Benthic foraminifera extinctions in the Cenozoic record

In the late Pliocene-middle Pleistocene a group of 95 species of elongate, cylindrical, deep-sea (lower bathyal-abyssal) benthic foraminifera became extinct. This Extinction Group (Ext. Gp), belonging to three families (all the Stilostomellidae and Pleurostomellidae, some of the Nodosariidae), was a major component (20-70%) of deep-sea foraminiferal assemblages in the middle Cenozoic and subsequently declined in abundance and species richness before finally disappearing almost completely during the mid-Pleistocene Climatic Transition (MPT). So what caused these declines and extinction? In this study 127 Ext. Gp species are identified from eight Cenozoic bathyal and abyssal sequences in the North Atlantic and equatorial Pacific Oceans. Most species are long-ranging with 80% originating in the Eocene or earlier. The greatest abundance and diversity of the Ext. Gp was in the warm oceanic conditions of the middle Eocene-early Oligocene. The group was subjected to significant changes in the composition of the faunal dominants and slightly enhanced species turnover during and soon after the rapid Eocene-Oligocene cooling event. Declines in the relative abundance and flux of the Ext. Gp, together with enhanced species loss, occurred during middle-late Miocene cooling, particularly at abyssal sites. The overall number of Ext. Gp species present began declining earlier at mid abyssal depths (in middle Miocene) than at upper abyssal (in late Pliocene-early Pleistocene) and then lower bathyal depths (in MPT). By far the most significant Ext. Gp declines in abundance and species loss occurred during the more severe glacial stages of the late Pliocene-middle Pleistocene. Clearly, the decline and extinction of this group of deep-sea foraminifera was related to the function of their specialized apertures and the stepwise cooling of global climate and deep water. We infer that the apertural modifications may be related to the method of food collection or processing, and that the extinctions may have resulted from the decline or loss of their specific phytoplankton or prokaryote food source, that was more directly impacted than the foraminifera by the cooling temperatures.

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Cite this as

Hayward, Bruce William, Johnson, Katherine, Sabaa, Ashwaq T, Kawagata, Shungo, Thomas, Ellen (2010). Dataset: Benthic foraminifera extinctions in the Cenozoic record. https://doi.org/10.1594/PANGAEA.774877

DOI retrieved: 2010

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.774877
Author Hayward, Bruce William
Given Name Bruce William
Family Name Hayward
More Authors
Johnson, Katherine
Sabaa, Ashwaq T
Kawagata, Shungo
Thomas, Ellen
Source Creation 2010
Publication Year 2010
Resource Type application/zip - filename: Hayward_2010
Subject Areas
Name: Paleontology

Related Identifiers
Title: Cenozoic record of elongate, cylindrical, deep-sea benthic foraminifera in the North Atlantic and equatorial Pacific Oceans
Identifier: https://doi.org/10.1016/j.marmicro.2010.01.001
Type: DOI
Relation: IsSupplementTo
Year: 2010
Source: Marine Micropaleontology
Authors: Hayward Bruce William , Johnson Katherine , Sabaa Ashwaq T , Kawagata Shungo , Thomas Ellen .