Denver, Colo. -- Human alteration of major waterways may cause more problems than drought downstream, according to a Penn State geologist who is studying circulation models of the ancient oceans.
"We have already seen some of the consequences of changing surface waterways," says Karen L. Bice, graduate student in geosciences. "The Colorado River barely flows to the ocean and the Aral Sea is drying up. We do have the capacity to alter the amounts of freshwater that run off into the oceans and that could alter ocean circulation patterns."
Bice, Dr. Eric J. Barron, professor of geosciences and director of Penn State's Earth System Science Center, and William H. Peterson, Earth System Science Center, are using a supercomputer-based General Circulation Model to look at the effects of continental runoff on ocean circulation patterns in the early Eocene about 55 million years ago when the Earth was substantially warmer than it is now.
The geography of the Eocene was different. The Tibetan plateau had not formed, India was the fastest moving continent and there was a large seaway in the subtropical middle latitudes called the Tethys Sea.
"What we found is that during the early Eocene, the oceans' deep water formation patterns may have been sensitive to variations in continental runoff," Bice told attendees today (Oct. 29) at the annual meeting of the Geological Society of America in Denver.
Researchers using the general circulation models have not previously considered continental runoff.
The reason that continental runoff can change ocean circulation patterns
is that the fresh water running out of continental rivers decreases the
salinity of the oceans' surface. Natural evaporation in the Tethys sea
tended to increase the salinity of the surface water. Circulation in the
oceans can be caused by colder water sinking below warmer water or saltier,
denser water sinkin
Contact: A'ndrea Elyse Messer