A team of 23 researchers spent two and a half weeks at sea on the research vessel Atlantis exploring the deep sea in the Western Aleutians.
They left Dutch Harbor June 15, and traveled as far west as Semisopochnoi Island, collecting data on the deep sea.
Throughout the expedition, researchers used specialized equipment to learn more about what lives in the waters around the Aleutians. The most notable tool was a research submersible named Alvin. On each dive, three researchers squeezed into the submarine, dropping down to the seafloor looking for corals, sponges, crabs and fish.
Amanda Demopoulos, an ecologist for the U.S. Geological Survey, led the expedition. She said it was absolutely thrilling.
"Our eyes were peeled on every dive trying to find these organisms and really add to our understanding of how they're distributed in space," she said.
The expedition took five years of planning.
"There is a substantial part of the Alaska sea floor that's been unexplored," Demopoulos said. "We are really chipping at the surface of what we know in this area."
The team completed 11 dives in the Alvin, going no deeper than two miles down. Demopoulos said the total distance they covered was like traveling from San Francisco to New York.
"We just spent the last couple of weeks or so traveling across the country, but underwater," she said. "It just absolutely blows my mind that we did that much spatial examination exploration in such a short period."
What did they find in the deep waters in the Western Aleutian Islands? A lot of coral and sponges.
"You couldn't see a rock, because every single stitch of seafloor was covered with sponges and all of these different kinds of corals," Demopoulos said.
She said they found coral almost 7-feet tall, which shows that the seafloor has been healthy enough for the coral to grow and stretch for many years.
The coral also provides habitat for crab and fish. And according to Demopoulos, researchers saw many different fish species. She said there's a connection between the deep-sea fish and the shallow-water fish that Aleutian communities rely on.
"Everything is connected, even though this deep, dark sea is there, the animals thrive on nutrients and food that's transported to them," she said. "They wouldn't be there if there wasn't healthy food raining out from the sea, from the ocean."
Another key tool the researchers used was high-resolution acoustic mapping — essentially pinging the seafloor with sound waves thousands of times to create detailed maps.
These maps revealed areas where underwater landslides have happened in the past. This information is crucial for predicting future tsunami risks in a region that's prone to earthquakes and volcanic eruptions.
"The data we've gathered on this mission are helping improve those models and our ability to keep humans safe," Demopoulos said. "That human connection is not only on the fish and the food that we eat, but also on the safety side, which I think people will value."
While the underwater exploration is now complete, researchers will spend months analyzing samples and data that could reveal new species.
"We have more questions after this expedition than we had when we started," Demopoulos said. "But that's the beauty of the exploration piece."
She said exploration opens up new possibilities for understanding how these deep-sea animals survive and thrive across the vast Aleutian seafloor.
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