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  • Alzey_Fm_Gp; Glycymeris planicostalis, growth increment width; Growth index; Number of years  (5)
  • AWI_Paleo; Paleoenvironmental Reconstructions from Marine Sediments @ AWI  (4)
  • File content; File format; File name; File size; Uniform resource locator/link to file  (4)
Document type
Keywords
Publisher
Years
  • 1
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    PANGAEA
    In:  Supplement to: Stein, Ruediger; Fahl, Kirsten; Gierz, Paul; Niessen, Frank; Lohmann, Gerrit (2017): Arctic Ocean sea ice cover during the penultimate glacial and the last interglacial. Nature Communications, 8(1), 13 pp, https://doi.org/10.1038/s41467-017-00552-1
    Publication Date: 2023-03-16
    Description: Coinciding with global warming, Arctic sea ice has rapidly decreased during the last four decades and climate scenarios suggest that sea ice may completely disappear during summer within the next about 50-100 years. Here we produce Arctic sea ice biomarker proxy records for the penultimate glacial (Marine Isotope Stage 6) and the subsequent last interglacial (Marine Isotope Stage 5e). The latter is a time interval when the high latitudes were significantly warmer than today. We document that even under such warmer climate conditions, sea ice existed in the central Arctic Ocean during summer, whereas sea ice was significantly reduced along the Barents Sea continental margin influenced by Atlantic Water inflow. Our proxy reconstruction of the last interglacial sea ice cover is supported by climate simulations, although some proxy data/model inconsistencies still exist. During late Marine Isotope Stage 6, polynya-type conditions occurred off the major ice sheets along the northern Barents and East Siberian continental margins, contradicting a giant Marine Isotope Stage 6 ice shelf that covered the entire Arctic Ocean.
    Keywords: AWI_Paleo; Paleoenvironmental Reconstructions from Marine Sediments @ AWI
    Type: Dataset
    Format: application/zip, 4 datasets
    Location Call Number Limitation Availability
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  • 2
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    PANGAEA
    In:  Supplement to: Abelmann, Andrea; Gersonde, Rainer; Knorr, Gregor; Zhang, Xu; Chapligin, Bernhard; Maier, Edith; Esper, Oliver; Friedrichsen, Hans; Lohmann, Gerrit; Meyer, Hanno; Tiedemann, Ralf (2015): The seasonal sea-ice zone in the glacial Southern Ocean as a carbon sink. Nature Communications, 6, 8136, https://doi.org/10.1038/ncomms9136
    Publication Date: 2023-03-30
    Description: Reduced surface-deep ocean exchange and enhanced nutrient consumption by phytoplankton in the Southern Ocean have been linked to lower glacial atmospheric CO2. However, identification of the biological and physical conditions involved and the related processes remains incomplete. Here we specify Southern Ocean surface-subsurface contrasts using a new tool, the combined oxygen and silicon isotope measurement of diatom and radiolarian opal, in combination with numerical simulations. Our data do not indicate a permanent glacial halocline related to melt water from icebergs. Corroborated by numerical simulations, we find that glacial surface stratification was variable and linked to seasonal sea-ice changes. During glacial spring-summer, the mixed layer was relatively shallow, while deeper mixing occurred during fall-winter, allowing for surface-ocean refueling with nutrients from the deep reservoir, which was potentially richer in nutrients than today. This generated specific carbon and opal export regimes turning the glacial seasonal sea-ice zone into a carbon sink.
    Keywords: AWI_Paleo; Paleoenvironmental Reconstructions from Marine Sediments @ AWI
    Type: Dataset
    Format: application/zip, 12 datasets
    Location Call Number Limitation Availability
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  • 3
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    PANGAEA
    In:  Supplement to: Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Lohmann, Gerrit; Bickert, Torsten; Pälike, Heiko (2018): Ocean and climate response to North Atlantic seaway changes at the onset of long-term Eocene cooling. Earth and Planetary Science Letters, 498, 185-195, https://doi.org/10.1016/j.epsl.2018.06.031
    Publication Date: 2023-01-13
    Description: Here we publish simulated early-middle Eocene annual mean ocean temperature, salinity, density, mixed layer depth and current velocities (at the depth of ~1500 m) with different gateways configurations in the North Atlantic region. The details of original paleogeography, compiled by GETECH, are provided in Vahlenkamp et al. [2018, doi:10.1016/j.epsl.2017.12.016]. The CO2 level is set to 840 ppm, while the obliquity to a minimum value. All data are averaged over the period of 100 years. All simulations were run with COSMOS (ECHAM5/MPIOM/OASIS3). The atmosphere component ECHAM5 was run in the resolution of T31/L19, while the ocean model MPIOM has a formal resolution of ~3.0°x1.8°. OASIS3 is a coupler between the atmosphere and ocean components. The gateway alterations with respect to original paleogeography include an opening of the Arctic and Tethyan Seaways, as well as changing the depth of the Greenland-Scotland Ridge to 50 m and 200 m [Vahlenkamp et al., 2018, doi:10.1016/j.epsl.2018.06.031]. We publish also one experiment with higher, 1000 ppm CO2 level. In order to compare our simulated temperatures with the data, we have collected 30 Eocene temperature reconstructions from literature. We compared these reconstructions with the zonal surface air temperatures as well as zonal surface ocean temperatures (annual, boreal winter and summer) from our base simulation. All data used are provided in this dataset.
