Emiliania huxleyi: bloom observations and the conditions that induce them

Tyrrell, Toby; Merico, Agostino

doi:10.1007/978-3-662-06278-4_4

Cited by 278 publications

(286 citation statements)

References 70 publications

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“…This finding is consistent with previous observations of a strict dominance of E. huxleyi with low abundances south of the PF (Saavedra-Pellitero et al, 2014;Winter et al, 2014). E. huxleyi is reported to bloom in waters with generally low silicic acid concentration resulting by its consumption by diatoms (Holligan et al, 1983;Townsend et al, 1994;Tyrrell and Merico, 2004). Additionally, this species has been shown to be tolerant to low iron concentration (Brand et al, 1983;Sunda and Huntsman, 1995;Muggli and Harrison, 1997;Findlay and Giraudeau, 2000;Holligan et al, 2010).…”

Section: Seasonality and Magnitude Of The Coccolith Fine Fraction Exportsupporting

confidence: 92%

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

Rembauville

Meilland

Ziveri

et al. 2016

Deep Sea Research Part I: Oceanographic Research Papers

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a b s t r a c tWe report the contribution of planktic foraminifers and coccoliths to the particulate inorganic carbon (PIC) export fluxes collected over an annual cycle (October 2011/September 2012) on the central Kerguelen Plateau in the Antarctic Zone (AAZ) south of the Polar Front (PF). The seasonality of PIC flux was decoupled from surface chlorophyll a concentration and particulate organic carbon (POC) fluxes and was characterized by a late summer (February) maximum. This peak was concomitant with the highest satellite-derived sea surface PIC and corresponded to a Emiliania huxleyi coccoliths export event that accounted for 85% of the annual PIC export. The foraminifer contribution to the annual PIC flux was much lower (15%) and dominated by Turborotalita quinqueloba and Neogloboquadrina pachyderma. Foraminifer export fluxes were closely related to the surface chlorophyll a concentration, suggesting food availability as an important factor regulating the foraminifer's biomass. We compared size-normalized test weight (SNW) of the foraminifers with previously published SNW from the Crozet Islands using the same methodology and found no significant difference in SNW between sites for a given species. However, the SNW was significantly species-specific with a threefold increase from T. quinqueloba to Globigerina bulloides. The annual PIC:POC molar ratio of 0.07 was close to the mean ratio for the global ocean and lead to a low carbonate counter pump effect ( $ 5%) compared to a previous study north of the PF (6-32%). We suggest that lowers counter pump effect south of the PF despite similar productivity levels is due to a dominance of coccoliths in the PIC fluxes and a difference in the foraminifers species assemblage with a predominance of polar species with lower SNW.

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Section: Seasonality and Magnitude Of The Coccolith Fine Fraction Exportsupporting

confidence: 92%

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

Rembauville

Meilland

Ziveri

et al. 2016

Deep Sea Research Part I: Oceanographic Research Papers

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“…The peak concentrations of Emiliania Huxleyi in this study were 4-6×10 6 cells L −1 (Paulino et al, 2008) which is representative of the concentrations found in the North Atlantic and Norwegian Sea (Tyrrell and Merico, 2004). The Delille et al (2005) experiment had much higher concentrations (4-6×10 7 cells L −1 ) more representative of the intense blooms found in the Norwegian Fjords (Tyrrell and Merico, 2004).…”

Section: Calcificationsupporting

confidence: 53%

“…The Delille et al (2005) experiment had much higher concentrations (4-6×10 7 cells L −1 ) more representative of the intense blooms found in the Norwegian Fjords (Tyrrell and Merico, 2004). Extrapolating the Delille et al (2005) calcification response to the PeECE III study cell numbers translates to a predicted reduction in PIC production of 6 µmol kg −1 (1×CO 2 -2×CO 2 treatment).…”

