Even though it's high summer in the Antarctic, the ocean around the Rothera research station is -1 Celsius. As some of the most productive oceans on the planet - a soup of microscopic plant and animal plankton - it's murky to boot. Not everyone's idea of the perfect scuba spot. But the divers I'm with seem positively excited about tipping themselves backwards into the depths. Image: A seal swims by icebergs off the British Antarctic Survey's Rothera base. File pic: Reuters "You can get these