Abstract. The boron isotopic composition (δ11B) of marine carbonates (e.g. corals) has been established as a reliable proxy for paleo-pH, with the strong correlation between δ11B of marine calcifiers and seawater pH being now well documented. However, further investigations are needed in order to better quantify other environmental parameters potentially impacting boron isotopic composition and boron concentration into coral aragonite. To achieve this goal the tropical scleractinian coral Acropora sp. was cultured under 3 different temperature (22, 25 and 28 °C) and two light conditions (200 and 400 μmol photon m−2 s−1). The δ11B indicates an internal increase in pH from ambient seawater under both light conditions. Changes in light intensities from 200 to 400 μmol photon m−2 s−1 could bias pH reconstructions by about 0.05 units. For both light conditions, a significant impact of temperature on δ11B can be observed between 22 and 25 °C corresponding to enhancements of about 0.02 pH-units, while no further δ11B increase can be observed between 25 and 28 °C. This non-linear temperature effect complicates the determination of a correcting factor. B/Ca ratios decrease with increasing light, confirming the decrease in pH at the site of calcification under enhanced light intensities. When all the other parameters are maintained constant, boron concentrations in Acropora sp. increase with increasing temperature and increasing carbonate ions concentrations. These observations contradict previous studies where B/Ca in corals was found to vary inversely with temperature suggesting that the controlling factors driving boron concentrations have not yet been adequately identified and might be influenced by other seawater variables and species specific responses.

Ocean Acidification

Acropora

10.5194/bgd-9-5969-2012

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Citations (4)

Using Zn isotopes to investigate trace metal partitions between dissolved and suspended loads in the Seine River, France

AGU Fall Meeting Abstracts (2007)

J. Chen Jérôme Gaillardet Pascale Louvat

Trace metal

TRACE (psycholinguistics)

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Stable tracer investigations in humans for assessing the biokinetics of ruthenium and zirconium radionuclides

Radiation Protection Dosimetry (2003)

I. Veronese M.C. Cantone A. Giussani T Maggioni C. Birattari

The interest in the biokinetics of ruthenium and zirconium in humans is justified by the potential radiological risk represented by their radionuclides. Only a few data related to the biokinetics of ruthenium and zirconium in humans are available and, accordingly, the biokinetic models currently recommended by the ICRP for these elements are mainly based on data from animal experiments. The use of stable isotopes as tracers, coupled with a proper analytical technique (nuclear activation analysis with protons) for their determination in biological samples, represents an ethically acceptable methodology for biokinetic investigations, being free from any radiation risk for the volunteer subjects. In this work, the results obtained in eight biokinetic investigations for ruthenium, conducted on a total of three healthy volunteers, and six for zirconium, performed on a total of three subjects, are presented and compared to the predictions of the ICRP models.

TRACER

10.1093/oxfordjournals.rpd.a006224

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Cosmogenic Nuclides, River Geochemistry, and Lanforms Reconstruction Methods Comparison to Study the Coopling Between Chemical Weahering and Mechanical Erosion in a Steep Reunion Island Basin.

AGU Fall Meeting Abstracts (2014)

Éric Gayer Pascale Louvat Laurent Michon

Cosmogenic nuclide

Nuclide

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