    Keywords: File content; File format; File name; File size; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 55 data points
    Location Call Number Limitation Availability
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  • 4
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    PANGAEA
    In:  Supplement to: Niezgodzki, Igor; Tyszka, Jaroslaw; Knorr, Gregor; Lohmann, Gerrit (2019): Was the Arctic Ocean ice free during the latest Cretaceous? The role of CO2 and gateway configurations. Global and Planetary Change, 177, 201-212, https://doi.org/10.1016/j.gloplacha.2019.03.011
    Publication Date: 2023-01-13
    Description: We provide the results of 11 Late Cretaceous climate simulations (Tab. 1 in Niezgodzki et al. [2019, doi:10.1016/j.gloplacha.2019.03.011]) produced with COSMOS in a coupled atmosphere-ocean configuration. Five of these experiments use a 3 x pre-industrial (PI) CO2 level (840 ppm) while 6 of them were run with 4xPI CO2 (1120 ppm). The experiments with the same CO2 levels differ by gateway configurations between the Arctic Ocean and North proto-Atlantic basin. In spin-up experiments we employ Maastrichtian (~70 Ma) paleogeography of Markwick and Valdes [2004, doi:10.1016/j.palaeo.2004.06.015]. More information about model scenarios and model set-up can be found in Niezgodzki et al. [2019, doi:10.1016/j.gloplacha.2019.03.011]. Here we publish simulated winter (DJF) surface temperatures (tsurf) and salinity (SAO), averaged March-April (Ma-Ap) sea surface temperature (THO) and SAO and monthly sea-ice compactness (SICOMO) of each experiment. Additionally, for two gateway configurations we show DJF and summer (JJA) 10m meridional (v10) and zonal (u10) wind speeds as well as JJA shortwave net surface radiation (srads), net clear sky surface radiation (srafs), longwave net surface radiation (trads) and clear sky surface radiation (trafs).
    Keywords: File content; File format; File name; File size; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 175 data points
    Location Call Number Limitation Availability
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  • 5
    Publication Date: 2023-01-13
    Keywords: Alzey_Fm_Gp; Glycymeris planicostalis, growth increment width; Growth index; Number of years
    Type: Dataset
    Format: text/tab-separated-values, 207 data points
    Location Call Number Limitation Availability
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  • 6
    Publication Date: 2023-01-13
    Keywords: Alzey_Fm_Gp; Glycymeris planicostalis, growth increment width; Growth index; Number of years
    Type: Dataset
    Format: text/tab-separated-values, 225 data points
    Location Call Number Limitation Availability
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  • 7
    Publication Date: 2023-01-13
    Keywords: Alzey_Fm_Gp; Glycymeris planicostalis, growth increment width; Growth index; Number of years
    Type: Dataset
    Format: text/tab-separated-values, 144 data points
    Location Call Number Limitation Availability
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  • 8
    Publication Date: 2023-01-13
    Keywords: Alzey_Fm_Gp; Glycymeris planicostalis, growth increment width; Growth index; Number of years
    Type: Dataset
    Format: text/tab-separated-values, 177 data points
    Location Call Number Limitation Availability
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  • 9
    Publication Date: 2023-01-13
    Keywords: Alzey_Fm_Gp; Glycymeris planicostalis, growth increment width; Growth index; Number of years
    Type: Dataset
    Format: text/tab-separated-values, 141 data points
    Location Call Number Limitation Availability
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  • 10
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    PANGAEA
    In:  Supplement to: Hasenclever, Jörg; Knorr, Gregor; Rüpke, Lars H; Köhler, Peter; Morgan, Jason Phipps; Garofalo, Kristin; Barker, Stephen; Lohmann, Gerrit; Hall, Ian R (2017): Sea level fall during glaciation stabilized atmospheric CO2 by enhanced volcanic degassing. Nature Communications, 8, 15867, https://doi.org/10.1038/ncomms15867
    Publication Date: 2023-01-13
    Description: Paleo-climate records and geodynamic modelling indicate the existence of complex interactions between glacial sea level changes, volcanic degassing, and atmospheric CO2, which may have modulated the climate system's descent into the last ice age. Between ~85-70 ka, during an interval of decreasing axial tilt, the orbital component in global temperature records gradually declined, while atmospheric CO2, instead of continuing is long-term correlation with Antarctic temperature, remained relatively stable. Based on novel global geodynamic models and the joint interpretation of paleo-proxy data as well as biogeochemical simulations, we show that a sea level fall in this interval caused enhanced pressure-release melting in the uppermost mantle, which may have induced a surge in magma and CO2 fluxes from mid-ocean ridges and oceanic hotspot volcanoes. Our results reveal a hitherto unrecognised negative feedback between glaciation and atmospheric CO2 predominantly controlled by marine volcanism on multi-millennial (suborbital) timescales of ~ 5,000-15,000 years.
    Keywords: File content; File format; File name; File size; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 10 data points
    Location Call Number Limitation Availability
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