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Researchers use historic hot springs to investigate the beginnings of life on Earth.
The study team, sponsored by the UK's Natural Environmental Study Council, looked into how the first living systems emerged from inert geological components on Earth more than 3.5 billion years ago. Scientists at Newcastle University discovered that mixing hydrogen, bicarbonate, and iron-rich magnetite under conditions similar to relatively mild hydrothermal vents results in the formation of a variety of organic molecules, most notably fatty acids stretching up to 18 carbon atoms in length. Their results, published in the journal Communications Earth & Environment, have the potential to show how some crucial molecules required for life are produced from inorganic compounds, which is critical to understanding a vital stage in how life started on Earth billions of years ago. Their findings may give a credible origin for the organic compounds that comprise ancient cell membranes, which were perhaps selected by early biochemical processes on primordial Earth. Fatty acids are long chemical molecules with areas that attract and repel water. They naturally form cell-like compartments in water, and it is possible that these molecules were responsible for the earliest cell membranes. Yet, despite their importance, it was uncertain where these fatty acids came from in the early stages of life. One idea is that they might have formed in the hydrothermal vents, where hot water mixed with hydrogen-rich fluids coming from underwater vents mixed with seawater containing CO2. The group replicated crucial aspects of the chemical environment found in early Earth's oceans and the mixing of the hot alkaline water from around certain types of hydrothermal vents in their laboratory. They found that when hot hydrogen-rich fluids were mixed with carbon dioxide-rich water in the presence of iron-based minerals that were present on the early Earth, it created the types of molecules needed to form primitive cell membranes. The lead author, Dr. Graham Purvis, conducted the study at Newcastle University and is currently a postdoctoral research associate at Durham University. He said, "Central to life's inception are cellular compartments, crucial for isolating internal chemistry from the external environment. These compartments were instrumental in fostering life-sustaining reactions by concentrating chemicals and facilitating energy production, potentially serving as the cornerstone of life's earliest moments. The results suggested that the convergence of hydrogen-rich fluids from alkaline hydrothermal vents with bicarbonate-rich waters on iron-based minerals could have precipitated the rudimentary membranes of early cells at the very beginning of life. T his process might have engendered a diversity of membrane types, some potentially serving as life's cradle when life first started. Moreover, this transformative process might have contributed to the genesis of specific acids found in the elemental composition of meteorites. Principal Investigator Dr. Jon Telling, a Reader in Biogeochemistry at the School of Natural Environmental Sciences, added, "We think that this research may provide the first step in understanding how life originated on our planet. Research in our laboratory now continues to determine the second key step: how these organic molecules, which are initially 'stuck' to the mineral surfaces, can lift off to form spherical membrane-bounded cell-like compartments--the first potential 'protocells' that went on to form the first cellular life." (ANI)
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