Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage
The Southern Ocean plays an important role in modulating Pleistocene atmospheric CO2 concentrations, but the underlying mechanisms are not yet fully understood. Here, we report the laser grain-size distribution and Mn geochemical data of a 523 kyr-long sediment record (core ANT30/P1-02 off Prydz Bay...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/363016 2023-07-23T04:15:48+02:00 Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage Wu, Li Wang, Rujian Xiao, Wenshen Krijgsman, Wout Li, Qianyu Ge, Shulan Ma, Tong Paleomagnetism 2018-02 image/pdf https://dspace.library.uu.nl/handle/1874/363016 en eng 1525-2027 https://dspace.library.uu.nl/handle/1874/363016 info:eu-repo/semantics/OpenAccess Biological pump Bottom water oxygenation Deep ventilation Lower MOC circuit Meridional overturning circulation Geophysics Geochemistry and Petrology Article 2018 ftunivutrecht 2023-07-02T02:25:01Z The Southern Ocean plays an important role in modulating Pleistocene atmospheric CO2 concentrations, but the underlying mechanisms are not yet fully understood. Here, we report the laser grain-size distribution and Mn geochemical data of a 523 kyr-long sediment record (core ANT30/P1-02 off Prydz Bay; East Antarctica) to trace past physical changes in the deep Southern Ocean. The core sediments are predominantly composed of clay and silt-sized material. Three grain size end-members (EM) as well as three sensitive grain size classes (SC) were discerned, interpreted as Ice Rafted Debris (EM1 and SC1), and coarse (EM2 and SC2) and fine (EM3, SC3) materials deposited from bottom nepheloid layers, respectively. Ratios of EM2/(EM2+EM3) and SC2/SC3 reveal changes in the local bottom current strength, which is related to the deep ocean diapycnal mixing rate, showing higher values during interglacial periods and lower values during glacial periods. MnO was enriched at each glacial termination, probably caused by abrupt elevations in Antarctic bottom water (AABW) formation rate. Lower AABW formation rate and reduced deep diapycnal mixing during glacial periods enhanced deep Southern Ocean stratification, contributing to glacial atmospheric CO2 drawdown. The elevated AABW formation and enhanced deep diapycnal mixing during glacial terminations alleviated such deep stratification, promoting deeply sequestered CO2 to outgas. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Prydz Bay Southern Ocean Utrecht University Repository Antarctic East Antarctica Prydz Bay Southern Ocean |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
Biological pump Bottom water oxygenation Deep ventilation Lower MOC circuit Meridional overturning circulation Geophysics Geochemistry and Petrology |
spellingShingle |
Biological pump Bottom water oxygenation Deep ventilation Lower MOC circuit Meridional overturning circulation Geophysics Geochemistry and Petrology Wu, Li Wang, Rujian Xiao, Wenshen Krijgsman, Wout Li, Qianyu Ge, Shulan Ma, Tong Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage |
topic_facet |
Biological pump Bottom water oxygenation Deep ventilation Lower MOC circuit Meridional overturning circulation Geophysics Geochemistry and Petrology |
description |
The Southern Ocean plays an important role in modulating Pleistocene atmospheric CO2 concentrations, but the underlying mechanisms are not yet fully understood. Here, we report the laser grain-size distribution and Mn geochemical data of a 523 kyr-long sediment record (core ANT30/P1-02 off Prydz Bay; East Antarctica) to trace past physical changes in the deep Southern Ocean. The core sediments are predominantly composed of clay and silt-sized material. Three grain size end-members (EM) as well as three sensitive grain size classes (SC) were discerned, interpreted as Ice Rafted Debris (EM1 and SC1), and coarse (EM2 and SC2) and fine (EM3, SC3) materials deposited from bottom nepheloid layers, respectively. Ratios of EM2/(EM2+EM3) and SC2/SC3 reveal changes in the local bottom current strength, which is related to the deep ocean diapycnal mixing rate, showing higher values during interglacial periods and lower values during glacial periods. MnO was enriched at each glacial termination, probably caused by abrupt elevations in Antarctic bottom water (AABW) formation rate. Lower AABW formation rate and reduced deep diapycnal mixing during glacial periods enhanced deep Southern Ocean stratification, contributing to glacial atmospheric CO2 drawdown. The elevated AABW formation and enhanced deep diapycnal mixing during glacial terminations alleviated such deep stratification, promoting deeply sequestered CO2 to outgas. |
author2 |
Paleomagnetism |
format |
Article in Journal/Newspaper |
author |
Wu, Li Wang, Rujian Xiao, Wenshen Krijgsman, Wout Li, Qianyu Ge, Shulan Ma, Tong |
author_facet |
Wu, Li Wang, Rujian Xiao, Wenshen Krijgsman, Wout Li, Qianyu Ge, Shulan Ma, Tong |
author_sort |
Wu, Li |
title |
Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage |
title_short |
Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage |
title_full |
Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage |
title_fullStr |
Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage |
title_full_unstemmed |
Late Quaternary Deep Stratification-Climate Coupling in the Southern Ocean: Implications for Changes in Abyssal Carbon Storage |
title_sort |
late quaternary deep stratification-climate coupling in the southern ocean: implications for changes in abyssal carbon storage |
publishDate |
2018 |
url |
https://dspace.library.uu.nl/handle/1874/363016 |
geographic |
Antarctic East Antarctica Prydz Bay Southern Ocean |
geographic_facet |
Antarctic East Antarctica Prydz Bay Southern Ocean |
genre |
Antarc* Antarctic Antarctica East Antarctica Prydz Bay Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Prydz Bay Southern Ocean |
op_relation |
1525-2027 https://dspace.library.uu.nl/handle/1874/363016 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772176834864087040 |