CP, 12, 981–1007, 2016
Clim. Past, 12, 981–1007, 2016
https://doi.org/10.5194/cp-12-981-2016
Major perturbations in the global carbon cycle and photosymbiont-bearing planktic foraminifera during the early Eocene
Valeria Luciani1, Gerald R. Dickens2,3, Jan Backman2, Eliana Fornaciari4, Luca Giusberti4, Claudia Agnini4, and Roberta D'Onofrio1 Valeria Luciani et al. Valeria Luciani1, Gerald R. Dickens2,3, Jan Backman2, Eliana Fornaciari4, Luca Giusberti4, Claudia Agnini4, and Roberta D'Onofrio1
1Department of Physics and Earth Sciences, Ferrara University, Polo Scientifico Tecnologico, Via G. Saragat 1, 44100 Ferrara, Italy
2Department of Geological Sciences, Stockholm University, 10691 Stockholm, Sweden
3Department of Earth Science, Rice University, Houston, TX 77005, USA
4Department of Geosciences, Padova University, Via G. Gradenigo 6, 35131 Padova, Italy
Correspondence: Valeria Luciani (valeria.luciani@unife.it)
Received: 10 Feb 2015 – Discussion started: 16 Mar 2015 – Revised: 23 Mar 2016 – Accepted: 24 Mar 2016 – Published: 15 Apr 2016
Abstract. A marked switch in the abundance of the planktic foraminiferal genera Morozovella and Acarinina occurred at low-latitude sites near the start of the Early Eocene Climatic Optimum (EECO), a multi-million-year interval when Earth surface temperatures reached their Cenozoic maximum. Stable carbon and oxygen isotope data of bulk sediment are presented from across the EECO at two locations: Possagno in northeast Italy and Deep Sea Drilling Project (DSDP) Site 577 in the northwest Pacific. Relative abundances of planktic foraminifera are presented from these two locations, as well as from Ocean Drilling Program (ODP) Site 1051 in the northwest Atlantic. All three sections have good stratigraphic markers, and the δ13C records at each section can be correlated amongst each other and to δ13C records at other locations across the globe. These records show that a series of negative carbon isotope excursions (CIEs) occurred before, during and across the EECO, which is defined here as the interval between the J event and the base of Discoaster sublodoensis. Significant though ephemeral modifications in planktic foraminiferal assemblages coincide with some of the short-term CIEs, which were marked by increases in the relative abundance of Acarinina, similar to what happened across established hyperthermal events in Tethyan settings prior to the EECO. Most crucially, a temporal link exists between the onset of the EECO, carbon cycle changes during this time and the decline in Morozovella. Possible causes are manifold and may include temperature effects on photosymbiont-bearing planktic foraminifera and changes in ocean chemistry.
Article (PDF, 19628 KB)
Article (19628 KB)
How to cite. Luciani, V., Dickens, G. R., Backman, J., Fornaciari, E., Giusberti, L., Agnini, C., and D'Onofrio, R.: Major perturbations in the global carbon cycle and photosymbiont-bearing planktic foraminifera during the early Eocene, Clim. Past, 12, 981–1007, https://doi.org/10.5194/cp-12-981-2016, 2016.
The symbiont-bearing planktic foraminiferal genera Morozovella and Acarinina were among the most important calcifiers of the early Paleogene tropical and subtropical oceans. However, a remarkable and permanent switch in the relative abundance of these genera happened in the early Eocene. We show that this switch occurred at low-latitude sites near the start of the Early Eocene Climatic Optimum (EECO), a multi-million-year interval when Earth surface temperatures reached their Cenozoic maximum.
The symbiont-bearing planktic foraminiferal genera Morozovella and Acarinina were among the most...