LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 15

Search options

  1. Article ; Online: Ocean science. When still waters ran deep.

    Kiefer, Thorsten

    Science (New York, N.Y.)

    2010  Volume 329, Issue 5989, Page(s) 290–291

    Language English
    Publishing date 2010-07-16
    Publishing country United States
    Document type Comment ; Journal Article
    ZDB-ID 128410-1
    ISSN 1095-9203 ; 0036-8075
    ISSN (online) 1095-9203
    ISSN 0036-8075
    DOI 10.1126/science.1192295
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 27: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)
    Zs.MG 77: Show issues

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Book: PAGES (Past Global Changes International Project)

    Kiefer, Thorsten

    Abstract: The PAGES (Past Global Changes) project, including the PAGES International Project Office in Bern, is funded by the Swiss and U.S. National Science Foundations. The current four-year grant runs from 2006-2010. PAGES was founded in 1991 and works to ... ...

    Institution PAGES International Project Office, Friedbuehlstrasse 11, 3008, Bern, CH
    Abstract The PAGES (Past Global Changes) project, including the PAGES International Project Office in Bern, is funded by the Swiss and U.S. National Science Foundations. The current four-year grant runs from 2006-2010. PAGES was founded in 1991 and works to coordinate international paleoscience research, communicate with the paleoscience community, and integrate past global change scientists from around the world into an international network OBJECTIVES AND METHODS: PAGES is a core project of the International Geosphere Biosphere Program (IGBP) and deals with the Earth's climatic and environmental history from the last few 100 years to several 100,000 years. The primary objective of PAGES is to improve our understanding of past climate and environmental change. SCIENTIFIC AREAS OF INTEREST: While PAGES itself is not a research institution, it helps to identify overarching issues in past global change science and ensure that they are addressed in a coherent manner. Four sets of questions of prime current interest will be targeted by PAGES during the coming years: 1. Climate Forcing and Sensitivity: What is the history of the main climate forcing factors (changes in solar irradiation due to changes in the Earth orbit, changes in solar irradiance due to variability in solar activity, variability of greenhouse gas concentration in the atmosphere, influence of volcanic activity, etc.) and the sensitivity of the climate system to these forcings? In what precise sequence have changes in forcings, surface climate, and ecological systems occurred? 2. Regional Climate Variability: How have global climate and the Earth's natural environment changed in the past? What are the main modes of variability that operated at different timescales, and how do they relate to each other and to the mean state of the climate system? 3. Earth System Dynamics: How have different parts of the Earth System interacted to produce climatic and environmental feedbacks on regional and global scale? What are the causes and thresholds of rapid transitions between quasi-stable climatic and environmental states, in particular on timescales that are relevant to society? How reversible are these changes? 4. Past Human-Climate-Ecosystem Interactions: To what extent and since when has human activity modified climate and the global/regional environment? How can human induced change be disentangled from natural responses to external forcing mechanisms and internal system dynamics? These questions are addressed through organized scientific activities under the umbrella of PAGES. The activities are carried out by the worldwide past global change community, the PAGES Scientific Steering Committee and the PAGES IPO, often in collaboration with other global change programs.
    Keywords Buero ; Finanzierung ; Atmosphaere ; Koordinate ; Forschung ; Globale Veraenderung ; Geosphaere ; Biosphaere ; Erdreich ; Umweltgeschichte ; Klima ; Umweltveraenderung ; Gebiet ; Zins ; Bestrahlung ; Gewaechshaus ; Gasfoermiger Stoff ; Oekosystem ; Sequenzierung ; Staat ; Erdsystem ; Umwelt ; Rechtsstreit ; Stall ; Klimaschwankung ; Systemtheorie ; Globale Aspekte ; Industrieanlage ; Koerperschaft ; Mesoklima ; Mensch ; Schweiz
    Language English
    Document type Book
    Remark project start: 08/01/2006 project end: 07/31/2010 grant ID:
    Database Environmental research database (UFORDAT) of the German Federal Environment Agency (UBA)

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  3. Book ; Thesis: Produktivität und Temperaturen im subtropischen Nordatlantik

