A Baffling Golden Orb
NOAA’s Seascape Alaska 5 expedition found a mysterious “golden
orb” (left) 2 miles deep. Genetic testing confirmed it was part of a
giant deep-sea anemone (right). Credit: NOAA Ocean Exploration.
More than two years ago, scientists found a mysterious “golden orb” two
miles below the ocean’s surface in the Gulf of Alaska. Since then, they
have been trying to figure out what it is. Could it be an egg of some
sea creature? A species of sponge never seen before? Some other new
organism? At last, they have an answer, but the discovery emphasized
just how much people have to learn about the ocean’s depths.
The golden orb was initially attached to a rocky outcropping at 2 miles deep. Researchers aboard a 2023 deep-sea expedition of the National Oceanic and Atmospheric Administration collected a sample using a remotely operated vehicle, but they were unable to identify it. They sent it to the Smithsonian National Museum of Natural History, where a team with expertise in genetics, deep sea biology, and animal structures worked to solve the puzzle.
The object didn’t have normal animal anatomy, but its surface was covered in stinging cells called cnidocytes, commonly found on corals and anemones. Then one scientist recognized that the cnidocytes were a specific type called spirocysts. Spirocysts are only found in a class of corals and anemones called Hexacorallia, so the researchers compared the golden orb to another Hexacorallia specimen found in 2016. The spirocysts looked similar, but a genetic comparison could confirm that.
Their first attempts to analyze the organism’s DNA did not reveal firm answers, probably because DNA from other organisms contaminated the sample. But further testing confirmed that the golden orb’s DNA was nearly identical to that of the 2016 Hexacorallia, a deep-sea anemone called Relicanthus daphneae. Scientists hadn’t recognized it because the orb was only part of the base of the anemone that attaches to rock.
It took two and a half years and a team of scientists, but they solved the mystery of the golden orb at last.
The golden orb was initially attached to a rocky outcropping at 2 miles deep. Researchers aboard a 2023 deep-sea expedition of the National Oceanic and Atmospheric Administration collected a sample using a remotely operated vehicle, but they were unable to identify it. They sent it to the Smithsonian National Museum of Natural History, where a team with expertise in genetics, deep sea biology, and animal structures worked to solve the puzzle.
The object didn’t have normal animal anatomy, but its surface was covered in stinging cells called cnidocytes, commonly found on corals and anemones. Then one scientist recognized that the cnidocytes were a specific type called spirocysts. Spirocysts are only found in a class of corals and anemones called Hexacorallia, so the researchers compared the golden orb to another Hexacorallia specimen found in 2016. The spirocysts looked similar, but a genetic comparison could confirm that.
Their first attempts to analyze the organism’s DNA did not reveal firm answers, probably because DNA from other organisms contaminated the sample. But further testing confirmed that the golden orb’s DNA was nearly identical to that of the 2016 Hexacorallia, a deep-sea anemone called Relicanthus daphneae. Scientists hadn’t recognized it because the orb was only part of the base of the anemone that attaches to rock.
It took two and a half years and a team of scientists, but they solved the mystery of the golden orb at last.
