SCIENCE:
350 Degrees is Bathwater
to These Animals
By Stephen Leahy
PUERTO AYORA, Galapagos
Islands, Ecuador ,
(IPS) - Marine
scientists returned to
the Galapagos Islands
this week to celebrate a
discovery that Charles
Darwin never dreamt of:
bizarre animals that
live in total darkness
around active deep-sea
volcanoes.
Thirty years ago,
researchers found the
first chimney spewing
super-hot water --
called a hydrothermal
vent -- 2,500 metres
below the surface on the
sea floor, with its own
thriving plant and
animal community. That
life could prosper
without sunlight or
photosynthesis changed
forever the very
definition of what
constitutes "life" on
the Earth. And it opened
a new window on the
possibilities of life
elsewhere in the
universe.
After all, if a tiny
shrimp can live in total
darkness, under tonnes
of pressure in a toxic
chemical soup boiling
away at 350 degrees C,
why could not life take
hold on some distant
planetoid where
conditions might not be
so harsh?
"We knew right away this
was the biggest thing in
biology in the past
century," recalls Fred
Grassle of Rutgers
University in New
Jersey, who mounted the
first biological
expedition in 1977 to
the newly discovered
hydrothermal vents in
the Pacific Ocean about
350 kilometres from the
Galapagos Islands.
Grassle is a tall, large
man, stooped a little
from age and bending to
speak to those who are
shorter than he. Or
perhaps he has been
shaped by the many hours
crammed into tiny deep
sea submersibles like
the famous "Alvin", in
which the original
discovery was made.
"At the time it was
thought that the deep
oceans were devoid of
life and what little
life there might be
depended on food falling
from above," Grassle
told a small auditorium
filled with local school
children in Puerto Ayora
as part of public
celebration of the 30th
anniversary of the vent
discovery.
He showed them old
slides of skinny,
smiling scientists
intently working on
home-made pieces of
equipment so they could
explore an environment
as exotic and as
dangerous as outer
space.
While the children are
aware the Galapagos
Islands are famous for
their unique flora and
fauna, the deep sea
world off the coast of
their island home is as
fantastic a realm as the
moon. And as deep sea
scientists like Grassle
like to say: "We know
more about the surface
of the moon than the
deep sea."
Located 1,000 kms off
the west coast of
Ecuador, the Galapagos
is also a very active
volcanic region, sitting
atop a magma hot spot on
the Nazca tectonic
plate. In 1977, the
submersible "Alvin"
followed a trail of
white clamshells to a
small collection of
fissures in the planet's
surface emitting
super-heated cloudy
water dubbed "black
smokers". Although hot
enough to melt most
metals, the water
doesn't boil because of
the tremendous pressure
at such depths.
Covering an area not
much bigger than a
baseball diamond, it was
thought to be the only
one on the planet,
Grassle told IPS.
A series of
difficult-to-conduct
experiments eventually
proved that the amazing
creatures -- tube worms,
shrimps and others --
living beside these
vents use the chemical
energy emitted from the
vents to survive. The
key component in this
unique ecological system
is chemosynthetic
bacteria that often live
in symbiosis with the
resident animals such as
clams and tube worms.
These specialized
bacteria oxidise the
toxic hydrogen sulfide
coming from the vents,
providing nutrients for
animals higher up the
food chain. And in the
case of tubeworms, which
don't have mouths or
stomachs, the bacteria
reside inside, providing
needed organic compounds
in exchange for a
comfortable home.
These sulphur-loving
bacteria take the place
of photosynthesis that
provides life on the
rest of the planet, said
Grassle. They are
ancient, and some
scientists speculate
that they may have been
the first life forms on
Earth.
These discoveries
sparked an international
bloom of deep sea
research. Today, about
100 vent sites have been
found in the Pacific and
Atlantic oceans. They
are located along the
40,000-mile-long
mountain range that
zigzags up and down the
middle of the world's
ocean basins like a
giant zipper, said
Christopher German,
co-chair of InterRidge,
an international
nonprofit organisation
and ChEss (Biogeography
of Deep-Water
Chemosynthetic
Ecosystems).
The ridge marks the area
where the Earth's
tectonic plates spread
apart and new crust
forms from hot lava
rising from the mantle,
German told IPS.
"Wherever we look along
the ridge, we find
vents," he said, "and
the vents in different
regions of the ocean
host very different
animals," he said.
Roughly 550 vent species
have been discovered
living in extreme
temperature and pressure
conditions, and new vent
species are discovered
at a rate of nearly two
per month, said Ron
Tyler, co-chair of ChEss,
one of the 14 field
programmes of the Census
of Marine Life, a global
collaboration to
document the ocean's
life by 2010.
"Vent science has
dominated the field of
deep-sea biology in the
last 30 years," Tyler
said in a statement.
Future vent exploration
may be more
mineralogical than
biological as at least
two mining companies are
mapping vent sites
because of their
abundance in gold,
copper and other
valuable metals.
Technological advances
make it possible to mine
the ocean floor at great
depths, although any
such operations are
complex and costly. And
the ecological impacts
on the creatures that
inhabit the vents could
be catastrophic for
those at the mine site
and those "downstream"
from the resulting
plumes of sediments that
would be dredged up.
Mining may begin as soon
as 2009, says Cindy Van
Dover, director of Duke
University Marine Lab in
the United States.
Scientists will need to
be proactive in
developing careful
guidelines for
companies, including
making full ecological
assessments of the
proposed mining area,
she said.
However, the true wealth
of hydrothermal vents is
their enormous
biodiversity, according
to Grassle.
"They opened our eyes to
the possibilities of
where and under what
conditions life could
thrive," he said. "What
I've learned in the past
30 years is that small
organisms like bacteria
are under-appreciated."
And that this discovery
took place off the coast
where Darwin made one of
the biggest scientific
breakthrough in history
"is a nice coincidence",
he added with a small
smile.
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