| CORALS AND SCLEROSPONGES |
Tongue of the Ocean, Pear Tree Bottom - Sclerosponge Minor Element Data
|
|
Rosenheim, B.E., P.K. Swart, and S.R. Thorrold. 2005. Minor and trace elements in sclerosponge Ceratoporella nicholsoni: Biogenic
aragonite near the inorganic endmember? Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 228, Issues 1-2, 22 November
2005, Pages 109-129.
| Data Coverage |
North: 23.92 * South: 18.47 |
|
West: -77.4 * East: -76.83 |
|
Altitude: -146 m |
Start Year: 1890 AD
End Year: 1990 AD
Data: Please Cite Data Contributors!
|
|
Summary: The trace and minor element composition have been investigated in the accretionary skeletons of two specimens of the Caribbean
sclerosponge species, Ceratoporella nicholsoni; one from Tongue of the Ocean, Bahamas (TOTO), and the other from Pear Tree
Bottom, Jamaica (PTB). Both sclerosponges were analyzed at high resolution using laser ablation ICP-MS (LA-ICP-MS) and verified
using wet chemical methods (ICP-OES). The shallow PTB sclerosponge (25 m) was analyzed for a short, temperature-calibrated
record of trace and minor elements while the TOTO sclerosponge (146 m) was analyzed for a century long record from subsurface
waters. The resulting Ba/Ca, Mg/Ca, Pb/Ca, and U/Ca ratios were compared with Sr/Ca ratios, which have been shown to reliably
record seasonal-scale temperature change in sclerosponges, close to equilibrium precipitation of inorganic aragonite. Sclerosponge
aragonite incorporates minor and trace elements according to general mineralogic constraints with less "vital" effects than
other calcium carbonate secreting organisms. This is perhaps most obvious in the behavior of Mg/Ca ratios which show an
inverse correlation to temperature unlike any other calcite or aragonite organism, despite having Mg concentrations (~1 mmol/mol)
within published estimates of equilibrium aragonite. Ratios of Mg/Ca and Ba/Ca show a strong positive correlation despite
large differences in ionic radii and U/Ca values (~3.15 Mmol/mol) are 2.5× higher in sclerosponge aragonite than in aragonite
from corals, supporting earlier work. Ratios of U/Ca show an insignificant correlation with temperature-dependent Sr/Ca ratios
(r2 = 0.05), supporting existing theories that temperature signals recorded by U/Ca ratios can be convolved with pH, [CO3-2],
and phosphate signals. Differences between sclerosponge aragonite and other calcium carbonate arising from siliceous spicule
contamination are unlikely because of the small mole percent of silicon in the aragonite. Small differences between the two
sclerosponges were noticed in Pb/Ca and Sr/Ca because of the average ages of the sampled material and average temperatures
of the ambient environment, respectively. Anomalies between LA-ICP-MS and ICP-OES were noticed in measurements of Ba/Ca and
Pb/Ca due to standardization differences for LA-ICP-MS (Ba/Ca) and measurements close to the instrument detection limits
of Pb (ICP-OES).
More Info on Corals and Sclerosponges |
|
|
Parameters: BaCa; UCa; Pb/Ca; SrCa; MgCa
|
|
Complete XML Record: noaa-coral-1922 (Last Revised: 2007-09-05 )
|
|
 |
DOC/NOAA/NESDIS/NCDC (National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce )
325 Broadway, E/CC23
Boulder, CO 80305
USA
|
| http://www.ncdc.noaa.gov/paleo/ |
| E-mail: bruce.a.bauer@noaa.gov |
| E-mail: paleo@noaa.gov |
Phone: 303-497-6280
Fax: 303-497-6513
|
|