Section: Calcificationmentioning

confidence: 96%

Marine ecosystem community carbon and nutrient uptake stoichiometry under varying ocean acidification during the PeECE III experiment

et al. 2008

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Abstract. Changes to seawater inorganic carbon and nutrient concentrations in response to the deliberate CO 2 perturbation of natural plankton assemblages were studied during the 2005 Pelagic Ecosystem CO 2 Enrichment (PeECE III) experiment. Inverse analysis of the temporal inorganic carbon dioxide system and nutrient variations was used to determine the net community stoichiometric uptake characteristics of a natural pelagic ecosystem perturbed over a range of pCO 2 scenarios (350, 700 and 1050 µatm). Nutrient uptake showed no sensitivity to CO 2 treatment. There was enhanced carbon production relative to nutrient consumption in the higher CO 2 treatments which was positively correlated with the initial CO 2 concentration. There was no significant calcification response to changing CO 2 in Emiliania huxleyi by the peak of the bloom and all treatments exhibited low particulate inorganic carbon production (∼15 µmol kg −1 ). With insignificant air-sea CO 2 exchange across the treatments, the enhanced carbon uptake was due to increase organic carbon production. The inferred cumulative C:N:P stoichiometry of organic production increased with CO 2 treatment from 1:6.3:121 to 1:7.1:144 to 1:8.25:168 at the height of the bloom. This study discusses how ocean acidification may incur modification to the stoichiometry of pelagic production and have consequences for ocean biogeochemical cycling.

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“…huxleyi is the most abundant and widespread coccolithophore species in the modern oceans (Holligan et al, 1983;Balch et al, 1992;Brown and Yoder, 1994). It forms massive annual spring blooms that are detectable from space by satellites and affects global climate and biogeochemical cycles of carbon and sulfur (Hatton et al, 2004;Rost and Riebesell, 2004;Tyrrell and Merico, 2004). E. huxleyi blooms are routinely infected and terminated by specific giant double-stranded DNA coccolithoviruses (Phycodnaviridae) (Bratbak et al, 1993;Brussaard et al, 1996;Schroeder et al, 2002;Wilson et al, 2002;Lehahn et al, 2014), the E. huxleyi virus (EhV), which is part of the nucleocytoplasmic large DNA virus (Asfarviridae, Ascoviridae, Iridoviridae, Marseilleviridae, Megaviridae, Mimiviridae, Pandoraviridae, Phycodnaviridae, Pithoviridae and Poxviridae) clade.…”

Section: Introductionmentioning

confidence: 99%

Modulation of host ROS metabolism is essential for viral infection of a bloom-forming coccolithophore in the ocean

et al. 2016

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The cosmopolitan coccolithophore Emiliania huxleyi is a unicellular eukaryotic alga responsible for vast blooms in the ocean. These blooms have immense impact on large biogeochemical cycles and are terminated by a specific large double-stranded DNA E. huxleyi virus (EhV, Phycodnaviridae). EhV infection is accompanied by induction of hallmarks of programmed cell death and production of reactive oxygen species (ROS). Here we characterized alterations in ROS metabolism and explored its role during infection. Transcriptomic analysis of ROS-related genes predicted an increase in glutathione (GSH) and H 2 O 2 production during infection. In accordance, using biochemical assays and specific fluorescent probes we demonstrated the overproduction of GSH during lytic infection. We also showed that H 2 O 2 production, rather than superoxide, is the predominant ROS during the onset of the lytic phase of infection. Using flow cytometry, confocal microscopy and multispectral imaging flow cytometry, we showed that the profound co-production of H 2 O 2 and GSH occurred in the same subpopulation of cells but at different subcellular localization. Positively stained cells for GSH and H 2 O 2 were highly infected compared with negatively stained cells. Inhibition of ROS production by application of a peroxidase inhibitor or an H 2 O 2 scavenger inhibited host cell death and reduced viral production. We conclude that viral infection induced remodeling of the host antioxidant network that is essential for a successful viral replication cycle. This study provides insight into viral replication strategy and suggests the use of specific cellular markers to identify and quantify the extent of active viral infection during E. huxleyi blooms in the ocean.

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Emiliania huxleyi: bloom observations and the conditions that induce them

Cited by 278 publications

References 70 publications

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

Marine ecosystem community carbon and nutrient uptake stoichiometry under varying ocean acidification during the PeECE III experiment

Modulation of host ROS metabolism is essential for viral infection of a bloom-forming coccolithophore in the ocean

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