    Kiefer, Thorsten

    zyklische und abrupte Veränderungen im späten Quartär = Productivity and temperatures in the subtropical North Atlantic

    (Berichte / Geologisch-Paläontologisches Institut und Museum, Christian-Albrechts-Universität Kiel ; 90)

    1998  

    Title variant Productivity and temperatures in the subtropical North Atlantic
    Author's details Kiefer, Thorsten
    Series title Berichte / Geologisch-Paläontologisches Institut und Museum, Christian-Albrechts-Universität Kiel ; 90
    Keywords Paläoklima ; Klimaschwankung ; Ökologie ; Holozän ; Temperatur ; Meerestiere ; Meeresgeologie ; Atlantischer Ozean ; Subtropen
    Language German
    Size V, 127 S, Ill., graph. Darst., Kt
    Publisher Geologisch-Paläontolog. Inst. und Museum, Christian-Albrechts-Univ
    Publishing place Kiel
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Univ., Diss.--Kiel, 1997
    Note Zsfassung in engl. Sprache
    Database Former special subject collection: coastal and deep sea fishing

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  4. Book ; Thesis: Produktivität und Temperaturen im subtropischen Nordatlantik

    Kiefer, Thorsten

    zyklische und abrupte Veränderungen im späten Quartär = Productivity and temperatures in the subtropical North Atlantic

    (Berichte / Geologisch-Paläontologisches Institut und Museum, Christian-Albrechts-Universität Kiel ; 90)

    1998  

    Title variant Productivity and temperatures in the subtropical North Atlantic
    Author's details Kiefer, Thorsten
    Series title Berichte / Geologisch-Paläontologisches Institut und Museum, Christian-Albrechts-Universität Kiel ; 90
    Keywords Paläoklima ; Klimaschwankung ; Ökologie ; Holozän ; Temperatur ; Meerestiere ; Meeresgeologie ; Atlantischer Ozean ; Subtropen
    Language German
    Size V, 127 S, Ill., graph. Darst., Kt
    Publisher Geologisch-Paläontolog. Inst. und Museum, Christian-Albrechts-Univ
    Publishing place Kiel
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Univ., Diss.--Kiel, 1997
    Note Zsfassung in engl. Sprache
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  5. Book: Produktivitaet und Temperaturen im subtropischen Nordatlantik: zyklische und abrupte Veraenderungen im spaeten Quartaer = Productivity and Temperatures in the Subtropical North Atlantic: Cyclic and Abrupt Changes During the Late Quaternary

    Kiefer, Thorsten

    1998  Volume 90, Page(s) V, 127

    Abstract: An Sedimentkernen vom Nord- und Ostrand des subtropischen Wirbels im Nordatlantik (Kerne 15612 und 15637) wurden fuer die letzten 220 000 Jahre sowohl glazial/interglaziale Veraenderungen in der Produktivitaet als auch solche waehrend abrupter ... ...

