Variable production of transparent exopolymeric particles by haploid and diploid life stages of coccolithophores grown under different CO2 concentrations

Pedrotti, Maria Luiza; Fiorini, Sarah; Kerros, Marie-Emmanuelle; Middelburg, Jack J.; Gattuso, Jean‐Pierre

doi:10.1093/plankt/fbs012

Cited by 14 publications

(17 citation statements)

References 44 publications

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“…Enhanced photosynthesis and nitrogen fixation have been shown to occur under higher pCO 2 conditions in laboratory and field experiments (Fu et al, 2007;Riebesell and Tortell, 2011). Phytoplankton production of TEP is stimulated by higher pCO 2 treatments at both species and community levels (Engel, 2002;Engel et al, 2004a;Mari, 2008;Pedrotti et al, 2012), which contributes to the formation of aggregates and so the vertical flux of POC and DOC. OA inhibits phytoplankton calcification which will decrease the ballast effect of calcium carbonate, so decreasing the vertical transport of POC (Barker et al, 2003).…”

Section: Ocean Acidificationmentioning

confidence: 99%

Mechanisms of microbial carbon sequestration in the ocean – future research directions

Jiao

Robinson²,

Azam³

et al. 2014

Biogeosciences

184

101

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Abstract. This paper reviews progress on understanding biological carbon sequestration in the ocean with special reference to the microbial formation and transformation of recalcitrant dissolved organic carbon (RDOC), the microbial carbon pump (MCP). We propose that RDOC is a concept with a wide continuum of recalcitrance. Most RDOC compounds maintain their levels of recalcitrance only in a specific environmental context (RDOC t ). The ocean RDOC pool also contains compounds that may be inaccessible to microbes due to their extremely low concentration (RDOC c ). This differentiation allows us to appreciate the linkage between microbial source and RDOC composition on a range of temporal and spatial scales.Analyses of biomarkers and isotopic records show intensive MCP processes in the Proterozoic oceans when the MCP could have played a significant role in regulating climate. Understanding the dynamics of the MCP in conjunction with the better constrained biological pump (BP) over geological timescales could help to predict future climate trends. Integration of the MCP and the BP will require new research approaches and opportunities. Major goals include understanding the interactions between particulate organic carbon (POC) and RDOC that contribute to sequestration efficiency, and the concurrent determination of the chemical composition of organic carbon, microbial community composition and enzymatic activity. Molecular biomarkers and isotopic tracers should be employed to link water column processes Published by Copernicus Publications on behalf of the European Geosciences Union. N. Jiao et al.: Mechanisms of microbial carbon sequestration in the oceanto sediment records, as well as to link present-day observations to paleo-evolution. Ecosystem models need to be developed based on empirical relationships derived from bioassay experiments and field investigations in order to predict the dynamics of carbon cycling along the stability continuum of POC and RDOC under potential global change scenarios. We propose that inorganic nutrient input to coastal waters may reduce the capacity for carbon sequestration as RDOC. The nutrient regime enabling maximum carbon storage from combined POC flux and RDOC formation should therefore be sought.

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Section: Ocean Acidificationmentioning

confidence: 99%

Mechanisms of microbial carbon sequestration in the ocean – future research directions

Jiao

Robinson²,

Azam³

et al. 2014

Biogeosciences

184

101

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“…These cases cannot be rescued by considering loss of photosynthate as (photo-) respired CO 2 or as dissolved organic matter or transparent exopolymeric particles (Raven 2011a, Pedrotti et al 2012). This correction gives PIC per integrated net photosynthetic C accumulation which is lower than PIC:POC (Raven 2011a).…”

Section: Functions Of Coccolithsmentioning

confidence: 99%

“…Von Dassow et al (2009) showed for Emiliania huxleyi that transcript levels of genes whose products are involved in coccolithogenesis (Ca 2+ , H + and HCO 3 − transporters) are expressed much more in the diploid (heterococcolith) than in the haploid (holococcolith) phase which has non-calcified coccoliths. The few studies concerning environmental effects on holococcoliths (Quintero-Torres et al 2007, Fiorini et al 2011a, Pedrotti et al 2012 will be discussed in the relevant sections.…”

Section: Heterococcoliths and Holococcolithsmentioning

confidence: 99%

“…This consists predominantly of liths which have become associated with other particulate organic matter, e.g. faecal pellets and transparent exopolymeric particles (Pedrotti et al 2012), and are effective ballast for export to the deep ocean, fuelling the biological pump of organic carbon (Rost & Riebesell 2004, Biermann & Engel 2010. While ballasting of particulate organic carbon (POC) by PIC increases the atmosphere-to-ocean CO 2 flux by decreasing mineralisation in the surface ocean, it also decreases PIC dissolution in the surface ocean, leaving a larger fraction of the CO 2 generated in PIC production in the surface ocean which decreases the atmosphereto-ocean flux of CO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Environmental controls on coccolithophore calcification

Raven

Crawfurd²

2012

Mar. Ecol. Prog. Ser.

