local air-sea CO2 uptake. This buffer capacity feedback mechanism helps to explain at least part of the observed trend of decreasing air-sea ΔpCO2 over time as reported in several other recent North Atlantic studies.