A deep-sea mystery that has stumped researchers for the past two-and-a-half years has a solution, with marine scientists from NOAA Fisheries and the Smithsonian National Museum of Natural History in the US finally determining the identity of a bizarre “golden orb” recovered from the Pacific in 2023.
If you had money on sponge, monstrous eyeball, or microbial biofilm, we’re sorry to say that you’re not walking away with any winnings today.
If you guessed it was the egg sac of some large, tentacled creature, you’re also wrong.
Ok, you might deserve a consolation prize – the lump of tissue plucked from rocks roughly 2 miles (3.2 kilometers) beneath the surface by a National Oceanic and Atmospheric Administration (NOAA) expedition was, in fact, left by a big animal with a lot of tentacles.
While their findings are yet to be peer-reviewed, preliminary results reveal that the material is, in fact, once anchored an individual Relicanthus daphneae sea anemone to the ocean floor.
These pinkish organisms can reach several feet (about a meter) across, and stretch the same in length, so they’re not tiny. While not exactly new to biology, the species was first described in 2006. And even then, its exact taxonomy was debated until phylogenetic studies confirmed its connection to its closest relatives.
Given its obscurity and the fact that the species is most at home far beneath the waves near hydrothermal vents, we may be forgiven for not immediately recognising the bronze-colored ‘cuticle’ for what it is.
When researchers on the NOAA Ship Okeanos Explorer brought the papery material to the surface during a survey in the Gulf of Alaska in the summer of 2023, they were baffled. The size of a fist with a hole in the top, it may have been an egg sac. Or a dead sponge. Or something completely novel to science.
“We work on hundreds of different samples, and I suspected that our routine processes would clarify the mystery,” says zoologist Allen Collins, director of NOAA Fisheries’ National Systematics Laboratory.
“But this turned into a special case that required focused efforts and expertise of several different individuals. This was a complex mystery that required morphological, genetic, deep-sea, and bioinformatics expertise to solve.”
The integrative approach combined a study of the organic structure and a genetic analysis. A close look at the surface revealed numerous cnidocytes – "stinging cells" common to jellyfish, coral polyps and anemones. Further inspection determined they were of a variety restricted to the class Hexacorallia.
A DNA analysis was complicated by contamination, requiring scientists to dig deeper into the specimen for a suitable sample.
At last, they got to the root of their answer. Literally.
“So often in deep ocean exploration, we find these captivating mysteries, like the 'golden orb'. With advanced techniques like DNA sequencing, we are able to solve more and more of them," says William Mowitt, acting director of NOAA Ocean Exploration.
“This is why we keep exploring – to unlock the secrets of the deep and better understand how the ocean and its resources can drive economic growth, strengthen our national security, and sustain our planet.”
This research can be read on the pre-publish server, arXiv.com
Source: NOAA
Fact-checked by Bronwyn Thompson
