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Skeletal microstructure and stable isotope signature of three bathyal solitary cold-water corals from the Azores

Marali S, Wisshak M, López Correa M, Freiwald A (2013)

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Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2013

Journal

Publisher: Elsevier

Book Volume: 373

Pages Range: 25-38

DOI: 10.1016/j.palaeo.2012.06.017

Open Access Link: https://doi.org/10.1016/j.palaeo.2012.06.017

Abstract

Skeletons of cold-water corals are potential geochemical archives that record oceanographic parameters, such as bottom water temperature in the deep sea. In this study, the three solitary scleractinian species, Caryophyllia cyathus, Desmophyllum cristagalli and Stenocyathus vermiformis, were sampled from upper bathyal 500m water depths in the southern Faial Channel (Azores archipelago). The stable carbon isotope (δ¹³C) and oxygen isotope (δ¹⁸O) compositions of the corals were analysed and related to their skeletal architecture. Background data, including data from high-resolution temperature logs and on the ambient seawater isotopic composition, were compared with δ¹⁸O-based temperature reconstructions to test the suitability of these cold-water corals as geochemical archives and to explore the role of vital effects on skeletal geochemistry. Although all of the corals experienced identical and near-stable salinities and temperatures, the stable isotopic signatures vary within and among species. Both δ¹³C and δ¹⁸O values fluctuate in relation to growth bandings and are therefore most likely dependent on calcification rates and associated kinetic vital effects. The studied specimens are ¹³C depleted with respect to equilibrium with ambient seawater, indicating significant uptake of respired CO2 by their skeletons. Skeletal δ¹⁸O values vary by up to 3.6‰ among the growth bands of one of the coral specimens, translating into an unrealistic reconstructed temperature amplitude of ~16°C. This contrasts with the minute intra-annual amplitude of the stable temperature regime (annual mean 12.30±0.25°C). Nevertheless, δ¹³C vs. δ¹⁸O regression lines can be used to deduce ambient temperatures by applying the lines technique (Smith et al., 2000; Palaios 15, 25-32), which yields temperatures that coincide with the measured maximum temperature range in the case of D. cristagalli and for most C. cyathus samples, but deviate by 2.95°C from the measured annual mean in the case of the S. vermiformis specimen. © 2012 Elsevier B.V.

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How to cite

APA:

Marali, S., Wisshak, M., López Correa, M., & Freiwald, A. (2013). Skeletal microstructure and stable isotope signature of three bathyal solitary cold-water corals from the Azores. Palaeogeography, Palaeoclimatology, Palaeoecology, 373, 25-38. https://doi.org/10.1016/j.palaeo.2012.06.017

MLA:

Marali, Soraya, et al. "Skeletal microstructure and stable isotope signature of three bathyal solitary cold-water corals from the Azores." Palaeogeography, Palaeoclimatology, Palaeoecology 373 (2013): 25-38.

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