Calcifying coral abundance near low-pH springs: implications for future ocean acidification

Crook, Elizabeth D.; Potts, D. C.; Rebolledo-Vieyra, M.; Hernandez, Laura; Paytan, Adina

doi:10.1007/s00338-011-0839-y

Cited by 121 publications

(136 citation statements)

References 24 publications

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“…Extension rates of P. cylindrica nubbins used in both the treatment and control flumes were similar to P. cylindrica from elsewhere in the GBR (31); however, this is not entirely surprising given that coral can maintain similar rates of extension under low-pH conditions at the cost of reduced skeletal density and hence rates of calcification (32). Nonetheless, we find that the skeletal densities in the low pH FOCE corals differed by less than 3% from the densities of control corals (Table S3).…”

Section: Resultssupporting

confidence: 53%

pH homeostasis during coral calcification in a free ocean CO ₂ enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

Georgiou

Falter

Trotter

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Geochemical analyses (δ 11 B 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 CO 2 -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 (pH cf ); the latter was derived from boron isotopic compositions (δ 11 B) of the coral skeleton. Furthermore, individual nubbins exhibited near constant δ 11 B compositions along their primary apical growth axes (±0.02 pH cf 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 (pH cf ∼8.4-8.6), with each nubbin having nearconstant pH cf 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.A tmospheric CO 2 has risen by more than 30% during the last century, causing a reduction in seawater pH of ∼0.1 units relative to preindustrial times, with a further reduction of 0.1-0.4 units predicted to occur by the end of this century (1). This process, commonly known as "ocean acidification," is expected to have severe impacts on calcifying marine organisms due to its effect on the thermodynamics of biomineralization (2). Our current understanding of the sensitivity of coral calcification to declining seawater pH has mainly been inferred from short-term laboratory-based studies that do not fully simulate real-world reef conditions, particularly the daily to seasonal variations in temperature, light, and pH (3-5). To address these shortcomings, we applied free ocean carbon enrichment (FOCE) technologies (6-9) to manipulate water chemistry in situ and thereby provide more realistic experimental conditions to investigate how future levels of acidification could affect marine organisms according to different representative concentration pathways (RCPs) (10). The FOCE system uses a flowthrough flume design that allows organisms to experience near natural conditions, in particular the daily and seasonal regimes of fluctuating temperature, light, and nutrients while maintaining offsets in flume water pH below ...

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Section: Resultssupporting

confidence: 53%

pH homeostasis during coral calcification in a free ocean CO ₂ enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

Georgiou

Falter

Trotter

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…study low Ω arag coincided with high nutrient levels (Crook et al, 2012), which could also cause increased bioerosion (Glynn, 1997). On the other hand Tribollet et al (2009) showed that coral blocks euendolithic micro-algae developed significantly under conditions of comparably low Ω arag levels at low nutrient levels (NH 4 + =0.4 µmole/L and PO 4 -3 =0.1 µmole/L).…”

Section: Discussionmentioning

confidence: 97%

Community calcification in Lizard Island, Great Barrier Reef: A 33 year perspective

Silverman

Schneider

Kline

et al. 2014

Geochimica et Cosmochimica Acta

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Measurements of community calcification (G net)However, it should be noted that the uncertainty in the live coral coverage estimates in this study and in 1978 were fairly large and inherent to this methodology. Using the reef calcification rate equation while assuming that seawater above the reef was at equilibrium with atmospheric PCO 2 and given that live coral cover had not changed G net should have declined by 30±8% since the LIMER study as indeed observed. We note, however, that the error in estimated G net decrease relative to the 1970's could be much larger due to the uncertainties in the coral coverage measurements. Nonetheless, The similarity between the predicted and the measured decrease in G net suggests that ocean acidification may be the primary cause for the lower CaCO 3 precipitation rate on the Lizard Island reef flat.

