Virtual Posters

The fjords of southwestern Spitsbergen are climatically sensitive area which is caused by present oceanographic regime characterized by north-flowing warm Atlantic Water in the West Spitsbergen Current and its influence on marine organisms living in these fjords. Distribution of foraminifera in marine waters is controlled by environmental factors as temperature and salinity, and any change in environmental conditions leads to the disturbance of foraminiferal assemblages equilibrium. To prove the significance of foraminifera assemblages as bioindicators of recent hydrological changes in the Hornsund fjord three surface sediment samples were taken at 77 m, 138 m and 240 m water depth and have been analyzed for benthic foraminifera, sediment grain size and organic matter. The results were compared to previous investigations in these areas (2002, 2004, 2005) and clearly showed increasing significance of Atlantic Waters in outer part of the fjord as well as in the central part since the last 7 years. Moreover, “arctic taxas” are retreating into the inner part of the fjord. Sampling stations were located in the central deeps along the axe of Hornsund fjord, reflecting variations in the influence of Atlantic Waters and the input of melt waters from neighboring glaciers. Sediment samples were collected by box-corer, which provide a good recovery of surficial sediments representing the most recent time interval. Between 300 and 400 individuals of benthic foraminifera were identified from the >100 µm fraction using a binocular microscope. In total 1933 individuals from 42 taxa were found to occur in the sediment samples. The most abundant benthic species in the samples are Elphidium excavatum f.clavata, Recurvoides turbinatus, Nonionella labradorica, Cassidulina reniforme and Bucella frigida which together constitute 71-84% of the total assemblage. The distribution of foraminiferal abundance shows consistently low numbers in the areas influenced by glaciers input, which may be mainly controlled by a high sediment load. Being supported by ecological and paleoclimatic studies from Svalbard, benthic foraminiferal taxa were divided into two groups- bioindicators the influence of Atlantic Water and tolerance of glacier proximal setting.