Major shifts in calcareous phytoplankton assemblages through the Eocene-Oligocene transition of Tanzania and their implications for low-latitude primary production

Dunkley Jones, Tom, Bown, Paul R., Pearson, Paul Nicholas ORCID: https://orcid.org/0000-0003-4628-9818, Wade, Bridget S., Coxall, Helen Kathrine and Lear, Caroline Helen ORCID: https://orcid.org/0000-0002-7533-4430 2008. Major shifts in calcareous phytoplankton assemblages through the Eocene-Oligocene transition of Tanzania and their implications for low-latitude primary production. Paleoceanography 23 (4) , PA4204. 10.1029/2008PA001640

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Abstract

A high-resolution record of exceptionally well preserved calcareous nannofossil assemblages from Tanzania is marked by two key transitions closely related to the climatic events of the Eocene-Oligocene transition (EOT). The first transition, at ∼34.0 Ma, precedes the first positive shift in δ 18O and coincides with a distinct interval of very low nannofossil abundance and a cooling in sea surface temperatures (SST). The second, at ∼33.63 Ma, is immediately above the Eocene-Oligocene boundary (EOB) and is associated with a significant drop in nannofossil diversity. Both transitions involve significant reductions in the abundance of holococcoliths and other oligotrophic taxa. These changes in calcareous phytoplankton assemblages indicate (1) a widespread and significant perturbation to the low-latitude surface ocean closely tied to the EOB, (2) a potential role for reduced carbonate primary production at the onset of global cooling, and (3) a significant increase in nutrient availability in the low-latitude surface ocean through the EOT.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	G Geography. Anthropology. Recreation > GC Oceanography Q Science > QE Geology
Additional Information:	Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/1944-9186/ (accessed 20/02/2014).
Publisher:	American Geophysical Union
ISSN:	0883-8305
Date of First Compliant Deposit:	30 March 2016
Last Modified:	20 May 2023 18:31
URI:	https://orca.cardiff.ac.uk/id/eprint/10121

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