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“…Seepage of groundwater can lead to areas of high pCO 2 and low pH in coastal ecosystems (Basterretxea et al 2010). Groundwater with a low carbonate saturation state (Ω≈0.5) and reduced pH (6.70-7.30) seeps through the seafloor, creating localized low seawater pH in the natural submarine groundwater springs at Puerto Morales, Mexico (Crook et al 2012). Submarine volcanic vents or groundwater seeps can also lead to high CO 2 and low pH in surface coastal waters.…”

Section: Regulation Of Seawater Ph In the Pre-disturbed Holocene Oceanmentioning

confidence: 99%

Is Ocean Acidification an Open-Ocean Syndrome? Understanding Anthropogenic Impacts on Seawater pH

Duarte

Hendriks

Moore

et al. 2013

Estuaries and Coasts

606

452

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Ocean acidification due to anthropogenic CO 2 emissions is a dominant driver of long-term changes in pH in the open ocean, raising concern for the future of calcifying organisms, many of which are present in coastal habitats. However, changes in pH in coastal ecosystems result from a multitude of drivers, including impacts from watershed processes, nutrient inputs, and changes in ecosystem structure and metabolism. Interaction between ocean acidification due to anthropogenic CO 2 emissions and the dynamic regional to local drivers of coastal ecosystems have resulted in complex regulation of pH in coastal waters. Changes in the watershed can, for example, lead to changes in alkalinity and CO 2 fluxes that, together with metabolic processes and oceanic dynamics, yield high-magnitude decadal changes of up to 0.5 units in coastal pH. Metabolism results in strong diel to seasonal fluctuations in pH, with characteristic ranges of 0.3 pH units, with metabolically intense habitats exceeding this range on a daily basis. The intense variability and multiple, complex controls on pH implies that the concept of ocean acidification due to anthropogenic CO 2 emissions cannot be transposed to coastal ecosystems directly. Furthermore, in coastal ecosystems, the detection of trends towards acidification is not trivial and the attribution of these changes to anthropogenic CO 2 emissions is even more problematic. Coastal ecosystems may show acidification or basification, depending on the balance between the invasion of coastal waters by anthropogenic CO 2 , watershed export of alkalinity, organic matter and CO 2 , and changes in the balance between primary production, respiration and calcification rates in response to changes in nutrient inputs and losses of ecosystem components. Hence, we contend that ocean acidification from anthropogenic CO 2 is largely an open-ocean syndrome and that a concept of anthropogenic impacts on marine pH, which is applicable across the entire ocean, from coastal to open-ocean environments, provides a superior framework to consider the multiple components of the anthropogenic perturbation of marine pH trajectories. The concept of anthropogenic impacts on seawater pH acknowledges that a regional focus is necessary to predict future trajectories in the pH of coastal waters and points at opportunities to manage these trajectories locally to conserve coastal organisms vulnerable to ocean acidification.

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Calcifying coral abundance near low-pH springs: implications for future ocean acidification

Cited by 121 publications

References 24 publications

pH homeostasis during coral calcification in a free ocean CO ₂ enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

pH homeostasis during coral calcification in a free ocean CO ₂ enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

Community calcification in Lizard Island, Great Barrier Reef: A 33 year perspective

Is Ocean Acidification an Open-Ocean Syndrome? Understanding Anthropogenic Impacts on Seawater pH

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Calcifying coral abundance near low-pH springs: implications for future ocean acidification

Cited by 121 publications

References 24 publications

pH homeostasis during coral calcification in a free ocean CO 2 enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

pH homeostasis during coral calcification in a free ocean CO 2 enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

Community calcification in Lizard Island, Great Barrier Reef: A 33 year perspective

Is Ocean Acidification an Open-Ocean Syndrome? Understanding Anthropogenic Impacts on Seawater pH

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pH homeostasis during coral calcification in a free ocean CO ₂ enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef

pH homeostasis during coral calcification in a free ocean CO ₂ enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef