Coralline algal Mg-O bond strength as a marine p CO 2 proxy
Past ocean acidification recorded in the geological record facilitates the understanding of rates and influences of contemporary p CO 2 enrichment. Most pH reconstructions are made using boron, however there is some uncertainty associated with vital effects and isotopic fractionation. Here we presen...
| Published in: | Geology |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Geological Society of America
2015
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| Subjects: | |
| Online Access: | http://eprints.gla.ac.uk/101893/ http://eprints.gla.ac.uk/101893/1/101893.pdf |
| Summary: | Past ocean acidification recorded in the geological record facilitates the understanding of rates and influences of contemporary p CO 2 enrichment. Most pH reconstructions are made using boron, however there is some uncertainty associated with vital effects and isotopic fractionation. Here we present a new structural proxy for carbonate chemistry; Mg-O bond strength in coralline algae. Coralline algae were incubated in control (380 μatm p CO 2 ), moderate (750 μatm p CO 2 ), and high (1000 μatm p CO 2 ) acidification conditions for 24 months. Raman spectroscopy was used to determine skeletal Mg-O bond strength. There was a positive linear relationship between p CO 2 concentration and bond strength mediated by positional disorder in the calcite lattice when accounting for seasonal temperature. The structural preservation of the carbonate chemistry system in coralline algal high-Mg calcite represents an alternative approach to reconstructing marine carbonate chemistry. Significantly, it also provides an important mechanism for reconstructing historic atmospheric CO 2 concentrations. |
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