April 23, 2019 | 67° F

Princeton professor talks discovery of new organism

Photo by Edwin Gano |

Princeton University professor Tullis Onstott talks about his research on the world’s deepest living multicellular organism Friday on Cook campus.

The world’s deepest living multicellular organism was recently discovered with the help of Professor Tullis Onstott of Princeton University.

Onstott gave a presentation Friday in the Marine Sciences Building on Cook campus explaining hisresearch on underwater organisms in South Africa.

One of the organisms, a worm known to the scientific community as Halicephalobus mephisto, was found as deep as 2.2 miles into the Earth’s surface, he said. This challenges previous notions of what types of organisms could be found at that depth.

According to National Geographic’s website, previously discovered worms, also known as nematodes, only lived within a few decameters of the surface. Single-cell creatures were thought to be the only organisms with the ability to live deeper.

Onstott, named one of TIME’s most influential people in 2007, said the research was conducted near hot springs in the gold mines of South Africa. The mines reach a depth of nearly 2.5 miles, and conditions there are harsh. 

The mines can reach temperatures of up to 140 degrees Fahrenheit near the bottom, he said. Cold air and water must be pumped through the mine to protect the miners and researchers.

South Africa was chosen as a research area due to the depth of its mines, he said. The conditions there are closest to the ground underneath the oceans where previous research was conducted.

“When we first went to South Africa, back in ’98, there was this [idea] that existed that 50 percent of the living organisms on our planet lived [in ‘deep surface’ environments],” he said. 

It is a very energy limited environment, he said. They expected few, slowly evolving bacteria to be present at that depth.

They found a complex organism instead, he said. 

The worms, nicknamed the “worms from hell,” live within the water found in tiny fissures in the rocks under the mines, he said. To find it, they had to filter water discovered within the rocks.

The “worms from hell” have been found to live off of the single-cell microbes that also make their homes in the rock, Onstott said. Methanogens, bacteria that produce methane, are crucial to the survival of these worms.

Another type of bacteria that was found is Desulforudis audaxviator, he said. These bacteria only exist deep within the South African mines and have evolved to survive only in that environment. 

Unlike most organisms on Earth, D. audaxviator does not depend on sunlight for energy.

Instead, these bacteria get their energy from the radioactive breakdown of certain elements in the environment, he said. 

This changed previous ideas that the amount of energy available to subsurface organisms was limited, he said. This means the rate at which the bacteria reproduced was much higher than previously thought.

The water the D. audaxviatorlived in was tested extensively to prove that they were native to the environment they were discovered in and not accidentally brought down there from the surface, he said.

It was found that the water the miners used was clean, he said. The water the bacteria and nematodes lived in was untouched. In addition, radiocarbon dating proved that the water was at least several thousand years old.

DNA samples from the organisms also support the age of the species, he said.

The next step in this research is to sequence the genome of the organisms found, he said.

According to TIME Magazine, the nematodes and bacteria found in South Africa resemble what NASA expects to find on Mars and other similar environments. Onstott is currently working with NASA to create instruments capable of detecting microbes.

Nikhilesh De

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