Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry
This dissertation assesses the changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget. The modern Equatorial Pacific Intermediate Water (EqPIW) is fed by three end-member components: Southern Ocean Intermediate Water (SOIW), Pacific Deep Water (PDW)...
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Language: | English |
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Universität Bremen
2016
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Online Access: | https://media.suub.uni-bremen.de/handle/elib/1166 https://nbn-resolving.org/urn:nbn:de:gbv:46-00105680-11 |
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ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/1166 2023-05-15T15:44:01+02:00 Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry Abwechselnde Dominanz polaren Zwischenwassermassen und deren Auswirkung auf das äquatoriale Nahrstoffbudget Rippert, Nadine Tiedemann, Ralf Bohrmann, Gerhard 2016-12-15 application/pdf https://media.suub.uni-bremen.de/handle/elib/1166 https://nbn-resolving.org/urn:nbn:de:gbv:46-00105680-11 eng eng Universität Bremen FB5 Geowissenschaften https://media.suub.uni-bremen.de/handle/elib/1166 urn:nbn:de:gbv:46-00105680-11 info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) CC-BY Living planktonic foraminifera Apparent calcification depth Western equatorial Pacific Stable isotopes Mg/Ca analyses foraminiferal vital effects North Pacific Equatorial Pacific South Pacific AAIW intermediate water sub-thermocline last glacial period LGM MIS 6 550 550 Earth sciences and geology ddc:550 Dissertation doctoralThesis 2016 ftsubbremen 2022-11-09T07:09:31Z This dissertation assesses the changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget. The modern Equatorial Pacific Intermediate Water (EqPIW) is fed by three end-member components: Southern Ocean Intermediate Water (SOIW), Pacific Deep Water (PDW) and, by a smaller proportion, North Pacific Intermediate Water (NPIW). This modern configuration of end-members in the EqPIW results in low productivity of siliceous phytoplankton in the Eastern Equatorial Pacific (EEP) today as SOIW is depleted in silicic acid compared to other nutrients. However, there is growing debate over whether SOIW was capable of stimulating glacial equatorial productivity. Furthermore, recent studies point towards a change in the lateral and vertical extent of both SOIW and NPIW during glacials, impacting the supply of nutrients to the EEP. Most upper ocean water mass reconstructions are based on planktonic foraminifera tests. Different foraminiferal species preferentially dwell in distinct water depths and thus, the calcitic tests of these species can be used to infer past climate conditions. This thesis assesses equatorial foraminiferal ACDs to identify a species suitable to trace nutrient-inflow of extra-tropical intermediate water masses. Using this determined species, this thesis then reconstructs the effect of variable nutrient injections from extra-tropical water masses on the equatorial Pacific upwelling waters using benthic and planktonic foraminiferal carbon isotopes (d13C). It was shown that d13C records from the Bering Sea (as an indicator for glacial NPIW (GNPIW)), the eastern tropical North Pacific and the EqPIW exhibit a similar temporal evolution during MIS 2. These results indicate increased GNPIW ventilation during glacials that spreads southward towards the eastern tropical North Pacific. During peak glacials the southward expansion of GNPIW was at a maximum and extended into the equatorial Pacific. Together with newly published evidence for a shallower penetration of ... Doctoral or Postdoctoral Thesis Bering Sea Planktonic foraminifera Southern Ocean Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) Bering Sea Pacific Southern Ocean |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
Living planktonic foraminifera Apparent calcification depth Western equatorial Pacific Stable isotopes Mg/Ca analyses foraminiferal vital effects North Pacific Equatorial Pacific South Pacific AAIW intermediate water sub-thermocline last glacial period LGM MIS 6 550 550 Earth sciences and geology ddc:550 |
spellingShingle |
Living planktonic foraminifera Apparent calcification depth Western equatorial Pacific Stable isotopes Mg/Ca analyses foraminiferal vital effects North Pacific Equatorial Pacific South Pacific AAIW intermediate water sub-thermocline last glacial period LGM MIS 6 550 550 Earth sciences and geology ddc:550 Rippert, Nadine Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry |
topic_facet |
Living planktonic foraminifera Apparent calcification depth Western equatorial Pacific Stable isotopes Mg/Ca analyses foraminiferal vital effects North Pacific Equatorial Pacific South Pacific AAIW intermediate water sub-thermocline last glacial period LGM MIS 6 550 550 Earth sciences and geology ddc:550 |
description |
This dissertation assesses the changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget. The modern Equatorial Pacific Intermediate Water (EqPIW) is fed by three end-member components: Southern Ocean Intermediate Water (SOIW), Pacific Deep Water (PDW) and, by a smaller proportion, North Pacific Intermediate Water (NPIW). This modern configuration of end-members in the EqPIW results in low productivity of siliceous phytoplankton in the Eastern Equatorial Pacific (EEP) today as SOIW is depleted in silicic acid compared to other nutrients. However, there is growing debate over whether SOIW was capable of stimulating glacial equatorial productivity. Furthermore, recent studies point towards a change in the lateral and vertical extent of both SOIW and NPIW during glacials, impacting the supply of nutrients to the EEP. Most upper ocean water mass reconstructions are based on planktonic foraminifera tests. Different foraminiferal species preferentially dwell in distinct water depths and thus, the calcitic tests of these species can be used to infer past climate conditions. This thesis assesses equatorial foraminiferal ACDs to identify a species suitable to trace nutrient-inflow of extra-tropical intermediate water masses. Using this determined species, this thesis then reconstructs the effect of variable nutrient injections from extra-tropical water masses on the equatorial Pacific upwelling waters using benthic and planktonic foraminiferal carbon isotopes (d13C). It was shown that d13C records from the Bering Sea (as an indicator for glacial NPIW (GNPIW)), the eastern tropical North Pacific and the EqPIW exhibit a similar temporal evolution during MIS 2. These results indicate increased GNPIW ventilation during glacials that spreads southward towards the eastern tropical North Pacific. During peak glacials the southward expansion of GNPIW was at a maximum and extended into the equatorial Pacific. Together with newly published evidence for a shallower penetration of ... |
author2 |
Tiedemann, Ralf Bohrmann, Gerhard |
format |
Doctoral or Postdoctoral Thesis |
author |
Rippert, Nadine |
author_facet |
Rippert, Nadine |
author_sort |
Rippert, Nadine |
title |
Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry |
title_short |
Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry |
title_full |
Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry |
title_fullStr |
Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry |
title_full_unstemmed |
Changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : Implications from foraminiferal geochemistry |
title_sort |
changing dominance of high-latitude intermediate waters and its impact on the equatorial nutrient-budget : implications from foraminiferal geochemistry |
publisher |
Universität Bremen |
publishDate |
2016 |
url |
https://media.suub.uni-bremen.de/handle/elib/1166 https://nbn-resolving.org/urn:nbn:de:gbv:46-00105680-11 |
geographic |
Bering Sea Pacific Southern Ocean |
geographic_facet |
Bering Sea Pacific Southern Ocean |
genre |
Bering Sea Planktonic foraminifera Southern Ocean |
genre_facet |
Bering Sea Planktonic foraminifera Southern Ocean |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/1166 urn:nbn:de:gbv:46-00105680-11 |
op_rights |
info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) |
op_rightsnorm |
CC-BY |
_version_ |
1766378237700603904 |