Brace yourself. To human senses, the gelid waters of the Arctic and North Atlantic oceans are beyond chilling.
(From Popular Science / by Kendra Pierre-Louis) — Because sea water is salty, the waters can actually reach temperatures below what we think of as freezing (as low as 28.8 degrees Fahrenheit instead of the usual 32) and remain liquid. Without protective gear, the human body can withstand maybe 15 minutes of these temperatures before succumbing to unconsciousness; 45 minutes before death.
And yet somehow, the Greenland shark—a species that can reach more than 15 feet in length and a scale-busting 880 pounds—calls these waters home. These cartilaginous fish do more than tough out frigid temps: they also resist diseases common in humans, like cancer, and may hold secrets to how we might live longer, healthier lives.
“This particular species of shark is fairly understudied, and is not particularly well known to research—or to anyone except for the Greenlanders,” says Holly Shiels. A physiologist at the University of Manchester, Shiels is fresh off an Arctic expedition where an international group of eight scientists aimed to change that.
“I came in because they wanted somebody to look at the cardiovascular system,” says Shiels. “Heart disease is a disease of the aged. We know that every year you live past 65 increases your incidence of having heart disease by an exceptionally, ridiculously high rate. So how do these animals continue to beat for 400 years? Do they have fibrosis? Do they have arrhythmia? Do they have any of the things that we associate with aging in human hearts?”
Shiels notes that the purpose of the trip, which she and her colleagues are chronicling after the fact in a series of shark diaries, was simply to observe—to help fill in the blank spots in our understanding of the Greenland shark. Researchers like Shiels are in a race against time to learn as much about the shark as possible, both to help protect the species and to see what aspects of their physiology can improve our understanding of human health and wellbeing.
Why the rush? Because escalating fishing pressures in the North Atlantic and the Arctic mean that increasingly, the Greenland shark has been showing up as bycatch; the unwanted creatures caught on fishing hooks and nets. And juvenile Greenland sharks are scarce. Given that it can take up to 150 years before a female shark can reproduce, we shouldn’t expect that to change radically any time soon. So we might be removing sharks from the ocean at a rate faster than they can be replaced.
Read the full story here: http://www.popsci.com/greenland-shark-secrets