The size of the eggs (alive and dead) of the euphausiid, Thysanoessa raschii (M. Sars, 1864) was studied in the various parts of the Barents Sea. There is a relationship between mortality and size in euphausiid eggs. Dead embryos dominated among eggs with both minimal or maximal diameters (embryos smaller than 300 mum and bigger than 350 mum; perivitelline space smaller than 25 mum and bigger than 50 mum). We suggest that this size-dependent mortality of euphausiid eggs is a result of stabilizing selection, thus establishing an equilibrium between egg size and number of eggs (= fecundity) in the Barents Sea population of T raschii.

The extent of environmental contamination and sources of polycyclic aromatic hydrocarbon (PAH) compounds to sediments of the White Sea are evaluated and compared with previously published results for adjacent Arctic Sea areas. Concentrations of two- to six-ring PAHs of molecular mass 128–278 including perylene and sediment characteristics are considered in this investigation. Mean ΣPAH concentration was 61±34 ng/g dw (n=11) for all samples and 87±43 ng/g dw (n=6) for pelite-rich samples (>83% pelite). These concentrations are 2–3 times lower than were previously reported for the SE Barents Sea. Concentrations of ΣPAH and ΣCPAH in the central White Sea have increased by a factor of 2-5 over pre-industrial background levels based on 210Pb age-dating of one sediment core. Using principal component analysis (PCA), two common factors explained 87.5% of the total variance for the White Sea data. Factor 1 is associated with high-temperature combustion processes and is related to emissions from a local aluminium smelter. Factor 2 is associated mainly with the introduction of petrogenic PAH compounds and perylene into Dvina Bay via the Severnaya Dvina River. A comparison of the White Sea and SE Barents Sea data indicates that similarities exist in the composition of parent PAH compounds. However, based on a comparative analysis of parent PAH ratios and relative contents of alkyl-substituted homologues, a common atmospheric source of anthropogenic pollutants can be ruled out. Further investigations are needed to determine whether sedimentary PAH signatures in areas of the Barents Sea that are in closer proximity to the White Sea are related to emissions from the aluminium smelter.