'Clumps' of opportunities for cutting edge science
The Division of Marine Geology and Geophysics at the University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science has kicked off the fall semester with the inauguration of sophisticated equipment that will help scientists study stable isotopes in a new manner. Stable isotopes are used by biogeochemists to help establish climate patterns from hundreds of thousands of years ago, using small organisms found in sediment cores.
Using a grant from the National Science Foundation and matching funds from UM, the Stable Isotope and Comparative Sedimentology Laboratories teamed up to purchase two new stable isotope mass spectrometers and associated preparation equipment, valued at more than $800,000.
"One of these mass spectrometers will enable our Stable Isotope Laboratory to be one of only a handful of laboratories in the world in which 'clumping,' a new way of analyzing isotopic compositions, is performed," said Dr. Peter Swart, UM professor and director of the Stable Isotope Laboratory that has been in existence since 1986.
Known as the 'clumped isotope' technique, this method relies of measuring the clumping of two rare isotopes of carbon dioxide given off during the dissolution of calcium carbonate by acid. Scientists then measure the abundance of mass 47, which is mainly 13C18O16O and compare this to a predicted composition. The difference between the two amounts is a direct measurement of temperature.
Traditional isotopic analyses of oxygen provided an estimate of both the temperature and the salinity of the water from which minerals and organisms formed. Hence it was impossible with only one measurement to know whether the salinity or the temperature of the original environment was fluctuating. The new method provides a way of measuring temperature only. One application might be to understand the magnitude of tropical temperature change during the last ice age. Conventional isotope methods cannot distinguish salinity and temperature, but the new method can.
"This is the most exciting technique to come along in the field of stable isotopes since the 1950's. It will revolutionize the use of stable isotopes to unravel geological processes. The determination of past temperature during the ice ages is an obvious example, but less apparent applications involve determining whether dinosaurs were warm or cold blooded, the origins of CO2 in the atmosphere, or the cementation history of carbonate rocks," concluded Swart.
At the present time UM is one of about ten laboratories worldwide which is routinely making these measurements.
Provided by University of Miami
