This proposal seeks to reconstruct El Nino-Southern Oscillation (ENSO) variability during the Holocene (last 10,000 years) and Last Glacial Maximum, using the stable isotope geochemistry of individual fossil planktonic foraminifera. The PIs propose to utilize the intraspecific variability contained within populations of oxygen isotopic data derived from individual Globigerinoides ruber in sediment core intervals to develop indices of ENSO variance from a shallow equatorial core (V21-30) at the center of maximum ENSO anomalies in the east Pacific. The research will build on recent work by the PI (Koutavas et al., 2006) which demonstrated that the intra-sample d18O variance of G. ruber individuals monitors seasonal and ENSO-driven variability in sea surface temperature (SST) and salinity. The PI's propose to generate a continuous Holocene record of oxygen isotope variance based on individual G. ruber (2,500 analyses) and to constrain ENSO variance during the Last Glacial Maximum with the same method (500 analyses). These data will be used to enhance our understanding of ENSO dynamics, a phenomenon of global environmental relevance. Broader impacts include support of a new Assistant Professor/PI (Koutavas) and a graduate student and undergraduate students.
