October 3, 2005
Crustaceans and Climate Change
Rosenstiel School researchers tap Little Salt Spring for climate change information
VIRGINIA KEY, FL– A new study recently published in the journal Palaeo links prehistoric climate and sea level changes at Little Salt Spring to human occupation on Florida’s west coast. A team of scientists from University of Miami’s Rosenstiel School of Marine & Atmospheric Science and Nova Southeastern University analyzed microscopic crustaceans, known as ostracods, to provide a complete, continuous record of the Spring necessary to reconstruct past climate conditions. This new study provides evidence indicating human occupation ceased because of diminished water quality suitable for human use.
“Prior to this study, the belief was that environmental changes provided new sources of freshwater in the Florida peninsula making Little Salt Spring less valuable to humans,” said Dr. John Gifford, associate professor of marine affairs and policy at the UM Rosenstiel School and principal investigator of the Little Salt Spring Archaeological Project. “This study provides new evidence that water quality, not quantity was the cause of human abandonment of the region.”
The authors, Gifford, Carlos A. Alvarez Zarikian, and Peter K. Swart from UM Rosenstiel School, and Patricia L. Blackwelder from Nova Southeastern University, concluded that deterioration of the water quality was due to the intrusion of mineralized water from the deeper, carbonate aquifers which was a result of sea level rise and fluctuations in rainfall patterns during that time.
They were able to reconstruct past weather conditions because of the unique anoxic environment in Little Salt Spring. The reconstruction of past weather conditions, like these at Little Salt Spring can possibly be used as a road map to understand Florida’s future environmental conditions, as well. This study provides further evidence that sea level and climate changes have affected where humans choose to live in Florida since prehistoric times.
Little Salt Spring is one of America’s most valuable archeological preserves, where extensive and well-preserved archeological materials have been carefully unearthed by scientists beginning in the 1970s revealing the origin of man in the hemisphere. The 240-foot deep, hourglass-shaped spring is fed from an underground source that has no dissolved oxygen in the water. Consequently, bacteria cannot grow and decompose wood and other organic materials, offering unique artifact preservation. Evidence uncovered at Little Salt Spring reveals human occupation and use in the region since the Late Pleistocene Age until about 5,000 years ago. Periods of human use in the region are linked to cooler climate conditions and lower relative sea level. Little Salt Spring provides an excellent source of past climate conditions because of its unique preservation qualities.
Ostracods, common inhabitants of aquatic environments including hot springs and caves, are beneficial for reconstructing past climate conditions because they are well preserved in the fossil record due to their unique body makeup of magnesium calcite. By analyzing these fossilized organisms scientists are able to document water temperature, salinity, and depth, important parameters to understanding past climate conditions.
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Rosenstiel School is part of the University of Miami and, since its founding in the 1940s, has grown into one of the world’s premier marine and atmospheric research institutions.
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Media Contact:
Annie Reisewitz
305-284-1601
a.reisewitz@miami.edu
