Barents Sea plankton production and controlling factors in a fluctuating climate

The Barents Sea and its marine ecosystem is exposed to many different processes related to the seasonal light variability, formation and melting of sea-ice, wind-induced mixing, and exchange of heat and nutrients with neighbouring ocean regions. A global model for the RCP4.5 scenario was downscaled, evaluated, and combined with a biophysical model to study how future variability and trends in temperature, sea-ice concentration, light, and wind-induced mixing potentially affect the lower trophic levels in the Barents Sea marine ecosystem. During the integration period (2010-2070), only a modest change in climate variables and biological production was found, compared to the interannual and decadal variability. The most prominent change was projected for the mid-2040s with a sudden decrease in biological production, largely controlled by covarying changes in heat inflow, wind, and sea-ice extent. The northernmost parts exhibited increased access to light during the productive season due to decreased sea-ice extent, leading to increased primary and secondary production in periods of low seaice concentrations. In the southern parts, variable access to nutrients as a function of wind-induced mixing and mixed layer depth were found to be the most dominating factors controlling variability in primary and secondary production.

Automated summary

The study found that in the coming decades, the Barents Sea marine ecosystem will be affected by climate variables and biological production, with a significant decrease projected for biological production in the mid-2040s and increased light in the northern parts, while variability in nutrient access in the southern parts will play a dominant role in controlling primary and secondary production.