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• 1 media/Blacksmoker_in_Atlantic_Ocean.jpg 2016-04-05T10:11:25+00:00 Black Smokers 20 image_header 2022-04-04T19:24:39+00:00 Arguably the most dramatic extreme environment on Earth is one we knew nothing about until 1977 when the submersible Alvin  discovered Black Smokers on the East Pacific Rise, a mid-oceanic ridge in the Pacific Ocean at a depth of 2.6 km.  Here, tectonic plates are separating at a rate of 7.5 cm/year. When plates separate, new oceanic crust (in the form of basaltic volcanism) is produced to fill that gap.  Abundant submarine volcanism means that there is a lot of very hot rock and molten lava at, or just beneath the ocean floor along mid-oceanic ridges.  Black smokers are hydrothermal vent openings on the sea floor, located generally approximately 2 km below the water surface, that emit very hot water that has been heated up by the hot rocks.  This superheated water (up to 400° C) is rich in dissolved minerals leached from the ocean floor. When the hot water is vented into the ocean, it suddenly cools and the dissolved minerals precipitate, appearing like a cloud of black smoke. When the superheated water comes in contact with the cold ocean water, it cools and sulfur-bearing minerals crystallize or precipitate out of solution and produce the solid structure that is called a “Black Smoker”.
  
  The real surprise was that the sites of Black Smokers were also home to thriving communities of life.  The basis for that life are extremophiles that convert the heat, methane, and sulfur compounds provided by black smokers into energy through a process called chemosynthesis.  
  
   
  
  This discovery had significant implications to theories on where life on Earth may have started.  Prior to that discovery, the scientific consensus was that life was originally powered by sunlight.  The most likely location for life to begin was thought to be some kind of shallow water setting.  But there were known problems with this idea. The early Earth was not a particularly stable setting as it would have been subject to frequent impacts.  But a deep oceanic setting would have been a more protected environment.  Hence, it has been suggested that deep sea vents were the site where life began. There is, in fact phylogenetic evidence, which, as stated above, we will not discuss, that suggests that thermophiles are in fact the last common ancestor of Archaea, Eukaryotes and Bacteria.  
   
  If you like the Science Guy (Bill Nye), you'll enjoy this 5 min clip discussing what we have outlined above.  If you don't, maybe the mention of giant red-blooded worms will peak your interest. 
  
  
  
  Please note that we still don’t know with certainty and there are a number of Abiogenesis or “Origin of life” theories, but the deep sea vent hypothesis is now favoured by many. The liquid oceans of the satellites of the outer planets are prime locations for the potential existence of these kinds of extremophiles.SaveSave