Two miles below the Gulf of Alaska, where the sunlight never reaches and the pressure crushes anything fragile, a small golden dome clung to a rock. The strange object was discovered in August 2023 and quickly confused scientists and the internet alike. For more than two years no one could say what it was.
Now researchers from NOAA and the Smithsonian National Museum of Natural History have solved the mystery. The so-called ‘golden sphere’ is not an alien egg or an unknown species. It is the surviving base of a rare deep-sea anemone known as Relicanthus daphneae.
The object was first spotted during NOAA’s Seascape Alaska 5 expedition. A remotely piloted vehicle descended 3,250 meters into a volcanic area and scanned the seabed. The golden dome stood out among basalt rocks and sponges.
The object was about four inches wide and had a smooth surface except for a small crack, making it look unfamiliar yet lifelike. Scientists watching the livestream debated whether it was an egg carton, a sponge or something entirely new before collecting it for analysis.
The specimen began its extensive examination procedure, which included microscopic analysis, comparison testing and genetic testing. The first DNA barcoding failed due to contamination by microbes living on the bulb.
The researchers used whole-genome sequencing, which identified a matching result. The sphere contained DNA from Relicanthus daphneae, a little-understood giant anemone whose tentacles can extend several meters. The mitochondrial genome was found to closely match known references, establishing the biological relationship.
The study concluded that the bulb was not a living organism, but a cuticle, an outer layer shed or left behind by the anemone. The anchoring process to the seabed requires the cuticle to position itself beneath the body of this species.
When the animal moves or dies, the sturdy base can remain attached to the rocks. That “golden footprint” is what researchers recovered, which explains why it lacked a mouth, muscles or recognizable anatomy.
The discovery didn’t end there. Genetic analysis showed that the sphere had become home to a community of microbes. Some processed nitrogen, while others resembled deep-sea sediment organisms.
In effect, the decaying anemone base had turned into a small recycling system on the ocean floor, where biological remains fuel chemical processes and support new life.
