Calcification patterns of the coccolithophore Coccolithus braarudii (Haptophyta), from the late Quaternary to present in the Southern Ocean

• Main Author: Cubillos, JC
• Format: Thesis
• Language: English
• Published: 2013
• Subjects: Coccolithus; Weight Index; Southern Ocean; Quaternary; Ocean acidification; calcification; South Tasman Rise
• Online Access: https://eprints.utas.edu.au/17498/; https://eprints.utas.edu.au/17498/1/front-Cubillos_Castillo_thesis.pdf; https://eprints.utas.edu.au/17498/2/Whole-exc-pub-mat-Cubillos_Castillo-thesis.pdf; https://eprints.utas.edu.au/17498/3/Whole-inc-pub-mat-Cubillos_Castillo-_thesis.pdf

Ocean acidification, caused by a decrease in pH due to elevated anthropogenic CO2 input from the atmosphere into the ocean, is the focus of intense current research with regard to biological impacts. Allegedly, the most affected species will be those that produce hard calcite and aragonite shells. In the present study, we assessed calcification and morphometry of the large-sized, heavily calcified coccolithophore genus Coccolithus, in the Southern Ocean, south of Tasmania. Firstly, we characterised the species, past and present, in the Southern Ocean using the following source materials: fossil core-top material from Core GC07 (South Tasman Rise); recent sediment trap samples collected during Sept 2003 - Feb 2004 from the Subantarctic Zone (SAZ) south of the subtropical front (STF); and two newly isolated culture strains from coastal Tasmania. Results showed that only a single taxon , designated Coccolithus braarudii [(Gaarder, 1962) Baumann et al., 2003] sensu Geisen et al. (2002) and Young et al., (2003), was consistently present in the Southern Ocean, with coccolith length ranging from 10-16 μm and consistent presence of a central bar across the central area.