Corals concentrate dissolved inorganic carbon to facilitate calcification

Allison, Nicola; Cohen, Itay; Finch, Adrian A.; Erez, Jonathan; Tudhope, Alexander W.

doi:10.1038/ncomms6741

Cited by 106 publications

(153 citation statements)

References 30 publications

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“…The effect of temperature and fluid saturation state (X) on inorganic aragonite precipitation rate is replotted from Burton and Walter (1987) Porites spp. field corals growing at ambient pCO 2 and a mean annual seawater temperature of 25°C is * 8.5 (Allison et al 2014). In paired laboratory measurements of both calcification fluid pH and [CO 3 2-] in a range of coral species, a coral calcification fluid of pH total 8.5 has an aragonite saturation state of * 8 (Cai et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

et al. 2018

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Understanding how rising seawater pCO 2 and temperatures impact coral aragonite accretion is essential for predicting the future of reef ecosystems. Here, we report 2 long-term (10-11 month) studies assessing the effects of temperature (25 and 28°C) and both high and low seawater pCO 2 (180-750 latm) on the calcification, photosynthesis and respiration of individual massive Porites spp. genotypes. Calcification rates were highly variable between genotypes, but high seawater pCO 2 reduced calcification significantly in 4 of 7 genotypes cultured at 25°C but in only 1 of 4 genotypes cultured at 28°C. Increasing seawater temperature enhanced calcification in almost all corals, but the magnitude of this effect was seawater pCO 2 dependent. The 3°C temperature increase enhanced calcification rate on average by 3% at 180 latm, by 35% at 260 latm and by [ 300% at 750 latm. The rate increase at high seawater pCO 2 exceeds that observed in inorganic aragonites. Responses of gross/net photosynthesis and respiration to temperature and seawater pCO 2 varied between genotypes, but rates of all these processes were reduced at the higher seawater temperature. Increases in seawater temperature, below the thermal stress threshold, may mitigate against ocean acidification in this coral genus, but this moderation is not mediated by an increase in net photosynthesis. The response of coral calcification to temperature cannot be explained by symbiont productivity or by thermodynamic and kinetic influences on aragonite formation.

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Section: Discussionmentioning

confidence: 99%

Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

et al. 2018

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“…KD have been calculated for aragonite under a range of different scenarios (Allison et al, 2014, 2017, Holcomb et al 2016and De Carlo et al, 2018. While it is likely that B(OH)4 -substitute for CO3 2-in aragonite (Balan et al, 2016), it is unknown which aqueous DIC species are involved in aragonite precipitation.…”

Section: Calculation Of Calcification Fluid Dic Parametersmentioning

confidence: 99%

“…[CO3 (Marubini et al, 2001;Schneider and Erez 2006;Jury et al, 2009). However, coral aragonite does not precipitate directly from seawater but from an extracellular calcifying fluid which multiple techniques (microsensors, pH sensitive dyes and skeletal boron geochemistry) indicate has significantly different DIC chemistry to the surrounding seawater (Al Horani et al, 2003;Venn 2011;Allison et al, 2014, Cai et al, 2016. The calcification fluid is probably derived from seawater and located between the coral tissue and underlying skeleton (Clode and Marshall, 2002).…”

Section: Introductionmentioning

confidence: 99%

The effect of ocean acidification on tropical coral calcification: insights from calcification fluid DIC chemistry

Allison¹

2018

Preprint

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Ocean acidification typically reduces calcification in tropical marine corals but the mechanism for this process is not understood. We use skeletal boron geochemistry (B/Ca and δ 11 B) to reconstruct the calcification fluid DIC of corals cultured over both high and low seawater pCO2 (180, 400 and 750 μatm). We observe strong positive correlations between calcification fluid pH and concentrations of the DIC species potentially implicated in aragonite precipitation (be they CO3 ). Similarly, with the exception of one outlier, the fluid concentrations of precipitating DIC species are strongly positively correlated with coral calcification rate. Corals cultured at high seawater pCO2 usually have low calcification fluid pH and low concentrations of precipitating DIC, suggesting that a reduction in DIC substrate at the calcification site is responsible for decreased calcification. The outlier coral maintained high pHCF and DICCF at high seawater pCO2 but exhibited a reduced calcification rate indicating that the coral has a limited energy budget to support proton extrusion from the calcification fluid and meet other calcification demands. We find no evidence that increasing seawater pCO2 enhances diffusion of CO2 into the calcification site. Instead the overlying [CO2] available to diffuse into the calcification site appears broadly comparable between seawater pCO2 treatments, implying that metabolic activity (respiration and photosynthesis) generates a similar [CO2] in the vicinity of the calcification site regardless of seawater pCO2.

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“…Because the isolation and small size of the calcifying fluid makes it difficult to sample directly, a variety of techniques have been employed to characterize its composition. These include microelectrodes inserted into tissue incisions or through the mouth (Al-Horani et al, 2003;Ries, 2011;Cai et al, 2016), pH-sensitive dyes (Venn et al, 2011(Venn et al, , 2013Holcomb et al, 2014;Comeau et al, 2017), Raman spectroscopy (DeCarlo et al, 2017), and a variety of skeletal-based 5 geochemical proxies (Rollion-Bard et al, 2010Inoue et al, 2011;Trotter et al, 2011;McCulloch et al, 2012b;Allison et al, 2014;Holcomb et al, 2014;DeCarlo et al, 2015). Although microelectrodes and pH-sensitive dyes are arguably the most direct methods, their utilities are limited by difficulties of applying them to corals living in their natural environment or developing seasonally-resolved time series.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, boron systematics (including δ 11 B and B/Ca) have become one of the most commonly applied proxies for the carbonate chemistry of coral calcifying fluid (cf) (Hönisch et al, 2004;Trotter et al, 2011;McCulloch et al, 2012bMcCulloch et al, , a, 2017Allison et al, 2014;DeCarlo et al, 2016;Stewart et al, 2016;Comeau et al, 2017;Wu et al, 2017;D'Olivo and McCulloch, 2017;Kubota et al, 2017;Ross et al, 2017;Schoepf et al, 2017). The sensitivity of boron isotopes to seawater pH arises from the borate versus boric acid speciation being pH-dependent and the isotopic fractionation between these species being constant 15 (Klochko et al, 2006).…”

mentioning

confidence: 99%

Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification

DeCarlo¹,

Holcomb²,

McCulloch³

2018

Preprint

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has not yet been a comprehensive analysis that considers both experimental datasets and explores the implications for interpreting coral skeletons. Here, we evaluate four potential K D formulations: three previously presented in the literature and one newly developed. We assess how well each formulation reconstructs the known fluid carbonate chemistry from the abiogenic experiments, and we evaluate the implications for deriving the carbonate chemistry of coral calcifying fluid. Three of the K D formulations performed similarly when applied to abiogenic aragonites precipitated from 10 seawater and to coral skeletons. Critically, we find that some uncertainty remains in understanding the mechanism of boron elemental partitioning between aragonite and seawater, and addressing this question should be a target of additional abiogenic precipitation experiments. Despite this, boron systematics can already be applied to quantify the coral calcifying fluid carbonate system, although uncertainties associated with the proxy system should be carefully considered for each application. Finally, we present a user-friendly computer code that calculates coral calcifying fluid carbonate chemistry, including propagation of 15 uncertainties, given inputs of boron systematics measured in coral skeleton.

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Corals concentrate dissolved inorganic carbon to facilitate calcification

Cited by 106 publications

References 30 publications

Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

The effect of ocean acidification on tropical coral calcification: insights from calcification fluid DIC chemistry

Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification

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