Life could have begun in soda lakes. That’s a new idea being proposed in a study from the University of Washington. It would help scientists resolve an issue called the phosphate problem. Find out more.
I can’t remember ever not believing in evolution. Nobody at home, school or church ever suggested that there was ever any other explanation for how life began and the diversity of life.
In high school, we studied the play Inherit the Wind by Jerome Lawrence and Robert E. Lee. Clarence Darrow (Henry Drummond in the play) became one of my idols for standing up for reason and science in the famous Scopes Monkey Trial.
The thing that solidified my views on evolution was reading Charles Darwin’s Origin of Species. Darwin was not only a scientific genius but also a brilliant, lyrical author.
“ENDLESS FORMS MOST BEAUTIFUL AND WONDERFUL”
I’ll never forget the first time I read his famous passage, “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”
That paragraph says it all. Even so, another passage about how life began has always stayed with me. It’s from a letter Darwin wrote to Joseph Hooker in 1871. It goes, “But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts,—light, heat, electricity etc. present, that a protein compound was chemically formed, ready to undergo still more complex changes, at the present day such matter would be instantly devoured, or absorbed, which would not have been the case before living creatures were formed.”
Darwin paints such a picturesque image of how life began. Science has already vindicated a great deal of what Darwin’s work predicted. His work is even more remarkable when we realize that Darwin had no way to know about genetics and DNA. Sean Carroll discusses the principles that have guided the scientific revolution from Darwin and Einstein to the origins of life, consciousness, and the universe in his book The Big Picture: On the Origins of Life, Meaning, and the Universe Itself.
LIFE BEGAN IN LAKES WITH HIGH PHOSPHOROUS CONTENT
Last week, a study from the University of Washington and published in the Proceedings of the National Academy of Sciences may have vindicated Darwin yet again. His lyrical description of the “warm little pond” corresponds very well to a new hypothesis that life began in lakes with high phosphorous content.
Readers will notice that Darwin mentions “phosphoric salts” in this hypothetical primordial pond. This is because one of the most critical ingredients in living things is the chemical element phosphorus.
It’s one of the six essential elements for life, and it forms the backbone of both RNA and DNA. The energy in a cell depends on phosphorous, and the chemical also holds down the lipids that divide cells from their external environment.
PHOSPHATE COMMON IN ORGANISMS BUT RARE IN NATURE
This leads to what biologists call the “phosphate problem.” The problem is that phosphorous is very common in all living organisms, and they require lots of it. Paradoxically, phosphorous is very rare in nature. So, how did living cells end up with so much phosphorus when life began?
This posed a challenge to Darwin in his day, and it is still an issue for modern scientists. The researchers at the University of Washington focused on carbonate-rich lakes. Farmers and ranchers all over the world encounter them. Soda lakes or alkaline lakes are two of the other names they go by.
These lakes form in dry areas with low spots in the terrain. They channel the water running down from the surrounding physical features. Because of the lack of humidity, the water evaporates quickly, which leaves behind salty, alkaline solutions.
MEASURED PHOSPHOROUS CONTENT IN THREE LAKES
The team measured the phosphorous content in three of these lakes. Mono Lake in California, Lake Magadi in Kenya and Lonar Lake in India were the chosen subjects. Concentration levels varied widely.
The readings depended on where in the lake the sample came from and the time of year. Overall, though, the study concluded that these kinds of lakes contain on the order of 50,000 times the phosphorus levels found in other lakes, rivers or even the ocean.
You might think that these soda lakes would be lifeless. Actually, it’s just the reverse. These bodies of water are rich in biodiversity, with everything from microbes to Lake Magadi’s world-renowned pink flamingoes.
“PUT PHOSPHOROUS INTO BUILDING BLOCKS OF LIFE”
Professor David Catling of UW explained, “The extremely high phosphate levels in these lakes and ponds would have driven reactions that put phosphorus into the molecular building blocks of RNA, proteins, and fats, all of which were needed to get life going.”
We also need to bear in mind that before life began on Earth around four billion years ago, our atmosphere was very high in carbon dioxide. This is also ideal for the formation of high phosphorous lakes. The C02 would have acidified the lakes, which would release any phosphorous contained in the bedrock.
Lead author Jonathan Toner outlined another contributing factor. “The early Earth was a volcanically active place, so you would have had lots of fresh volcanic rock reacting with carbon dioxide and supplying carbonate and phosphorus to lakes. The early Earth could have hosted many carbonate-rich lakes, which would have had high enough phosphorus concentrations to get life started.”
COMPELLING REASON TO CONSIDER CARBON RICH LAKES
None of this is conclusive proof that life began in phosphorous lakes. The team doesn’t make that leap. However, they do say that their study provides “a compelling reason to consider carbonate-rich lakes as plausible settings for the origin of life.”
We always have more to learn if we dare to know.
University of Washington
A carbonate-rich lake solution to the phosphate problem of the origin of life
The Big Picture: On the Origins of Life, Meaning, and the Universe Itself
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Why Mars? Why Not Life on Venus?