If there are no more krill there will be no more blue whales.
Within the offshore water column (the space between the surface and the seabed), there is not the range of fish that you find in the warmer waters to the north, and they are nothing like the show ponies you find on tropical coral reefs.
Of the fish around Antarctica, the most interesting to my mind, is the ghostly crocodile ice fish that can grow up to half a meter in length. I say ‘ghostly’ because its blood does not contain any red blood cells, which makes it colorless, hence its rather spectral appearance. But the crocodile ice fish is not really a creature of the water column, it is a bottom-hugging, lie-in-wait predator with a big mouth.
This brings me to the seabed, and what we call the benthic communities that live upon it. This is a completely different ecosystem, and one that changes with depth. In the more shallow zones, up to about 150 meters (500 feet), where we start to lose the light, the seabed is alive with fish, starfish, brittle stars, shell fish, octopi, corals, sea urchins, sea cucumbers, sea squirts, worms and much more, including a wide variety of plants. But as the seabed deepens, diversity narrows.
One of the most interesting phenomena of the polar seas is what is called "gigantism." For reasons not fully understood, cold waters seems to promote growth and longevity. For instance, there are giant isopods and sea spiders that are as large as serving dishes. And my favorite, huge sponges that, in theory, were around at the time of the pyramids and before. That makes them the longest living organism on the planet!
