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CSIRO
Team Brings Back Deep Ocean Life Sample Bismarck Sea - May 9,
2000 - A huge undersea chimney, laced with gold and other minerals
and swarming with remarkable lifeforms has been recovered from
the seabed in the Bismarck Sea, north of Papua New Guinea, by
the CSIRO Research Vessel Franklin. The find is part of a voyage
of discovery by the RV Franklin to probe the mysteries of vast
hydrothermal systems on the ocean floor, spewing out plumes of
superheated mineral-rich fluids like those which formed giant
ore bodies like Mt Isa and Broken Hill over a billion years ago.
As well as studying ore-forming processes, the researchers are
hunting for "extremophile" microbes endowed with the natural ability
to process minerals at high temperature. Their aim is to help
make Australia's $37 billion mineral export industry cleaner,
greener, safer and more competitive. Their search is being conducted
in an eerie landscape nearly two kilometres below the surface
of the ocean. Smoking undersea chimneys pump mineral fluids from
deep in the earth's crust into the surrounding seawater, shattered
mineral columns resemble ancient ruins, and undersea hills are
mantled in snow-white carpets of bacteria and organic hydrates
- compounds which can only exist at the extreme pressures of the
deep ocean. During the search, Franklin's dredge snagged the huge
chimney of a black smoker, a tubular encrustation of minerals
that would make a prized museum display, according to expedition
leader Dr Ray Binns, of CSIRO Exploration & Mining. "Our dredge
must have fallen right over its top. This anchored the ship for
over an hour but it finally broke off at the base," he says. "Luckily
for us it got wedged into the dredge frame on its point of balance,
so it stayed there while we winched it all the way up to the ship.
It proved to be 2.7 metres long, 80 cm in diameter at the base,
and weighed some 800 kg in water at least, closer to a tonne in
air. "It must have been an actively venting chimney, for live
snails dropped into the dredge bag, and fluid dripping from it
was quite acidic, although there was no characteristic smell of
rotten eggs (from hydrogen sulfide gas) often found with smaller
chimneys. "Our first examination indicated it was teeming with
bacteria and archaea (very ancient and primitive life forms).
The microbiologists aboard were delighted," Dr Binns says A major
goal of the expedition is to identify particular microbes that
can be used to process minerals on dry land, and so develop more
efficient and cleaner ways to win metals, explains project designer
Dr Dave Dekker of CSIRO Exploration & Mining. "We believe that
microbes such as these deep sea bugs may enable Australia's miners
to exploit lower grade ore deposits, extract metals more cheaply,
clean up waste streams and may even improve mine safety." Microbiologist
Dr Peter Franzmann of CSIRO Land & Water says that the mineral-mining
bugs are possibly relatives of some of the earliest forms of life
to emerge on the planet, more than three billion years ago. "Back
then, conditions were similar to what we now see in these seafloor
hydrothermal vents - high temperatures, lots of volcanic activity,
darkness, with the nutrients to sustain life pouring out of the
earth itself." Dr Binns says the recovered chimney is "a particularly
handsome specimen, but rather fragile, consisting mainly of the
mineral known as sphalerite (zinc sulfide)". "The Franklin's crew
managed to slide it out of the yoke without breaking it using
the ship's crane. For the time being we've got it swathed in cheesecloth
provided by the ship's cook, kept damp with seawater and wrapped
with plastic". The RV Franklin berthed in Rabaul last Thursday
(4 May) and is now moving from the Bismarck Sea into the Pacific
with another research team. Led by Dr Brent McInnes of CSIRO Exploration
& Mining, scientists from Australia, Papua New Guinea, New Zealand
and USA are visiting submarine volcanoes in the Tabar-Lihir-Tanga-Feni
and Solomon Island chains. Besides studying the volcanoes themselves,
this team is also searching for undersea hot-springs that might
be depositing gold and other minerals. The chances of finding
such springs are good, for the nearby Ladolam deposit on the island
of Lihir is the largest and youngest epithermal gold deposit in
the world. The geological setting of the volcanoes targeted by
the second cruise is different from those of the Bismarck Sea,
so any further discoveries will expand the range of modern ore-forming
environments that scientists can use to understand how ore bodies
formed in the past. The outcomes will include better strategies
for future mineral exploration on land, which is becoming harder
all the time, now that prospectors have found most of the ore
bodies that crop out at the surface
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