NOAA/WDS Paleoclimatology - Ortiz et al 1996 Northeast Pacific Modern Planktonic Foraminifera Isotope Data

We assess the utility of four species of living planktonic foraminifera as tracers of thermocline and intermediate water masses in the northern Pacific Ocean, based on their water-column distribution and shell isotopic composition. Assuming oxygen isotopic equilibria with the water column, we infer apparent calcification depths. This allows an estimate of apparent carbon isotopic disequilibria. We then relax the assumption of oxygen isotopic equilibrium to examine habitat effects on kinetic disequilibrium processes. In the California Current, left-coiling Neogloboquadrina pachyderma and Globigerina calida calcify in the upper thermocline. Globorotalia scitula resides within the Shallow Salinity Minumum (potential density σ θ = 25.1–26.7), while Globoquadrina hexagona is associated with the deeper, North Pacific Intermediate Water (σ θ = 26.7–26.9). Apparent carbon isotopic disequilibria corrected for oxygen isotopic disequilibria, range from 1.0–1.9‰ in these asymbiotic species. The carbon isotopic disequilibrium can be modeled as a single exponential function of temperature or a logarithmic function of potential food supply. We infer that carbon isotopic disequilibrium increases with metabolic rate, related to temperature and/or food supply. Kinetic processes of oxygen and carbon isotopic disequilibria yields reasonable depth habitats if the slope of the oxygen:carbon isotopic shift is about 0.35, consistent with culture data. Our finding of a link between environment, metabolism, and isotopic disequilibrium observed in oceanic settings suggests the potential to better reconstruct the structure and biological processes of the upper water column from geologic data.

本归档古气候学（Paleoclimatology）研究数据集可由美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration，NOAA）下属的国家环境信息中心（National Centers for Environmental Information，NCEI）提供，该数据集隶属于古气候学世界数据服务（World Data Service，WDS）。该研究对应的NCEI研究类型为古海洋学（Paleoceanography）。本数据集包含仪器观测相关参数，地理覆盖范围为北太平洋。时间覆盖区间为距今（Before Present，BP）前60至50日历年。请查阅元数据以获取参数及研究点位的详细信息。使用本数据集时，请引用本研究。