    Abstract An Sedimentkernen vom Nord- und Ostrand des subtropischen Wirbels im Nordatlantik (Kerne 15612 und 15637) wurden fuer die letzten 220 000 Jahre sowohl glazial/interglaziale Veraenderungen in der Produktivitaet als auch solche waehrend abrupter Klimawechsel rekonstruiert. Damit kann fuer die heute extrem niedrigproduktive Region die Klimawirksamkeit des CO2-Entzugs aus der Atmosphaere durch die Biologische Pumpe besser bewertet werden. Die Primaerproduktivitaet wurde aus dem Artenspektrum der Planktonforaminiferen mit der SIMMAX-Transfertechnik abgeschaetzt. Ergaenzend wurde anhand der Akkumulationsrate von biogenem Barium, Benthosforaminiferen und organischem Kohlenstoff (Corg) der Export von organischem Material in tiefere Wasserschichten und dessen Einbettung ins Sediment abgeleitet. Die Primaerproduktion am heutigen Nordrand des subtropischen Wirbels schwankte zwischen hoeheren glazialen (250-350 gC/m2a) und niedrigeren interglazialen Werten (150-200 gC/m2a). Am Ostrand des subtropischen Wirbels war die kaltzeitliche Produktivitaet im Mittel sogar rund 4 mal hoeher als heute und waehrend der Interglaziale (100 gC/m2a). Waehrend der Kaltstadien entzog die biologische Pumpe in diesen Gebieten der Atmosphaere somit ungefaehr 2 bis 4 mal so viel Kohlenstoff wie heute. Allerdings war die Speicherwirkung am Ostrand des subtropischen Wirbels fuer den ueberwiegenden Anteil auf rund 2000 Jahre begrenzt, da nach der Differenz zwischen Exportproduktion und Corg-Akkumulation der Grossteil des Kohlenstoffs in der Wassersaeule remineralisiert und nur wenig davon im Sediment deponiert wurde. Kurzfristigere Produktivitaetsschwankungen wurden in den Stadien 2-4 und 6 festgestellt und korrespondieren in der Regel mit den Heinrich-Schmelzwasserereignissen. Innerhalb des Heinrich-Guertels (40-55 Grad N) wurden die Schmelzwasserereignisse insbesondere an deren Beginn und Ende von kurzen Produktivitaetsschueben begleitet. Die Produktivitaetsschuebe wurden vermutlich von naehrstoffreichen Auftriebswaessern gespeist, die zusammen mit dem Aufstieg von Schmelzwasser an den Flanken von Eisbergen und durch Konvektion entlang ozeanischer Fronten am Rand des Schmelzwasserteppichs in die euphotische Zone gelangten. Zudem duerfte ein Teil der Produktion im naehrstoffreichen Wasser unterhalb einer flachen und stabilen Schmelzwasserdeckschicht stattgefunden haben. Allerdings verschlechterten sich mit zunehmender Eisbergdichte die Lichtverhaeltnisse offensichtlich derart, dass die Phytoplanktonproduktion waehrend der Hochphase der Heinrich-Ereignisse einbrach. (gekuerzt)
    Keywords Bohrkern ; Schmelzwasser ; Luftbewegung ; Sedimentkoerper ; Kohlendioxid ; Eis ; Barium ; Klimaaenderung ; Palaeoklimatologie ; Sediment ; Artenvielfalt ; Primaerproduktion ; Plankton ; Atmosphaere ; Auftrieb ; Kohlenstoff ; Produktivitaet ; Turbulenz ; Meeresorganismen ; Meeresbiologie ; Organische Substanz ; Biologische Aktivitaet ; Wassertemperatur ; Zirkulation ; Meeresstroemung
    Language German
    Document type Book
    Database OPAC and Environmental database (ULIDAT) of The Federal Environment Agency (UBA)

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  6. Book: Produktivitaet und Temperaturen im subtropischen Nordatlantik

    Kiefer, Thorsten

    zyklische und abrupte Veraenderungen im spaeten Quartaer

    1998  Volume 90, Page(s) V, 127 S.

    Keywords Produktivitaet
    Language German
    Document type Book
    Database OPAC and Environmental database (ULIDAT) of The Federal Environment Agency (UBA)

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  7. Book ; Online: (Table 2) C-14 age data from ODP Hole 145-883, supplementary data to: Sarnthein, Michael; Kiefer, Thorsten; Grootes, Pieter Meiert; Elderfield, Harry; Erlenkeuser, Helmut (2006): Warmings in the far northwestern Pacific promoted pre-Clovis immigration to America during Heinrich event 1. Geology, 34(3), 141-144

    Sarnthein, Michael / Elderfield, Harry / Erlenkeuser, Helmut / Grootes, Pieter Meiert / Kiefer, Thorsten

    2006  

    Abstract: Well-dated multidecadal- to centennial-scale sediment records from the subarctic northwest Pacific show that the early deglacial 18.5-15.0 ka was marked by 3 pronounced short-term warmings of ~5°C. They lasted 500-1500 yr each and were coeval with early ... ...

