Geographical and seasonal differences in morphology and dynamics of the coccolithophore Calcidiscus leptoporus

Renaud, Sabrina; Ziveri, Patrizia; Broerse, Alexandra T.C.

doi:10.1016/s0377-8398(02)00081-6

Cited by 65 publications

(46 citation statements)

References 25 publications

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“…The considerable overlap in C L , ∅ and C N in Calcidiscus species makes species differentiation based solely on any one of these parameters difficult. However, the species-specific coccosphere geometry identified here lends further support to the genetic distinction between these species, alongside previously identified morphological and ecological differences (Knappertsbusch et al, 1997;Knappertsbusch, 2000;Geisen et al, 2002Geisen et al, , 2004Renaud et al, 2002;Sáez et al, 2003;Baumann et al, 2016).…”

Section: Within-species Range In Coccosphere Geometrysupporting

confidence: 85%

Physiology regulates the relationship between coccosphere geometry and growth phase in coccolithophores

et al. 2017

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Abstract. Coccolithophores are an abundant phytoplankton group that exhibit remarkable diversity in their biology, ecology and calcitic exoskeletons (coccospheres). Their extensive fossil record is a testament to their important biogeochemical role and is a valuable archive of biotic responses to environmental change stretching back over 200 million years. However, to realise the full potential of this archive for (palaeo-)biology and biogeochemistry requires an understanding of the physiological processes that underpin coccosphere architecture. Using culturing experiments on four modern coccolithophore species (Calcidiscus leptoporus, Calcidiscus quadriperforatus, Helicosphaera carteri and Coccolithus braarudii) from three long-lived families, we investigate how coccosphere architecture responds to shifts from exponential (rapid cell division) to stationary (slowed cell division) growth phases as cell physiology reacts to nutrient depletion. These experiments reveal statistical differences in coccosphere size and the number of coccoliths per cell between these two growth phases, specifically that cells in exponential-phase growth are typically smaller with fewer coccoliths, whereas cells experiencing growth-limiting nutrient depletion have larger coccosphere sizes and greater numbers of coccoliths per cell. Although the exact numbers are species-specific, these growth-phase shifts in coccosphere geometry demonstrate that the core physiological responses of cells to nutrient depletion result in increased coccosphere sizes and coccoliths per cell across four different coccolithophore families (Calcidiscaceae, Coccolithaceae, Isochrysidaceae and Helicosphaeraceae), a representative diversity of this phytoplankton group. Building on this, the direct comparison of coccosphere geometries in modern and fossil coccolithophores enables a proxy for growth phase to be developed that can be used to investigate growth responses to environmental change throughout their long evolutionary history. Our data also show that changes in growth rate and coccoliths per cell associated with growthphase shifts can substantially alter cellular calcite production. Coccosphere geometry is therefore a valuable tool for accessing growth information in the fossil record, providing unprecedented insights into the response of species to environmental change and the potential biogeochemical consequences.

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Section: Within-species Range In Coccosphere Geometrysupporting

confidence: 85%

Physiology regulates the relationship between coccosphere geometry and growth phase in coccolithophores

et al. 2017

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“…Together with the Gephyrocapsa-Emiliania plexus, Calcidiscus is probably the best documented coccolithophorid genus (Brand 1981;Knappertsbusch et al 1997, Knappertsbusch 2000Baumann and Sprengel 2000;Renaud and Klaas 2001;Renaud et al 2002;Quinn et al, 2003). Like the aforementioned genera it has a broad, inter-oceanic occurrence spanning a range of ecological variation and a very good, continuous fossil record through the last 23 Ma.…”

Section: Calcidiscus Spp (Plate 4)mentioning

confidence: 99%

“…Similarly, in modern Calcidiscus three morphotypes have been tentatively distinguished based on size variation and subtle morphological differences (Kleijne 1991(Kleijne , 1993Knappertsbusch et al 1997), but there has been uncertainty as to whether they intergrade or are discrete and hence whether they are ecophenotypes (Knappertsbusch 2000;Renaud and Klaas 2001). New data from plankton samples, life-cycle stages, culture studies and molecular genetic work all indicate that they in fact represent discrete species that probably diverged in the Middle Miocene (Geisen et al 2002;Renaud et al 2002;Sáez et al 2003;Quinn et al 2003). Similarly the Helicosphaera species, previously regarded as varieties of H. carteri, although only separated by slight morphological variation seem likely to have diverged in the Miocene, based on both geological record and molecular clock data.…”

