Extremophile Worm With Three Sexes And High Arsenic Tolerance Found In Mono Lake

A newly discovered nematode species can thrive under high-salt, high-pH, and arsenic-rich conditions. Rick Whitacre/Shutterstock

One of the many stunning facets of our world is the ability of its many creatures to adapt to all sorts of nooks and crannies on Earth. Joining the latest encyclopedia of life on Earth is a new species of worm that can withstand 500 times the lethal human dose of arsenic, ferries its young around like mother kangaroos do joeys, and possesses three sexes – hermaphrodite, male, and female.

This worm, temporarily given the name Auanema, calls home none other than Mono Lake – a salty, alkaline body of water bound by the arid Great Basin and the chilly eastern Sierras of California. Tufa towers of limestone rise from the lake’s surface in a grand display of its harsh conditions. The lake has no fish – it’s too extreme. Instead, it holds trillions of brine shrimp and alkali flies. Auanema may be the most illustrious new addition, but the team also discovered seven more nematodes, three known species and five that are wiggly new additions.


"We drove for a couple of miles on a sandy road with our cars (they were not 4WD so we almost sunk in the sand) until a dead end. Then we walked for ~2 miles with a stereoscope, a table, a chair, a parasol, all kind of tubes and many other sampling equipments," study author Amir Sapir, from the University of Haifa in Israel, told IFLScience of the process to collect these critters. 

"Inside the lake, we went as deep as we can by foot with ziplock bags and collected the sediment, leaving behind us a row of flowing ziplock bags. We collected the bags on the way back."

Reporting their findings in Current Biology, the team surveyed animal life in the sediment of Mono Lake by gathering samples from three different sites over two consecutive years, uncovering a variety of diverse clades and lifestyles that suggests multiple colonization events took place in Mono Lake. The discovery of eight new species includes microbe grazers, predators, and parasites, which makes them the dominant animals in the lake in terms of species richness.

This newly discovered nematode species can thrive under high-salt, high-pH, and arsenic-rich conditions, but is also surprisingly versatile because it can also live in "normal" conditions in the laboratory. Caltech

Nematodes can teach us about resilience: the ability to thrive under adversity," study author Paul Sternberg, Bren Professor of Biology, told IFLScience. "Sometimes this is not a good thing for us, since some roundworms are parasites, able to cope with the adverse conditions for them, in our bodies. I think nematodes should be the first animals we send to Mars."


Identifying and studying these 1,000-celled nematodes may reveal more about the biology of these critters as they also thrive in the Antarctic desert, deep sea, and subterranea, demonstrating a broad success to inhabit various extreme environments. Live birthing is also a common feature of extremophile nematodes, possibly serving Auanema as a means to protect its young from the salty, arsenic waters of Mono Lake. 

"Understanding biodiversity is important for so many reasons: many organisms can act like canaries in a coal mine, alerting us to danger," said Sternberg. "Others can teach us how to thrive under what seem to be harsh conditions: chemicals, temperature, acidity or alkalinity, salt, radiation, you name it. Also, there are so many mysteries about life: each species has an interesting story to tell us."