Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas
The vertical density gradients in the Nordic Seas are crucial for the preconditioning of the surface water to thermohaline sinking in winter. These gradients can be reconstructed from paired oxygen isotope data in tests of different species of planktonic foraminifera, the isotopic signatures of whic...
Published in: | Marine Micropaleontology |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2003
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/1974/ https://oceanrep.geomar.de/id/eprint/1974/1/Simstich.pdf https://doi.org/10.1016/S0377-8398(02)00165-2 |
id |
ftoceanrep:oai:oceanrep.geomar.de:1974 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:1974 2024-09-30T14:31:42+00:00 Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas Simstich, Johannes Sarnthein, Michael Erlenkeuser, Helmut 2003 text https://oceanrep.geomar.de/id/eprint/1974/ https://oceanrep.geomar.de/id/eprint/1974/1/Simstich.pdf https://doi.org/10.1016/S0377-8398(02)00165-2 en eng Elsevier https://oceanrep.geomar.de/id/eprint/1974/1/Simstich.pdf Simstich, J., Sarnthein, M. and Erlenkeuser, H. (2003) Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas. Marine Micropaleontology, 48 . pp. 107-125. DOI 10.1016/S0377-8398(02)00165-2 <https://doi.org/10.1016/S0377-8398%2802%2900165-2>. doi:10.1016/S0377-8398(02)00165-2 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2003 ftoceanrep https://doi.org/10.1016/S0377-8398(02)00165-2 2024-09-04T05:04:40Z The vertical density gradients in the Nordic Seas are crucial for the preconditioning of the surface water to thermohaline sinking in winter. These gradients can be reconstructed from paired oxygen isotope data in tests of different species of planktonic foraminifera, the isotopic signatures of which represent different calcification depths in the water column. Comparison of δ18O values from foraminiferal tests in plankton hauls, sediment traps, and nearby core top samples with the calculated δ18Ocalcite profile of the water column revealed species-specific δ18O vital effects and the role of bioturbational admixture of subfossil specimens into the surface sediment. On the basis of core top samples obtained along a west–east transect across various hydrographic regions of the Nordic Seas, δ18O values of Turborotalita quinqueloba document apparent calcification depths within the pycnocline at 25–75 m water depth. The isotopic signatures of Neogloboquadrina pachyderma (s) reflect water masses near and well below the pycnocline between 70 and 250 m off Norway, where the Atlantic inflow leads to thermal stratification. Here, temperatures in the calcification depth of N. pachyderma (s) differ from sea surface temperature by approximately −2.5°C. In contrast, N. pachyderma (s) calcifies very close to the sea surface (20–50 m) in the Arctic domain of the western Nordic Seas. However, further west N. pachyderma (s) prefers somewhat deeper, more saline water at 70–130 m well below the halocline that confines the low saline East Greenland Current. This implies that the δ18O values of N. pachyderma (s) do not fully reflect the freshwater proportion in surface water and that any reconstruction of past meltwater plumes based on δ18O is too conservative, because it overestimates sea surface salinity. Minimum δ18O differences (<0.2‰) between N. pachyderma (s) and T. quinqueloba may serve as proxy for sea regions with dominant haline and absent thermal stratification, whereas thermal stratification leads to δ18O differences ... Article in Journal/Newspaper Arctic East Greenland east greenland current Foraminifera* Greenland Neogloboquadrina pachyderma Nordic Seas Planktonic foraminifera OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Arctic Greenland Norway Marine Micropaleontology 48 1-2 107 125 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The vertical density gradients in the Nordic Seas are crucial for the preconditioning of the surface water to thermohaline sinking in winter. These gradients can be reconstructed from paired oxygen isotope data in tests of different species of planktonic foraminifera, the isotopic signatures of which represent different calcification depths in the water column. Comparison of δ18O values from foraminiferal tests in plankton hauls, sediment traps, and nearby core top samples with the calculated δ18Ocalcite profile of the water column revealed species-specific δ18O vital effects and the role of bioturbational admixture of subfossil specimens into the surface sediment. On the basis of core top samples obtained along a west–east transect across various hydrographic regions of the Nordic Seas, δ18O values of Turborotalita quinqueloba document apparent calcification depths within the pycnocline at 25–75 m water depth. The isotopic signatures of Neogloboquadrina pachyderma (s) reflect water masses near and well below the pycnocline between 70 and 250 m off Norway, where the Atlantic inflow leads to thermal stratification. Here, temperatures in the calcification depth of N. pachyderma (s) differ from sea surface temperature by approximately −2.5°C. In contrast, N. pachyderma (s) calcifies very close to the sea surface (20–50 m) in the Arctic domain of the western Nordic Seas. However, further west N. pachyderma (s) prefers somewhat deeper, more saline water at 70–130 m well below the halocline that confines the low saline East Greenland Current. This implies that the δ18O values of N. pachyderma (s) do not fully reflect the freshwater proportion in surface water and that any reconstruction of past meltwater plumes based on δ18O is too conservative, because it overestimates sea surface salinity. Minimum δ18O differences (<0.2‰) between N. pachyderma (s) and T. quinqueloba may serve as proxy for sea regions with dominant haline and absent thermal stratification, whereas thermal stratification leads to δ18O differences ... |
format |
Article in Journal/Newspaper |
author |
Simstich, Johannes Sarnthein, Michael Erlenkeuser, Helmut |
spellingShingle |
Simstich, Johannes Sarnthein, Michael Erlenkeuser, Helmut Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas |
author_facet |
Simstich, Johannes Sarnthein, Michael Erlenkeuser, Helmut |
author_sort |
Simstich, Johannes |
title |
Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas |
title_short |
Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas |
title_full |
Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas |
title_fullStr |
Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas |
title_full_unstemmed |
Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas |
title_sort |
paired d18o signals of neogloboquadrina pachyderma (s) and turborotalita quinqueloba show thermal stratification in nordic seas |
publisher |
Elsevier |
publishDate |
2003 |
url |
https://oceanrep.geomar.de/id/eprint/1974/ https://oceanrep.geomar.de/id/eprint/1974/1/Simstich.pdf https://doi.org/10.1016/S0377-8398(02)00165-2 |
geographic |
Arctic Greenland Norway |
geographic_facet |
Arctic Greenland Norway |
genre |
Arctic East Greenland east greenland current Foraminifera* Greenland Neogloboquadrina pachyderma Nordic Seas Planktonic foraminifera |
genre_facet |
Arctic East Greenland east greenland current Foraminifera* Greenland Neogloboquadrina pachyderma Nordic Seas Planktonic foraminifera |
op_relation |
https://oceanrep.geomar.de/id/eprint/1974/1/Simstich.pdf Simstich, J., Sarnthein, M. and Erlenkeuser, H. (2003) Paired d18O signals of Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba show thermal stratification in Nordic Seas. Marine Micropaleontology, 48 . pp. 107-125. DOI 10.1016/S0377-8398(02)00165-2 <https://doi.org/10.1016/S0377-8398%2802%2900165-2>. doi:10.1016/S0377-8398(02)00165-2 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/S0377-8398(02)00165-2 |
container_title |
Marine Micropaleontology |
container_volume |
48 |
container_issue |
1-2 |
container_start_page |
107 |
op_container_end_page |
125 |
_version_ |
1811636118826778624 |