A guide to extant coccolithophore taxonomy

Uptake of half of the fossil fuel CO2 into the ocean causes gradual seawater acidification. This has been shown to slow down calcification of major calcifying groups, such as corals, foraminifera, and coccolithophores. Here we show that two of the most productive marine calcifying species, the coccolithophores Coccolithus pelagicus and Calcidiscus leptoporus, do not follow the CO2-related calcification response previously found. In batch culture experiments, particulate inorganic carbon (PIC) of C. leptoporus changes with increasing CO2 concentration in a nonlinear relationship. A PIC optimum curve is obtained, with a maximum value at present-day surface ocean pCO2 levels (∼360 ppm CO2). With particulate organic carbon (POC) remaining constant over the range of CO2 concentrations, the PIC/POC ratio also shows an optimum curve. In the C. pelagicus cultures, neither PIC nor POC changes significantly over the CO2 range tested, yielding a stable PIC/POC ratio. Since growth rate in both species did not change with pCO2, POC and PIC production show the same pattern as POC and PIC. The two investigated species respond differently to changes in the seawater carbonate chemistry, highlighting the need to consider species-specific effects when evaluating whole ecosystem responses. Changes of calcification rate (PIC production) were highly correlated to changes in coccolith morphology. Since our experimental results suggest altered coccolith morphology (at least in the case of C. leptoporus) in the geological past, coccoliths originating from sedimentary records of periods with different CO2 levels were analyzed. Analysis of sediment samples was performed on six cores obtained from locations well above the lysocline and covering a range of latitudes throughout the Atlantic Ocean. Scanning electron micrograph analysis of coccolith morphologies did not reveal any evidence for significant numbers of incomplete or malformed coccoliths of C. pelagicus and C. leptoporus in last glacial maximum and Holocene sediments. The discrepancy between experimental and geological results might be explained by adaptation to changing carbonate chemistry.

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Species-specific responses of calcifying algae to changing seawater carbonate chemistry

Coccolith ultrastructure and biomineralisation

Genotypic variation in the coccolithophorid speciesEmiliania huxleyi

Geographic distribution of living and Holocene coccolithophores in the Mediterranean Sea

The descriptive terminology applicable to coccoliths and other calcareous nannofosils is reviewed and revised. A listing of about 400 terms is given with brief explanations and explanatory figures. General terms are given first, followed by terms for specific taxonomic groups. Appendices list terms we have not used and summarize terms, such as caneolith, which have been proposed for particular types of coccoliths.

Guidelines for coccolith and calcareous nannofossil terminology

Holococcolithophorids from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean

Distribution and malformation of extant calcareous nannoplankton in the Indonesian Seas

Five new species of the coccolithophorid genus Alisphaera (Haptophyta/Prymnesiophyta) are described from tropical to arctic waters: Alisphaera extenta Kleijne et al. sp. nov., Alisphaera pinnigera ...

Five new species of the coccolithophorid genus Alisphaera (Haptophyta), with notes on their distribution, coccolith structure and taxonomy

Flosculosphaera calceolariopsis gen. et sp. nov. and F. sacculus et sp. nov. (Prymnesio-phyceae) are described from subtropical N.E. Atlantic Ocean surface and subsurface water samples. Descriptions are based upon scanning electron microscope observations. The holococcolith-bearing species have coccoliths which are characterized by a short, hollow tube that flares out distally and forms a vaulted roof on one side of the coccolith rim. The distal opening may be partially occluded. These coccoliths, termed flosculoliths, represent a new type of holococcolith. The taxonomic positions of F. calceolariopsis and F. sacculus are considered, with reference to existing holococcolithophorid taxa.

Annelies Kleijne

Papers

Guidelines for coccolith and calcareous nannofossil terminology

Holococcolithophorids from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean

Distribution and malformation of extant calcareous nannoplankton in the Indonesian Seas

Five new species of the coccolithophorid genus Alisphaera (Haptophyta), with notes on their distribution, coccolith structure and taxonomy

Flosculosphaera calceolariopsis gen. et sp. nov. and F. sacculus sp. nov., new coccolithophorids (Prymnesiophyceae) from the N.E. Atlantic