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June
20, 2007 ARCTIC
OCEAN HISTORY IS DECIPHERED BY
OCEAN-DRILLING RESEARCH Sediment
cores retrieved from the Arctic’s deep-sea floor by the
Integrated Ocean
Drilling Program’s Arctic Coring Expedition (ACEX) have
provided long-absent
data to scientists who report new findings in the June 21 issue of
Nature. A
team of ACEX researchers report that the Arctic Ocean changed from a
landlocked
body of water (a ‘lake stage’) through a poorly
oxygenated ‘estuarine sea’
phase to a fully oxygenated ocean at 17.5 million years ago during the
latter
part of the early Miocene era. The authors attribute the change in
Arctic
conditions to the evolution of the Fram Strait into a wider, deeper
passageway
that allowed an inflow of saline North Atlantic water into the Arctic
Ocean.
Scientists believe that the deep-water connection between the northern
Atlantic
and Arctic Oceans is a key driver of global ocean circulation patterns
and
global climate change. In
2004, the offshore ACEX research team cored a 428-meter thick sediment
sequence
from the crest of the Lomonosov ridge in the central Arctic Ocean, near
the
North Pole. These sediments provide the first geological validation of
the
Cenezoic paleoenvironmental history of the Arctic Ocean. Current
evidence of
the onset of the ventilated circulation system is preserved in the
chemical and
physical properties and the micropaleontology of the recovered seafloor
sediments. Co-chief
scientist Jan Backman, Stockholm University, comments on the
significance of
the new findings, saying, “If we can learn what has happened
in the geological
past, we can begin to use that knowledge to look into the future.
Scientists
engaged in climate change studies are advancing an important area of
knowledge
about the planet we live on.” ## Contact: This
text
derived from: Recommend this Article to a Friend Back to: News |
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