    Abstract Well-dated multidecadal- to centennial-scale sediment records from the subarctic northwest Pacific show that the early deglacial 18.5-15.0 ka was marked by 3 pronounced short-term warmings of ~5°C. They lasted 500-1500 yr each and were coeval with early to late stages of cold Heinrich event 1 in the North Atlantic. These regional climate windows may have promoted a pre-Clovis emigration of people from the cold-arid monsoon climate in East Asia to the climatically more favorable, then-emerged Beringian and Aleutian shelf regions and the Americas, as suggested by archeological findings.
    Language English
    Dates of publication 2006-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1130/G22200.1
    DOI 10.1594/PANGAEA.723920
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  8. Book ; Online: Paleonutrient and productivity records from the subarctic North Pacific, supplementary data to: Gebhardt, Holger; Sarnthein, Michael; Grootes, Pieter Meiert; Kiefer, Thorsten; K?hn, Hartmut; Schmieder, Frank; R?hl, Ursula (2008): Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V. Paleoceanography, 23, PA4212

    Gebhardt, Holger / Grootes, Pieter Meiert / K?hn, Hartmut / Kiefer, Thorsten / R?hl, Ursula / Sarnthein, Michael / Schmieder, Frank

    2008  

    Abstract: Our study addresses fundamental questions of the mode and timing of orbital and millennialscale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past ... ...

    Abstract Our study addresses fundamental questions of the mode and timing of orbital and millennialscale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past abundance of nutrients in surface waters despite strong stratification, and the North Pacific - North Atlantic seesaw of oscillations in sea surface temperature (SST). We do this by generating and interpreting multiple records for glacial terminations I-V down two long piston cores, one each from the western and eastern subarctic Pacific. Chlorins and biogenic opal are proxies for surface water productivity; delta 13C of epibenthic foraminifera is a record of deepwater ventilation; and the delta 13C of N. pachyderma sin. is a tracer of nutrients in subsurface waters that extend up to the sea surface during times of vertical mixing. The degree of mixing is traced by pairing SST and delta 18O records of planktic surface and subsurface (pycnocline) dwellers. Tight age control is deduced from a suite of age-calibrated 14C plateau boundaries for Termination I, and benthic ?18O, and geomagnetic events for the last 800 kyr. 14C paleoreservoir ages record the ages of surface and deep waters to uncover short-term changes in MOC over Termination I. We have defined a standard sequence of short-term productivity events for Termination I and subsequent interglacials, also evident during Terminations II to V over the last 450 ka. The peak-glacial regime of stable stratification and low productivity terminated, together with the end of ice rafting and melting, near 17 ka, ~2000 yr after the onset of Termination I. Pulses of vertical mixing and incursion of warm surface waters from the subtropics followed. Convected young water masses finally penetrated down to 2350 m water depth after a further 1500 yr, at ~14.5 ka, significantly improving bottom water ventilation through the late deglacial and earliest interglacial. Mixing with upwelled nutrients from the pycnocline induced shortterm maxima in algal production of chlorins and biogenic opal near 17-15 and 15-12 ka, respectively. Deglacial meltwater incursions in the Aleutian Current and silica input from North American rivers also promoted East Pacific productivity after 15.5 ka. Productivity decreased during the late deglacial and early interglacial, coeval with an exceptional peak in CaCO3 preservation caused by both low organic flux and well ventilated deepwater. Subsequently, low-salinity and cool surface waters and in turn, stratification were gradually restored. A second, opal-dominated productivity maximum marked the ends of interglacials. The deglacial pulses of vertical mixing around 17-11 ka imply an important contribution of the North Pacific to the coeval release of oceanic CO2 into the atmosphere and support the east-west seesaw model of climate change.
    Language English
    Dates of publication 2008-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1029/2007PA001513
    DOI 10.1594/PANGAEA.701578
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  9. Book ; Online: A global compolation of late Holocene planktonic foraminiferal d18O, supplementary data to: Waelbroeck, Claire; Mulitza, Stefan; Spero, Howard; Dokken, Trond; Kiefer, Thorsten; Cortijo, Elsa (2005): A global compilation of Late Holocene planktonic foraminiferal d18O: Relationship between surface water temperature and d18O. Quaternary Science Reviews, 24(7-9), 853-868

    Waelbroeck, Claire / Cortijo, Elsa / Dokken, Trond / Kiefer, Thorsten / Mulitza, Stefan / Spero, Howard

    2005  

    Abstract: We review the different sources of uncertainty affecting the oxygen isotopic composition of planktonic foraminifera and present a global planktonic foraminifera oxygen isotope data set that has been assembled within the MARGO project for the Late ... ...

