Modelling ocean acidification in the Nordic and Barents Seas in present and future climate

An ecosystem model, NORWECOM.E2E including a module for the carbonate system, has been used to investigate the effects of rising atmospheric CO2 and climate change on the ocean's acid-base state in the Nordic and Barents Seas. Using the 20C3M control run and the A1B emission scenario, a downscaling of the GISS-AOM global climate model has been used to force the ecosystem model for a reference (1981-2000) and a future climate (2046-2065) simulation respectively. The simulations demonstrate how the saturation state of seawater with respect to aragonite will evolve, with a shoaling of the saturation horizon of approximately 1200 m in the Nordic Seas, and a large increase in area extent of under saturated surface waters. The simulated pH change in the surface water is − 0.19 from 2000 to 2065, while the model estimates an almost doubling of the CO2 air-sea flux in the Barents Sea increasing the uptake from 23 to 37 gC m− 2 yr− 1. The main driver for the modelled changes in surface fCO2 is the change in DIC, with only minor contributions from temperature, salinity and total alkalinity.