Our new study tests whether Mg/Ca ratios measured with laser-induced breakdown spectroscopy (LIBS) can reveal when Indigenous communities in ancient Tampa Bay, Florida, harvested their oysters. Working with 20 archaeological eastern oysters (Crassostrea virginica) from shell mounds and middens in Bishop Harbor, we compared rapid LIBS elemental maps with traditional oxygen isotope (δ18O) analysis of the same shells.
Alexandria Marie Firenzi is a doctoral researcher at the University of Nevada, Reno (UNR; Reno, Nevada, USA). Her work focuses on reconstructing past sea-surface temperature and salinity variability along the northeastern Pacific coast of North America, with particular attention to the El Niño-Southern Oscillation and coastal current dynamics within the Southern California Bight. She visited our lab and is keen to share some data!
Our new study delivers the most extensive calibration to date of Patella caerulea (the Mediterranean limpet) as a recorder of sea surface temperatures (SSTs) across the Central and Eastern Mediterranean. The study combined laser-induced breakdown spectroscopy (LIBS) for measuring Mg/Ca ratios with isotope ratio mass spectrometry (IRMS) to analyse oxygen isotope values (δ18O). By analysing 131 modern shells from 22 sites, we explored the relationship between magnesium-to-calcium (Mg/Ca) ratios and oxygen isotope values as palaeotemperature proxies.