    Abstract We review the different sources of uncertainty affecting the oxygen isotopic composition of planktonic foraminifera and present a global planktonic foraminifera oxygen isotope data set that has been assembled within the MARGO project for the Late Holocene time slice. The data set consists of over 2100 data from recent sediment with thorough age control, that have been checked for internal consistency. We further examine how the oxygen isotopic composition of fossil foraminifera is related to hydrological conditions, based on published results on living foraminifera from plankton tows and cultures. Oxygen isotopic values (delta18O) of MARGO recent fossil foraminifera are 0.2-0.8 per mil higher than those of living foraminifera. Our results show that this discrepancy is related to the stratification of the upper water mass and generally increases at low latitudes. Therefore, as stratification of surface waters and seasonality depends on climatic conditions, the relationship between temperature and delta18O established on fossil foraminifera from recent sediment must be used with caution in paleoceanographic studies. Before models predicting seasonal flux, abundance and delta18O composition of a foraminiferal population in the sediment are available, we recommend studying relative changes in isotopic composition of fossil planktonic foraminifera. These changes primarily record variations in temperature and oxygen isotopic composition of sea water, although part of the changes might reflect modifications of planktonic foraminifera seasonality or depth habitat
    Language English
    Dates of publication 2005-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1016/j.quascirev.2003.10.014
    DOI 10.1594/PANGAEA.738561
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  10. Book ; Online: Paleoceanography on sediment core MD01-2416, supplementary data to: Sarnthein, Michael; Gebhardt, Holger; Kiefer, Thorsten; Kucera, Michal; Cook, M; Erlenkeuser, Helmut (2004): Mid Holocene origin of the sea surface salinity low in the Subarctic North Pacific. Quaternary Science Reviews, 23(20-22), 2089-2099

    Sarnthein, Michael / Cook, M / Erlenkeuser, Helmut / Gebhardt, Holger / Kiefer, Thorsten / Kucera, Michal

    2004  

    Abstract: IMAGES core MD01-2416 (51?N, 168?E) provides the first centennial-scale multiproxy record of Holocene variation in North Pacific sea-surface temperature (SST), salinity, and biogenic productivity. Our results reveal a gradual decrease in subarctic SST by ...

    Abstract IMAGES core MD01-2416 (51?N, 168?E) provides the first centennial-scale multiproxy record of Holocene variation in North Pacific sea-surface temperature (SST), salinity, and biogenic productivity. Our results reveal a gradual decrease in subarctic SST by 3-5??C from 11.1 to 4.2?ka and a stepwise long-term decrease in sea surface salinity (SSS) by 2-3 p.s.u. Early Holocene SSS were as high as in the modern subtropical Pacific. The steep halocline and stratification that is characteristic of the present-day subarctic North Pacific surface ocean is a fairly recent feature, developed as a product of mid-Holocene environmental change. High SSS matched a salient productivity maximum of biogenic opal during B?lling-to-Early Holocene times, reaching levels similar to those observed during preglacial times in the warm mid-Pliocene prior to 2.73 Ma. Similar productivity spikes marked every preceding glacial termination of the last 800?ka, indicating recurrent short-term events of mid-Pliocene-style intense upwelling of nutrient-rich Pacific Deepwater in the Pleistocene. Such events led to a repeated exposure of CO2-rich deepwater at the ocean surface facilitating a transient CO2 release to the atmosphere, but the timing and duration of these events repudiate a long-term influence of the subarctic North Pacific on global atmospheric CO2 concentration.
    Language English
    Dates of publication 2004-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1016/j.quascirev.2004.08.008
    DOI 10.1594/PANGAEA.738119
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top