No one on the research team anticipated anything especially out of the ordinary when the remotely operated vehicle Deep Discoverer descended more than two miles into the Gulf of Alaska in 2023. Oddly shaped corals, strange fish, and alien-looking invertebrates clinging to rocks are just a few of the oddities that deep-sea expeditions frequently discover. When working on NOAA’s Okeanos Explorer, scientists become accustomed to the unexpected. However, that day’s footage from the ROV’s camera showed something different. At about 3,250 meters below the surface, a rounded, golden, mound-shaped object with a tiny hole in it rested on a rocky outcropping. It was beyond explanation.
The video quickly went viral. Online rumors about alien eggs, undiscovered species, and some sort of geological artifact went wild, as was to be expected. The theories varied greatly even within the scientific community. Was the sponge dead? A case for eggs? Had something recently come out or crawled into it? Using a suction sampler, the team collected the object and sent it to the Smithsonian National Museum of Natural History, where researchers likely anticipated prompt responses. They didn’t.
More than two years of meticulous, occasionally frustrating scientific research ensued; this type of research rarely makes headlines but is essential to the actual process of oceanic discovery. Starting with a physical examination, researchers at NOAA Fisheries and the Smithsonian discovered fibrous layers filled with cnidocytes, which are stinging cells present in anemones and corals. That was a hint, but it wasn’t a full picture. The specimen was then reduced to a subgroup known as Hexacorallia after scientist Abigail Reft more precisely identified the cells as spirocysts. Similar cellular structures were found in an object collected in 2021 on the Schmidt Ocean Institute’s research ship Falkor, indicating that this was not an isolated anomaly.
The next attempt, DNA barcoding, was unsuccessful. The results appear to have been tainted by genetic material from microscopic organisms that were present in the sample. It’s the kind of setback that undoubtedly felt depressing in the lab, the kind where a simple case subtly turns into a puzzle that takes years to solve. Ultimately, the team used whole-genome sequencing, a more thorough and resource-intensive method that ultimately produced a definitive response. Relicanthus daphneae, a massive deep-sea anemone that is extremely rare, hardly known, and not something that most marine biologists come across in their work, was matched by the genetic material.
It turns out that the golden orb was not a living thing at all. It was a remnant, more precisely the anemone’s basal disc, which serves as its seafloor anchor. In essence, what the Deep Discoverer had discovered was the remaining tissue from an anemone that had eventually separated and moved on. The building that was left behind had solidified into that peculiar golden shape, sitting by itself on a rock at a crushing depth and appearing to have no right to exist.
That conclusion contains something worthwhile. One of the world’s least explored habitats is the ocean floor, and this organism was so rarely seen that even its discarded tissue was able to confound a group of seasoned scientists for more than two years. It’s possible that dozens of comparable structures are currently sitting in the deep sea, unnoticed and unnamed. Although Relicanthus daphneae’s giant, arm-trailing form has been documented, its true prevalence is still unknown.
According to Allen Collins, director of NOAA Fisheries’ National Systematics Laboratory, what appeared to be a simple identification turned into a collaborative effort involving morphological, genetic, deep-sea, and bioinformatics expertise. That’s a big deal. The mystery surrounding the golden orb has been solved, and it is now listed in the Smithsonian’s Invertebrate Zoology Collection under accession number USNM_IZ_1699903. However, the deep ocean retains its secrets well and only reluctantly, slowly, and typically not without resistance.
