Environmental and biological controls on Mg and Li in deep-sea scleractinian corals

dc.contributor.author Case, David H.
dc.contributor.author Robinson, Laura F.
dc.contributor.author Auro, Maureen E.
dc.contributor.author Gagnon, Alexander C.
dc.date.accessioned 2011-03-09T14:25:12Z
dc.date.available 2011-03-09T14:25:12Z
dc.date.issued 2010-09-06
dc.description Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 300 (2010): 215-225, doi:10.1016/j.epsl.2010.09.029. en_US
dc.description.abstract Deep-sea scleractinian corals precipitate aragonite skeletons that provide valuable archives of past ocean conditions. During calcification biological mediation causes variability in trace metal incorporation and isotopic ratios of the aragonite such that signals caused by environmental controls can be overwhelmed. This complicates the interpretation of geochemical proxies used for paleo-reconstructions. In this study we examine the environmental controls on the Mg/Li ratio of 34 individuals from seven genera of deep-sea scleractinian corals: Desmophyllum, Balanophyllia, Caryophyllia, Enallopsammia, Flabellum, Trochocyanthus, and Lophelia. In addition we examine the distributions of Mg and Li in Desmophyllum and Balanophyllia using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Both Mg/Ca and Li/Ca ratios increased by more than a factor of 2 in the center of calcification regions compared to the outer, fibrous regions of the coral skeleton. As a result, replicate ~10 mg subsamples of coral show less variability in the Mg/Li ratio than Mg/Ca. Microscale Mg and Li results are consistent with Rayleigh-type incorporation of trace metals with additional processes dominating composition within centers of calcification. Comparison of Mg/Li to seawater properties near the site of collection shows that the ratio is not controlled by either carbonate ion or salinity. It appears that temperature is the major control on the Mg/Li ratio. For all 34 samples the temperature correlation (R2=0.62) is significantly better than for Mg/Ca (R2=0.06). For corals of the family Caryophyllidae the R2 value increases to 0.82 with the exclusion of one sample that was observed to have an altered, chalky texture. Despite this excellent correlation the scatter in the data suggests that the Mg/Li ratio of deep-sea corals cannot be used to reconstruct temperature to better than approximately ±1.6°C without better temperature control and additional calibration points on modern coral samples. en_US
dc.description.sponsorship Financial Support was provided by the USGS WHOI Co-operative agreement, NSF-ANT grant numbers 0636787 and 80295700 and the WHOI Ocean Life Institute. David Case was supported by the WHOI Summer Student Fellowship. en_US
dc.format.mimetype application/pdf
dc.identifier.uri https://hdl.handle.net/1912/4379
dc.language.iso en_US en_US
dc.relation.uri https://doi.org/10.1016/j.epsl.2010.09.029
dc.subject Biomineralization en_US
dc.subject Paleoceanography en_US
dc.subject Deep-sea coral en_US
dc.subject Mg/Ca en_US
dc.subject Mg/Li en_US
dc.subject Thermometry en_US
dc.title Environmental and biological controls on Mg and Li in deep-sea scleractinian corals en_US
dc.type Preprint en_US
dspace.entity.type Publication
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relation.isAuthorOfPublication.latestForDiscovery a3012b0f-cc28-4df3-bf6e-862623a0adaa
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