Epibiosis on three ascidian species living on soft substrates at Potter Cove, King George Island, Antarctica

RIMONDINO, C.; TORRE, L.; SAHADE, R.; TATIÁN, M.

POLAR RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 34 p. 1 - 9

0800-0395

The muddy bottoms that characterize the inner Potter Cove show a high density and richness of macrobenthic species, particularly ascidians. In other areas, ascidians have been reportedto play the role of ecosystem- engineers, as they support a significant number of epibionts,increasing benthic diversity. In this study, a total of 21 sessile macro-epibiotic taxa present on the ascidian species Corella antarctica Sluiter, 1905, Cnemidocarpa verrucosa (Lesson, 1830)and Molgula pedunculata Herdman, 1881 were identified, with Bryozoa being the most diverse. There were differences between the three ascidian species in terms of richness, percentage cover and diversity of sessile macro-epibionts. The morphological characteristics of the tunic surface,the available area for colonization (and its relation with the age of the basibiont individuals) and the pH of the ascidian tunic, seem to explain the observed differences. Recent environmental changes in the study area (increase of suspended particulate matter caused by glaciers retreat) have been related to observed shifts in the benthic community structure, negatively affecting the abundance and distribution of the studied ascidian species. Considering the diversity of sessile macro-epibionts that settle on these species, the impact of these environmental shifts could be greater than that estimated so far.