Re: [compost_tea] Deep Under the Sea-New finds in Microbiology

From: David Loring <dloring3_at_cox.net>
Date: Tue, 9 Sep 2003 08:16:08 -0700


  ----- Original Message -----
  From: Tim Kiphart
  To: Compost Tea List Serve
  Sent: Tuesday, September 09, 2003 6:25 AM
  Subject: [compost_tea] Deep Under the Sea-New finds in Microbiology


  Thought some might be interested in this article from NY Times.
  Tim


  September 9, 2003
  Deep Under the Sea, Boiling Founts of Life Itself
  By WILLIAM J. BROAD



  What started as a hunch is now illuminating the origins of life.

  A few years back, Dr. Derek R. Lovley and colleagues at the University of
  Massachusetts found that a few kinds of bacteria used iron as a means of
  respiration (just as humans use oxygen to burn food) and that a surprisin=
g
  but common byproduct of this form of microbial breathing was magnetite, a
  hard black magnetic mineral.

  The scientists wondered if hidden swarms of microbes might account for th=
e
  vast deposits of magnetite that dot the earth and sea.

  So they turned to one of the strangest, most ancient of environments - th=
e
  deep sea's volcanic gashes, where mineral-rich waters hot enough to melt
  lead gush forth to nourish riots of life ranging from microbes to
  eight-foot-long tube worms. From the deep Pacific and other sites, the
  scientists obtained many samples of hot fluids.

  To their surprise, they found that all the heat-loving microbes, known as
  hyperthermophiles, could breathe iron and make magnetite. Not only that, =
but
  one type broke the high-temperature record, thriving at an astonishing 25=
0
  degrees - far above the boiling temperatures usually associated with
  sterilization. The alien organism was judged to be among the most primiti=
ve
  forms of life ever discovered.

  "It was a crapshoot," Dr. Lovley said of the hunt. "The surprising thing =
was
  that all the hyperthermophiles turned out to use iron."

  That discovery, he and other scientists say, suggests that all life on ea=
rth
  may have originated from a microbe that breathed iron - potentially a key
  insight to learning about the chemical pathways that eons ago led to the
  dawn of biologic evolution.

  In the quarter century since the discovery of the hydrothermal ("hot wate=
r")
  vents, scientists have found a world's worth of life: hundreds of unfamil=
iar
  species, new genera, new families and whole new orders. Together, they
  constitute major gains in measures of global biologic diversity, and they
  have gained a name: the dark biosphere.

  Today in Los Angeles, filmmakers, drawing on waves of such excitement, ar=
e
  releasing a big-screen movie that celebrates the vents.

  "It has been a passion for a number of us," said Dr. Richard A. Lutz, a
  Rutgers biologist who aided the film and the original discovery. "We've b=
een
  enamored by the vents ever since."

  The ocean floor was once thought to be a wasteland that possessed no ligh=
t,
  no heat, no plants and very little life, if any.

  That image shattered in 1977, when oceanographers working deep in the
  Pacific found bizarre ecosystems lush with clams, mussels and long tube
  worms.

  When brought to the surface, the creatures smelled of rotten eggs, a sign=
 of
  sulfur. It turned out that the ecosystem's main energy source was sulfur
  compounds emitted by the hot vents, in particular hydrogen sulfide. The
  primary producers (like plants on land) were tiny microbes thriving on
  volcanic heats and chemical energies rising from the earth's interior.

  The dark ecosystems forced scientists to conclude that not all life on ea=
rth
  depends on the sun's energy or on photosynthesis.

  As similar communities were found in the deep, intrigued scientists
  theorized that the vents were perhaps windows on a deep microbial world, =
a
  hidden biosphere extending for miles into the earth's crust, with a total
  mass rivaling or exceeding that of all surface life. Even stranger, they
  suggested that life on earth might have begun in such realms, nurtured by=
 a
  steady diet of hot chemicals.

  Since those frenetic early days, ocean scientists have found not only sco=
res
  of such deep oases but strong evidence that they do in fact represent the
  tip of a very old, very large ecosystem. Recent papers report censuses of
  the tribe's most fundamental members - microbes.

