Evidence for ocean acidification in the Great Barrier Reef of Australia

Wei, Gangjian; McCulloch, Malcolm T.; Mortimer, Graham; Deng, Wenfeng; Xie, Luhua

doi:10.1016/j.gca.2009.02.009

Cited by 153 publications

(161 citation statements)

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“…(Douville et al, 2010;Hemming et al, 1998;Krief et al, 2010;Pelejero et al, 2005;Shinjo et al, 2013b;Wei et al, 2009) (Lécuyer et al, 2002;Penman et al, 2013).Benthic foraminifera calcite presentlower δ 11 B (14-17‰), except for the high-magnesium calcite of large foraminifera (26‰),whilehigher values (21-25‰) were measured on planktonic species (Holcomb et al, 2015;Hönisch et al, 2008;Rae et al, 2011;Sanyal et al, 1996). For gorgonian calcite corals, recent studies of the genus Keratoisis (bamboo coral) revealed low values of δ 11 B, between 14 and 17‰ (Farmer et al, 2015).…”

Section: Impact On δ 11 B B/ca and Reconstructed Phmentioning

confidence: 96%

“…Contrarily, boron isotopes in Porites sp. skeleton has been used with success to reconstruct paleo-pH of surface seawater and ocean acidification related to the inception and development of the industrial era (e.g., Douville et al, 2010;Liu et al, 2009;Shinjo et al, 2013a;Wei et al, 2009;Wu et al, 2013). Even if boron isotopes in corals are now considered to be directly the reflect of pH of the calcification fluid (Allison et al, 2010;Blamart et al, 2007;Rollion-Bard et al, 2003;Venn et al, 2011), Trotter et al(2011) highlighted that pH of the calcification in scleractinian corals depends on pH of seawater.…”

Section: Introductionmentioning

confidence: 99%

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Intra-skeletal calcite in a live-collected Porites sp.: Impact on environmental proxies and potential formation process

Lazareth

Soares-Pereira

Douville

et al. 2016

Geochimica et Cosmochimica Acta

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Geochemical proxies measured in the carbonate skeleton of tropical coral Porites sp. have commonly been used to reconstruct sea surface temperature (SST) and more recently seawater pH. Nevertheless, both reconstructed SST and pH depend on the preservation state of the skeleton, here made of aragonite; i.e., diagenetic processes and its related effects should be limited. In this study, we report on the impact of the presence of intra-skeletal calcite on the skeleton geochemistry of a live-collected Porites sp..The Porites skeleton preservation state was analyzed using X-ray diffraction and scanning electron microscopy. Sr/Ca, Mg/Ca, U/Ca, Ba/Ca, Li/Mg, and B/Ca ratios were measured at a monthly and yearly resolution using solution ICP-MS and multi-collector ICP-MS. Theδ 11 B signatures and the calcite percentages were acquired at a yearly timescale. The coral colony presents two parts, one with less than 3% calcite (referred to as "no-calcite" skeleton), the other one, corresponding to the skeleton formed during the last 4 yrs. of growth,with calcite percentages varying from 13 to 32% (referred to as "with calcite" skeleton). This intra-skeletal calcite replaces partly or completely numerouscenter of calcification (COCs). All geochemical tracers investigated are significantlyimpacted by the presence of calcite. Thereconstructed SSTdecreasesby about0.1°C per calcite-percent as inferred fromthe Sr/Ca ratio. Such impact reaches up to 0.26°C per calcite-percent for temperature deduced from the Li/Mg ratio. So, less than 5% of such intra-skeletal calcite does not prevent SST reconstructions using Sr/Ca ratio, but the percentage and type of calcite have to be determined before fine SST interpretation. Seawater pH reconstruction inferredfrom boron isotopes drop by about -0.011 pH-unit per calcitepercent. Such sensitivity to calcite presence is particularly dramatic for fine paleo-pH reconstructions. Here we suggest that after being brought to shallow waters following a cyclone, the studied coral was seasonally subjected to rainfall-related water freshening that could have mimicked a vadose environment like can be encountered on raised fossil coral reefs. Nevertheless, the process of calcite precipitation remains to be determined.

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Section: Impact On δ 11 B B/ca and Reconstructed Phmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Intra-skeletal calcite in a live-collected Porites sp.: Impact on environmental proxies and potential formation process

Lazareth

Soares-Pereira

Douville

et al. 2016

Geochimica et Cosmochimica Acta

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“…It is also conceivable that this response has contributed to the increased rate of skeletal extension on the GBR since the 1900s (Fig. 8b); where pH is predicted to have dropped by about 0.2-0.3 units from the 1940s to the present day (Wei et al, 2009).…”

Section: Ocean Acidificationmentioning

confidence: 99%

A new conceptual model of coral biomineralisation: hypoxia as the physiological driver of skeletal extension

