Yellowstone Lake, on its surface, is an immense body of deep, cold water that could be fatal in a matter of minutes to anyone who fell into it. But deep down, on the lakebed, hundreds of hydrothermal vents are furnace-like, generating water temperatures of more than 300 degrees in some parts of the lake. Beyond the astonishing temperatures, though, researchers from the Woods Hole Oceanographic Institution hope their studies help them answer how "environmental processes and climate affect continental hydrothermal systems."