Although both the Arctic and the Antarctic conjure up visions of frozen desolation, below the ice and water surface lie regions of staggering abundance. Possibly the most challenging of all marine environments, the polar regions offer many surprises for the intrepid diver.

Frozen Environment

Polar waters are found in the regions around the Arctic and Antarctic, though the precise lines of demarcation are blurred. Where polar waters start and temperate waters end varies between the poles. For the Arctic it is the 50°F (10°C) above-water July temperature boundary, while for the Antarctic it is seen as the line of the Antarctic Convergence, a zone where cold Antarctic waters sink below warmer northern currents.

Both the Antarctic and Arctic have quite consistent water temperatures, because the low angle of the sun and the reflective qualities of the ice minimize the impact of solar radiation. The temperature of the water hovers around an extremely chilly 32°F (0°C), only just above the freezing point for seawater, which is 29°F( 1.8°C). However, although they may seem similar, the Antarctic and Arctic are actually quite different in terms of their physical geography and marine ecosystems. Read the rest of this entry »