Embargoed until 2 p.m. EST
NSF PR 01-05 - January 24, 2001
Media contact:
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Program contacts:
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Phil Taylor
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prtaylor@nsf.gov
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Don Rice
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New Group of Microorganisms Discovered in the Open
Sea
Archaea, one of three separate domains of life on our
planet, were undiscovered until 1970. Since then,
they had been found mostly in extreme environments
such as high-temperature volcanic vents on the ocean
floor, continental hot springs and fumeroles, and
highly salty or acidic waters. Now, scientists funded
by the National Science Foundation (NSF) have found
unexpected, astounding numbers of archaea living in
Earth's largest biome, the open sea.
The researchers--David Karl and Markus Karner of the
University of Hawaii, and Edward DeLong of the Monterey
Bay Aquarium Research Institute--have published a
paper in this week's issue of the journal Nature
on their discovery: "Archaeal dominance in the mesopelagic
zone of the Pacific Ocean." The concentration of archaea
in their study leads the scientists to conclude that
archaea are "a large percentage of the biomass of
the open ocean," says Karl. "These organisms could
make up 50 percent of life in the open sea." The research
is the first to note their numerical abundance.
"This remarkable new insight will have a major impact
on our view of how the oceans function ecologically,
"says Phil Taylor, director of NSF's biological oceanography
program, which, along with NSF's chemical oceanography
program, funded the research. "We are compelled by
this discovery to increase our efforts to understand
the diversity of life in the oceans, and the specific
roles that important species and groups play in the
sea."
The research is part of the Hawaii Ocean Time-series
(HOT) project, an NSF-sponsored study of the north
Pacific Ocean. Monthly sampling was conducted throughout
the water column, from the surface to 4,750 meters
deep. Two specific archaeal groups--pelagic euryarchaeota
and pelagic crenarchaeota--were found in high numbers
in the samples.
In the past, archaea were known as archaebacteria,
but it has since been found that they are fundamentally
distinct from true bacteria. Very little is known
about these life forms. According to Karl, they were
only discovered because of "their unusual genetic
and molecular structures." Marine scientists have
yet to understand how archaea take in nutrients, multiply,
or what ecological role they play.
The habitat range for these archaea, the Nature
paper authors note, is unusually broad. "As a dominant
component of the ocean, archaea are thus far from
confined to extreme niche habitats," they write. "Rather,
the distribution of these archaea suggests that a
common adaptive strategy has allowed them to radiate
throughout nearly the entire water column."
The discovery of these numbers of a group of microorganisms
living in a previously unsampled area "points out
the basic ignorance we have of the planet we live
on," maintains Karl. This research, he says, further
reveals the need for a reclassification of the characteristics
of the archaea kingdom.
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