Bryozoan assemblages from two submarine caves in the Aegean Sea (Eastern Mediterranean)

Abstract

Although bryozoans are one of the dominant sessile phyla in Mediterranean marine caves, little information is available on the bryozoan diversity of this habitat in the eastern basin. In this study, bryozoan assemblages of two Aegean marine caves located at different depths and characterised by different morphology were studied. The examination of 30 quadrats (20 × 20 cm) scraped from the vertical walls and cave ceilings, at increasing distances from the entrances, yielded 74 taxa (67 living and 47 dead), half of which were shared by both caves. Cheilostomes largely prevailed (59 taxa) over cyclostomes and ctenostomes (14 and 1 species, respectively). Nodular to fungiform bioconstructions were formed by species with multilayered colonies in both caves. Differences in the taxonomic structure of bryozoan assemblages between the two caves as well as on the spatial variability of diversity, abundance and growth morphologies within each cave seem to be linked to the different cave morphology and associated environmental conditions. Moreover, a considerable number of taxa were reported for the first time from the Eastern Mediterranean and the marine cave habitat, supporting the idea that knowledge of their bryozoan diversity is far from being considered complete.