Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions
Abstract Coral skeletons exhibit a complex composition of mineral and organic components, with the water content playing a significant role in their structure. Water associated with organic matrices constitutes the major share, whereas nonstructural water (skeleton inclusion water) is present in muc...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-06-01
|
| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024GC011981 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850119904487800832 |
|---|---|
| author | Yao Wu Dana Hölkermann Amrei Grund Sophie Warken Norbert Frank |
| author_facet | Yao Wu Dana Hölkermann Amrei Grund Sophie Warken Norbert Frank |
| author_sort | Yao Wu |
| collection | DOAJ |
| description | Abstract Coral skeletons exhibit a complex composition of mineral and organic components, with the water content playing a significant role in their structure. Water associated with organic matrices constitutes the major share, whereas nonstructural water (skeleton inclusion water) is present in much smaller amounts, typically less than 0.5 wt% of the coral skeleton. The isotopic composition of this water may reflect biomineralization processes or environmental conditions during skeleton formation. Here, we present fluid inclusion hydrogen and oxygen isotopic compositions of cold‐water coral skeletons from Angola and Iceland. We confirmed the kinetic isotope fractionation when coral skeletons were crushed at a temperature of 120°C using a cavity ring‐down spectroscopy analyzer. δ18O and δ2H values are not reproducible across analytical setups with varying temperature parameters. When coral fragments are encapsulated in a glass tube, the amount of released water and its isotopic signature are far more reproducible. δ18O and δ2H values of coral skeleton inclusion water from Angola show no significant differences between the Holocene and the last glacial period. The δ2H values are characterized by strong isotopic fractionation compared to seawater. Our study highlights that current methods do not adequately capture the variability in the initial δ18O and δ2H of the “quasi‐free” skeleton inclusion water in coral aragonite. It is also possible that there are varying degrees of exchange of skeleton inclusion water with seawater. A better understanding of the coral calcification process is still necessary to establish a clearer link between the isotopic compositions of seawater and skeleton inclusion water. |
| format | Article |
| id | doaj-art-035182a8a47b43a1805e41f8b3d6b0d0 |
| institution | OA Journals |
| issn | 1525-2027 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj-art-035182a8a47b43a1805e41f8b3d6b0d02025-08-20T02:35:31ZengWileyGeochemistry, Geophysics, Geosystems1525-20272025-06-01266n/an/a10.1029/2024GC011981Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid InclusionsYao Wu0Dana Hölkermann1Amrei Grund2Sophie Warken3Norbert Frank4Institute of Environmental Physics Heidelberg University Heidelberg GermanyInstitute of Environmental Physics Heidelberg University Heidelberg GermanyInstitute of Environmental Physics Heidelberg University Heidelberg GermanyInstitute of Environmental Physics Heidelberg University Heidelberg GermanyInstitute of Environmental Physics Heidelberg University Heidelberg GermanyAbstract Coral skeletons exhibit a complex composition of mineral and organic components, with the water content playing a significant role in their structure. Water associated with organic matrices constitutes the major share, whereas nonstructural water (skeleton inclusion water) is present in much smaller amounts, typically less than 0.5 wt% of the coral skeleton. The isotopic composition of this water may reflect biomineralization processes or environmental conditions during skeleton formation. Here, we present fluid inclusion hydrogen and oxygen isotopic compositions of cold‐water coral skeletons from Angola and Iceland. We confirmed the kinetic isotope fractionation when coral skeletons were crushed at a temperature of 120°C using a cavity ring‐down spectroscopy analyzer. δ18O and δ2H values are not reproducible across analytical setups with varying temperature parameters. When coral fragments are encapsulated in a glass tube, the amount of released water and its isotopic signature are far more reproducible. δ18O and δ2H values of coral skeleton inclusion water from Angola show no significant differences between the Holocene and the last glacial period. The δ2H values are characterized by strong isotopic fractionation compared to seawater. Our study highlights that current methods do not adequately capture the variability in the initial δ18O and δ2H of the “quasi‐free” skeleton inclusion water in coral aragonite. It is also possible that there are varying degrees of exchange of skeleton inclusion water with seawater. A better understanding of the coral calcification process is still necessary to establish a clearer link between the isotopic compositions of seawater and skeleton inclusion water.https://doi.org/10.1029/2024GC011981fluid inclusion waterδ18O and δ2Hcoral skeletonsCRDSfractionation |
| spellingShingle | Yao Wu Dana Hölkermann Amrei Grund Sophie Warken Norbert Frank Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions Geochemistry, Geophysics, Geosystems fluid inclusion water δ18O and δ2H coral skeletons CRDS fractionation |
| title | Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions |
| title_full | Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions |
| title_fullStr | Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions |
| title_full_unstemmed | Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions |
| title_short | Environmental and Calcification Impacts on the δ18O and δ2H Values of Cold‐Water Coral Skeleton Fluid Inclusions |
| title_sort | environmental and calcification impacts on the δ18o and δ2h values of cold water coral skeleton fluid inclusions |
| topic | fluid inclusion water δ18O and δ2H coral skeletons CRDS fractionation |
| url | https://doi.org/10.1029/2024GC011981 |
| work_keys_str_mv | AT yaowu environmentalandcalcificationimpactsonthed18oandd2hvaluesofcoldwatercoralskeletonfluidinclusions AT danaholkermann environmentalandcalcificationimpactsonthed18oandd2hvaluesofcoldwatercoralskeletonfluidinclusions AT amreigrund environmentalandcalcificationimpactsonthed18oandd2hvaluesofcoldwatercoralskeletonfluidinclusions AT sophiewarken environmentalandcalcificationimpactsonthed18oandd2hvaluesofcoldwatercoralskeletonfluidinclusions AT norbertfrank environmentalandcalcificationimpactsonthed18oandd2hvaluesofcoldwatercoralskeletonfluidinclusions |