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Globoquadrina dehiscens is a species of planktic foraminifera which lived during the Miocene Epoch. While this species has an easily recognizable test, the paleoecology of G. dehiscens from prior studies indicate it has a variable position in the water column. One study placed G. dehiscens in the intermediate section of the water column, but this was based on limited sample size. Additionally, little work has been done on determining if and how G. dehiscences changes location in the water column throughout its life cycle. The purpose of this study is to establish the dwelling depth of Globoquadrina dehiscens and if that dwelling depth changed through its life cycle. This was accomplished through stable isotopic analyses (δ13C, δ18O) of fossil specimens in six different size fractions from samples that span the Miocene Climate Optimum at IODP Site U1510. By comparing the stable isotopic values of this species to those of known species who live in the mixed-layer and thermocline, it will be possible to determine where and how G. dehiscens lived and moved throughout the water column during its life cycle. Through this work it will be possible to determine if G. dehiscens can be reliably used to reconstruct Miocene ocean conditions. Understanding the location of an additional species that is common in the warm Miocene could help illustrate past ocean conditions that are used as analogues for future warming.



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Isotope Paleoecology of the Miocene Planktic Foraminifera Globoquadrina Dehiscens as Inferred from International Ocean Discovery Program Site U1510, Southwest Pacific