Hydrodynamical and biogeochemical spatiotemporal variability in the White Sea: A modeling study

We present a three-dimensional finite element biogeochemical ocean general circulation model that consists of a finite-element numerical model FEMAO for an ice-covered sea coupled with the biogeochemical model BFM; we applied the model to the White Sea. Strong tidal mixing, sea ice dynamics, and riverine inputs affect the area. All these elements are considered in the present study. We also discuss the spatiotemporal variability of geophysical and biogeochemical fields including water temperature and salinity, current velocity, sea ice dynamics, and biogeochemical tracers. We compare model results for 2003-2012 with all available published physical and biogeochemical data. The modeled thermohaline fields and sea ice season are shown to agree well with the available observations. The impact of sea ice dynamics and benthic-pelagic coupling on plankton phenology is analyzed using a set of numerical experiments. Overall, sea ice is found to delay the pelagic spring bloom, which would occur two months earlier in the absence of sea ice. Simulations indicate that in terms of plankton phenology, the Onezhskiy and Kandalakshskiy bays are the areas most affected by benthic processes. We also discuss the sensitivity of model results to boundary conditions; in particular, we quantify the impact of river discharge on the results of the model.