Silicon isotopes in Antarctic sponges : an interlaboratory comparison
Date
2010-06-08Author
Hendry, Katharine R.
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Leng, Melanie J.
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Robinson, Laura F.
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Sloane, Hilary J.
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Blusztajn, Jerzy S.
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Rickaby, Rosalind E. M.
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Georg, R. Bastian
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Halliday, Alex N.
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https://hdl.handle.net/1912/4380As published
https://doi.org/10.1017/S0954102010000593Keyword
Biogeochemistry; Porifera; Nutrient; Calibration; Silicic acidAbstract
Cycling of deep-water silicon (Si) within the Southern Ocean, and its transport
into other ocean basins, may be an important player in the uptake of
atmospheric carbon, and global climate. Recent work has shown that the Si
isotope (denoted by δ29Si or δ30Si) composition of deep-sea sponges reflects the
availability of dissolved Si during growth, and is a potential proxy for past deep
and intermediate water silicic acid concentrations. As with any geochemical
tool, it is essential to ensure analytical precision and accuracy, and consistency
between methodologies and laboratories. Analytical bias may exist between
laboratories, and sponge material may have matrix effects leading to offsets
between samples and standards. Here, we report an interlaboratory evaluation
of Si isotopes in Antarctic and subAntarctic sponges. We review independent
methods for measuring Si isotopes in sponge spicules. Our results show that
separate subsamples of non-homogenised sponges measured by three methods
yield isotopic values within analytical error for over 80% of specimens. The
relationship between δ29Si and δ30Si in sponges is consistent with kinetic
fractionation during biomineralisation. Sponge Si isotope analyses show
potential as palaeoceaongraphic archives, and we suggest Southern Ocean
sponge material would form a useful additional reference standard for future
spicule analyses.
Description
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Antarctic Science 23 (2011): 34-42, doi:10.1017/S0954102010000593.