Section: Synthesis Speciation and Divergences (Plate 7)mentioning

confidence: 99%

Species level variation in coccolithophores

et al. 2004

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Coccolithophores are an ideal test group for investigating fine-scale differentiation within the phytoplankton since their taxonomy is rather well-documented and their biomineralised periplasts -the coccoliths -provide a rich suite of qualitative and quantitative morphological characters and a uniquely extensive fossil record. In addition, extant coccolithophore species can be grown in culture and hence are available for studies of morphological variability under controlled conditions, molecular genetic studies and cytological research.For the CODENET project the following extant species with seemingly global occurrence and spanning the biodiversity of coccolithophores were selected: Coccolithus pelagicus, Calcidiscus leptoporus, Umbilicosphaera sibogae, Syracosphaera pulchra, Gephyrocapsa oceanica, and Helicosphaera carteri. These were used as case studies to elucidate their species level biodiversity. The key merit of our approach was the use of multiple, independent lines of evidence, so as to remove the ambiguity implicit in any one type of study. In each case morphotypes of previously uncertain significance have been shown to represent discrete genotypes and probably well-separated species, with divergence times ranging 314 Geisen et al. from about 100 kyrs to >10 myrs. The evolutionary significance of these results is discussed.

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“…Although sometimes placed in different families, C. braarudii (Coccolithaceae) and C. leptoporus (Calcidiscaceae) are closely related morphologically and genetically (Edvardsen et al 2000, and both are temperate coccolithophores (Sáez et al 2003). However, their ecology is still poorly understood, despite investigations into their distribution and ecological strategies through surveys such as those of Price et al (1998), Cachão & Moita (2000), Renaud & Klaas (2001), Beaufort & Heussner (2001) and Renaud et al (2002).…”

Section: Introductionmentioning

confidence: 99%

Ecology of oceanic coccolithophores. I. Nutritional preferences of the two stages in the life cycle of Coccolithus braarudii and Calcidiscus leptoporus

Houdan¹,

Probert²,

Zatylny³

et al. 2006

Aquat. Microb. Ecol.

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Coccolithus braarudii and Calcidiscus leptoporus are 2 coccolithophores (Prymnesiophyceae: Haptophyta) known to possess a complex heteromorphic life cycle, with alternation between a motile holococcolith-bearing haploid stage and a non-motile heterococcolith-bearing diploid stage. The ecological implications of this type of life cycle in coccolithophores are currently poorly known. The nutritional preferences of each stage of both species, and their growth response to conditions of turbulence were investigated by varying their growth conditions. Of the different culture media tested, only the synthetic seawater medium did not support the growth of both stages of C. braarudii and C. leptoporus. With natural seawater-based media, the growth rate of the haploid phase of both coccolithophores was stimulated by the addition of soil extract (K/2: 0.23 ± 0.02 d -1 and K/2 with soil extract 0.35 ± 0.01 d -1 for the C. braarudii haploid stage), while the diploid phase was not, indicating that the motile stage is capable of utilizing compounds present in soil extract or ingesting bacteria that are activated in enriched media. The addition of sodium acetate to the medium also stimulated the haploid phase of C. braarudii, and further experiments using labeled bacteria demonstrated the capacity for phagotrophy of this motile stage. The effect of nutrient concentrations on the growth rates of both species was evaluated, showing clear differences between the 2 phases of the life cycle, with higher growth rates for the diploid stage in nutrient-rich media (K/2: 0.34 ± 0. leptoporus).Responses of the 2 phases of both coccolithophores to physical turbulence were also different, with a haploid flagellate stage sensitive to mixing and a more resistant non-motile diploid stage. The results of these experiments strongly indicate that each morphological stage of C. braarudii and C. leptoporus corresponds to a different ecological niche, the motile haploid stage exploiting a more stable oligotrophic niche than the diploid non-motile stage, in accordance with field observations. The 2-dimensional phytoplankton niche space model of Margalef (1978; Oceanol Acta 1:493-509), defined by nutrients and turbulence, was amended to integrate this hypothesis.

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Geographical and seasonal differences in morphology and dynamics of the coccolithophore Calcidiscus leptoporus

Cited by 65 publications

References 25 publications

Physiology regulates the relationship between coccosphere geometry and growth phase in coccolithophores

Physiology regulates the relationship between coccosphere geometry and growth phase in coccolithophores

Species level variation in coccolithophores

Ecology of oceanic coccolithophores. I. Nutritional preferences of the two stages in the life cycle of Coccolithus braarudii and Calcidiscus leptoporus

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