Meet the mysterious, magnetic microbes dwelling in the Mariana Trench

Meet the mysterious, magnetic microbes dwelling in the Mariana Trench thumbnail
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This article was originally featured on Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

In 2018, Yang Hao was a graduate student looking for cosmic dust in seafloor sediments collected from the Mariana Trench. He was looking for interstellar material and more information about the origin of life. He explored the ocean’s deepest parts to find out. Yang discovered a tiny shelled organism sticking to a piece of seafloor sediment he was probing with a magnet needle as part of his hunt for meteorite powder. It was a foraminifera named Resigella Bilocularis . R.bilocularis , like other foraminifera is a single-celled builder of shells. This foraminifera is magnetic, which is a surprise considering the rest. Yang was so fascinated by his discovery, he decided to refocus his doctorate research and learn more about this curious creature.

Male organisms include bacteria, single-celled alga, insects, mollusks and birds. Many people believe that they are able to use the mineral magnetite to orient themselves and navigate according the Earth’s magnetic field. Some organisms can make magnetite from iron taken from their environment. For many organisms, including foraminifera, it remains a mystery as to where the magnetite came from.

Although they need to do more research to be certain, Yang and his team believe R.bilocularis is making its own magnetite. This could be true, since R.bilocularis is the first single-celled magnetic eukaryote to be found so deep in the ocean. Researchers could learn more about its magnetism and help unravel the evolutionary history of this trait.

The scientists came to this position after analyzing 1,000 specimens of the foraminifera that they collected from the Mariana Trench on expeditions between 2016 and 2019. Their work showed that the magnetite in R. Bilocularis has a chemical and physical structure that is different from the magnetite found in the surrounding sediments and that produced by bacteria. This suggests that the foraminifera may be making its own.

YouTube video

Dead Resigella bilocularis clearly respond when exposed to a magnetic field. Researchers aren’t able to confirm whether the magnetic sensitivity of living foraminifera can be used. Video By Yang Hao Courtesy Hakai magazine.

Difficult though it may be to study foraminifera in a lab designed to expose the single-celled organisms to pressures as much as 1,000 times those at sea level, Yang is determined to do so. Yang is currently working to keep the foraminifera in the laboratory alive and sequence its genome. If he succeeds in his quest, the implications could even exceed the size of this tiny organism.

” There isn’t a lot of known magnetite production,” says M. Renee Bellinger (an evolutionary biologist at University of Hawai’i in Hilo), who was not involved with the study. “Studying something deep-sea could help us understand how the ability of producing magnetite evolved .”

Although Yang didn’t find the cosmic origin of all life on Earth, he may be closer to understanding the origins and evolution of magnetic life.

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