Tuesday, December 23, 2014

Marine biology

There are a lot of neat creatures living in the ocean around Antarctica: not just whales, seals, and penguins! There’s quite a diversity of invertebrates (animals without backbones) living on the ocean floor. We call these benthic invertebrates. (“Benthic” means they live on the bottom.)

There are several scientists at Rothera who study these benthic invertebrates, and they shared some of their animals with me. There are some animals you are probably familiar with: sea stars (or starfish), brittle stars, sea cucumbers, and anemone. There are also other really neat animals that you may not know, like feather stars, sun stars (big sea stars with lots of arms), sea lemons (a type of snail), and nudibranchs (a type of mollusk). You can see many of these animals in these pictures I took from the marine water tanks in the lab.
Sun star with a feather star in the background
Sea star, with a sea cucumber to the right
Sea lemon, sea star, and brittle star
Terri, one of the marine biologists, tells me that they’ve learned that these benthic invertebrates are less abundant in the water here than they used to be. With the increasing temperatures from climate change, there is less ice over the water. Specifically, the “fast sea ice” is declining. Fast ice is the ice that’s thick and fastened to land, so it doesn’t float or drift around. It holds everything floating on the water in place, including icebergs. Fast sea ice used to cover the ocean for around 8 months of the year. Now, because it’s warmer, the fast sea ice is only around for 2 months of the year. Without the fast ice, ice bergs can float around and move more than they used to. The bottoms of ice bergs are very deep and, here along the coast, they scrape the bottom of the ocean. The benthic invertebrates at the bottom of the ocean can’t run away from the ice bergs. Because most of them have soft bodies without shells, and get smashed by the moving ice bergs. That is one of the many changes this region is experiencing due to climate change!

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