  "We find bugs pretty much everywhere we look," said Dr. John A. Baross, a
  biologist at the University of Washington who studies hyperthermophiles a=
nd
  used a deep-sea robot to retrieve the water sample containing superhot
  organism.

  Much of the exploration focuses on the West Coast - offshore from Califor=
nia
  to Canada - because a long volcanic gash fairly close to shore makes
  scientific visits there relatively easy. The National Science Foundation =
has
  financed much of the work, along with the National Oceanic and Atmospheri=
c
  Administration.

  Five years ago, in a first, scientists off Vancouver Island raised from t=
he
  depths parts of four rocky vent chimneys, two dead and two live ones spew=
ing
  hot smoke rich in chemicals and microbes. Dark and rough, they were up to
  seven feet tall and weighed up to two tons, the hot ones teeming with wor=
ms,
  sea spiders and limpets.

  In the June issue of Applied and Environmental Microbiology, the scientis=
ts,
  including Dr. Baross as well as Matthew O. Schrenk, Dr. Deborah S. Kelley
  and Dr. John R. Delaney, all of the University of Washington, reported th=
e
  dissection of a chimney that had been venting fluids of 575 degrees. Desp=
ite
  the temperature, it was riddled with signs of life.

  "Direct microscopic observation indicated that micro-organisms were attac=
hed
  to mineral surfaces throughout the structure," they wrote, adding that th=
e
  discovery suggested that further research would expand "the known upper
  temperature limits of life."

  A different census focused on a volcanic gash off Oregon that erupted in
  1998, 1999 and 2000, the outbursts monitored by undersea microphones. Eac=
h
  time, the scientists took samples more than a mile down. Such eruptions a=
re
  windfalls for biologists since not only molten rock but large volumes of
  hot, microbe-rich water spew forth. The huge clouds of life - thought to
  originate deep within the cracks, fissures and pores of the rocky seabed =
-
  allow experts to glimpse a normally invisible world.

  Julie A. Huber, Dr. David A. Butterfield and Dr. Baross, all of the
  University of Washington, reported their census of microbes up to third o=
f a
  mile down in the April issue of Microbiology Ecology, published by the
  Federation of European Microbiological Societies.

  They said that even at the greatest depths, under crushing pressures, the
  rocky seabed was composed of about 30 percent open pores, giving it plent=
y
  of living space for diminutive organisms.

  The scientists zeroed in on the raw genetic material of the collected
  microbes, thus finding more than methods of culturing them with special
  foods could ever discern. (The science of what hyperthermophiles like to =
eat
  and breathe is still young.)

  To the scientists' surprise, they found a huge diversity of organisms who=
se
  composition swung wildly over time. The 1998 eruption produced 35 species=
 of
  bacteria, compared with 37 and 57 from 1999 and 2000.

  But the numbers of archaea - ancient organisms often found in hot places
  like those thought to exist on the ancient earth - went in the opposite
  direction, declining from 63 to 60 to 52, according to paper by the same
  authors in the April 2002 issue of Applied and Environmental Microbiology=
.

  The reason behind the swings is still murky. "We're straining to understa=
nd
  better how these systems work," Dr. Baross said in an interview. "It's a
  very complicated puzzle. Until a couple of years ago, we had no pieces. N=
ow,
  to some extent, we're starting to put the puzzle together."

  Three years ago, scientists told of finding fossil microbes that lived ne=
ar
  vents formed 3.2 billion years ago, confirming that hyperthermophiles wer=
e
  among earth's earliest inhabitants. That discovery has quickened the sear=
ch
  for descendants of primordial vent life.

  Biologists say the recent discovery of the extremely high-temperature,
  iron-breathing organism by the University of Massachusetts scientists, wh=
o
  included Dr. Kazem Kashefi, suggests that the dark biosphere runs deeper =
and
  hotter than previously documented. And sulfur, they add, may turn out to
  play a smaller role than previously believed. The iron finding is reporte=
d
  in the Aug. 15 issue of Science.

  Dr. Lovley and Dr. Kashefi are betting that the common metal (the earth's
  most abundant element) will prove important. Its transformations, they
  wrote, "may have been the first form of microbial respiration as life
  evolved on a hot, early earth."


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Received on Tue Sep 09 2003 - 12:51:17 EDT

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