Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years
Changes in Southern Ocean export production have broad biogeochemical and climatic implications. Specifically, iron fertilization likely increased subantarctic nutrient utilization and enhanced the efficiency of the biological pump during glacials. However, past export production in the subantarctic...
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Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.934588 |
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.934588 2023-05-15T16:02:29+02:00 Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years Toyos, Maria H Winckler, Gisela Arz, Helge Wolfgang Lembke-Jene, Lester Lange, Carina Beatriz Kuhn, Gerhard Lamy, Frank LATITUDE: -57.499170 * LONGITUDE: -70.274670 * DATE/TIME START: 2016-03-20T17:30:00 * DATE/TIME END: 2016-03-20T17:30:00 2021-08-05 application/zip, 3 datasets https://doi.pangaea.de/10.1594/PANGAEA.934588 en eng PANGAEA Toyos, Maria H; Winckler, Gisela; Arz, Helge Wolfgang; Lembke-Jene, Lester; Lange, Carina B; Kuhn, Gerhard; Lamy, Frank (accepted): Variations in export production, lithogenic sediment transport and iron fertilization in the Pacific sector of the Drake Passage over the past 400 ka. Climate of the Past, https://doi.org/10.5194/cp-2021-85 https://doi.pangaea.de/10.1594/PANGAEA.934588 Access constraints: access rights needed info:eu-repo/semantics/restrictedAccess Drake Passage glacial-interglacial changes iron fertilization Mass accumulation rates paleoproductivity Southern Ocean Subantarctic zone thorium normalization Dataset 2021 ftpangaea https://doi.org/10.5194/cp-2021-85 2023-01-20T07:34:48Z Changes in Southern Ocean export production have broad biogeochemical and climatic implications. Specifically, iron fertilization likely increased subantarctic nutrient utilization and enhanced the efficiency of the biological pump during glacials. However, past export production in the subantarctic Southeast Pacific is poorly documented, and its connection to Fe fertilization, potentially related to Patagonian Ice Sheet dynamics is unknown. We report biological productivity changes over the past 400 ka, based on a combination of 230Thxs-normalized and stratigraphy-based mass accumulation rates of biogenic barium, organic carbon, biogenic opal, and calcium carbonate as indicators of paleo-export production in a sediment core upstream of the Drake Passage (57.5º S; 70.3º W). In addition, we use fluxes of iron and lithogenic material as proxies for terrigenous input, and thus potential micronutrient supply. Stratigraphy-based mass accumulation rates are strongly influenced by bottom-current dynamics, which result in variable sediment focussing or winnowing at our site. Carbonate is virtually absent in the core, except during peak interglacial intervals of the Holocene, and Marine Isotope Stages (MIS) 5 and 11, likely caused by transient decreases in carbonate dissolution. All other proxies suggest that export production increased during most glacial periods, coinciding with high iron fluxes. Such augmented glacial iron fluxes at the core site were most likely derived from glaciogenic input from the Patagonian Ice Sheet promoting the growth of phytoplankton. Additionally, glacial export production peaks are also consistent with northward shifts of the Subantarctic and Polar Fronts, which positioned our site south of the Subantarctic Front and closer to silicic acid-rich waters of the Polar Frontal Zone. However, glacial export production near the Drake Passage was lower than in the Atlantic and Indian sectors of the Southern Ocean, which may relate to complete consumption of silicic acid in the study area. Our ... Dataset Drake Passage Ice Sheet Southern Ocean PANGAEA - Data Publisher for Earth & Environmental Science Southern Ocean Drake Passage Pacific Indian ENVELOPE(-70.274670,-70.274670,-57.499170,-57.499170) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
Drake Passage glacial-interglacial changes iron fertilization Mass accumulation rates paleoproductivity Southern Ocean Subantarctic zone thorium normalization |
spellingShingle |
Drake Passage glacial-interglacial changes iron fertilization Mass accumulation rates paleoproductivity Southern Ocean Subantarctic zone thorium normalization Toyos, Maria H Winckler, Gisela Arz, Helge Wolfgang Lembke-Jene, Lester Lange, Carina Beatriz Kuhn, Gerhard Lamy, Frank Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years |
