Meet the mysterious, magnetic microbes dwelling in the Mariana Trench

Yang Hao was a graduate student in 2018 who was hunting for cosmic dust in Mariana Trench bottom sediments. He was expecting to discover more about the origins of life on Earth and the role interplanetary material may have had in igniting it by scouring the deepest parts of the ocean. Yang was shocked to find a tiny shelled critter adhering to the equipment while poking a little of seabed sand with a magnetic needle in search of meteorite dust. Resigella bilocularis, a foraminifera, was the organism. R. bilocularis, like other foraminifera, is a single-celled shell constructor. But, unlike other foraminifera discovered at the ocean's bottom, this one has a unique feature: it is magnetic.Yang was so taken aback by his discovery that he decided to spend his doctoral studies on learning everything he could about this strange critter.

Many animals exhibit magnetic attraction, including bacteria, single-celled algae, insects, mollusks, fish, birds, and even humans. The mineral magnetite, which they utilize to orient themselves and travel according to the Earth's magnetic fields, is supposed to give them their abilities. Magnetite can be produced by some organisms utilising iron from their surroundings. The origin of magnetite remains a mystery for many creatures, including foraminifera and other eukaryotes.

Yang and his team believe R. bilocularis produces its own magnetite, however additional research is needed to be positive. If this is the case, understanding more about R. bilocularis' magnetism might help researchers unravel the evolutionary history of this characteristic, as it is the first magnetic single-celled eukaryote discovered thus deep in the ocean.

The scientists arrived at this conclusion after examining 1,000 foraminifera specimens taken during missions to the Mariana Trench between 2016 and 2019. Their findings reveal that the chemical and physical structure of R. bilocularis magnetite differs from that of surrounding sediment and bacteria-produced magnetite, indicating that the foraminifera is producing its own.

Yang is determined to research foraminifera in a facility intended to expose the single-celled creatures to pressures up to 1,000 times those at sea level, notwithstanding how difficult it may be. He's presently focusing on keeping the foraminifera alive and decoding its DNA in the lab. If he succeeds, the ramifications might be far greater than the size of this little organism.

“There is not a lot of magnetite known to be produced,” adds M. Renee Bellinger, an evolutionary biologist at the University of Hawai'i in Hilo who was not involved in the work. “Studying something from a deep-sea environment that is potentially ancient in origin could help to understand how the ability to produce magnetite evolved in the first place.” 

While Yang was unable to fathom the cosmic beginnings of life on Earth, he may be on the verge of discovering the origins of magnetic life.