Phytoplankton Calcification in a High-CO2 World

National Oceanography Centre, Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
Science (Impact Factor: 33.61). 05/2008; 320(5874):336-40. DOI: 10.1126/science.1154122
Source: PubMed


Ocean acidification in response to rising atmospheric CO2 partial pressures is widely expected to reduce calcification by marine organisms. From the mid-Mesozoic, coccolithophores
have been major calcium carbonate producers in the world's oceans, today accounting for about a third of the total marine
CaCO3 production. Here, we present laboratory evidence that calcification and net primary production in the coccolithophore species
Emiliania huxleyi are significantly increased by high CO2 partial pressures. Field evidence from the deep ocean is consistent with these laboratory conclusions, indicating that over
the past 220 years there has been a 40% increase in average coccolith mass. Our findings show that coccolithophores are already
responding and will probably continue to respond to rising atmospheric CO2 partial pressures, which has important implications for biogeochemical modeling of future oceans and climate.

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    • "Calcifying organisms (e.g., corals, coccolithophores, and coralline algae) decrease calcification rates and the saturation states of the mineralogical forms of their calcium carbonate (CaCO 3 ) shells (Kleypas and Langdon, 2006). The physiological processes of some phytoplankton species are affected by decreased pH, including photosynthesis (Iglesias-Rodriguez et al., 2008; Crawley et al., 2010), uptake rates of trace metals (Shi et al., 2010), and toxin production of some harmful algal blooms (Fu et al., 2008). Elevated CO 2 partial pressure can also affect natural phytoplankton assemblages and shift community composition (Feng et al., 2009; Gao et al., 2012). "
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    ABSTRACT: Offshore geologic storage of carbon dioxide (CO2), known as offshore carbon capture and sequestration (CCS), has been under active investigation as a safe, effective mitigation option for reducing CO2 levels from anthropogenic fossil fuel burning and climate change. Along with increasing trends in implementation plans and related logistics on offshore CCS, thorough risk assessment (i.e. environmental impact monitoring) needs to be conducted to evaluate potential risks, such as CO2 gas leakage at injection sites. Gas leaks from offshore CCS may affect the physiology of marine organisms and disrupt certain ecosystem functions, thereby posing an environmental risk. Here, we synthesize current knowledge on environmental impact monitoring of offshore CCS with an emphasis on biological aspects and provide suggestions for better practice. Based on our critical review of preexisting literatures, this paper: 1) discusses key variables sensitive to or indicative of gas leakage by summarizing physico-chemical and ecological variables measured from previous monitoring cruises on offshore CCS; 2) lists ecosystem and organism responses to a similar environmental condition to CO2 leakage and associated impacts, such as ocean acidification and hypercapnia, to predict how they serve as responsive indicators of short- and long-term gas exposure, and 3) discusses the designs of the artificial gas release experiments in fields and the best model simulation to produce realistic leakage scenarios in marine ecosystems. Based on our analysis, we suggest that proper incorporation of biological aspects will provide successful and robust long-term monitoring strategies with earlier detection of gas leakage, thus reducing the risks associated with offshore CCS.
    No preview · Article · Feb 2016 · Environmental Impact Assessment Review
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    • "Emiliania huxleyi has attracted most recent attention in coccolithophore research due to its dominance in present-day oceans, its importance in biogeochemical cycles, and accompanying relevance to ocean chemistry and climate of the Anthropocene (e.g. Bidigare et al., 1997; Riebesell et al., 2000; Iglesias-Rodriguez et al., 2008; De Bodt et al., 2010; Suffrian et al., 2011; Müller et al., 2012; Bach et al., 2013; Sett et al., 2014; Tchernov et al., 2014; Young et al., 2014; Aloisi, 2015; Holtz et al., 2015). The strain RCC 1256 used in this study produces lightly calcified coccoliths assigned to the morphotype A (Langer and Bode, 2011). "
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    ABSTRACT: By recreating a range of geologically relevant concentrations of dissolved inorganic carbon (DIC) in the laboratory, we demonstrate that the magnitude of the vital effects in both carbon and oxygen isotopes of coccolith calcite of multiple species relates to ambient DIC concentration. Under high DIC levels, all the examined coccoliths exhibit significantly reduced isotopic offsets from inorganic calcite compared to the substantial vital effects expressed at low (preindustrial and present-day) DIC concentrations. The supply of carbon to the cell exerts a primary control on biological fractionation in coccolith calcite via the modulation of coccolithophore growth rate, cell size and carbon utilisation by photosynthesis and calcification, altogether accounting for the observed interspecific differences between coccolith species. These laboratory observations support the recent hypothesis from field observations that the appearance of interspecific vital effect in coccolithophores coincides with the long-term Neogene decline of atmospheric CO2 concentrations and bring further valuable constraints by demonstrating a convergence of all examined species towards inorganic values at high pCO2 regimes. This study provides palaeoceanographers with a biogeochemical framework that can be utilised to further develop the use of calcareous nannofossils in palaeoceanography to derive sea surface temperature and pCO2 levels, especially during periods of relatively elevated pCO2 concentrations, as they prevailed during most of the Meso-Cenozoic.
    Full-text · Article · Jan 2016 · Biogeosciences
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    • "On the other hand, there are non-calcifying phytoplankton species that benefit from a higher availability of carbon enhancing their growth (Rost et al., 2008; Low-Decarie et al., 2014). Although a direct effect of a lowered pH on phytoplankton (Riebesell et al., 2000a; Kim et al., 2006) and zooplankton (Pedersen and Hansen, 2003; Mayor et al., 2007; Cripps et al., 2014) has been reported for some species, other studies point at only the indirect effects of OA, e.g. by changes in phytoplankton availability, quality, or changes in C : N : P ratios affecting higher levels (Iglesias-Rodriguez et al., 2008; Suffrian et al., 2008; Nielsen and Lewandowska, 2011; Aberle et al., 2012, 2015; Winder et al., 2012; Lewandowska et al., 2014). Here, we present an indoor mesocosm study on the combined effects of enhanced CO 2 and warming on natural autumn plankton communities from Kiel Fjord, characterized by a diatomdominated phytoplankton bloom in autumn (Wasmund et al., 2008). "
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    ABSTRACT: Global warming and ocean acidification are among the most important stressors for aquatic ecosystems in the future. To investigate their direct and indirect effects on a near-natural plankton community, a multiple-stressor approach is needed. Hence, we set up mesocosms in a full-factorial design to study the effects of both warming and high CO2 on a Baltic Sea autumn plankton community, concentrating on the impacts on microzooplankton (MZP). MZP abundance, biomass, and species composition were analysed over the course of the experiment. We observed that warming led to a reduced time-lag between the phytoplankton bloom and an MZP biomass maximum. MZP showed a significantly higher growth rate and an earlier biomass peak in the warm treatments while the biomass maximum was not affected. Increased pCO2 did not result in any significant effects on MZP biomass, growth rate, or species composition irrespective of the temperature, nor did we observe any significant interactions between CO2 and temperature. We attribute this to the high tolerance of this estuarine plankton community to fluctuations in pCO2, often resulting in CO2 concentrations higher than the predicted end-of-century concentration for open oceans. In contrast, warming can be expected to directly affect MZP and strengthen its coupling with phytoplankton by enhancing its grazing pressure.
    Full-text · Article · Nov 2015 · ICES Journal of Marine Science
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