“The past is the key to the present” is a mantra that all geologists are familiar with, and it’s why we do what we do! In the paleoclimatology lab at RSMAS (aka “Club Mud”), researchers use marine sediments to reconstruct past climate changes. Understanding the natural rhythms, cycles, and perturbations of the climate cycle in the past can help us to better predict climate change in the future, and the potential added impact of human activities on future climate change.
Club Mud students have used the geochemistry of fossils and sediments in cores from the Tropical Atlantic (southern Caribbean) and Tropical Pacific (Gulf of Papua) to reconstruct changes in tropical sea surface temperature, sea level, and precipitation patterns for periods spanning hundreds of thousands of years. The tropics are a large source of heat and water vapor to the atmosphere, and so an important part of the global climate system to study. Of particular interest is the migration of the Intertropical Convergence Zone (ITCZ), a band of precipitation where the Northern hemisphere and Southern hemisphere trade winds converge. The ITCZ moves north and south across the equator on an annual basis, resulting in wet and dry seasons in the tropics. Longer-term shifts associated with cooling and warming climate trends can result in prolonged drought or flooding conditions that can affect human populations in equatorial countries.
Dr. Larry Peterson with the Avaatech XRF Core Scanner
One invaluable instrument that Club Mud researchers use to help understand changes in ITCZ position is an X-Ray Fluorescence Scanner, which was the second of its kind in the US. The XRF scanner obtains information about the chemical composition of sediment cores far more rapidly than conventional analysis would allow, and at up to sub-annual resolution. This instrument lets us study long archives that may have previously been too expensive or time-consuming to investigate. We can then use the data we get to investigate ITCZ migration over long time periods and a wide variety of climatic conditions, but at timescales that are relevant to human society. The more we know about the past, the better we can hope to predict the future.
-Kelly Gibson
Marine Geology & Geophysics student
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