The exposed rock topside soaks up warmth from the sun, melting the covering snow. This underwater ice cliff may be formed from this meltwater migrating through permeable rock and freezing when it encounters cold seawater, or it may be formed from a very cold underwater rock mass freezing seawater. A huge ice mound hung down from the sea ice ceiling and touched bottom. The sea urchin Sterechinus neumayeri is a ubiquitous scavenger in shallow water here at the Couloir Cliffs icefalls. The urchins are in right foreground of this photo.
Animals trapped in the frozen icefall are a food source.
Nearby there was a long nemertean worm frozen in place on the icefall suggesting that it had been crawling along when meltwater streamed down over it and froze it in place. It was a frozen meal awaiting the arrival of the urchins. The Sterechinus neumayeri urchins look for food on the bottom and up on the icefall itself. The brown color of the icefall is due to diatoms which the urchins scrape off and eat. Photographs may not be used in any form without the express written permission of Norbert Wu.