Macro - epibenthic communities and diversity of Arctic Kongsforden , Sval - bard , in relation to depth and substrate

Low and relatively constant temperatures, seasonal pulses of primary production, changes in ice cover, siltation and salinity are the main characteristics of polar marine ecosystems. Shallow coastal systems are especially affected by ice as a disruptive factor, which has a huge effect in structuring the established benthic communities, both in the Antarctic (Dayton 1990, Clarke 1996a, Grebmeier & Barry 1991, Sahade et al. 1998, Gutt 2001, Gutt & Piepenburg 2003) and the Arctic (Laudien et al., this issue). Despite these similarities the two polar ecosystems differ considerably in their evolutionary histories. While the Antarctic has been evolving isolated the last 20 million years, the Arctic Holocene history only reaches back some 10 thousand years (Clarke & Crame 1992, Dunton 1992, Dayton et al. 1994). These differences are reflected in the recent biota with the Arctic being impoverished in respect to the Antarctic in terms of species richness, diversity and abundance of organisms (Poore & Wilson 1993, Rex et al. 1993, Clarke 1996a,b, Arntz et al. 1997, Gray 2002). However, at small-scale these differences are not evident and several Arctic benthic communities exhibiting high abundance and diversity have been described (e.g., Grebmeier et al. 1989, Kendall 1996, Sejr et al. 2000). The major difficulties in comparing both polar ecosystems are due to the use of different methods, depth ranges, scales, and analytical procedures.