Strange golden sphere at the bottom of the sea

The Seascape Alaska 5 expedition from the US National Oceanic and Atmospheric Administration (NOAA) discovered the mysterious golden sphere during a deep dive in Alaskan waters in 2023. The sphere is soft, smooth, about 10 cm wide and clings tightly to the rock on the seabed 3,200 m deep. Using a suction device, a remote-controlled vehicle brought the object onto the Okeanos Explorer for further study.

However, even after direct inspection, the expedition still could not identify the golden sphere. They put forward many hypotheses such as this being an egg, a sponge, or a microbial mat.

In the new analysis, Allen Collins, a zoologist at the Smithsonian National Museum of Natural History, and his colleagues carefully analyzed the sphere, decoding a mystery that has existed for many years. New research, published in the database bioRxiv This month, it was revealed that this is a substance produced by deep-sea anemone-like creatures Relicanthus daphneae secrete.

“First we looked for its general anatomy, to see if it had a mouth or muscles. Features like that would help reveal this was a specific type of animal. But we didn’t find any of these,” Collins told Live Science on April 27.

The team then placed the golden sphere under a microscope and discovered the layer’s characteristic stinging cells Hexacorallia belongs to the industry Cnidariansthe phylum includes more than 11,000 species of aquatic invertebrates such as jellyfish, hydra, sea anemones, and corals. Next, they conducted genetic testing and detected DNA from the species R. daphneae with many microorganisms. According to Estefanía Rodríguez, curator of marine invertebrates at the American Museum of Natural History in New York, a member of the research team, the golden sphere is an epidermal structure that the anemone-like creature secretes underneath its body to firmly adhere to rocks.

Theo Collins, R. daphneae probably secretes a cuticle to adhere to the rock but then detaches to move to a better position, continuing to attach there by creating a new cuticle. That’s why the golden sphere was left behind where the Seascape Alaska 5 expedition passed.

Jon Copley, a marine ecologist from the University of Southampton said, R. daphneae are often found near hydrothermal vents in the Pacific, Southern Ocean, and Indian Ocean, but this may be because scientists survey them more often than other deep-sea environments. He suspects this strange animal may have a wider distribution and that new research will help understand more about its range.

“This is why we continue to explore – to unlock the mysteries of the deep sea and better understand how the ocean and its resources can drive economic growth, enhance national security, and maintain the sustainability of the planet,” William Mowitt, acting director of NOAA’s Ocean Exploration Program, shared with Science Alert.