113

107

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Coccolithophores are major contributors to global marine planktonic calcification, and in nature coccolithophores are invariably calcified through almost all of their life cycle. The response of calcification to environmental factors is essential in understanding the persistence of coccolithophores through at least 220 million years of changing global environments, and their prospects for current environmental change. So far the responses examined have been at the level of acclimation rather than adaptation in evolution. Variation in results of CO 2 manipulation experiments can be tentatively attributed to variation among genotypes rather than differences in experimental procedure. Comparisons of methods using the same genotype, and of several genotypes using a single method, suggest significant variation among genotypes. The general response is a decreased particulate inorganic carbon (PIC) to particulate organic carbon (POC) ratio in higher than present CO 2 concentrations and vice versa for lower CO 2 concentrations. Fewer studies have investigated the effect of other environmental factors. Decreased availability of phosphorus and, to a lesser extent, nitrogen, as well as decreasing photosynthetically active radiation (PAR) down to a certain low value increase PIC:POC, while variable results have been found for changes in ultraviolet radiation (UVR). Many of these results can be accommodated by considering the restriction of calcification to the G1 phase of the cell cycle and the length of this phase under different growth conditions. Fewer studies have investigated the interactions among environmental factors which change with increased CO 2 and increasing sea surface temperature; the shoaling of the thermocline will increase the mean PAR and UVR whilst decreasing nitrogen and phosphorus availability. More studies of these interactions, as well as of genetic adaptation in response to changed environmental factors, are needed.

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“…It accounts for up~50% of calcite raining down on marine sediments, with the other 50% derived from foraminifera (Broecker and Clark, 2009). Export of CaCO 3 is facilitated by its high density (2.7 g cm −3 ), inherent protective organic coatings (Hassenkam et al, 2011), association with particulate organic matter [marine snow, transparent exopolymeric particles and faecal pellets (Pedrotti et al, 2012;Collins et al, 2015)] and supersaturation in the upper water column (Westbroek et al, 1993;Balch et al, 2007;Berelson et al, 2007;Broecker and Clark, 2009). While there are no coccolith-specific estimates, the total PIC sinking-flux below 2000 m may be as much as 50 Tmol C year −1 (Berelson et al, 2007), with associated CaCO 3 :POC ratios (or 'rain ratios') having important implications for POC transport to the deep ocean and biological pump efficiency (Armstrong et al, 2002;Klaas and Archer, 2002;Ridgwell et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

The mutual interplay between calcification and coccolithovirus infection

Johns

Grubb

Nissimov

et al. 2018

Environmental Microbiology

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Two prominent characteristics of marine coccolithophores are their secretion of coccoliths and their susceptibility to infection by coccolithoviruses (EhVs), both of which display variation among cells in culture and in natural populations. We examined the impact of calcification on infection by challenging a variety of Emiliania huxleyi strains at different calcification states with EhVs of different virulence. Reduced cellular calcification was associated with increased infection and EhV production, even though calcified cells and associated coccoliths had significantly higher adsorption coefficients than non-calcified (naked) cells. Sialic acid glycosphingolipids, molecules thought to mediate EhV infection, were generally more abundant in calcified cells and enriched in purified, sorted coccoliths, suggesting a biochemical link between calcification and adsorption rates. In turn, viable EhVs impacted cellular calcification absent of lysis by inducing dramatic shifts in optical side scatter signals and a massive release of detached coccoliths in a subpopulation of cells, which could be triggered by resuspension of healthy, calcified host cells in an EhV-free, 'induced media'. Our findings show that calcification is a key component of the E. huxleyi-EhV arms race and an aspect that is critical both to the modelling of these host-virus interactions in the ocean and interpreting their impact on the global carbon cycle.

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Variable production of transparent exopolymeric particles by haploid and diploid life stages of coccolithophores grown under different CO2 concentrations

Cited by 14 publications

References 44 publications

Mechanisms of microbial carbon sequestration in the ocean – future research directions

Mechanisms of microbial carbon sequestration in the ocean – future research directions

Environmental controls on coccolithophore calcification

The mutual interplay between calcification and coccolithovirus infection

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