A B.C. “soda lake” thought to contain the highest concentration of natural phosphate in the world has offered a new glimpse of how life may have evolved on Earth, a new study has found.
The , published in the journal Communications Earth & Environment earlier this month, adds evidence to the hypothesis that life evolved in a volcanic landscape, where shallow pools of water contain the concentrated elements and right conditions required to make the leap from chemistry to biology.
The search for a modern analog to life’s primordial beginnings drew researchers from the University of Washington to two lakes in British Columbia’s Caribou Plateau between Cache Creek and 100 Mile House.
Emerging from the last Ice Age, Last Chance Lake is up to 13 times saltier than the ocean, and filled with a number of substances required for life, said lead author Sebastian Haas, a researcher at the University of Washington’s Department of Earth and Space Sciences.
“The key to the origin of life is a chemical story,” said Haas. “You need a little bit of everything.”
But not all of the elements required for life are equally abundant. One of the most limiting ingredients to biological success is phosphate — a vital ingredient in DNA, life’s blueprint, and its partner, RNA, which puts that cellular recipe into action.
When scientists have tried to replicate life’s building blocks under laboratory conditions, they have consistently required phosphate concentrations up to a million times higher than those normally found in the world's oceans and lakes, said Haas.
B.C. lake shows extreme conditions are possible
Soda lakes open up the possibility that nature could indeed have created environments rich enough in phosphate to catalyze early life.
The lakes get their name from their high concentrations of sodium and carbonate, basically baking soda, and are found in certain spots around the world — in East Africa’s Rift Valley, Brazil, Kazakhstan, Hungary and in dry climates in Washington, Oregon and Northern California.
But in Haas’s search for the right conditions for early life, nothing compared to B.C.’s Last Chance Lake. Groundwater that feeds the lake leaches elements from surrounding volcanic rock, and windy conditions drive evaporation rates that concentrate the dissolved elements.
That has made the 25-centimetre-deep lake the world’s largest known natural dumping ground for dissolved phosphate.​
​Too salty to swallow, Haas said the lake offers a lens to understand ancient equivalents on early Earth.
“It could have possibly been the setting for the origin of life,” Haas said.
​Second lake offers ideal natural experiment
A hundred metres away and still on federal land, Goodenough Lake was found to have remarkably similar water chemistry, but with thick mats of cyanobacteria. That offered the research team a window into how life has adapted to survive in the extreme conditions today.
The two lakes also provided the perfect conditions for a natural controlled experiment.
“We needed to understand the lake as we see it today to draw inferences of what the lake would have looked like without life,” said Haas.
Throughout 2021 and 2022, the team sampled the waters and sediments of both lakes.
In most lakes, phosphate reacts with calcium to form calcium phosphate, the same solid material found in our bones and tooth enamel. The chemical reaction removes phosphate from the water and out of reach of any perspective life.
But tests on the water at Last Chance Lake revealed its calcium was consumed and locked away in a reaction with high concentrations of carbonate to produce dolomite — the same sedimentary rock of Northern Alps fame. The chemical environment freed up the lake's phosphate and theoretically kept it within the reach of any potential life.
Last Chance Lake, the study found, offered a “plausible environment” for the emergence of life four billion years ago.
A clue in the search for extraterrestrial life
Back in the lab, Haas said the salty, phosphate-rich conditions of the B.C. lake can inform scientists looking to synthesize life’s building blocks. The team’s findings could also have implications in the search for life beyond Earth.
“Where did life come from? How did it emerge? It’s a big unanswered question in science. It also informs our search for life elsewhere in the solar system,” Haas said.
The study concluded that the same extreme phosphate conditions found in the B.C. lake also “apply to the subsurface ocean of Saturn’s moon, Enceladus” and “may have also occurred on early Mars” — a planet with similar rocks to the B.C. lakes and that “very likely” had lakes in its past.
“We’re not talking aliens with the green ears, but microbes,” said Haas.
