GULF OF ALASKA — The National Oceanic and Atmospheric Administration announced that scientists have identified a "golden orb" discovered thousands of feet underwater off the coast of Alaska in 2023 as the base of a giant sea anemone. Genetic and morphological analysis determined that the object was almost identical to Relicanthus daphneae.

NOAA scientists discovered the orb on August 30, 2023, during a deep-sea expedition off Alaska. The remotely operated vehicle Deep Discoverer encountered the golden, mound-shaped object with a hole in it, attached to a rock substrate at a depth of more than 10,800 feet below the sea surface.

The specimen was collected and sent to the Smithsonian National Museum of Natural History for study. Researchers determined that the orb was made of fibrous material covered with stinging cells called spirocysts, a specialized cellular structure that exists only in cnidarians.

Scientists compared the orb's cells to those of a specimen collected in 2021 and determined they were the same species. Whole-genome sequencing showed that the orb and the 2021 specimen were genetically almost identical to Relicanthus daphneae, and analysis determined that the orb had once been part of the base of a giant sea anemone. NOAA suggested that the anemone might have died or moved to a new location, explaining why the base remained behind.

"This turned into a special case that required focused efforts and expertise of several different individuals. This was a complex mystery that required morphological, genetic, deep-sea and bioinformatics expertise to solve," said Allen Collins, director of NOAA Fisheries National Systematics Laboratory.

Relicanthus daphneae can grow to have a pink-colored, cylindrical body up to three feet across, with tentacles reaching up to six feet in length. The species has the largest spirocysts among all known cnidarians.

"With advanced techniques like DNA sequencing, we are able to solve more and more of them. This is why we keep exploring—to unlock the secrets of the deep and better understand how the ocean and its resources can drive economic growth, strengthen our national security, and sustain our planet," said William Mowitt, acting director of NOAA Ocean Exploration.