The water in Iceland’s groundwater fissures “is basically the same water we’re drinking from the tap,” says Jónína Ólafsdóttir, a freshwater biologist who’s been scuba diving in the cracks in the Earth’s crust for years. “I can take my regulator out at any time during the dive and take a sip if I’m thirsty.” The water isn’t just clean—it’s also remarkably clear. If it weren’t for the bubbles, Ólafsdóttir might appear to be suspended in thin air while diving. “I’ve never seen this kind of visibility anywhere else I’ve been diving in the world,” she says.
The water column appears devoid of life. Yet tiny animals surround Ólafsdóttir and her team. They’re conducting an unprecedented survey of the fissures’ ecosystem, including the thousands of invertebrates that live in the algae mats and caves within them.
During their project, which was funded in part by a grant from the National Geographic Society, Ólafsdóttir and her team explored about a dozen fissures and discovered a copepod species, Eucyclops borealis, that had never been documented before in Iceland.
Their biggest surprise was coming across an unusual fissure that wasn’t exposed to open air or sunlight. “I didn’t expect anything like that underground fissure to be there,” says Ólafsdóttir. She brought samples from the cave back to the lab and found animals that were very meticulously adapted to their environment. “[The cave-adapted animals] are living in complete darkness, in freezing water, with very little to eat. But despite that, they’re thriving. They have no pigment, and they are blind. They are kind of a model for the power of evolution.”
Ólafsdóttir explains that when it comes to researching such tiny animals, it’s often a long time before you realize that you’ve made a discovery. While it’s instantly gratifying to discover an underground fissure, for example, or to complete a very challenging dive in a cave, the post-expedition work in the lab can be a slow process. “It’s funny,” she laughs, “the scientific analysis of the invertebrates—it creeps up on you.”
Ólafsdóttir is thankful she gets to work in such a beautiful and unique place. “The reason I wanted to learn to dive was because I wanted to see different areas and species that you can’t access very easily. I have a team of both very, very good divers as well as biologists working together, so I have the best of both worlds.”
Find out more about Ólafsdóttir’s work by checking out this article and video by National Geographic reporters who dove with her in Iceland. Or listen to an interview with Ólafsdóttir on National Geographic’s radio show: