Much of the Antarctic Ocean carries surface ice all the time, in the form of icebergs, pancake ice and other dynamic sea ice systems. Creatures survive the superchilled temperatures in different ways – fur, feathers and fat come to mind when you think of seals and penguins inhabiting that polar landscape.
Another survival adaptation found in the fish population exists in the Antarctic Toothfish, pictured here. It survives temperatures fatal to many other fish by creating a protein antifreeze that keeps its blood from freezing.
Antarctic Toothfish are large, deep-sea predatory fish that live only in the Antarctic Ocean. A marine biologist named Cassandra Brooks is one of the scientists researching the toothfish, in large part because commercial fisheries depleted a related species, the Patagonian toothfish. (Patagonian toothfish are found in the northern waters of the Southern Ocean and off the tip of South America.)
Looking for more fish for us to eat, the commercial fisheries came across the Antarctic Toothfish. As Brooks explains in a blog post, she chose to research the dissostichus mawsoni because it is being fished heavily even though there isn’t much information about how it lives and breeds. That’s how she and her fellow researchers learned about the toothfish’s biological antifreeze, “glycoprotein”:
Some of the coldest ocean waters on earth, where temperatures fall below the freezing point of fresh water, are found in the Southern Ocean surrounding Antarctica. Nearly every fish on the planet would freeze to death if it tried to brave such harsh conditions. The Antarctic toothfish, however, thrives in this icy environment. How does it do it?
Antarctic toothfish have evolved remarkable traits that allow them to survive in sub-freezing waters. One of these traits is a slow heartbeat—a beat only once every six seconds. The main secret of these unique fish, though—who have a natural lifespan of 50 years and can clock in at around 300 pounds when full-grown—lies in a special protein that acts like antifreeze. By making this unique antifreeze glycoprotein, the Antarctic toothfish are able to keep their blood from freezing. It’s a remarkable evolutionary solution to surviving in the frigid waters of the Antarctic.
Equally remarkable is the site where Brooks posts many more equally brief, accessible summaries of her technical research. Last weekend I came across an expansive, detail-rich site that is now bookmarked on my laptop: Ice Stories: Dispatches From Polar Scientists.
The site is spearheaded by The Exploratorium – the “museum of science, art and human perception” in San Francisco. They helped celebrate the most recent International Polar Year by giving cameras and blogging tools to a range of polar scientists so they could document their research and adventures online. (IPY was 2007-08, extended by this project to the end of 2009.)
The project started in Antarctica in 2007 and moved to the Arctic in the summer of 2008,. Now it is back in Antarctica until the end of 2009. Podcasts and webcasts from the McMurdo and Palmer research stations, and even the South Pole, are posted almost daily.
The site offers perspectives from biologists, cosmologists, glaciologists, geologists, and marine scientists working in Antarctica and the Arctic. I particularly appreciate the mix of facts, wonderment, and connection to practical issues that impact us collectively, such as international fishing industries, or climate change.
Last but not least, I like that the Ice Stories site actively contributes to an ecology of internet-based knowledge as a freely distributed resource. All content and images are available for non-commercial use under Creative Commons licensing. So anyone can look through the posts for information and thought leads – or simply for visual inspiration: