Coccospheres confer mechanical protection: New evidence for an old hypothesis

Jaya, Balila Nagamani; Hoffmann, Ramona; Kirchlechner, Christoph; Dehm, Gerhard; Scheu, Christina; Langer, Gerald

doi:10.1016/j.actbio.2016.07.036

Cited by 28 publications

(31 citation statements)

References 27 publications

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“…All the biometry work was carried out on the basis of SEM images using ImageJ software (http: //rsb.info.nih.gov/ij/), following Poulton et al (2011). Three coccolithophore species (Gladiolithus flabellatus, Calciosolenia murrayi, and Algirosphaera robusta) present in the SCS do not have k s values in Young and Ziveri (2000) or in similar coccolith calcite estimates (e.g., Knappertsbusch and Brummer, 1995;Beaufort and Heussner, 1999). For the body coccolith of G. flabellatus, a k s value is estimated as 0.0016, adjusted from Florisphaera profunda (0.04) and based on their similar rectangle shapes.…”

Section: Coccosphere and Coccolith Biometry And Calcite Estimatesmentioning

confidence: 99%

“…In the context of the coccolithophore biogeographical zones of Winter et al (1994), the coccolithophore assemblages investigated in the SCS belong to the tropical zone, comprising E. huxleyi, G. oceanica, Gephyrocapsa ericsonii, Oolithotus fragilis, U. irregularis, F. profunda, and A. robusta. Reticulofenestra sessilis was also sporadically found at 75 m depth at sampling stations, and this species is reported to be exclusively found in lower photic water of the tropical zone, where it may form symbioses with diatoms (i.e., Thalassiosira species) (Winter et al, 1994;Young et al, 2003;Jordan, 2012). The coccolithophore flora of the SCS is similar to the "high temperature" and "warm oligotrophic" assemblages in the equatorial Pacific Ocean (Hagino et al, 2000).…”

Section: Coccolithophore Biogeography In the South China Seamentioning

confidence: 99%

“…With the same DSL, coccosphere diameter in field samples is larger. It also seems that an E. huxleyi cell in the field can produce more or multilayer coccoliths, which could be a defense against zooplankton grazing or bacterial attack and offer mechanical protection (Young, 1994;Jaya et al, 2016) in natural conditions. As seen in Fig.…”

Section: Environmental Influences On Emiliania Huxleyi Biometrymentioning

confidence: 99%

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Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

et al. 2016

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Abstract. Coccolithophore contributions to the global marine carbon cycle are regulated by the calcite content of their scales (coccoliths) and the relative cellular levels of photosynthesis and calcification rates. All three of these factors vary between coccolithophore species and with response to the growth environment. Here, water samples were collected in the northern basin of the South China Sea (SCS) during summer 2014 in order to examine how environmental variability influenced species composition and cellular levels of calcite content. Average coccolithophore abundance and their calcite concentration in the water column were 11.82 cells mL−1 and 1508.3 pg C mL−1, respectively, during the cruise. Water samples can be divided into three floral groups according to their distinct coccolithophore communities. The vertical structure of the coccolithophore community in the water column was controlled by the trophic conditions, which were regulated by mesoscale eddies across the SCS basin. The evaluation of coccolithophore-based calcite in the surface ocean also showed that three key species in the SCS (Emiliania huxleyi, Gephyrocapsa oceanica, Florisphaera profunda) and other larger, numerically rare species made almost equal contributions to total coccolith-based calcite in the water column. For Emiliania huxleyi biometry measurements, coccolith size positively correlated with nutrients (nitrate, phosphate), and it is suggested that coccolith length is influenced by light and nutrients through the regulation of growth rates. Larger-sized coccoliths were also linked statistically to low pH and calcite saturation states; however, it is not a simple cause and effect relationship, as carbonate chemistry was strongly co-correlated with the other key environmental factors (nutrients, light).

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Section: Coccosphere and Coccolith Biometry And Calcite Estimatesmentioning

confidence: 99%

Section: Coccolithophore Biogeography In the South China Seamentioning

confidence: 99%

Section: Environmental Influences On Emiliania Huxleyi Biometrymentioning

confidence: 99%

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Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

et al. 2016

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“…As the arrangement of the coccospheres in these species is less rigid, the organic layer may act primarily to adhere the coccoliths to the cell, rather than hold them in a specific position. The ability of the coccoliths to move flexibly within a layer of polysaccharide is important for the ability of E. huxleyi coccospheres to resist a mechanical load, suggesting that the polysaccharide layer contributes directly to the protective role of coccosphere (Jaya et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

An Extracellular Polysaccharide-Rich Organic Layer Contributes to Organization of the Coccosphere in Coccolithophores

et al. 2018

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Coccolithophores are globally abundant marine microalgae characterized by their ability to form calcite platelets (coccoliths). The coccoliths are produced internally in a Golgiderived vesicle. Mature coccoliths are extruded from the cell to form a protective covering on the cell surface, known as the coccosphere. Current evidence indicates that calcite precipitation in the coccolith vesicle (CV) is modulated by coccolith-associated polysaccharides (CAPs). Whilst previous research into CAPs has focussed on their roles in calcite precipitation within the CV, little is known of their extracellular roles. Using fluorescent lectins, we visualize the extracellular polysaccharide-rich organic layer associated with external coccoliths and demonstrate that it differs between species in structure and composition. Biochemical analysis of polysaccharide extracted from coccoliths indicated substantial differences between species in monosaccharide composition and uronic acid content. In Coccolithus braarudii our studies indicate that polysaccharide-rich material is extruded with the coccoliths, where it plays a role in the adhesion of the coccoliths to the cell surface and contributes to the overall organization of the coccosphere. Together, these results highlight the important extracellular roles of CAPs and their contribution to the dynamic nature of the coccosphere.

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“…An A morphotype ("A*") exhibiting partial and irregular extension of inner tube elements over the central area (but not closure of spaces between distal shield radial elements) was dominant in the Benguela upwelling zone (not the more extreme R/overcalcified types) (Henderiks et al, 2012), while the A_CC type, although rare in front of Chile, was dominant in the Northeast Atlantic (Bay of Biscay) in winter (Smith et al, 2012). The function of coccoliths is still not 25 certain, but they may have a role in physical defense against grazing or bacterial attack (Jaya et al, 2016;Monteiro et al, 2016). It is interesting to speculate that high productivity conditions in eastern boundary coasts promote persistent higher abundances of grazers or phytopathogenic bacteria, against which the overcalcified coccoliths might provide better defense.…”

Section: Discussion 20mentioning

confidence: 99%

Overcalcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high CO<sub>2</sub> waters are not pre-adapted to ocean acidification

Dassow¹,

Díaz-Rosas²,

Bendif³

et al. 2017

Preprint

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Abstract. Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to 15 acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the Eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally overcalcified morphotypes 20 whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hypercalcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO 2 (400 µatm vs. 1200 µatm), the overcalcified morphotypes showed the same growth inhibition (-29.1±6.3%) as moderately calcified morphotypes isolated from non-acidified water (-30.7±8.8%). Under OA conditions, production rates of particulate organic carbon (POC) 25 increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC/POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. OA affected coccolith morphology equally or more strongly in overcalcified strains compared to moderately calcified strains. OA conditions appear not to directly select for exceptionally overcalcified morphotypes over other morphotypes directly, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest 30 that oceanic planktonic microorganisms, despite their rapid turn-over and large population sizes, do not necessarily exhibit adaptations to naturally high CO 2 upwellings, and this ubiquitous coccolithophore may be near a limit of its capacity to adapt to ongoing ocean acidification.

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Coccospheres confer mechanical protection: New evidence for an old hypothesis

Cited by 28 publications

References 27 publications

Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

An Extracellular Polysaccharide-Rich Organic Layer Contributes to Organization of the Coccosphere in Coccolithophores

Overcalcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high CO<sub>2</sub> waters are not pre-adapted to ocean acidification

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Coccospheres confer mechanical protection: New evidence for an old hypothesis

Cited by 28 publications

References 27 publications

Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

An Extracellular Polysaccharide-Rich Organic Layer Contributes to Organization of the Coccosphere in Coccolithophores

Overcalcified forms of the coccolithophore &lt;i&gt;Emiliania huxleyi&lt;/i&gt; in high CO&lt;sub&gt;2&lt;/sub&gt; waters are not pre-adapted to ocean acidification

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Overcalcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high CO<sub>2</sub> waters are not pre-adapted to ocean acidification