Growth and composition of high-Mg calcite in the skeleton of a Bermudian gorgonian (Plexaurella dichotoma) : potential for paleothermometry
Bond, Zoe A.
Cohen, Anne L.
Smith, Struan R.
Jenkins, William J.
MetadataShow full item record
KeywordGorgonian; Octocoral; Mg/Ca; Sr/Ca; Sea surface temperature; Biomineralization; Growth bands; SIMS ion microprobe; Bermuda
We used Secondary Ion Mass Spectrometry (SIMS) ion microprobe to analyze magnesium-to-calcium (Mg/Ca) and strontium-to-calcium (Sr/Ca) ratios of high-Mg calcite loculi within the skeleton of a shallow water gorgonian, Plexaurella dichotoma, from Bermuda. A cross-section of the gorgonian skeleton reveals loculi embedded within proteinaceous gorgonin arranged in concentric rings about the axial core. Viewed in cross-section, the loculi are fan-shaped, 10-140 μm in diameter, and composed of bundles of needle-shaped crystals that appear to radiate out from a calcification center. Discrete sample spots, each 20 μm diameter, were sputtered from successive loculi along a sample track 3 mm long. Over this distance, twenty-five bands of high-low density gorgonin couplets were encountered, estimated to represent the period 1963 to 1988. Mg/Ca ratios show an overall, positive correlation with annual sea surface temperatures (SSTs) that is strongest in the autumn months (October- December). High-resolution analyses along the growth axes of individual loculi reveal low variability and no trend, consistent with our interpretation of seasonal growth of these calcite inclusions. The sensitivity of Mg/Ca to interannual changes in average autumn temperatures is 0.47 mmol/mol per ºC. Conversely, interannual variability in calcite Sr/Ca does not follow the interannual variability in SST and may be influenced primarily by growth rate.
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 6 (2005): Q08010, doi:10.1029/2005GC000911.
Showing items related by title, author, creator and subject.
Lack of growth enhancement by exogenous growth hormone treatment in yellow perch (Perca flavescens) in four separate experiments Jentoft, Sissel; Topp, Nicole; Seeliger, Matthew; Malison, Jeffrey A.; Barry, Terence P.; Held, James A.; Roberts, Steven B.; Goetz, Frederick W. (2005-03-02)The effect of exogenous growth hormone (GH) treatment on the growth of juvenile yellow perch (Perca flavescens) was investigated in four experiments. In the first two experiments, juvenile yellow perch were reared at either ...
Coherent patterns in bacterial growth, growth efficiency, and leucine metabolism along a northeastern Pacific inshore-offshore transect del Giorgio, Paul A.; Condon, Robert H.; Bouvier, Thierry; Longnecker, Krista; Bouvier, Corinne; Sherr, Evelyn B.; Gasol, Josep M. (Association for the Sciences of Limnology and Oceanography, 2011-01)We investigated the patterns in bacterial growth, production, respiration, growth efficiency (BGE), and bacterial leucine respiration and C-to-leucine yield (i.e., conversion factor [CF]) along a transect off the coast of ...
Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons Natanson, Lisa J.; Gervelis, Brian J.; Winton, Megan V.; Hamady, Li Ling; Gulak, Simon J. B.; Carlson, John K. (Springer, 2013-11-19)Age and growth estimates for the dusky shark, Carcharhinus obscurus, were derived from vertebral centra collected in the northwestern Atlantic Ocean. Sample collection spanned the years prior to and following the implementation ...