HIGH-RESOLUTION OXYGEN AND CARBON ISOTOPE PROFILES IN LOBLOLLY PINE TREE RINGS AS A PROXY FOR HURRICANE RECONSTRUCTION ALONG THE EAST-COAST OF THE US

There is much debate about the relationship between hurricanes and climate change; specifically whether climate change causes hurricane frequency and/or intensity to increase. However, records of storm data prior to the 1900’s are fragmentary, allowing little comparison with modern records. The use of stable isotope geochemistry for tree-ring analysis has become more widely used in paleotempestology. While a majority of isotope research on tree rings investigates low-resolution δ¹⁸O values only, we explored ultra-high-resolution δ¹⁸O values as a hurricane proxy and, in addition, studied δ¹³C values as well. In this study, carbon and oxygen isotopes were analyzed from tree-rings of Loblolly Pine from coastal North Carolina. Rings formed during known hurricane years as well as rings formed during years with no hurricanes were subsampled (60 um slices) using a sliding microtome and alpha-cellulose was extracted. Profiles of carbon and oxygen isotopes in hurricane and non-hurricane years will be compared to evaluate the potential of high-resolution isotope measurements to detect short-lived (~weeks) climatic events occurring during the growing season of the tree. We expect hurricane years to show a lower oxygen isotopic signature because hurricane precipitation typically has low δ¹⁸O values. We also expect δ¹³C values to increase during hurricanes due to the storm surge. The increase in soil salinity should result in a closure of the stomata and an increase in the water-use efficiency. Determining the hurricane effects on carbon and oxygen isotopes will further the understanding of paleotempestology and its proxies.