topic_facet |
Drake Passage glacial-interglacial changes iron fertilization Mass accumulation rates paleoproductivity Southern Ocean Subantarctic zone thorium normalization |
description |
Changes in Southern Ocean export production have broad biogeochemical and climatic implications. Specifically, iron fertilization likely increased subantarctic nutrient utilization and enhanced the efficiency of the biological pump during glacials. However, past export production in the subantarctic Southeast Pacific is poorly documented, and its connection to Fe fertilization, potentially related to Patagonian Ice Sheet dynamics is unknown. We report biological productivity changes over the past 400 ka, based on a combination of 230Thxs-normalized and stratigraphy-based mass accumulation rates of biogenic barium, organic carbon, biogenic opal, and calcium carbonate as indicators of paleo-export production in a sediment core upstream of the Drake Passage (57.5º S; 70.3º W). In addition, we use fluxes of iron and lithogenic material as proxies for terrigenous input, and thus potential micronutrient supply. Stratigraphy-based mass accumulation rates are strongly influenced by bottom-current dynamics, which result in variable sediment focussing or winnowing at our site. Carbonate is virtually absent in the core, except during peak interglacial intervals of the Holocene, and Marine Isotope Stages (MIS) 5 and 11, likely caused by transient decreases in carbonate dissolution. All other proxies suggest that export production increased during most glacial periods, coinciding with high iron fluxes. Such augmented glacial iron fluxes at the core site were most likely derived from glaciogenic input from the Patagonian Ice Sheet promoting the growth of phytoplankton. Additionally, glacial export production peaks are also consistent with northward shifts of the Subantarctic and Polar Fronts, which positioned our site south of the Subantarctic Front and closer to silicic acid-rich waters of the Polar Frontal Zone. However, glacial export production near the Drake Passage was lower than in the Atlantic and Indian sectors of the Southern Ocean, which may relate to complete consumption of silicic acid in the study area. Our ... |
format |
Dataset |
author |
Toyos, Maria H Winckler, Gisela Arz, Helge Wolfgang Lembke-Jene, Lester Lange, Carina Beatriz Kuhn, Gerhard Lamy, Frank |
author_facet |
Toyos, Maria H Winckler, Gisela Arz, Helge Wolfgang Lembke-Jene, Lester Lange, Carina Beatriz Kuhn, Gerhard Lamy, Frank |
author_sort |
Toyos, Maria H |
title |
Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years |
title_short |
Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years |
title_full |
Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years |
title_fullStr |
Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years |
title_full_unstemmed |
Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years |
title_sort |
concentration, accumulation rates, th fluxes, focusing factors, and productivity proxies on core ps97/093-2 over the past 400,000 years |
publisher |
PANGAEA |
publishDate |
2021 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.934588 |
op_coverage |
LATITUDE: -57.499170 * LONGITUDE: -70.274670 * DATE/TIME START: 2016-03-20T17:30:00 * DATE/TIME END: 2016-03-20T17:30:00 |
long_lat |
ENVELOPE(-70.274670,-70.274670,-57.499170,-57.499170) |
geographic |
Southern Ocean Drake Passage Pacific Indian |
geographic_facet |
Southern Ocean Drake Passage Pacific Indian |
genre |
Drake Passage Ice Sheet Southern Ocean |
genre_facet |
Drake Passage Ice Sheet Southern Ocean |
op_relation |
Toyos, Maria H; Winckler, Gisela; Arz, Helge Wolfgang; Lembke-Jene, Lester; Lange, Carina B; Kuhn, Gerhard; Lamy, Frank (accepted): Variations in export production, lithogenic sediment transport and iron fertilization in the Pacific sector of the Drake Passage over the past 400 ka. Climate of the Past, https://doi.org/10.5194/cp-2021-85 https://doi.pangaea.de/10.1594/PANGAEA.934588 |
op_rights |
Access constraints: access rights needed info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.5194/cp-2021-85 |
_version_ |
1766398133844049920 |