Marine benthic populations in Antarctica: patterns and processes

Sampling difficulties have meant that there have been more studies of population patterns than of proc-esses in Antarctic benthos, but a number of generalizations can be made. Benthic marine invenebrates in Antarctica have species/abundance relationships similar to those found in temperate or tropical regions but, several striking examples of gigantism notwithstanding. most species are small. Diversity is generally high, particularly in comparison with the Arctic, although some taxa (for example molluscs) are low in diversity when compared with temperate or tropicaJ faunas. Most species produce larger eggs than related non-polar species, and embryonic development is typically slow. Although the Southern Ocean contains fewer taxa reproducing by feeding pelagic larvae than elsewhere, such larvae are by no means absent. Somewhat paradoxically, these larvae are often released in winter. Post-juvenile growth rates are typically slow, and recruitment rates are slow and episodic. The low temperature slows many biological processes, but other fac-tors are also involved. Ice is an irnponant factor in many biological processes, and the recently described sub-decadal variability in the e"tent of winter sea-ice is likely to e"ert a profound influence on benthic ceo-10gica1 processes in Antarctica. It has long been traditional in ecology to draw a distinc