translated from Spanish: Lakes high in phosphorus could have given rise to life on earth

New research from the University of Washington (USA) has revealed that life on Earth could have emerged in lakes high in phosphorus, as published by its authors in ‘Proceedings of the National Academy of Sciences’. Life as we know it requires phosphorus, one of the six major life chemical elements that form the backbone of DNA and RNA molecules, acts as the main currency of change for energy in all cells and anchors the lipids that separate the s cells around you.» For 50 years, what’s called ‘the phosphate problem’ has plagued studies on the origin of life,» admits first author Jonathan Toner, assistant research professor at the University of Washington in Earth and Space Sciences.The problem is that chemical reactions that make the basic components of living beings need a lot of phosphorus, but phosphorus is scarce. New research has found an answer to this problem in certain types of lakes. The study focuses on carbonate-rich lakes, which form in dry environments within depressions that channel water from the surrounding landscape. Due to high evaporation rates, lake waters are concentrated in salty and alkaline solutions, or high pH. These lakes, also known as alkaline lakes, are found all over the world. Researchers first observed phosphorus measurements in existing carbonate-rich lakes, including Mono Lake, in California; Magadi Lake, in Kenya, and Lake Lonar, in the India.Si well the exact concentration depends on where the samples were taken and during which season, the researchers found that carbonate-rich lakes have phosphorus levels up to 50,000 times more found in seawater, rivers and other types of lakes. Such high concentrations point to the existence of some common natural mechanism that accumulates phosphorus in these lakes. Today, these carbonate-rich lakes are biologically rich and sustain a life ranging from microbes to the famous flocks of flamingos of Lake Magadi. These living things affect the chemistry of the lake. Researchers conducted laboratory experiments with carbonate-rich water bottles in different chemical compositions to understand how lakes accumulate phosphorus and how high concentrations of phosphorus could reach a lifeless environment. The reason these waters have high phosphorus is their carbonate content. In most lakes, calcium, which is much more abundant on Earth, binds to phosphorus to produce solid calcium phosphate minerals, which life cannot access. But in carbonate-rich waters, carbonate outperforms phosphate to bind to calcium, leaving some of the phosphate unadhered. Laboratory tests that combined ingredients at different concentrations show that calcium binds to carbonate and leaves phosphate freely available in water. «It’s a direct idea, which is his appeal,» Toner says. Solve the phosphate problem in an elegant and plausible way.» Phosphate levels could rise even higher, at levels of one million times in seawater, when lake waters evaporate during dry seasons, along shorelines or in pools separate dismembered from the lake’s main body.» Extremely high levels of phosphate in these lakes and ponds would have provoked reactions that put phosphorus in the molecular building blocks of RNA, proteins and fats, all of which were necessary for life to follow,» explains co-author David Catling, a Professor of Earth and Space Sciences at UW. The carbon dioxide-rich air on the early Earth, about four billion years ago, would have been ideal for creating such lakes and allowing them to reach maximum levels of phosphorus. Carbonate-rich lakes tend to form in atmospheres with high carbon dioxide content. In addition, carbon dioxide dissolves in water to create acidic conditions that efficiently release phosphorus from rocks.» The early Earth was a volcanically active place, so it would have had many fresh volcanic rocks reacting with carbon dioxide and supplying carbonate and phosphorus to the lakes, Toner points out. The early Earth could have housed many carbonate-rich lakes, which would have had phosphorus concentrations high enough to begin life.» Another recent study by the two authors showed that this type of lakes can also provide abundant cyanide to support the formation of amino acids and nucleotides, the basic components of proteins, DNA and RNA. Prior to that, researchers had struggled to find a natural environment with enough cyanide to maintain the origin of life. Cyanide is poisonous to humans, but not to primitive microbes, and is critical to the type of chemistry that easily creates the basic components of life.

Original source in Spanish

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