A murky photo returned from a 1985 expedition is one of the few existing images of Yellowstone Lake's hydrothermal features. (Image: Bob Landis // Global Foundation for Ocean Exploration) 2016 marks the 100th anniversary of the National Park Service, a milestone that has set off a year of celebration for what historian Wallace Stegner called “the best idea we ever had.” The first park, Yellowstone, predates the Service itself, and despite its 4.1 million yearly visitors that are putting real stress on a highly interconnected ecosystem, certain portions of the park remain a nearly unadulterated wilderness. One of these sites is the floor of Yellowstone Lake, a 350 square-kilometer body of water that reaches depths of 120 meters. And while much of Yellowstone’s thermal activity manifests on the surface - think rainbow-colored hot springs, gooey mudpots that smell of sulfur, and spurting geysers - the same forces create heated water and unique oases of microbial life at the lake bottom.
To better explore this unique ecosystem, a team of scientists and engineers spearheaded by the Global Foundation for Ocean Exploration is building a custom-designed remotely operated vehicle (ROV) named Yogi. The ROV, which has its own Kickstarter campaign, will be outfitted with high-definition cameras, a dexterous robotic arm, samplers to procure and isolate water and sediment from the lake floor, sonar, and an array of geochemical sensors. Dave Lovalvo, the President of the Global Foundation for Ocean Exploration, is leading the effort to build and deploy Yogi. It’s been a long road: Lovalvo participated in the first submersible reconnaissance of Yellowstone Lake in 1985, an effort that returned alluring images of bizarre rock formations poking up into the aqueous twilight. And now, thirty years later, he’s ready to tackle the engineering challenges that have bedeviled lake-floor exploration. It may sound counterintuitive, but shallower isn’t necessarily easier when it comes to ROV design, and Yellowstone Lake presents some challenges that even the Mariana Trench can’t match. “The visibility in the deep sea is tremendous,” Lovalvo explains, “but we don’t get that kind of clear water in a lake environment. It’s a flocculent, very fluffy bottom, and any time you get close you can easily stir it up.” To make matters worse, relatively small lakes like Yellowstone lack strong currents to whisk the suspended silt away. And while hydrothermal vent fields in the deep sea can cover hundreds of square meters, the features Yogi will be pursuing are isolated rock towers. “It’s much more challenging to actually find these thermal vents,” says Lovalvo. The final engineering challenge will be the ROV’s payload real estate. Weighing in at about one-tenth of its deep-sea kin, Yogi will nonetheless pack nearly as powerful an analytical punch. “We’re looking to miniaturize all of the equipment that we can,” says Lovalvo. “We have to be sure we’ve really sharpened the pencil when it comes to designing the equipment." Aboard its dedicated research vessel - which boasts a dynamic positioning system that maintains its location by automatically controlling the thrusters - Yogi will provide eager scientists with access to a hidden world. Microbiologists hope to get a closer look at the lake's bizarre hydrothermal deposits and their attendant microbial communities. While hot water permeates much of the park, the lake offers three key variables: a darkness that precludes photosynthetic activity, depth that produces a higher-pressure environment, and dissolved gases like hydrogen and methane that offer potential sources of energy. For geophysicists, the conduits on the lake bottom also provide a glimpse into unique heat flow patterns associated with hot spots - it’s a place where subsurface magmatic and tectonic forces meet surface-linked seasonal changes. Probing the powerful influences beneath the lake could offer clues about the hot spot’s next moves. As a platform optimized for large lakes, Lovalvo believes Yogi will be well suited for a range of future expeditions around the world, potentially including Lake Baikal, Lake Victoria, or Lake Malawi. But it all starts at Yellowstone, a place Lovalvo has sought to understand his entire career. “The only true way of preserving a National Park is to understand it,” he says, “and there are a lot of parts of this great place that we still don’t understand, even after all these years."