Anomalous shifts in tropical Pacific planktonic and benthic foraminiferal test size during the Paleocene-Eocene thermal maximum

Kunio Kaiho, Kotaro Takeda, Maria Rose Petrizzo, James C. Zachos

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Paleocene-Eocene warming and changes in oceanic hydrography should have significantly impacted the ecology of marine microorganisms, both at the surface and on the seafloor. We analyzed several key characteristics of foraminifera from two Shatsky Rise (ODP Leg 198) cores spanning the P/E boundary including the maximum test diameters of the largest calcareous trochospiral benthic foraminifera and largest shallow-dwelling planktonic foraminifera, and the stable carbon and oxygen isotope ratios of benthic foraminifera and bulk samples. We also qualitatively constrained changes in bottom water dissolved oxygen concentrations by quantifying changes in benthic species abundances. We find warming synchronous with an unusual increase in the size of surface-water planktonic in contrast to deep-water benthic foraminifera which decrease in size. We suggest that a decline in bottom water dissolved oxygen is the primary mechanism responsible for the size reduction of Pacific deep-sea benthic foraminifera, whereas the contemporaneous size increase of surface-water planktonic foraminifera is attributed to an increase in thermal stratification and decrease in local nutrient supply.

Original languageEnglish
Pages (from-to)456-464
Number of pages9
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume237
Issue number2-4
DOIs
Publication statusPublished - 2006 Aug 4

Keywords

  • Benthic foraminifera
  • Dissolved oxygen
  • Eocene
  • Nutrient
  • Paleocene
  • Planktonic foraminifera
  • Size
  • Stable isotope

ASJC Scopus subject areas

  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes
  • Palaeontology

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