Coral Sr/Ca and Mg/Ca records in Con Dao Island off the Mekong Delta: Assessment of their potential for monitoring ENSO and East Asian monsoon

Mitsuguchi, Takehiro; Dang, Phong X.; Kitagawa, Hiroyuki; Uchida, Tetsuo; Shibata, Yasuyuki

doi:10.1016/j.gloplacha.2008.08.002

Cited by 41 publications

(37 citation statements)

References 89 publications

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“…But the physiology within the coral colony may account for differing amounts of Mg among skeletal structures. A recent study (Nothdurft et al, 2005) showed that brucite exists in a wide range of common reef-building coral in Great Barrier Reef and Florida. Elevated Mg concentrations in modern scleractinians may promote the formation of high-Mg calcite cements, as observed in Holocene corals from Heron Reef (Nothdurft et al, 2005), and then cause the deviation from the normal SST-Mg/Ca curves.…”

Section: Model 3: Both Chemical Reaction and Adsorption Of Boron Incomentioning

confidence: 99%

“…Mg is a common trace element in corals and the Mg/Ca ratio has been used to investigate the paleothermometry of seawater (Watanabe et al, 2001;Mitsuguchi et al, 2008;Allison et al, 2010). The incorporation of Mg into coral skeleton is controlled by varying factors.…”

Section: Introductionmentioning

confidence: 99%

“…The incorporation of Mg into coral skeleton is controlled by varying factors. Mg can exist in the form of brucite in corals (Smith and Delong, 1978;Nothdurft et al, 2005) and Mg content in scleractinian corals varies between different genera and localities (Fallon et al, 1999). Nothdurft et al (2005) studied brucite in living scleractinian corals colonies (Acropora, Pocillopora, Porites) from subtidal and intertidal settings in the Great Barrier Reef, Australia, and subtidal Montastraea from the Florida Keys, United States.…”

Section: Introductionmentioning

confidence: 99%

“…Mg can exist in the form of brucite in corals (Smith and Delong, 1978;Nothdurft et al, 2005) and Mg content in scleractinian corals varies between different genera and localities (Fallon et al, 1999). Nothdurft et al (2005) studied brucite in living scleractinian corals colonies (Acropora, Pocillopora, Porites) from subtidal and intertidal settings in the Great Barrier Reef, Australia, and subtidal Montastraea from the Florida Keys, United States. Their results suggested that high containing activity combined with high pH and low pCO 2 led to localized brucite precipitation in organic biofilms of coral skeletons and that brucite in living coral skeletons is an indicator of extreme microenvironments in shallow-marine settings.…”

Section: Introductionmentioning

confidence: 99%

“…Their results suggested that high containing activity combined with high pH and low pCO 2 led to localized brucite precipitation in organic biofilms of coral skeletons and that brucite in living coral skeletons is an indicator of extreme microenvironments in shallow-marine settings. The occurrence of brucite in corals can bring a higher Mg/Ca ratio and be responsible for reported anomalies in Mg/Ca vs. sea-surface temperature (SST) plots in corals (Nothdurft et al, 2005). Defining the source of such anomalies is critical for using Mg/Ca in corals to reconstruct the paleothermometry of seawater (Mg/Ca-SST proxy).…”

Section: Introductionmentioning

confidence: 99%

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Boron isotope fractionation during brucite deposition from artificial seawater

2011

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Abstract. Experiments involving boron incorporation into brucite (Mg(OH) 2 ) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite and the influence of it on Mg/Ca-SST proxy and δ 11 B-pH proxy. The results show that both the concentration of boron in deposited brucite ([B] d ) and its boron partition coefficient (K d ) between deposited brucite and final seawater are controlled by the pH of the solution. The incorporation capacity of boron into brucite is almost the same as that into corals, but much stronger than that into oxides and clay minerals. The isotopic compositions of boron in deposited brucite (δ 11 B d ) are higher than those in the associated artificial seawater (δ 11 B isw ) with fractionation factors ranging between 1.0177 and 1.0569, resulting from the preferential incorporation of B(OH) 3 into brucite. Both boron adsorptions onto brucite and the precipitation reaction of H 3 BO 3 with brucite exist during deposition of brucite from artificial seawater. The simultaneous occurrence of both processes determines the boron concentration and isotopic fractionation of brucite. The isotopic fractionation behaviors and mechanisms of boron incorporated into brucite are different from those into corals. The existence of brucite in corals can affect the δ 11 B and Mg/Ca in corals and influences the Mg/Ca-SST proxy and δ 11 B-pH proxy negatively. The relationship between δ 11 B and Mg/Ca in corals can be used to judge the existence of brucite in corals, which should provide a reliable method for better use of δ 11 B and Mg/Ca in corals to reconstruct paleo-marine environment.

