Meeting Abstract

S4-1.3  Thursday, Jan. 5  Dispersal capabilities, barophysiology and the evolution of Antarctic community structure THATJE, Sven; University of Southampton, School of Ocean and Earth Science, National Oceanography Centre, Southampton svth@noc.soton.ac.uk

The apparent scarcity of planktonic larval development in polar invertebrates has caused heated discussion amongst ecologists for most of the last century. In this paper I review the knowledge of reproductive traits in marine invertebrates thriving in Antarctica from an evolutionary perspective of cold adaptation. I will examine the means by which polar invertebrates may overcome physical, physiological (presented by temperature or hydrostatic pressure), and geographical barriers, and critically assess current views of ecological as well as evolutionary driving forces behind reproductive trade-offs in cold waters. The ‘mobility’ of any kind of life history stage is particularly important in the isolated Southern Ocean where continental shallow-water benthos had to contend with the threat to species survival presented by the advancing continental ice sheets of late-Cenozoic climate oscillations; these by far exceeded local physical disturbance by grounded ice seen in shallow Antarctic waters today. Increasing molecular and phylogeographic evidence suggests that the mobility of invertebrates during those times may have been crucial for survival. Possible refugia, either in isolated continental shelf pockets, the circum-Antarctic deep sea, or Southern Ocean Islands, or emigration to lower latitudes have been proposed for periods of glacial conditions. I will discuss the question of whether larvae or any other kind of drifting stages played a predominant role in defining benthic community resilience over geological periods of time in Antarctica. Finally, I will provide a highly personal view on a necessary cross-disciplinary scientific revolution for the sake of better understanding how life in cold waters has evolved.