Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs
IODP Expedition 341 succeeded in recovering a continuous sedimentary record of Miocene to Late Pleistocene climate history at drill Site U1417 in the Gulf of Alaska, NE Pacific. Site U1417 sediments provide an excellent opportunity to reconstruct North Pacific sea surface conditions during late Neog...
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Format: | Conference Object |
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Adam Mickiewicz University
2019
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Online Access: | https://epic.awi.de/id/eprint/52242/ http://palaeoarc.amu.edu.pl/wp-content/uploads/2019/05/PaleoArctic-Abstracts.pdf https://hdl.handle.net/10013/epic.c135cf37-b4c1-4011-8606-74e91e86116f |
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ftawi:oai:epic.awi.de:52242 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
unknown |
description |
IODP Expedition 341 succeeded in recovering a continuous sedimentary record of Miocene to Late Pleistocene climate history at drill Site U1417 in the Gulf of Alaska, NE Pacific. Site U1417 sediments provide an excellent opportunity to reconstruct North Pacific sea surface conditions during late Neogene large-scale (global) climate transitions. The Mid Pleistocene Transition (MPT) - one of the most prominent intervals of global Quaternary climate change - is clearly identifiable in Site U1417 sediments (Jaeger et al., 2014). To fully exploit the environmental information archived in U1417 sediments, a sampling strategy has been pursued that permits direct correlation of different (independent) proxy data obtained from biomarker, micropalaeontological, sedimentological and geochemical (XRF) analyses. Mid Pleistocene SSTs in the Gulf of Alaska are in good agreement with SST reconstructions for the North Atlantic and the NW Pacific. A general cooling at about 1 Ma supports earlier hypotheses of an overall Northern Hemisphere ocean cooling as a prerequisite for the increase in continental ice volume. While phytoplankton productivity seems rather independent from SST at Site U1417, it is strongly related to elevated TAR values depicting enhanced input of terrestrial leaf-wax lipids (Meyers, 1997). The transport of these lipids is supposed to be effected by strong winds carrying dust from Alaskan loess deposits to the open ocean as well as by icebergs released from Alaskan tidewater glaciers. The latter is supported by the occasional coincidence of high IRD contents and TAR values. The close relationship between the TAR record, Ba/Al values and the abundance of diatoms, however, strengthens that together with the leaf-wax lipids also iron-bearing dust was exported leading to high productivity events at Site U1417 throughout the Mid Pleistocene. The distinct "on-off" pattern in diatom productivity evolved with the onset of the MPT, which suggests that the expansion of the Northwest Cordilleran Ice Sheet lead to an effective production of glacigenic iron-rich dust that was exported i) by strong northwesterly winds and ii) by icebergs. The observation that productivity peaks in the Gulf of Alaska are not confined to glacial or interglacial periods points to a rather local feedback between the export of iron-bearing dust and an immediately responding ocean surface. The identification of these hitherto unconsidered fertilization mechanisms that potentially fostered ocean productivity and hence the sequestration of atmospheric carbon into the deep ocean are further detailed by Müller et al. (2018). |
format |
Conference Object |
author |
Müller, Juliane Romero, Oscar E. Cowan, Ellen A. Forwick, Matthias McClymont, Erin L. Asahi, Hirofumi März, Christian Suto, Itsuki Mix, Alan C. Stoner, Joseph S. |
spellingShingle |
Müller, Juliane Romero, Oscar E. Cowan, Ellen A. Forwick, Matthias McClymont, Erin L. Asahi, Hirofumi März, Christian Suto, Itsuki Mix, Alan C. Stoner, Joseph S. Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs |
author_facet |
Müller, Juliane Romero, Oscar E. Cowan, Ellen A. Forwick, Matthias McClymont, Erin L. Asahi, Hirofumi März, Christian Suto, Itsuki Mix, Alan C. Stoner, Joseph S. |
author_sort |
Müller, Juliane |
title |
Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs |
title_short |
Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs |
title_full |
Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs |
title_fullStr |
Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs |
title_full_unstemmed |
Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs |
title_sort |
mid pleistocene productivity events in the subpolar ne pacific: iron fertilization from aeolian dust and icebergs |
publisher |
Adam Mickiewicz University |
publishDate |
2019 |
url |
https://epic.awi.de/id/eprint/52242/ http://palaeoarc.amu.edu.pl/wp-content/uploads/2019/05/PaleoArctic-Abstracts.pdf https://hdl.handle.net/10013/epic.c135cf37-b4c1-4011-8606-74e91e86116f |
geographic |
Gulf of Alaska Pacific |