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Section: Model 3: Both Chemical Reaction and Adsorption Of Boron Incomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Boron isotope fractionation during brucite deposition from artificial seawater

2011

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Lead in the western South China Sea: Evidence of atmospheric deposition and upwelling

Chen

Goodkin

Boyle

et al. 2016

Geophysical Research Letters

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In recent decades, rapid industrial developments have increased lead (Pb) inputs to the South China Sea. To quantify the increasing variability, we investigated 170 years of skeletal Pb and Pb isotopes from an offshore, central Vietnamese coral. The Pb/Ca in the coral was 10–16 nmol/mol before the mid‐1950s and increased to more than 30 nmol/mol by 2000. While the regional phaseout of leaded petrol commenced in 2000, coral Pb/Ca continued increasing until 2004, possibly due to regional upwelling and the transport of previously emitted Pb from tropical Pacific waters. The 206Pb/207Pb ratio in the coral was 1.191–1.195 before mid‐1950s, suggesting natural sources. Since then, the ratio decreased, reaching ~1.165 in 2004. Lead isotopes show high linearity between natural and Chinese emitted Pb, with the latter contributing ~40%~60% of the skeletal Pb after 2000.

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Intrareef variations in Li/Mg and Sr/Ca sea surface temperature proxies in the Caribbean reef‐building coral Siderastrea siderea

et al. 2016

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Caribbean sea surface temperatures (SSTs) have increased at a rate of 0.2°C per decade since 1971, a rate double that of the mean global change. Recent investigations of the coral Siderastrea siderea on the Belize Mesoamerican Barrier Reef System (MBRS) have demonstrated that warming over the last 30 years has had a detrimental impact on calcification. Instrumental temperature records in this region are sparse, making it necessary to reconstruct longer SST records indirectly through geochemical temperature proxies. Here we investigate the skeletal Sr/Ca and Li/Mg ratios of S. siderea from two distinct reef zones (forereef and backreef) of the MBRS. Our field calibrations of S. siderea show that Li/Mg and Sr/Ca ratios are well correlated with temperature, although both ratios are 3 times more sensitive to temperature change in the forereef than in the backreef. These differences suggest that a secondary parameter also influences these SST proxies, highlighting the importance for site‐ and species‐specific SST calibrations. Application of these paleothermometers to downcore samples reveals highly uncertain reconstructed temperatures in backreef coral, but well‐matched reconstructed temperatures in forereef coral, both between Sr/Ca‐SSTs and Li/Mg‐SSTs, and in comparison to the Hadley Centre Sea Ice and Sea Surface Temperature record. Reconstructions generated from a combined Sr/Ca and Li/Mg multiproxy calibration improve the precision of these SST reconstructions. This result confirms that there are circumstances in which both Li/Mg and Sr/Ca are reliable as stand‐alone and combined proxies of sea surface temperature. However, the results also highlight that high‐precision, site‐specific calibrations remain critical for reconstructing accurate SSTs from coral‐based elemental proxies.

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Coral Sr/Ca and Mg/Ca records in Con Dao Island off the Mekong Delta: Assessment of their potential for monitoring ENSO and East Asian monsoon

Cited by 41 publications

References 89 publications

Boron isotope fractionation during brucite deposition from artificial seawater

Boron isotope fractionation during brucite deposition from artificial seawater

Lead in the western South China Sea: Evidence of atmospheric deposition and upwelling

Intrareef variations in Li/Mg and Sr/Ca sea surface temperature proxies in the Caribbean reef‐building coral Siderastrea siderea

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