Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.470 IF 3.470
  • IF 5-year value: 4.009 IF 5-year
    4.009
  • CiteScore value: 3.45 CiteScore
    3.45
  • SNIP value: 1.166 SNIP 1.166
  • IPP value: 3.28 IPP 3.28
  • SJR value: 1.929 SJR 1.929
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 64 Scimago H
    index 64
  • h5-index value: 43 h5-index 43
Discussion papers
https://doi.org/10.5194/cp-2019-84
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-2019-84
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 15 Jul 2019

Submitted as: research article | 15 Jul 2019

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Climate of the Past (CP).

Can morphological features of coccolithophores serve as a reliable proxy to reconstruct environmental conditions of the past?

Giulia Faucher1, Ulf Riebesell2, and Lennart Thomas Bach3 Giulia Faucher et al.
  • 1Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, Milano, 20133 Italia
  • 2Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24105, Germany
  • 3Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia

Abstract. Morphological changes in coccoliths, tiny calcite platelets covering the outer surface of coccolithophores, can be the result of physiological responses to environmental changes. Coccoliths recovered from sedimentary successions may therefore provide information on paleo-environmental conditions prevailing at the time when the coccolithophores were alive. To calibrate the biomineralization responses of ancient coccolithophore to climatic changes studies often compared the biological responses of living coccolithophore species with paleo-data from calcareous nannofossils. However, there is uncertainty whether the morphological responses of living coccolithophores are representative for those of the fossilized ancestors. To investigate this, we cultured four living coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica, Coccolithus pelagicus subsp. braarudii, and Pleurochrysis carterae) that have been evolutionarily distinct for millions of years, exposed them to changing environmental conditions (i.e. changing light intensity, Mg / Ca ratio, nutrient availability, temperature and carbonate chemistry) and evaluated their responses in coccolith morphology (i.e. size, length, width, malformation). The motivation for this study was that if the species show the same morphological response to changes in any of the tested abiotic environmental factors, then there is a reason to assume that this response is conserved over geological timescales and that coccolith morphology can serve as a paleo-proxy for that specific factor. In contrast with this concept, we found that the four species responded differently to changing light intensity, Mg / Ca ratio, nutrient availability and temperature in terms of coccolith morphology. The lack of a common response reveals the difficulties in using coccolith morphology as a proxy for paleo-environmental conditions. However, a common response was observed under changing seawater carbonate chemistry (i.e. rising CO2) which consistently induced malformations. This commonality provides some confidence that malformations found in the sedimentary record could be indicative for high CO2 levels.

Giulia Faucher et al.
Interactive discussion
Status: open (until 08 Dec 2019)
Status: open (until 08 Dec 2019)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Giulia Faucher et al.
Giulia Faucher et al.
Viewed  
Total article views: 634 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
571 60 3 634 23 3 6
  • HTML: 571
  • PDF: 60
  • XML: 3
  • Total: 634
  • Supplement: 23
  • BibTeX: 3
  • EndNote: 6
Views and downloads (calculated since 15 Jul 2019)
Cumulative views and downloads (calculated since 15 Jul 2019)
Viewed (geographical distribution)  
Total article views: 434 (including HTML, PDF, and XML) Thereof 432 with geography defined and 2 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 12 Nov 2019
Publications Copernicus
Download
Short summary
We designed 5 experiments choosing different coccolithophore species that have been evolutionarily distinct for millions of years. If all species showed the same morphological response to an environmental driver, this could be indicative of a response pattern which is conserved over geological timescales. We found an increase in the percentage of malformed coccoliths under altered CO2 that provides evidence that this response could be used as paleo-proxy for episodes of acute CO2 perturbations.
We designed 5 experiments choosing different coccolithophore species that have been...
Citation