geographic_facet |
Gulf of Alaska Pacific |
genre |
Arctic glaciers Ice Sheet North Atlantic Alaska |
genre_facet |
Arctic glaciers Ice Sheet North Atlantic Alaska |
op_source |
EPIC31st International Conference ‘Processes and Palaeo-environmental changes in the Arctic: from past to present’ (PalaeoArc), Adam Mickiewicz University, Poznań, 2019-05-20-2019-05-24Adam Mickiewicz University |
op_relation |
Müller, J. orcid:0000-0003-0724-4131 , Romero, O. E. , Cowan, E. A. , Forwick, M. , McClymont, E. L. , Asahi, H. , März, C. , Suto, I. , Mix, A. C. and Stoner, J. S. (2019) Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs , 1st International Conference ‘Processes and Palaeo-environmental changes in the Arctic: from past to present’ (PalaeoArc), Adam Mickiewicz University, Poznań, 20 May 2019 - 24 May 2019 . hdl:10013/epic.c135cf37-b4c1-4011-8606-74e91e86116f |
_version_ |
1766298077439721472 |
spelling |
ftawi:oai:epic.awi.de:52242 2023-05-15T14:25:38+02:00 Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs Müller, Juliane Romero, Oscar E. Cowan, Ellen A. Forwick, Matthias McClymont, Erin L. Asahi, Hirofumi März, Christian Suto, Itsuki Mix, Alan C. Stoner, Joseph S. 2019-05-24 https://epic.awi.de/id/eprint/52242/ http://palaeoarc.amu.edu.pl/wp-content/uploads/2019/05/PaleoArctic-Abstracts.pdf https://hdl.handle.net/10013/epic.c135cf37-b4c1-4011-8606-74e91e86116f unknown Adam Mickiewicz University Müller, J. orcid:0000-0003-0724-4131 , Romero, O. E. , Cowan, E. A. , Forwick, M. , McClymont, E. L. , Asahi, H. , März, C. , Suto, I. , Mix, A. C. and Stoner, J. S. (2019) Mid Pleistocene productivity events in the subpolar NE Pacific: iron fertilization from aeolian dust and icebergs , 1st International Conference ‘Processes and Palaeo-environmental changes in the Arctic: from past to present’ (PalaeoArc), Adam Mickiewicz University, Poznań, 20 May 2019 - 24 May 2019 . hdl:10013/epic.c135cf37-b4c1-4011-8606-74e91e86116f EPIC31st International Conference ‘Processes and Palaeo-environmental changes in the Arctic: from past to present’ (PalaeoArc), Adam Mickiewicz University, Poznań, 2019-05-20-2019-05-24Adam Mickiewicz University Conference notRev 2019 ftawi 2021-12-24T15:45:38Z IODP Expedition 341 succeeded in recovering a continuous sedimentary record of Miocene to Late Pleistocene climate history at drill Site U1417 in the Gulf of Alaska, NE Pacific. Site U1417 sediments provide an excellent opportunity to reconstruct North Pacific sea surface conditions during late Neogene large-scale (global) climate transitions. The Mid Pleistocene Transition (MPT) - one of the most prominent intervals of global Quaternary climate change - is clearly identifiable in Site U1417 sediments (Jaeger et al., 2014). To fully exploit the environmental information archived in U1417 sediments, a sampling strategy has been pursued that permits direct correlation of different (independent) proxy data obtained from biomarker, micropalaeontological, sedimentological and geochemical (XRF) analyses. Mid Pleistocene SSTs in the Gulf of Alaska are in good agreement with SST reconstructions for the North Atlantic and the NW Pacific. A general cooling at about 1 Ma supports earlier hypotheses of an overall Northern Hemisphere ocean cooling as a prerequisite for the increase in continental ice volume. While phytoplankton productivity seems rather independent from SST at Site U1417, it is strongly related to elevated TAR values depicting enhanced input of terrestrial leaf-wax lipids (Meyers, 1997). The transport of these lipids is supposed to be effected by strong winds carrying dust from Alaskan loess deposits to the open ocean as well as by icebergs released from Alaskan tidewater glaciers. The latter is supported by the occasional coincidence of high IRD contents and TAR values. The close relationship between the TAR record, Ba/Al values and the abundance of diatoms, however, strengthens that together with the leaf-wax lipids also iron-bearing dust was exported leading to high productivity events at Site U1417 throughout the Mid Pleistocene. The distinct "on-off" pattern in diatom productivity evolved with the onset of the MPT, which suggests that the expansion of the Northwest Cordilleran Ice Sheet lead to an effective production of glacigenic iron-rich dust that was exported i) by strong northwesterly winds and ii) by icebergs. The observation that productivity peaks in the Gulf of Alaska are not confined to glacial or interglacial periods points to a rather local feedback between the export of iron-bearing dust and an immediately responding ocean surface. The identification of these hitherto unconsidered fertilization mechanisms that potentially fostered ocean productivity and hence the sequestration of atmospheric carbon into the deep ocean are further detailed by Müller et al. (2018). Conference Object Arctic glaciers Ice Sheet North Atlantic Alaska Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Gulf of Alaska Pacific |