Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 13219-13224 |
| Number of pages | 6 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 112 |
| Issue number | 43 |
| Early online date | 5 Oct 2015 |
| DOIs | |
| Publication status | Published - 27 Oct 2015 |
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pH homeostasis during coral calcification in a free ocean CO2 enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef. / Georgiou, Lucy; Falter, James; Trotter, Julie; Kline, D.I.; Holcomb, Michael; Dove, S.G.; Hoegh-Guldberg, O.; Mcculloch, Malcolm.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 112, No. 43, 27.10.2015, p. 13219-13224.Research output: Contribution to journal › Article
TY - JOUR
T1 - pH homeostasis during coral calcification in a free ocean CO2 enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef
AU - Georgiou, Lucy
AU - Falter, James
AU - Trotter, Julie
AU - Kline, D.I.
AU - Holcomb, Michael
AU - Dove, S.G.
AU - Hoegh-Guldberg, O.
AU - Mcculloch, Malcolm
PY - 2015/10/27
Y1 - 2015/10/27
N2 - © 2015 PNAS. Geochemical analyses (δ11B and Sr/Ca) are reported for the coral Porites cylindrica grown within a free ocean carbon enrichment (FOCE) experiment, conducted on the Heron Island reef flat (Great Barrier Reef) for a 6-mo period from June to early December 2010. The FOCE experiment was designed to simulate the effects of CO2- driven acidification predicted to occur by the end of this century (scenario RCP4.5) while simultaneously maintaining the exposure of corals to natural variations in their environment under in situ conditions. Analyses of skeletal growth (measured from extension rates and skeletal density) showed no systematic differences between low-pH FOCE treatments (ΔpH = ∼-0.05 to -0.25 units below ambient) and present day controls (ΔpH = 0) for calcification rates or the pH of the calcifying fluid (pHcf); the latter was derived from boron isotopic compositions (δ11B) of the coral skeleton. Furthermore, individual nubbins exhibited near constant δ11B compositions along their primary apical growth axes (±0.02 pHcf units) regardless of the season or treatment. Thus, under the highly dynamic conditions of the Heron Island reef flat, P. cylindrica up-regulated the pH of its calcifying fluid (pHcf ∼8.4-8.6), with each nubbin having nearconstant pHcf values independent of the large natural seasonal fluctuations of the reef flat waters (pH ∼7.7 to ∼8.3) or the superimposed FOCE treatments. This newly discovered phenomenon of pH homeostasis during calcification indicates that coral living in highly dynamic environments exert strong physiological controls on the carbonate chemistry of their calcifying fluid, implying a high degree of resilience to ocean acidification within the investigated ranges.
AB - © 2015 PNAS. Geochemical analyses (δ11B and Sr/Ca) are reported for the coral Porites cylindrica grown within a free ocean carbon enrichment (FOCE) experiment, conducted on the Heron Island reef flat (Great Barrier Reef) for a 6-mo period from June to early December 2010. The FOCE experiment was designed to simulate the effects of CO2- driven acidification predicted to occur by the end of this century (scenario RCP4.5) while simultaneously maintaining the exposure of corals to natural variations in their environment under in situ conditions. Analyses of skeletal growth (measured from extension rates and skeletal density) showed no systematic differences between low-pH FOCE treatments (ΔpH = ∼-0.05 to -0.25 units below ambient) and present day controls (ΔpH = 0) for calcification rates or the pH of the calcifying fluid (pHcf); the latter was derived from boron isotopic compositions (δ11B) of the coral skeleton. Furthermore, individual nubbins exhibited near constant δ11B compositions along their primary apical growth axes (±0.02 pHcf units) regardless of the season or treatment. Thus, under the highly dynamic conditions of the Heron Island reef flat, P. cylindrica up-regulated the pH of its calcifying fluid (pHcf ∼8.4-8.6), with each nubbin having nearconstant pHcf values independent of the large natural seasonal fluctuations of the reef flat waters (pH ∼7.7 to ∼8.3) or the superimposed FOCE treatments. This newly discovered phenomenon of pH homeostasis during calcification indicates that coral living in highly dynamic environments exert strong physiological controls on the carbonate chemistry of their calcifying fluid, implying a high degree of resilience to ocean acidification within the investigated ranges.
U2 - 10.1073/pnas.1505586112
DO - 10.1073/pnas.1505586112
M3 - Article
VL - 112
SP - 13219
EP - 13224
JO - National Academy of Sciences, Proceedings
JF - National Academy of Sciences, Proceedings
SN - 0027-8424
IS - 43
ER -