Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry
Abstract Reconstructing intermediate and bottom‐water temperature in the Arctic Ocean is key for understanding paleoclimatic phenomena, such as the region's interactions with warm Atlantic waters, stratification, and sea‐ice dynamics. However, benthic proxy archives are sparse throughout the Ar...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2021-02-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2020GC009379 |
| _version_ | 1797637957365006336 |
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| author | Maximiliano Rodriguez John M. Doherty Ho Lai Hilary Man Rujian Wang Wenshen Xiao Baochun Zhou Benoit Thibodeau Christelle Not |
| author_facet | Maximiliano Rodriguez John M. Doherty Ho Lai Hilary Man Rujian Wang Wenshen Xiao Baochun Zhou Benoit Thibodeau Christelle Not |
| author_sort | Maximiliano Rodriguez |
| collection | DOAJ |
| description | Abstract Reconstructing intermediate and bottom‐water temperature in the Arctic Ocean is key for understanding paleoclimatic phenomena, such as the region's interactions with warm Atlantic waters, stratification, and sea‐ice dynamics. However, benthic proxy archives are sparse throughout the Arctic circle compared to lower latitudes. Trace‐element ratios (E/Ca) derived from ostracodes, a group of bivalved microscopic crustaceans, have shown promise in this regard. Samples for E/Ca measurements typically require rigorous cleaning prior to analysis, and signs of contamination are routinely monitored through the presence of other trace elements such as Al, Fe, and Mn, which are associated with suspected sources of overprinting. However, there has not yet been an intra‐valve investigation of all of these trace elements, which may hinder our ability to effectively identify geochemical overprinting. Here, we present several elemental concentration and E/Ca ratio measurements in two ostracode genera, Krithe and Polycope, extracted from Chukchi Sea sediment samples. We further investigate the intra‐valve distribution of elements within single shells of adult and juvenile specimens using electron probe microanalysis (EPMA). Our findings suggest that brushing and bleach treatments may not be effective for completely eliminating clays from the edges of valves, which can bias paleoclimatologically relevant trace‐element proxies such as Mg/Ca ratios, particularly in the case of incomplete or small samples with low amounts of calcite material. In addition, we report the first trace‐element data from the genus Polycope, which shows potential as a new Arctic paleotemperature archive. |
| first_indexed | 2024-03-11T12:56:39Z |
| format | Article |
| id | doaj.art-900c6fa413274033b30531b04b5a0905 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:56:39Z |
| publishDate | 2021-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-900c6fa413274033b30531b04b5a09052023-11-03T17:00:55ZengWileyGeochemistry, Geophysics, Geosystems1525-20272021-02-01222n/an/a10.1029/2020GC009379Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca PaleothermometryMaximiliano Rodriguez0John M. Doherty1Ho Lai Hilary Man2Rujian Wang3Wenshen Xiao4Baochun Zhou5Benoit Thibodeau6Christelle Not7Department of Earth Sciences and Swire Institute of Marine Science The University of Hong Kong Hong Kong SAR Hong KongDepartment of Earth Sciences and Swire Institute of Marine Science The University of Hong Kong Hong Kong SAR Hong KongDepartment of Earth Sciences and Swire Institute of Marine Science The University of Hong Kong Hong Kong SAR Hong KongState Key Laboratory of Marine Geology Tongji University Shanghai ChinaState Key Laboratory of Marine Geology Tongji University Shanghai ChinaShanghai Natural History Museum, Branch of Shanghai Science and Technology Museum Shanghai ChinaDepartment of Earth Sciences and Swire Institute of Marine Science The University of Hong Kong Hong Kong SAR Hong KongDepartment of Earth Sciences and Swire Institute of Marine Science The University of Hong Kong Hong Kong SAR Hong KongAbstract Reconstructing intermediate and bottom‐water temperature in the Arctic Ocean is key for understanding paleoclimatic phenomena, such as the region's interactions with warm Atlantic waters, stratification, and sea‐ice dynamics. However, benthic proxy archives are sparse throughout the Arctic circle compared to lower latitudes. Trace‐element ratios (E/Ca) derived from ostracodes, a group of bivalved microscopic crustaceans, have shown promise in this regard. Samples for E/Ca measurements typically require rigorous cleaning prior to analysis, and signs of contamination are routinely monitored through the presence of other trace elements such as Al, Fe, and Mn, which are associated with suspected sources of overprinting. However, there has not yet been an intra‐valve investigation of all of these trace elements, which may hinder our ability to effectively identify geochemical overprinting. Here, we present several elemental concentration and E/Ca ratio measurements in two ostracode genera, Krithe and Polycope, extracted from Chukchi Sea sediment samples. We further investigate the intra‐valve distribution of elements within single shells of adult and juvenile specimens using electron probe microanalysis (EPMA). Our findings suggest that brushing and bleach treatments may not be effective for completely eliminating clays from the edges of valves, which can bias paleoclimatologically relevant trace‐element proxies such as Mg/Ca ratios, particularly in the case of incomplete or small samples with low amounts of calcite material. In addition, we report the first trace‐element data from the genus Polycope, which shows potential as a new Arctic paleotemperature archive.https://doi.org/10.1029/2020GC009379Arctic Oceanbottom water temperatureMg/CaostracodSr/Catrace element distribution |
| spellingShingle | Maximiliano Rodriguez John M. Doherty Ho Lai Hilary Man Rujian Wang Wenshen Xiao Baochun Zhou Benoit Thibodeau Christelle Not Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry Geochemistry, Geophysics, Geosystems Arctic Ocean bottom water temperature Mg/Ca ostracod Sr/Ca trace element distribution |
| title | Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry |
| title_full | Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry |
| title_fullStr | Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry |
| title_full_unstemmed | Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry |
| title_short | Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry |
| title_sort | intra valve elemental distributions in arctic marine ostracodes implications for mg ca and sr ca paleothermometry |
| topic | Arctic Ocean bottom water temperature Mg/Ca ostracod Sr/Ca trace element distribution |
| url | https://doi.org/10.1029/2020GC009379 |
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