Role of silicon in the development of complex crystal shapes in coccolithophores

Langer, Gerald; Taylor, Alison R.; Walker, Charlotte E.; Meyer, Erin M.; Ben-Joseph, Oz; Gal, Assaf; Harper, Glenn; Probert, Ian; Brownlee, Colin; Wheeler, Glen

doi:10.1111/nph.17230

Cited by 28 publications

(43 citation statements)

References 62 publications

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“…The coccolith size rules model presented here, as well as the coccolithophore size rules, are limited to placolith heteroccoliths. For example, the model is likely not applicable to Braarudosphaera bigelowii which produces coccoliths outside of the cell (Hagino et al, 2016), holococcoliths which have a different crystallographic structure (Langer et al, 2021), highly elongated cells such as Placorhombus ziveriae or Calciosolenia brasiliensis (Young et al, 2003), or coccolithophores with a very high number of coccoliths and very low coccolith size variability (e.g., Florisphaera profunda, Coronosphaera maxima; Young et al, 2003). Further coccolith growth and cell life cycle observations of various species are critically needed to extend the taxonomic range of applicability of the coccolith size rules model.…”

Section: Discussionmentioning

confidence: 99%

Coccolith size rules – What controls the size of coccoliths during coccolithogenesis?

Suchéras-Marx

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Walker

et al. 2022

Marine Micropaleontology

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Coccoliths are calcite platelets produced inside coccolithophore cells and extruded to form a covering on the cell surface called a coccosphere. The size of coccoliths is an important parameter often used to identify species, and observations on extant species have shown an influence of abiotic parameters (e.g., CO 2 , light, nutrient concentration) on coccolith size. However, the sometimes large range of coccolith sizes occurring within a single coccosphere questions the mechanisms controlling coccolith size. A link was previously shown between cell/coccosphere size and coccolith size called the "coccolithophore size rule". In this study, we query the mechanisms controlling the size of a coccolith during coccolithogenesis. Two working hypotheses are formulated: (1) coccolith size is smaller than cell diameter, and (2) coccolithogenesis mainly occurs during a specific growth phase (G1 interphase). We propose two numerical models (each with two variants) to test the constraining effect of these hypotheses on coccolith size distribution within a population. Neither model can accurately reproduce the size distribution of an empirical coccolith population, indicating that additional factors likely influence coccolith size. According to both hypotheses, the comparison of coccolith size and cell size is only pertinent at the time of formation of a coccolith. In light of these results, we suggest that application of the coccolithophore size rules model should be limited to multipopulational studies, and we confirm the basis of the link between coccolith number and cell cycle. The coccolith size rule model proposed here requires verification with further observations of coccolithophore and coccolith growth data.

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Section: Discussionmentioning

confidence: 99%

Coccolith size rules – What controls the size of coccoliths during coccolithogenesis?

Suchéras-Marx

Viseur

Walker

et al. 2022

Marine Micropaleontology

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“…Coccolith morphology was classified into two categories, normal and malformed. We used a simplified categorisation compared to earlier studies (in this study ‘malformed’ contained the groups termed ‘minor’, ‘major’ and ‘type R’ (Langer et al ., 2021)) as malformation levels were generally low and a high-resolution categorisation would not have provided additional information. A total of 200 coccoliths were analysed per sample.…”

Section: Methodsmentioning

confidence: 99%

Distinct physiological responses ofCoccolithus braarudiilife cycle phases to light intensity and nutrient availability

Langer

Jie

Kottmeier

et al. 2022

Preprint

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Coccolithophores feature a haplo-diplontic life cycle comprised of diploid cells producing heterococcoliths and haploid cells producing morphologically different holococcoliths. These life cycle phases of each species appear to have distinct spatial and temporal distributions in the oceans, with the heavily-calcified heterococcolithophores (HET) often more prevalent in winter and at greater depths, whilst the lightly-calcified holococcolithophores (HOL) are more abundant in summer and in shallower waters. The haplo-diplontic life cycle may therefore allow coccolithophores to expand their ecological niche, switching between life cycle phases to exploit conditions that are more favourable. However, coccolithophore life cycles remain poorly understood and fundamental information on the physiological differences between life cycle phases is required if we are to better understand the ecophysiology of coccolithophores. In this study, we have examined the physiology of HET and HOL phases of the coccolithophore Coccolithus braarudii in response to changes in light and nutrient availability. We found that the HOL phase was more tolerant to high light than the HET phase, which exhibited defects in calcification at high irradiances. The HET phase exhibited defects in coccolith formation under both nitrate (N) and phosphate (P) limitation, whilst no defects in calcification were detected in the HOL phase. The HOL phase grew to a higher cell density under P-limitation than N-limitation, whereas no difference was observed in the maximum cell density reached by the HET phase at these nutrient concentrations. HET cells grown under a light:dark cycle divided primarily in the dark and early part of the light phase, whereas HOL cells continued to divide throughout the 24 h period. The physiological differences may contribute to the distinct biogeographical distributions observed between life cycle phases, with the HOL phase potentially better adapted to high light, low nutrient regimes, such as those found in seasonally stratified surface waters.

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“…Spearman correlation was performed in R using the "cor.test" function from the "stats" package (R Core Team, 2019). We also visualized environmental drivers by plotting the distributions of cell concentrations and environmental parameters within the water column or within the first two axes of a principal component analysis (PCA) and then interpolating values using the multilevel B-spline approximation (MBA) algorithm described by Lee et al (1997). Prior to conducting the PCA, samples with a Cook's distance greater than 4 times the sample size were removed.…”

Section: Environmental Driversmentioning

confidence: 99%

Haplo-diplontic life cycle expands coccolithophore niche

et al. 2021

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Abstract. Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo-diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases and potentially expands coccolithophore niche volume. Research has, however, to date largely overlooked the life cycle of coccolithophores and has instead focused on the diploid life cycle phase of coccolithophores. Through the synthesis and analysis of global scanning electron microscopy (SEM) coccolithophore abundance data (n=2534), we find that calcified haploid coccolithophores generally constitute a minor component of the total coccolithophore abundance (≈ 2 %–15 % depending on season). However, using case studies in the Atlantic Ocean and Mediterranean Sea, we show that, depending on environmental conditions, calcifying haploid coccolithophores can be significant contributors to the coccolithophore standing stock (up to ≈30 %). Furthermore, using hypervolumes to quantify the niche of coccolithophores, we illustrate that the haploid and diploid life cycle phases inhabit contrasting niches and that on average this allows coccolithophores to expand their niche by ≈18.8 %, with a range of 3 %–76 % for individual species. Our results highlight that future coccolithophore research should consider both life cycle stages, as omission of the haploid life cycle phase in current research limits our understanding of coccolithophore ecology. Our results furthermore suggest a different response to nutrient limitation and stratification, which may be of relevance for further climate scenarios. Our compilation highlights the spatial and temporal sparsity of SEM measurements and the need for new molecular techniques to identify uncalcified haploid coccolithophores. Our work also emphasizes the need for further work on the carbonate chemistry niche of the coccolithophore life cycle.

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Role of silicon in the development of complex crystal shapes in coccolithophores

Cited by 28 publications

References 62 publications

Coccolith size rules – What controls the size of coccoliths during coccolithogenesis?

Coccolith size rules – What controls the size of coccoliths during coccolithogenesis?

Distinct physiological responses ofCoccolithus braarudiilife cycle phases to light intensity and nutrient availability

Haplo-diplontic life cycle expands coccolithophore niche

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