Scientific News  Biology To unknown science animals and plants RESEARCH FINDS LIFE 1000 FEET BENEATH OCEAN FLOOR
RESEARCH FINDS LIFE 1000 FEET BENEATH OCEAN
FLOOR
A new study has discovered an abundance of
microbial life deep beneath the ocean floor in ancient basalt that forms part of
the Earth's crust, in research that once more expands the realm of seemingly
hostile or remote environments in which living organisms can apparently thrive.
The research was done off the coast of Oregon
near a sea-floor spreading center on the Juan de Fuca Ridge, by scientists from
Oregon State University and several other institutions. It will be published
Friday in the journal Science.
In 3.5 million-year-old crust almost 1,000 feet
beneath the bottom of the ocean, researchers found moderately hot water moving
through the heavily-fractured basalt. The water was depleted in sulfate and
greatly enriched with ammonium, suggesting biological activity in a
high-pressure, undersea location far from the types of carbon or energy sources
upon which most life on Earth is based. It was one of the most precise
biological samplings ever taken from deep under the ocean floor, scientists say.
"This is one of the best views we've ever
had of this difficult-to-reach location in the Earth's crust and the life forms
that live in it," said Michael Rappe, a research associate at OSU. "Until
now we knew practically nothing about the biology of areas such as this, but we
found about the same amount of bacteria in that water as you might find in
surrounding seawater in the ocean. It was abundant."
According to Steve Giovannoni, an OSU professor
of microbiology and one of the co-authors of the publication, the work
represented a highly complicated "plumbing job," among other things.
It took advantage of an existing hole and pipe casing that had been drilled
previously in that area by the Ocean Drilling Program, through about 825 feet of
sedimentary deposits on the ocean floor and another 175 feet of basalt, or
hardened lava about 3.5 million years old.
Using the existing casing, scientists were able
to fit an experimental seal and deliver to the seafloor, for testing and
characterization, the crustal fluids from far below.
"People have wondered for a long time what
types of organisms might live within Earth's crust," Giovannoni said.
"This has given us one of the best looks we've ever had at that environment."
The researchers found organisms growing without
the need to consume organic molecules, as does most life on Earth. Instead, they
processed carbon dioxide and inorganic molecules such as sulfide or hydrogen.
DNA analysis of these microbes suggested they are closely related to known
sulfate and nitrate "reducers" that are common in other environments.
The level of biological activity was sufficiently high that ammonia levels in
the subsurface samples were 142 times higher than those in nearby seawater.
"As more research such as this is done,
we'll probably continue to be surprised at just how far down we can find life
within the Earth, and the many different environments under which it's able to
exist," Rappe said.
The deep ocean crust, the researchers said, is an
immense biosphere in its own right that covers most of the Earth.
###
Contact:
Source of the given news and the copyrights
belong to a Oregon
State University
Publishing date: January 15, 2003
Back
| 
