QUANTITATIVE BIOGEOGRAPHY OF BENTHIC FORAMINIFERA: LEVERAGING PAST DATA FOR FUTURE UNDERSTANDING (Invited Presentation)

Benthic foraminifera are powerful tools for understanding biotic responses to environmental change both in the modern and through the fossil record. We are actively building a global database of benthic foraminiferal occurrences that includes the relative abundances of species within surface-sediment and sediment-core samples to allow investigations of ecological structure alongside global biogeographic structure. Here, we present initial analyses of the modern biogeography of benthic foraminifera using occurrence data compiled by Culver and Buzas in Smithsonian Contributions and data syntheses from ongoing databasing of assemblages from the Pacific Ocean. In addition to site-based analyses examining assemblages as reported, we also use range-though assumptions constrained by both the geographic and bathymetric ranges of species to project species onto an equal-area spatial grid and examine spatial patterns in diversity and taxonomic dissimilarity. These analyses produce quantitative biogeographic units that highlight taxonomically distinct, high-diversity, regions and biogeographic boundaries along coastlines. Unlike other biogeographic province schemes, the biogeographic units for this dataset emerge without regard to ocean basin – assemblages of benthic foraminifera are often more similar between the Atlantic and the Pacific than they are to other biogeographic units in the same ocean basin. The latitudinal boundaries between biogeographic units are primarily controlled by taxonomic turnover and the nested component of faunal dissimilarity primarily aligns with water depth. We further explore the relationships between these spatial patterns and modern oceanographic variables and find relationships to both temperature and primary productivity. Ultimately, these investigations will allow us to calibrate foraminiferal faunal variation to key environmental variables and better use foraminiferal faunas to reconstruct paleoceanographic change through the Cenozoic fossil record.