The mystery lasted more than two years. A golden and strange object, found more than 3,200 meters deep in it seabedleft scientists unanswered since 2023. Now, finally, they have an explanation.
The call «golden egg» It was discovered during an expedition of the United States National Oceanic and Atmospheric Administration (NOAA) in the Gulf of Alaska. The object was shaped like a mound, golden in color, and had a hole in the center, attached to a rock more than three kilometers below sea level. From the first moment, it captured the public’s attention and generated all kinds of speculation.
Was it an egg? A dead sponge? Had something come out of there, or entered? Scientists aboard research vessel Okeanos Explorer They could not immediately identify him. The team collected the object with an underwater vacuum cleaner and sent it to the Smithsonian Institution’s National Museum of Natural History for analysis.
The answer came after years of work. Scientists determined that the «golden egg» is actually a fragment of dead cells that formed the basis of a giant anemone deep water, known as Relicanthus daphneae. Specifically, it is the part with which the anemone adhered to the rocky substrate, as indicated in a statement.
The «golden egg» riddle: how the deep ocean mystery was solved
The identification process was long and complex. The zoologist Allen Collinsdoctor of science and director of the National Systematics Laboratory of NOAA Fisheries—with physical headquarters in the Smithsonian Museum—explained the difficulties of the case. «I work with hundreds of different samples and figured our routine processes would clear up the mystery,» Collins said.
«But this became a special case that required concentrated efforts and the expertise of several individuals. It was a complex mystery which required knowledge of morphology, genetics, deep-sea biology and bioinformatics to solve it,» he explained.
The first examination of the object revealed that it did not have the typical anatomy of an animal. It was a fibrous material with a layered surface, packed with cnidocytes: the characteristic stinging cells of cnidarians, the group that includes corals and anemones. The scientist Abigail Reftfrom the National Systematics Laboratory, identified the cells as spirocysts, a type exclusive to the Hexacorallia subgroup within cnidarians.
The team also examined a similar sample, collected in 2021 during an expedition by the Schmidt Ocean Institute research vessel Falkor. This sample presented equivalent cnidocystswhich provided additional evidence about the nature of the object.
The initial genetic analysis was inconclusive, probably because DNA from other microorganisms present in the sample interfered with the results. The researchers then deepened the analysis with whole genome sequencing, which confirmed the presence of animal DNA and a large amount of genetic material from the giant deep-sea anemone.
Sequencing of the mitochondrial genomes of both samples confirmed that they were almost identical to the known reference genome of Relicanthus daphneae.
The captain William Mowittacting director of NOAA Ocean Exploration, highlighted the importance of this type of discoveries. «Often in deep ocean exploration, we encounter captivating mysteries like the ‘golden egg.’ ADNwe are able to solve more and more of them,» Mowitt said.
«That’s why we continue exploring: to reveal the secrets of the depths and better understand how the ocean and its resources can drive economic growth, strengthen our national security and sustain the planet,» he noted.
The deep ocean still holds many secrets to reveal. NOAA expeditions with the Okeanos Explorer They will resume in May 2026, with a first departure in deep waters near Hawaii. Additionally, on April 30, 2026, Collins will give a webinar on discoveries from the 2023 expeditions in Alaska, including the «golden egg» case.
