A New Interpretation of the Dominance and Diversity of Horseshoe Island (Antarctic Peninsula) Epibenthic Communities

Abstract

This study investigates the epibenthic communities of Lystad Bay on Horseshoe Island (Western Antarctica) using underwater video imaging techniques during the eight Turkish Antarctic Expedition in 2024. The primary objective of the study was to assess species diversity across different depths, substrate structures and potential ice scouring. Six sampling stations were selected, varying in depth (3-34 m) and substrate type (rocky, sandy, and muddy). Results show that a general tendency for an increase in species diversity with depth, particularly below 19 m, and is higher on sandy-muddy substrates than on rocky ones. The analysis of video footage identified 30 species from six phyla, with the highest species richness recorded at deeper stations (St 6) and the lowest at shallower rocky areas (St 1). The analysis of diversity indices (Shannon- Weiner, Margalef, and Pielou's evenness) indicates that substrate type exerts a significant influence on species richness, with sandy-mud habitats exhibiting higher diversity. Station 4 exhibited a low species richness, possibly as a result of local ice scouring impacts despite its depth and the presence of suitable benthic habitat. This study highlights the importance of oceanographic and environmental factors, such as ice scouring and terrestrial inputs, are in determining the organization of Antarctic benthic communities. Further research is required to understand the long-term effects of comprehend these elements on the biodiversity of the Antarctic ecosystem. This study is the inaugural comprehensive study in this region and will serve as a pivotal reference point for future research endeavours.