In August 2023, a mysterious golden orb discovered on the seafloor in the Gulf of Alaska has been identified by researchers as a biological remnant of the deep-sea anemone Relicanthus daphneae. The object, initially puzzling to scientists, was determined after extensive analysis to be a cuticle or pedal disc shed by the organism.
Discovery and Initial Observations
On August 30, 2023, during NOAA's Seascape Alaska 5 expedition, the remotely operated vehicle Deep Discoverer observed a small, golden, mound-shaped object approximately four inches (10 cm) across. It was found attached to a rock among white sea sponges at a depth of roughly 3,250 meters (over two miles) southwest of Walker Seamount in the Gulf of Alaska. The object appeared smooth, had a small opening on one side, and was collected using a suction sampler for further study.
Identification Process
Researchers from the National Oceanic and Atmospheric Administration (NOAA) and the Smithsonian National Museum of Natural History conducted a multi-year investigation involving morphological, genetic, and bioinformatics methods.
- Initial Analysis: The specimen lacked recognizable animal features. Light microscopy revealed it was composed of fibrous layers containing specialized stinging structures (spirocysts) unique to the subclass Hexacorallia, which includes sea anemones and stony corals.
- Genetic Testing: Initial DNA barcoding was inconclusive due to contamination from other microscopic life. Subsequent whole-genome sequencing and mitochondrial genome analysis confirmed a near-identical genetic match to the deep-sea anemone Relicanthus daphneae.
- Morphological Conclusion: Researchers identified the object as a cuticle—specifically the pedal disc or base—that the anemone secreted to attach itself to a rock substrate. The material is composed primarily of chitin and is shed when the organism detaches to move or possibly during a form of asexual reproduction known as pedal laceration.
Scientific Context
Relicanthus daphneae is a rarely collected deep-sea anemone species. Individual polyps can reach about 12 inches (30 cm) across, with long tentacles that can extend up to six feet (two meters) in length. The species is thought to be globally distributed at depths between 1,200 and 4,000 meters (0.75–2.5 miles), often observed near hydrothermal vents. The organism is believed to perch on rocks or sponges, extending its tentacles into currents to capture prey.
A similar specimen collected in 2021 during an expedition on the Schmidt Ocean Institute's R/V Falkor also contained these specialized stinging structures.
Broader Implications
The investigation demonstrated the utility of combining morphological analysis with modern genomic techniques for deep-sea species identification. The specimen also hosted a diverse community of microorganisms on and beneath the cuticle, representing a novel microhabitat that may contribute to nutrient cycling on the seafloor.
The findings were posted on the preprint server bioRxiv on April 21, 2026, and have not yet been peer-reviewed. The taxonomic classification of R. daphneae remains a subject of scientific discussion, with some genetic analyses suggesting it may belong to a sister group to true anemones, while morphological analysis supports its classification as a sea anemone.