At a lightless depth of approximately 3,251 meters (2 miles) beneath the Gulf of Alaska, marine scientists and the public are puzzled by a golden object, roughly the size of a softball, clinging to a rock. Is it an egg, a sponge, or something entirely unknown? A recent study from the Smithsonian National Museum of Natural History provides a fascinating answer: these “golden spheres” are remnants of a rare species of sea anemone.
This ‘golden sphere’ was discovered approximately 3,300 meters deep in the Gulf of Alaska. Image credit: NOAA Ocean Exploration, Seascape Alaska.
The intriguing “Golden Orb” was collected on August 30, 2023, using a remotely operated vehicle launched from a U.S. exploration vessel, Oceanos Explorer.
Measuring about 10 centimeters (4 inches) in diameter, this mysterious object was found among small glass sponges on the ocean floor, southwest of Walker Seamount in the Gulf of Alaska.
Its smooth, metallic sheen and torn opening sparked immediate curiosity regarding its origins.
“An initial inspection revealed no signs of typical animal anatomy—such as a mouth, intestines, or musculature—but rather a loose collection of fibrous material covered by a smooth, layered surface,” stated study lead author Dr. Stephen Orskavich, alongside his team.
Further microscopic examinations showed that the surface was replete with unique specialized puncture structures belonging to hexacoralia, a diverse group of cnidarians that includes sea anemones and stony corals.
Relicanthus daphneae features pale purple or pink tentacles, growing up to about 2.1 m (7 ft) long. Image credit: Craig Smith & Diva Amon, ABYSSLINE Project.
The researchers also analyzed similar specimens collected during a 2021 expedition aboard the Schmidt Oceanographic Research Vessel, Falcor, discovering comparable stinging structures.
Genetic analysis confirmed the connection: DNA extracted from the “Golden Orb” aligns with Relicanthus daphneae, a mysterious deep-sea anemone recognized for its considerable size and long flowing tentacles.
Collectively, this evidence suggests that the “golden spheres” are not living organisms but rather biological debris formed at the base of sea anemones.
The specimen corresponds to Relicanthus daphneae, individuals that attach themselves to bedrock.
“This specimen represents a novel microhabitat composed of remnants of the originally secreted cuticle from Relicanthus daphneae, a rarely observed and recently classified species found between 1,200 and 4,000 meters (0.75 to 2.5 miles), while hosting microbial communities above and below its epidermis,” noted the scientists.
“These significant discoveries would not have been possible without the unique golden color and enigmatic egg-like appearance of the specimen.”
This Relicanthus daphneae was documented during a 2016 expedition aboard the NOAA ship Oceanus Explorer in the Mariana Islands region. Image credit: NOAA Ocean Exploration, Mariana Deep Sea Exploration.
Though rarely collected, Relicanthus daphneae is believed to have a worldwide distribution.
Individual polyps can reach approximately 30 cm (12 inches) in diameter, with long, winding tentacles that may extend twice that width.
Observations indicate that these creatures perch on rocks or sponges, using their tentacles to snag prey from the currents.
They may also traverse the ocean floor, leaving traces of the same golden cuticle behind.
The exact reason for shedding this material is still uncertain. One possibility is a method of asexual reproduction known as pedal laceration.
“Our findings underscore that the biodiversity and biological behaviors of obscure deep-sea species remain largely unexplored, emphasizing the importance of comprehensive specimen collection and rigorous taxonomic tracking in telepresence-based ocean exploration,” the authors concluded.
Their study was published online on April 21, 2026, on the BioRxiv preprint server.
_____
Stephen R. Orskavich et al. The Curious Incident of the Golden Orb – Remains of Relicanthus daphneae (Cnidaria, Anthozoa, Hexagram), deep sea anemone. BioRxiv published online on April 21, 2026. doi: 10.64898/2026.04.17.719276
Source: www.sci.news