Wooldridge

2013

Biogeosciences

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That corals skeletons are built of aragonite crystals with taxonomy-linked ultrastructure has been well understood since the 19th century. Yet, the way by which corals control this crystallization process remains an unsolved question. Here, I outline a new conceptual model of coral biomineralisation that endeavours to relate known skeletal features with homeostatic functions beyond traditional growth (structural) determinants. In particular, I propose that the dominant physiological driver of skeletal extension is night-time hypoxia, which is exacerbated by the respiratory oxygen demands of the coral's algal symbionts (= zooxanthellae). The model thus provides a new narrative to explain the high growth rate of symbiotic corals, by equating skeletal deposition with the "work-rate" of the coral host needed to maintain a stable and beneficial symbiosis. In this way, coral skeletons are interpreted as a continuous (long-run) recording unit of the stability and functioning of the coral–algae endosymbiosis. After providing supportive evidence for the model across multiple scales of observation, I use coral core data from the Great Barrier Reef (Australia) to highlight the disturbed nature of the symbiosis in recent decades, but suggest that its onset is consistent with a trajectory that has been followed since at least the start of the 1900s. In concluding, I outline how the proposed capacity of cnidarians (which includes modern reef corals) to overcome the metabolic limitation of hypoxia via skeletogenesis also provides a new hypothesis to explain the sudden appearance in the fossil record of calcified skeletons at the Precambrian–Cambrian transition – and the ensuing rapid appearance of most major animal phyla

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“…Although the development of laser ablation analytical techniques has made high-resolution elemental ratio analysis faster and more convenient than traditional wet chemical methods (Sinclair et al 1998;Fallon et al 1999;McCulloch et al 2003;Deng et al 2010), the analytical precision of the laser ablation method remains generally poor relative to that expected from, for example, changes in seawater temperature. For many isotopic proxies, especially the non-traditional isotope systems such as magnesium, calcium, boron, and clumped isotopes, a series of complex chemical separation and purification procedures are needed, and these procedures remain burdensome (Pelejero et al 2005;Böhm et al 2006;Ghosh et al 2006;Wei et al 2009;Yoshimura et al 2011). Consequently, the high-resolution analysis of these geochemical systems is generally not practical, especially over multi-decadal timescales.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, relative to the large quantity of high-resolution studies, annual to multi-year resolution coral-based studies are still relatively rare. In addition, of those coral-based studies undertaken at annual to pent-annual resolutions (Dunbar et al 1994;Cole et al 2000;Hendy et al 2002;Pelejero et al 2005;Calvo et al 2007;Linsley et al 2008;Abram et al 2009;Wei et al 2009;Deng et al 2013;Zinke et al 2014), few have focused on the replication of the lowresolution geochemical records of multiple coral cores. Some studies have evaluated the climatic significance of annual coral records averaged using monthly or sub-annual values from each year (Lough 2004;Smith et al 2006;Pfeiffer et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of annual resolution coral geochemical records as climate proxies in the Great Barrier Reef of Australia

et al. 2014

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Sampling of annually banded massive coral skeletons at annual (or higher) resolutions is increasingly being used to obtain replicate long-term time series of changing seawater conditions. However, few of these studies have compared and calibrated the lower annual resolution records based on coral geochemical tracers with the corresponding instrumental climate records, although some studies have inferred the climatic significance of annual coral series derived from averages of monthly or sub-annual records. Here, we present annual resolution analysis of coral records of elemental and stable isotopic composition that are approximately 70 years long. These records were preserved in two coexisting colonies of Porites sp. from Arlington Reef, on the Great Barrier Reef in Australia, and are used to evaluate the climatic significance of annually resolved coral geochemical proxies. The geochemical records of coral sample ''10AR2,'' with its faster and relatively constant annual growth rate, appear to have been independent of skeletal growth rate and other vital effects. The annual resolution of Sr/Ca and Dd 18 O time series was shown to be a good proxy for annual sea surface temperature (SST; r = -0.67, n = 73, p \ 0.0000001) and rainfall records (r = -0.34, n = 67, p \ 0.01). However, a slower growing coral sample, ''10AR1'' showed significantly lower correlations (r = -0.20, n = 71, p = 0.05 for Sr/Ca and SST; r = -0.19, n = 67, p = 0.06 for Dd 18 O and rainfall), indicating its greater susceptibility to biological/metabolic effects. Our results suggest that while annually resolved coral records are potentially a valuable tool for determining, in particular, long timescale climate variability such as Pacific Decadal Oscillation, Interdecadal Pacific Oscillation, and other climatic factors, the selection of the coral sample is important, and replication is essential.

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Evidence for ocean acidification in the Great Barrier Reef of Australia

Cited by 153 publications

References 62 publications

Intra-skeletal calcite in a live-collected Porites sp.: Impact on environmental proxies and potential formation process

Intra-skeletal calcite in a live-collected Porites sp.: Impact on environmental proxies and potential formation process

A new conceptual model of coral biomineralisation: hypoxia as the physiological driver of skeletal extension

Evaluation of annual resolution coral geochemical records as climate proxies in the Great Barrier Reef of Australia

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