The importance of advection on production of Calanus finmarchicus in the Atlantic part of the Barents Sea

A nutrient-phytoplankton-zooplankton model was made to determine zooplankton production in the Atlantic part of the Barents Sea. Temperature and flow fields from a hydrodynamic model were used as input to the biological model to scale growth and advection of zooplankton. From an area of strong ocean current activity in the southwest entry of the Barents Sea, monthly updated field data on Calanus finmarchicus biomass from March to October were used to scale the advection of this species into the model area. Based on literature values, the initial stock of C. finmarchicus in the model area was set to 1000 CI m ⁻³ . The annual secondary production in the Atlantic part of the Barents Sea was estimated to 7.2 g C m ⁻² . The total import from March to October over the western border of the model domain was 7 × 10 ⁶ tons of carbon. This is four times the amount of locally produced biomass (i.e. secondary production within the model borders). Our results show that high values of zooplankton growth occur at the western part of the area and along two branches stretching eastwards into the Barents Sea. The areas of high growth coincide with the spatial distribution of advected zooplankton, which can be seen from the biomass distribution and confirmed by an index describing advection versus growth. Given our modelled ocean current regime, the shelf areas in the southwestern corner of the model domain seem to be key areas for zooplankton advection into the Atlantic parts of the Barents Sea.