Microscopic plant and animal life is providing
scientists clues about the climate system that existed as long
as 10,000 years ago, David M. Anderson of NOAA‘s
National Geophysical Data
Center told attendees of the American
Geophysical Union‘s fall
meeting in San Francisco today.
"The variability of sea ice and fresh
water export from the Arctic via the East Greenland Current is
a fundamental aspect of the climate system, yet little is known
about how it varies from decade to decade or from one millennium
to the next," Anderson said. "We hypothesize that it
might be possible to reconstruct the presence of the East Greenland
Current from the stable isotope gradients recorded in foraminifers
– microscopic marine animals whose calcite skeletons are
preserved in seafloor sediments."
Initial calibration studies reveal that
both horizontal and vertical gradients in oxygen and carbon isotopes
are recorded in sediments, Anderson said. By determining the
composition of the sediments, scientists are able to reconstruct
ocean circulation patterns and produce a time series of change
much longer than the 100+ year
instrumental record of climate. The ultimate goal of this project
is to understand the ocean’s role in climate, and to determine
how the slowly changing aspects of our climate such as the Arctic
Oscillation and the thermohaline circulation could alter our
climate in the coming decades.
