"Everything is everywhere. The environment selects."

One thing that puzzled me was, how do microbes always seem to show up in extreme environments ready to carpe diem? When new hydrothermal vents open on the cold, dark, ocean floor, where do the hyperthermophiles come from? Are they floating in some dormant state waiting for a gush of boiling sulfuric acid to wake them up or are they already down in plumbing systems below the seafloor in the crust and do they just happen to be ejected through new vents? What about the bacteria, archaea, and fungi colonizing the Titanic? How did they find the Titanic when it took us more than 70 years using secret navy technologies? Were the iron-loving microbes already at work on the new steel before the ship set sail? Were they already present in the ocean scratching out a meager existence from molecules in the bottom sediments? [Charles] Pellegrino pondered whether microbes from the toilets on the Titanic and the throats of passengers survived and mingled. When I posed the question to [Roy] Cullimore he quoted Dutch microbiologist Baas Becking:

"Everything is everywhere. The environment selects."

--from Tim Friend's book The Third Domain: The Untold Story of Archaea and the Future of Biotechnology