Tuesday, May 6, 2014

On the Origins of Life

            Four billion years ago, the Earth was just a floating ball of rock; insanely hot, an atmosphere of carbon dioxide, it’s amazing that life could ever exist here. But as Ian Malcolm said, “Life, uh, finds a way.” And indeed it did. Life started in the oceans of primordial Earth; a soup of amino and nucleic acids, lipids, and carbohydrates that just happened to be in the right place at the right time to become the original cell. Many believed that a bolt of lightning might have provided the original energy needed for this transformation, but a new study presents another possible origin.
            Recently, NASA scientists believe they may have found what provided the electrical energy needed to create life. Deep down on the bottom of the ocean floor, hydrothermal vents are spewing out sulfur, magma, and apparently, electricity. The hypothesis was first proposed under the name “submarine alkaline hydrothermal emergence of life”, but NASA has now managed to unify all of the data into one unified picture.

A "Black Smoker" Vent
(Photo credit: NOAA)

            But not every hydrothermal vent produces the conditions needed to create life. While it was assumed in the 1980’s when the hypothesis was first proposed that “black smokers”, vents that produce extremely hot, acidic water, were responsible, but this may not be the case. The vents that NASA scientists use in their new study produce cooler, alkaline water and are not nearly as harsh.

An alkaline vent, dubbed "The Lost City"
(Photo credit: The University of Washington)

            Michael Russell, the head scientist for this study, states that these alkaline vents created an unbalanced state, conflicting with the ancient acidic oceans. This imbalance created the free energy needed to create life, Russell believes. In fact, Russell believes that these vents could have created two imbalances.
            The first imbalance was a proton imbalance. This would have been caused by the alkaline fluids interacting with the acidic oceans that surround them. This gradient could have been used to produce energy in a fashion similar to how mitochondria function. The other imbalance could have been an electrical imbalance. The ancient oceans were loaded with carbon dioxide, which when coming into contact with the methane producing vent could have become more advanced carbon compounds, which are important for the formation of life.
            But life isn’t just electricity and carbohydrates, proteins are also needed. Will in the primordial soup that was Earth’s ancient ocean, enzymes could be found floating in the water. These enzymes could then come into contact with the rock chimneys of these alkaline vents, where two different “protein engines” could take over.
            The first would have harnessed the proton gradient from earlier in order to produce energy storing molecules which could be used later. The other used an element known as molybdenum, which can allow for the transfer of two electrons at once instead of one; a key concept needed in most key chemical reactions.

            So, this study presents a lot of interesting information. We now have a practical, new idea on the origins of life. This information could be applied to any rocky, wet planet in terms of identifying if life could exist there. So, while we are still not terribly certain on how life started on Earth, we now have a good idea of what may have happened. And while it may take decades to truly figure out how life started, Russell and his team while be willing to tackle these problems until they’re solved.

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1 comment:

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