Ecohydrodynamic model of the Baltic Sea. Part 2. Validation of the model

The ecohydrodynamic model for the Baltic Sea consists of two interacting parts: one describes the hydrodynamics of the water (3HD), the other organic matter production and destruction (ProDeMo).The results of the simulation were validated.The modelled processes were compared with direct observations, which demonstrated the recurrence of cycles, from the spring diatom blooms through the summer depletion of nutrient salts and algal blooms, to autumn blooms of diatoms and the subsequent destruction of organic matter, and intensified mineralisation of detritus in winter.Ca libration yielded a set of coefficients complementing the algorithm of equations describing the production and destruction of organic matter in the coastal zone.V erification of the model has demonstrated that in multi-year simulations it is stable and also that it follows the laws of conservation of mass and energy.T he third procedural stage of the model investigation was validation, in which statistical measures in the form of bias, correlation coefficients and effectiveness between simulations and observations not used in calibration describe the quality of ecohydrodynamic modelling in southern Baltic Sea waters

Influence of coastal upwelling on chlorophyll a concentration in the surface water along the Polish coast of the Baltic Sea

Space-time variations in chlorophyll a (Chl a) concentrations in the surface water of upwelling regions along the Polish coast of the Baltic Sea were analysed. Carried out between 1998 and 2002 in the warmer season (from April till October), the measurements were targeted mainly at the Hel upwelling. Satellite-derived sea surface temperature (AVHRR) and Chl a data (SeaWiFS) were used. Generally speaking, the Chl a concentration increased in the upwelling plume, except along the Hel Peninsula, where two scenarios took place: a reduction in Chl a concentration in spring and an increase in autumn

Latitudinal biodiversity patterns of meiofauna from sandy littoral beach

Meiofaunal samples from arctic (Bear Island, Franz Josef Land, Hopen, Kolguev), temperate (Baltic Sea, North Sea), subtropical (Tunisia, Greece), tropical (Emirates, Ghana) and antarctic sandy beaches were collected at the medium water mark. The highest average meiofaunal density was found in the temperate zone (1300 individuals 10 cm–2) and the lowest in both polar regions: in arctic (79 individuals 10 cm–2) and in antarctic (35 individuals 10 cm–2) samples. Nematodes dominated the meiofauna community in warm regions, while turbellarians were more common in cold water regions. Sixteen higher taxa were recorded in tropical sites, while only eight taxa were observed in the sampled cold regions. This difference was mainly due to the presence of small specimens of macrofauna in the tropics. When only 'true meiofauna' higher taxa were compared, no latitudinal trends were found