Geology Reference
In-Depth Information
Few experimentalists of the 1950s considered the staggering complexities of natural geo-
chemical environments, altered as they are by daily cycles of night/day, hot/cold, wet/dry,
and more. Nor did they consider the range of natural gradients—in temperature, for ex-
ample,asvolcanicmagmacontactscoldoceanwater;orinsalinity,asafreshstreamenters
the salty ocean. And none of Miller's experiments incorporated rocks and minerals, chem-
ically diverse with dozens of major and minor elements, and their reactive energetic crys-
talline faces. Earth's sunlit surface, they assumed, was where all the action must have oc-
curred.
Miller's influence was strong, and he and his followers dominated the origins-of-life
community for more than three decades. A flood of publications ensued, new journals
arose, and honors and awards were bestowed, while government funding flowed to the
“Millerites.” Then in the late 1980s, the discovery of deep-sea black smoker ecosystems
gaverisetoaviablealternativeto“primordialsoup.”Inthosedeepdarkzones,farfromthe
sunlit ocean surface, mineral-rich fluids interact with hot volcanic crust to generate ocean-
floor geyserlike vents. Jets of scalding water contact the frigid deep ocean to create a con-
stant precipitation of minerals (the microscopic particles that produce the black “smoke”).
Life abounds in those astounding hidden places, fueled bythe chemical energyat the inter-
face between crust and ocean.
The battle over origins paradigms reveals a lot about the sociology of science. On the
one hand, the Miller-Urey process produced a suite of biomolecules stunningly similar to
what life actually uses. The mix of amino acids, carbohydrates, lipids, and bases almost
looks like a well-balanced diet. As Harold Urey quipped, “If God did not do it this way,
then He missed a good bet.” But the true believers of the Miller camp did more than just
supportthelightning-seededprimordialsoupidea;withavengeance,theypubliclyrejected
any and all competing ideas.
The effectiveness of the La Jolla cabal's obstructionism began to decline with the start-
ling discovery of those living black smokers described above, coupled with the powerful
influence and far-reaching ambitions of NASA. The existence of black smokers at under-
sea vents underscored a growing awareness that life abounds in extreme environments—in
placeswhereapreviousgenerationofbiologistswouldnothavelooked.Wenowknowthat
microbes thrive in acidic streams flowing from mine waste and boiling pools above vol-
canic zones. They eke out a living inside frozen Antarctic rocks, and they persist on strato-
spheric dust particles miles above Earth's surface. Vast microbial ecosystems miles below
Earth'ssolidsurface, wherecells liveinthenarrowest ofcracksandfissuresandsubsiston
the meager chemical energy of minerals, may well account for half of Earth's biomass—as
muchasallthetreesandelephantsandantsandpeoplecombined.Ifsuchextremophilelife
can thrive—if a significant fraction of Earth's life survives in deep environments protected
from the violent insults of asteroids and comets—why couldn't life have originated there?
