Extended calibration of cold-water coral Ba/Ca using multiple genera and co-located measurements of dissolved barium concentration
Biological productivity and ocean circulation are both important oceanographic variables that control the distribution of dissolved barium in the ocean interior ([Ba]sw). The ability to accurately reconstruct [Ba]sw will provide key constraints on these processes in the past. The geochemistry of col...
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| Main Authors: | , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
13 September 2018
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| In: |
Chemical geology
Year: 2018, Volume: 499, Pages: 100-110 |
| ISSN: | 1872-6836 |
| DOI: | 10.1016/j.chemgeo.2018.09.012 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.chemgeo.2018.09.012 Verlag, lizenzpflichtig, Volltext: http://www.sciencedirect.com/science/article/pii/S0009254118304522 
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| Author Notes: | Peter T. Spooner, Laura F. Robinson, Freya Hemsing, Paul Morris, Joseph A. Stewart |
| Summary: | Biological productivity and ocean circulation are both important oceanographic variables that control the distribution of dissolved barium in the ocean interior ([Ba]sw). The ability to accurately reconstruct [Ba]sw will provide key constraints on these processes in the past. The geochemistry of cold-water corals has the potential to unlock paleoceanographic records at spatial and temporal resolutions not available using other sedimentary archives. Previous studies have suggested that the Ba/Ca ratio of coral skeletons is linearly related to [Ba]sw. However, these efforts have used a limited number of species, sparse global seawater databases, or have not explicitly measured the Ba/Ca ratio. Here we investigate the Ba/Ca ratio in a well-constrained set of cold-water scleractinian (aragonitic) corals as a proxy for [Ba]sw, using 58 specimens from 7 coral genera along with co-located measurements of [Ba]sw. We find that traditional chemical cleaning procedures do not significantly affect the Ba/Ca ratio of cold-water coral skeletons, allowing rapid sample throughput. We also determine that intra-sample variation in Ba/Ca ratios can be reduced by using larger sample sizes (e.g. 20mg). By combining our results with existing data, we find that cold-water coral Ba/Ca is linearly related to [Ba]sw according to the relationship: Ba/Ca μmol/mol=[0.15±0.02] [Basw nmol/kg]+[2.5±1.4], (R2=0.7). We observe no species-specific ‘vital effects’ in cold-water coral Ba/Ca ratios, but site-specific effects could be a factor. Nevertheless, our results highlight the potential of Ba/Ca in cold-water corals to reconstruct biological and physical changes in the ocean interior. |
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| Item Description: | Gesehen am 02.04.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1872-6836 |
| DOI: | 10.1016/j.chemgeo.2018.09.012 |