Mg/Ca, Sr/Ca and U/Ca ratios of a porites coral from Sanya Bay, Hainan Island, South China Sea and their relationships to sea surface temperature

Wei, Gangjian; Sun, Min; Li, Xian‐Hua; Nie, Baofu

doi:10.1016/s0031-0182(00)00105-x

Cited by 136 publications

(90 citation statements)

References 25 publications

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“…Pearson correlation analyses between the Na/Ca, Mg/Ca and Sr/ Ca data of each sample are shown in Table 2. For all the samples, the Mg/Ca and Sr/Ca results show clear cyclical variations and are strongly negatively correlated with each other (r = -0.688 to -0.917; p < 0.0001); both can be assumed to reflect the annual cycle of SST at each location because (1) it has been demonstrated that coral Sr/Ca and Mg/Ca ratios are negatively and positively correlated with SST, respectively, although the Mg/Ca-SST correlation becomes very weak in some corals (e.g., Beck et al, 1992;Mitsuguchi et al, 1996Mitsuguchi et al, , 2003Mitsuguchi et al, , 2008Fallon et al, 1999Fallon et al, , 2003Wei et al, 2000;Watanabe et al, 2001a;Quinn and Sampson, 2002;Allison and Finch, 2007) and …”

Section: Resultsmentioning

confidence: 99%

Na/Ca variability in coral skeletons

2010

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Section: Resultsmentioning

confidence: 99%

Na/Ca variability in coral skeletons

2010

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“…Sr/Ca in seawater, and consequently in the coral skeleton, can be impacted by heavy precipitations in specific settings (Wei et al, 2000). Consequently, even if geochemical modifications related to environmental changes after the coral colony displacement cannot be completely excluded, this phenomenon participatesmost probably only partially to the observed change.…”

Section: Origin Of the Intra-skeletal Calcite: Biogenic Vs Early Diamentioning

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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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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“…2011), which cannot be explained by a simple temperature dependency of uranium incorporation (Min et al, 1995;Shen and Dunbar, 1995;Wei et al, 2000). For example taking the equation (Min et al, 1995) T ( • C) = 48.0-21.5 · U / Ca (µmol mol −1 ), a value of our data set of 1.13 (µmol mol −1 , 6.0 • C Stjernsund) would result in temperatures too warm for a CWC site (23.7 • C).…”

Section: The Effect Of Coral Physiology and Symbiotic Algae On Uraniumentioning

confidence: 99%

The influence of seawater pH on U / Ca ratios in the scleractinian cold-water coral <i>Lophelia pertusa</i>

Raddatz

Rüggeberg²,

Flögel

et al. 2014

Biogeosciences

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Abstract. The increasing pCO 2 in seawater is a serious threat for marine calcifiers and alters the biogeochemistry of the ocean. Therefore, the reconstruction of past-seawater properties and their impact on marine ecosystems is an important way to investigate the underlying mechanisms and to better constrain the effects of possible changes in the future ocean. Cold-water coral (CWC) ecosystems are biodiversity hotspots. Living close to aragonite undersaturation, these corals serve as living laboratories as well as archives to reconstruct the boundary conditions of their calcification under the carbonate system of the ocean.We investigated the reef-building CWC Lophelia pertusa as a recorder of intermediate ocean seawater pH. This species-specific field calibration is based on a unique sample set of live in situ collected L. pertusa and corresponding seawater samples. These data demonstrate that uranium speciation and skeletal incorporation for azooxanthellate scleractinian CWCs is pH dependent and can be reconstructed with an uncertainty of ±0.15. Our Lophelia U / Ca-pH calibration appears to be controlled by the high pH values and thus highlighting the need for future coral and seawater sampling to refine this relationship. However, this study recommends L. pertusa as a new archive for the reconstruction of intermediate water mass pH and hence may help to constrain tipping points for ecosystem dynamics and evolutionary characteristics in a changing ocean.

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Mg/Ca, Sr/Ca and U/Ca ratios of a porites coral from Sanya Bay, Hainan Island, South China Sea and their relationships to sea surface temperature

Cited by 136 publications

References 25 publications

Na/Ca variability in coral skeletons

Na/Ca variability in coral skeletons

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

The influence of seawater pH on U / Ca ratios in the scleractinian cold-water coral <i>Lophelia pertusa</i>

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Mg/Ca, Sr/Ca and U/Ca ratios of a porites coral from Sanya Bay, Hainan Island, South China Sea and their relationships to sea surface temperature

Cited by 136 publications

References 25 publications

Na/Ca variability in coral skeletons

Na/Ca variability in coral skeletons

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

The influence of seawater pH on U / Ca ratios in the scleractinian cold-water coral &lt;i&gt;Lophelia pertusa&lt;/i&gt;

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The influence of seawater pH on U / Ca ratios in the scleractinian cold-water coral <i>Lophelia pertusa</i>