Comparison of bryozoan assemblages from two contrasting Arctic shelf regions

The structure of bryozoan assemblages from two Arctic regions (East Greenland and West Spitsbergen shelf) was compared. Both areas are located at the same latitude and the samples were taken from similar depths; however, the regions differed in water temperature and oceanography. East Greenland, which has lower mean annual water temperatures, was found to be one third richer in taxa (86 species) than West Spitsbergen (59 species). Diversity (Shannon–Wiener index – H′) and abundance were also higher on average in East Greenland (e.g. H′ = 2.49) than West Spitsbergen (e.g. H′ = 2.12). However for species richness, diversity and abundance there were no significant statistical differences between means (ANOVA) from the two regions. In spite of these similarities the investigated assemblages differed to a large extent in both species composition and dominance structure. There were 55 species that occurred only in East Greenland and 28 species that were present only in West Spitsbergen. There was higher proportion of species with an Arctic distribution in East Greenland (46%) than in West Spitsbergen (24%). Observed dissimilarities were concluded to be due to different hydrological conditions between the two regions.