Nancy Knowlton diving towards an “underwater condo,” freshly placed in the Red Sea. Photo Credit: Michael Berumen

In case you haven’t heard yet, humans are wrecking the oceans. That doesn’t just mean that significant swaths of ocean life could go extinct — it means some kinds of life could go extinct before we ever even know they existed at all.

In fact, scientists estimate that they have never even given a name to some 33 to 91 percent of the different organisms living in the global oceans. (Given our lack of knowledge, the large range here is understandable.)

“Just the other week, a paper came out saying that we might be facing a mass extinction in the ocean,” notes Smithsonian Institution marine researcher Nancy Knowlton. “But actually, we don’t really know what lives in the ocean, apart from a handful of large things like fishes, corals and some snails.”

Knowlton is part of a pretty clever research solution to this problem — what she calls “underwater condos” (pictured above). Their scientific name is significantly less cool: ARMS, or Autonomous Reef Monitoring Structures.

The condos are built out of square plates, in a stack of 10, with gaps that let marine organisms go in and out. They make a new home, so to speak, and then scientists can remove the plates and see what actually lives there.

Like this:

An “underwater condo” plate. Credit: Matthieu Leray

In a new study out in the Proceedings of the National Academy of Sciences, Knowlton and fellow Smithsonian Institution researcher Matthieu Leray report on what these underwater homes have allowed them to do — namely, categorize large volumes of marine life, including many previously unknown species.

For the study, they examined plates from 18 condos that had been installed on oyster reefs off the coasts of Virginia and Florida. Such oyster beds, notes the paper, are teeming with life, just like coral reefs are — and are in similar peril. As many as 85 percent of them have been “lost due to anthropogenic impacts,” says the study — meaning the life in and around the beds may also have been lost.

The scientists used DNA sequencing to rapidly process information about all the life found on plates, sampling the DNA of the new organisms and matching it with known sequences. Not only did the researchers find that a large diversity of life came to live in the condos — some 2,000 different types of living things after the structures had been in place for 6 months. But less than 15 percent of the resulting genetic sequences corresponded with known organisms whose DNA is already categorized in scientific databases.

And, it is important to note, this was just from sampling marine life off the coasts of Florida and Virginia. There are far more unexamined parts of the world ocean.

Fortunately, the condos work everywhere, says Knowlton. The Smithsonian’s MarineGEO program has installed hundreds of them around the world in the hope of learning more about species — before they vanish. “We have them in 700 feet in Curacao for example, on the carbon dioxide seeps of Papua New Guinea that simulate an acid ocean of the future, and someday we hope to get them to Antarctica,” Knowlton says.

That won’t save the oceans — but it will definitely help create a much better DNA record of what evolution toiled, over vast periods, to produce.

“When people talk about threats to biodiversity or protecting biodiversity, until these methods were developed we really didn’t know how to study it,” says Knowlton.