The carbonate "clumped isotope" (∆47) paleothermometer is a new, rapidly developing tool for reconstructing past ocean temperatures. Unlike the δ18O paleothermometer, this emerging proxy approach can determine temperature without relying on assumptions about seawater δ18O. The proposed research will advance the development of the clumped isotope technique using modern marine sediments collected at varying depths and known temperatures in the Florida Straits. Led by an investigator at the University of New Hampshire, the project will undertake critical studies to determine whether the clumped isotope proxy is subject to "vital effects"; whether the ∆47-temperature relationship depends on carbonate mineralogy; and, through collaboration with researchers at Yale and Johns Hopkins Universities, whether apparent variations in the relationship may be explained by inter-laboratory differences. The results will reduce the uncertainty of the ∆47-temperature relationship and generate several species-specific clumped isotope proxy calibrations.
By refining the clumped isotope paleothermometer, this research has the potential to further our understanding of how ocean-climate conditions have changed in the past. In particular, a benthic foraminifer clumped isotope paleothermometer will allow reconstruction of deep water temperature, which is a high priority goal in the field because of its relevance for understanding changes in ice volume and thermohaline circulation through time. The project will provide support for an early-career female investigator as well as research opportunities for students at the graduate and undergraduate levels; in particular, the project will involve students from UNH's McNair Scholars Program, which encourages students from underrepresented groups to pursue doctoral degrees.
