Compositional variability in a cold‐water scleractinian, Lophelia pertusa: New insights into “vital effects”

Abstract

[1] We analyzed Sr/Ca and Mg/Ca ratios in the thecal wall of Lophelia pertusa, a cold-water coral, using SIMS ion microprobe techniques. The wall grows by simultaneous upward extension and outward thickening. Compositional variability displays similar trends along the upward and outward growth axes. Sr/Ca and Mg/Ca ratios oscillate systematically and inversely. The sensitivity of Lophelia Sr/Ca ratios to the annual temperature cycle (À0.18 mmol Á mol À1 /°C) is twice as strong as that exhibited by tropical reef corals, and four times as strong as the temperature dependence of Sr/Ca ratios of abiogenic aragonites precipitated experimentally from seawater. A comparison of the skeletal composition of Lophelia with results from precipitation calculations carried out using experimentally determined partition coefficients suggests that both temperature-dependent element partitioning and seasonal changes in the mass fraction of aragonite precipitated from the calcifying fluid influence the composition of Lophelia skeleton. Results from calculations that combine these effects reproduce both the exaggerated amplitude of the Sr/Ca and Mg/Ca oscillations and the inverse relationship between Sr/Ca and Mg/Ca ratios.

Morphological and compositional changes in the skeletons of new coral recruits reared in acidified seawater: Insights into the biomineralization response to ocean acidification

“…As seawater saturation state decreased in the experimental aquaria, Sr/Ca ratios of the skeletons increased by 13% and Mg/Ca ratios decreased by 45%. Both the trend and the relative magnitude of changes in Sr/Ca and Mg/Ca ratios are consistent with a Rayleigh distillation process in which compositional variability in the coral skeleton is driven primarily by changes in the mass fraction of aragonite precipitated by the coral from an isolated ''batch'' or reservoir of calcifying fluid (hereafter referred to as the ''mass fraction'') Cohen et al, 2006;Gagnon et al, 2007]. The data were modeled using the following solution to the Rayleigh distillation equation [Rayleigh, 1896]:…”

The influence of seawater pH on U / Ca ratios in the scleractinian cold-water coral <i>Lophelia pertusa</i>

“…7). Previous studies that analysed Mg / Ca ratios in L. pertusa show comparable absolute values in the theca wall as well as in the COC (compare Cohen et al, 2006;Sinclair et al, 2006). These studies could clearly identify the COC by scanning electron microscope pictures.…”

“…Case et al, 2010;Cohen et al, 2006;Gagnon et al, 2007;Lutringer et al, 2005;Montagna et al, 2006;Raddatz et al, 2013;RollionBard et al, 2009;Rüggeberg et al, 2008;Smith et al, 2000). To date only a few studies have focused on the reconstruction of the carbonate system using CWC skeletons (Anagnostou et al, 2011(Anagnostou et al, , 2012Blamart et al, 2007;McCulloch et al, 2012;Rollion-Bard et al, 2011a, b;Thresher et al, 2011).…”

Skeletal reorganisation affects geochemical signals, exemplified in the stylasterid hydrocoral Errina dabneyi (Azores Archipelago)

“…Smith et al 2000, Cohen et al 2006). This applies to many azooxanthellate coldwater scleractinians, including the intensely studied Lophelia pertusa Linnaeus, 1758 .…”