Inner space” it has been called.Dark and cold, inhabited by bizarre, fearsome-looking crea-tures, it
is
a little reminiscent of the outerspace of science fiction movies. Likeouter space, humans can venture intothis mysterious realm only with the aidof elaborate, specially designed craft.Even then there is an element of risk.But “inner space” is here on earth; it con-sists of the waters of the sea that liebelow the sunlit surface layer. The oceandepths are the least known of all ourplanet’s environments