Biogeographic response of marine plankton to Cenozoic environmental changes

Anshuman Swain; Adam Woodhouse; William F Fagan; Andrew J Fraass; Christopher M Lowery

doi:10.1038/s41586-024-07337-9

Biogeographic response of marine plankton to Cenozoic environmental changes

Nature. 2024 Apr 17. doi: 10.1038/s41586-024-07337-9. Online ahead of print.

Authors

Anshuman Swain^#^{1

2

3

4}, Adam Woodhouse^#^{5

6}, William F Fagan⁷, Andrew J Fraass⁸, Christopher M Lowery⁵

Affiliations

¹ Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA. anshumanswain@fas.harvard.edu.
² Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA. anshumanswain@fas.harvard.edu.
³ Department of Paleobiology, National Museum of Natural History, Washington, DC, USA. anshumanswain@fas.harvard.edu.
⁴ Department of Biology, University of Maryland, College Park, MD, USA. anshumanswain@fas.harvard.edu.
⁵ University of Texas Institute for Geophysics, University of Texas at Austin, Austin, TX, USA.
⁶ School of Earth Sciences, University of Bristol, Bristol, UK.
⁷ Department of Biology, University of Maryland, College Park, MD, USA.
⁸ School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada.

^# Contributed equally.

PMID: 38632405
DOI: 10.1038/s41586-024-07337-9

Abstract

In palaeontological studies, groups with consistent ecological and morphological traits across a clade's history (functional groups)¹ afford different perspectives on biodiversity dynamics than do species and genera^2,3, which are evolutionarily ephemeral. Here we analyse Triton, a global dataset of Cenozoic macroperforate planktonic foraminiferal occurrences⁴, to contextualize changes in latitudinal equitability gradients¹, functional diversity, palaeolatitudinal specialization and community equitability. We identify: global morphological communities becoming less specialized preceding the richness increase after the Cretaceous-Palaeogene extinction; ecological specialization during the Early Eocene Climatic Optimum, suggesting inhibitive equatorial temperatures during the peak of the Cenozoic hothouse; increased specialization due to circulation changes across the Eocene-Oligocene transition, preceding the loss of morphological diversity; changes in morphological specialization and richness about 19 million years ago, coeval with pelagic shark extinctions⁵; delayed onset of changing functional group richness and specialization between hemispheres during the mid-Miocene plankton diversification. The detailed nature of the Triton dataset permits a unique spatiotemporal view of Cenozoic pelagic macroevolution, in which global biogeographic responses of functional communities and richness are decoupled during Cenozoic climate events. The global response of functional groups to similar abiotic selection pressures may depend on the background climatic state (greenhouse or icehouse) to which a group is adapted.