Hydrothermal Vents and the Origin of Life on Earth
Hydrothermal systems, as well as the thermal, geological, biological and chemical processes that are associated with like environments, have probably operated continuously since Earth’s surface became cool enough for oceanic formation approximately four billion years ago (Martin et el 2008, Schulte 2007). Their discovery revolutionized origin of life studies by challenging modern conceptions of components necessary for survival. Vent species have the genetic potential to grow and survive in an extreme range of conditions, many of which were transiently present as Earth evolved over millions of years (Thiel & Koslow 2001). Reactive gasses, dissolved elements and thermochemical gradients operating on spatial scales of meters to centimeters were all characteristic elements of early Earth (Martin et el 2008). Until about 3.8 billion years ago Earth’s surface was a violent and harsh environment, constantly bombarded with debris from space. As the Universe cooled and expanded the surface collisions subsided. The fossil record shows biological processes originated around the same time, approximately 3.8 to 3.5 bya. Oceanic temperatures at that time are estimated at 70 to 100 C due to heat generated by collisions and atmospheric composition. The oceans also would have been highly acidic due to the carbon dioxide-rich, oxygen-free atmosphere (Schulte 2007).
Volcanic and hydrothermal activity on early Earth was much more frequent then today. (Schulte 2007). Early hydrothermal vent systems would have been potentially chemically reactive environments with conditions favorable for the sustained prebiotic synthesis of the reduced organic compounds necessary for life (Martin et el 2008). Hydrothermal systems could have been where organic compounds were first synthesized on early Earth. Research has shown that amino and carboxylic acids can be generated in vent environments. The constant supply of energy from geochemical and thermal reactions may have provided the circumstances necessary for the origination of life. Vents may have provided a safe haven for life to develop away from the constant changes in atmosphere, solar radiation and surface conditions on early Earth (Schulte 2007).
Implications for the field of astrobiology
The discovery of hydrothermal vents caused great excitement in the astrobiological community- geothermal energy had not been seriously considered as a source of potential energy for the biosynthesis and maintenance of carbon-based life forms (Thiel & Koslow 2001). Astrobiologists began to re-examine planets and moons in our solar system for evidence of geothermal or seismic activity. Europa, one of Jupiter’s moons, has become a popular focus since the tidal pull of Jupiter produces enough heat to keep liquid water under the satellite’s icy surface. Jupiter’s gravitational force may also provide enough heat to melt parts of Europa’s rocky mantle, creating appropriate conditions for geothermal activity and possible formation of hydrothermal habitats (Schulte 2007).
Thanks for Reading! Literature Consulted:
Martin, W., J. Baross, D. Kelley and M. Russell. “Hydrothermal Vents and the Origin of Life.” Nature. 6 (2008): 805-814.
Schulte, M. “The Emergence of Life on Earth.” Oceanography. 20.1 (2007): 42-49.
Thiel, H. and A. Koslow, eds. Managing Risks to Biodiversity and the Environment on the High Sea, Including Tools Such as Marine Protected Areas- Scientific Requirements and Legal Aspects. 27 Feb 2001, Isle of Vilm, Germany. German Federal Agency for Nature Conservation, 2001. Print.
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