Word: ice
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...team led by microbiologist Jill Mikucki of Dartmouth College, set out to look for any such hangers-on at a particularly unforgiving place: Blood Falls, on the East Antarctic Ice Sheet. Blood Falls got its unlovely name due to red staining that comes from a snout on the Taylor Glacier - the result of heavy deposits of iron in its water. In ages past, a fjord ran through the area and brought with it swarms of marine life, but more than 1.5 million years ago the ice began to rise, and a pool of seawater became trapped - and then capped - creating...
...Mikucki collected did not teem with a riot of different microbial species the way ocean water does, but there was at least one species, thriving and dividing and doing all of the other things single-celled species do. "How [were] they able to persist below hundreds of meters of ice and live in permanently cold and dark conditions over hundreds of millions of years?" Mickucki asks...
...trick, she found, was that they learned how to change their diet. When Mikucki studied the organisms' DNA and energy-processing systems, she found that they were indeed descended from species that once lived in the open ocean. Underneath the ice, they were deprived of light to run photosynthesis, and instead they relied on what they found around them - principally sulfur and iron - to generate energy. The genes responsible for that alternative metabolism are also found in other marine organisms but they're less important to those species because the oceans provide more options for food...
...enough for life to have taken hold - life that would have then had to retreat into underground water deposits and make the same kind of hurry-up adaptation Mikucki's microbes did. Similar adaptive metabolism could be in evidence on the Jovian moon Europa, where a layer of surface ice may cover a globe-girdling ocean. (See pictures of Mars' patterns...
...flying over them and literally counting them. You have to make sure you're counting them all but not double-counting. When you don't have an accurate baseline you don't have a good understanding of how the species works and what the threat is. Walrus are an ice-dependent species so there are also climate change concerns. The loss of ice is affecting their reproduction and the success of young walruses. (See pictures of global warming...