It may not be long before sharks invade Antarctic waters. Due to global warming the Antarctic seas are changing and becoming an inviting ground for sharks that will soon turn to the prey-rich southern waters, says Cheryl Wilga of the University of Rhode Island.
Sharks have been kept out of Antarctica because of trimethylamine oxide, or TMAO, which is a chemical found in shark tissues that is typically adverse to extreme cold and necessary for their bodies to function. Sharks retain lots of urea in their tissues (which is excreted by other animals, in the form of urine), and this helps them maintain a balance of water and salt in their bodies so they don’t dehydrate as they swim in the salty seas. But urea can damage tissues, so sharks have adapted and produce TMAO, which prevents the high concentrations of urea from wreaking havoc on their bodies.
Wilga’s data show that TMAO has its limits—at cold temperatures it can fatally disrupt body functions and kill the shark. If the temperatures of the Southern Ocean warms—just a few degrees, as it is rapidly doing—the ‘TMAO barrier” that keeps sharks out will crumble, and they’ll feast on “a veritable smorgasbord” of defenseless Antarctic prey, says Wilga.
And this can only mean one thing: In the future world of warmer waters, nature documentaries will get even more gory. Still, in the giant future wars between shark and penguin, I wouldn’t write off a collective counterattack. The toothy beasts won’t know what hit them.