Kaustubh Thirumalai Thomas M. Cronin Laura Gemery Elizabeth Thomas Patrick Rafter Maya Prabhakar 2024 <div id="141887958" class="article-section-wrapper js-article-section js-content-section " data-section-parent-id="0"><p>In this work, we utilize a transect of core top, mid- to late Holocene, sediments from the Eastern Siberian Sea to the central Arctic Ocean, spanning gradients in upper-ocean water column properties, to examine regional planktic foraminiferal species abundances and geochemistry. We present species- and morphotype-specific foraminiferal assemblages at these sites and stable isotope analyses of neogloboquadrinids. We find little variation in planktic species populations, and only small variations in<span>&nbsp;</span><i>N. pachyderma</i><span>&nbsp;</span>morphotype distributions, between sites. Spatial averages of<span>&nbsp;</span><i>N. pachyderma</i><span>&nbsp;</span>morphotype and<span>&nbsp;</span><i>N. incompta</i><span>&nbsp;</span>δ¹⁸O values show no significant differences, suggesting a similar calcification depth for all morphotypes of<span>&nbsp;</span><i>N. pachyderma</i><span>&nbsp;</span>and<span>&nbsp;</span><i>N. incompta</i><span>&nbsp;</span>across our sites, which we estimate to be between ∼ 50–150 m. Values of δ¹⁸O of a group of unencrusted specimens delineate a shallower calcification habitat.<span>&nbsp;</span><i>Neogloboquadrina pachyderma-2</i><span>&nbsp;</span>Mg/Ca values yield temperatures outside the range of observations using available calibration equations, pointing toward the need for more Arctic-specific Mg/Ca-temperature calibrations.</p></div> application/pdf 10.61551/gsjfr.54.1.1 en Cushman Foundation for Foraminiferal Research Morphotypical and geochemical variations of planktic foraminiferal species in Siberian and Central Arctic Ocean core tops article