Seawater carbonate chemistry and zooxanthellate coral Cladocora caespitosa boron isotopic and elemental systematics during experiments, 2011

DOI

Boron isotopic and elemental systematics are used to define the vital effects for the temperate shallow water Mediterranean coral Cladocora caespitosa. The corals are from a range of seawater pH conditions (pHT ~ 7.6 to ~ 8.1) and environmental settings: (1) naturally living colonies harvested from normal pH waters offshore Levanto, (2) colonies transplanted nearby a subsea volcanic vent system, and (3) corals cultured in aquaria exposed to high (700 µatm) and near present day (400 µatm) pCO2 levels. B/Ca compositions measured using laser ablation inductively coupled mass spectrometry (LA-ICPMS) show that boron uptake by C. caespitosa cultured at different pCO2 levels is independent of ambient seawater pH being mainly controlled by temperature-dependent calcification. In contrast, the boron isotope compositions (delta11Bcarb) of the full suite of corals determined by positive thermal ionisation mass spectrometry (PTIMS) shows a clear trend of decreasing delta11Bcarb (from 26.7 to 22.2 %o) with decreasing seawater pH, reflecting the strong pH dependence of the boron isotope system. The delta11Bcarb compositions together with measurements of ambient seawater parameters enable calibration of the boron pH proxy for C. caespitosa, by using a new approach that defines the relationship between ambient seawater pH (pHsw) and the internally controlled pH at the site of calcification (pHbiol). C. caespitosa exhibits a linear relationship between pHsw and the shift in pH due to physiological processes (deltapH = pHbiol - pHsw) giving the regression deltapHClad = 4.80 - 0.52* pHsw for this species. We further apply this method ("deltapH-pHsw") to calibrate tropical species of Porites, Acropora, and Stylophora reported in the literature. The temperate and tropical species calibrations are all linearly correlated (r2 > 0.9) and the biological fractionation component (deltapH) between species varies within ~ 0.2 pH units. Our "deltapH-pHsw" approach provides a robust and accurate tool to reconstruct palaeoseawater pHsw for both temperate and tropical corals, further validating the boron fractionation factor (alphaB3-B4 = 1.0272) determined experimentally by Klochko et al. (2006) and the boron isotope pH proxy, both of which have been the foci of considerable debate.

Supplement to: Trotter, Julie; Montagna, Paolo; McCulloch, Malcolm T; Silenzi, Sergio; Reynaud, Stéphanie; Mortimer, Graham; Martin, Sophie; Ferrier-Pagès, Christine; Gattuso, Jean-Pierre; Rodolfo-Metalpa, Riccardo (2011): Quantifying the pH 'vital effect' in the temperate zooxanthellate coral Cladocora caespitosa: Validation of the boron seawater pH proxy. Earth and Planetary Science Letters, 303, 163-173

Identifier
DOI https://doi.org/10.1594/PANGAEA.767603
Related Identifier IsSupplementTo https://doi.org/10.1016/j.epsl.2011.01.030
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.767603
Provenance
Creator Trotter, Julie (ORCID: 0000-0002-0505-488X); Montagna, Paolo ORCID logo; McCulloch, Malcolm T ORCID logo; Silenzi, Sergio; Reynaud, Stéphanie; Mortimer, Graham; Martin, Sophie ORCID logo; Ferrier-Pagès, Christine ORCID logo; Gattuso, Jean-Pierre ORCID logo; Rodolfo-Metalpa, Riccardo
Publisher PANGAEA
Publication Year 2011
Funding Reference Seventh Framework Programme https://doi.org/10.13039/100011102 Crossref Funder ID 211384 https://cordis.europa.eu/project/id/211384 European Project on Ocean Acidification
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 29568 data points
Discipline Earth System Research
Temporal Coverage Begin 2006-08-23T00:00:00Z
Temporal Coverage End 2007-07-02T00:00:00Z