Microelectrode characterization of coral daytime interior pH and carbonate chemistry

Cai, Wei‐Jun; Ma, Yuening; Hopkinson, Brian M.; Grottoli, Andréa G.; Warner, Mark E.; Ding, Qian; Hu, Xinping; Yuan, Xiangchen; Schoepf, Verena; Xu, Hui; Han, Chengyou; Melman, Todd F.; Hoadley, Kenneth D.; Pettay, D. Tye; Matsui, Yohei; Baumann, Justin H.; Levas, Stephen; Ye, Ying; Wang, Yongchen

doi:10.1038/ncomms11144

Cited by 132 publications

(151 citation statements)

References 43 publications

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“…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). Corals cultured at high seawater pCO 2 are unable to attain the same high calcification fluid pH observed in their low seawater pCO 2 counterparts , perhaps because low seawater pH may inhibit the dissipation of H ?…”

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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“…[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 calcification fluid is probably derived from seawater and located between the coral tissue and underlying skeleton (Clode and Marshall, 2002). Corals actively increase the pH of the fluid above that of seawater (Al Horani et al, 2003;Venn et al, 2011Venn et al, , 2012Cai et al, 2016). This may serve as a mechanism to concentrate DIC, one of the substrates required for aragonite precipitation (Allison et al, 2014).…”

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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“…Observing this fluid has proved difficult though, due to its small size and isolation beneath the living polyp (Clode and Marshall, 2002). Estimates of fluid carbonate chemistry have so far been derived from micro-electrodes, pH-sensitive dyes, boron isotopes, B/Ca, U/Ca, and bulk calcification rates (AlHorani et al, 2003;Trotter et al, 2011;Venn et al, 2011;DeCarlo et al, 2015;Cai et al, 2016;Holcomb et al, 2016;Raybaud et al, 2017). However, these approaches do not always agree (Ries, 2011;Holcomb et al, 2014), and they have so far focused on calcifying fluid carbonate chemistry without considering the effect of [Ca 2+ ] on Ar .…”

Section: Introductionmentioning

confidence: 99%

Coral calcifying fluid aragonite saturation states derived from Raman spectroscopy

DeCarlo¹,

D’Olivo²,

Foster³

et al. 2017

Biogeosciences

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Abstract. Quantifying the saturation state of aragonite ( Ar ) within the calcifying fluid of corals is critical for understanding their biomineralization process and sensitivity to environmental changes including ocean acidification. Recent advances in microscopy, microprobes, and isotope geochemistry enable the determination of calcifying fluid pH and [CO ]/K sp ) has proved elusive. Here we test a new technique for deriving Ar based on Raman spectroscopy. First, we analysed abiogenic aragonite crystals precipitated under a range of Ar from 10 to 34, and we found a strong dependence of Raman peak width on Ar with no significant effects of other factors including pH, Mg/Ca partitioning, and temperature. Validation of our Raman technique for corals is difficult because there are presently no direct measurements of calcifying fluid Ar available for comparison. However, Raman analysis of the international coral standard JCp-1 produced Ar of 12.3 ± 0.3, which we demonstrate is consistent with published skeletal Mg/Ca, Sr/Ca, B/Ca, δ 11 B, and δ 44 Ca data. Raman measurements are rapid (≤ 1 s), high-resolution (≤ 1 µm), precise (derived Ar ± 1 to 2 per spectrum depending on instrument configuration), accurate ( ±2 if Ar < 20), and require minimal sample preparation, making the technique well suited for testing the sensitivity of coral calcifying fluid Ar to ocean acidification and warming using samples from natural and laboratory settings. To demonstrate this, we also show a high-resolution time series of Ar over multiple years of growth in a Porites skeleton from the Great Barrier Reef, and we evaluate the response of Ar in juvenile Acropora cultured under elevated CO 2 and temperature.

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Microelectrode characterization of coral daytime interior pH and carbonate chemistry

Cited by 132 publications

References 43 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

Coral calcifying fluid aragonite saturation states derived from Raman spectroscopy

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