GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    facet.materialart.
    Unbekannt
    On‐site non‐destructive determination of the remanent magnetization of archaeological finds using field magnetometers (2021)
    Details
    Publikationsdatum: 2022-09-22
    Beschreibung: The determination of the natural remanent magnetization (NRM) of archaeological features can be used for magnetic modelling, joining of shards, archaeomagnetic dating or the investigation of the firing–cooling–collapsing order of ancient buildings. The measurement of NRM is normally conducted on cylindrical or cubic samples in the laboratory. Nevertheless, archaeological finds should preferably not be destroyed, and laboratory instruments are high in costs. Therefore, we propose a lightweight and portable measurement set‐up including already available field magnetometers (preferably caesium magnetometers) in which the archaeological sample of arbitrary shape, in our case a piece of daub, is mounted inside a gimbal to be rotated in all directions. The magnetic field of the sample is measured at a large number of rotational positions with the magnetometer kept at fixed position. In these measurements, the unknown direction of the NRM vector of the sample is rotated, whereas the average magnetic susceptibility of the sample and the ambient magnetic field are constant and known. Hence, the vector of NRM can be determined through least‐squares inversion. For the inversion computation, the sample volume is discretized either as voxel model or approximated as an equivalent sphere. Under certain conditions depending on sample–sensor distance, dipole moment and radius of the sample, the approximation by a sphere is valid without effect on the accuracy of results. Empirically determined functions quantifying these conditions for different sensor sensitivities and noise levels are provided. Validation with laboratory measurements on palaeomagnetic subsamples from the destroyed daub samples indicate that the NRM can be determined by our proposed method with a maximum error in inclination of 2°, in declination of 20° and in magnetization of ±0.6 A/m. This is accurate enough, for example, to determine from daub pieces of burnt house remains whether the building was burnt and cooled before or after it collapsed.
    Beschreibung: German Research Foundation http://dx.doi.org/10.13039/501100001659
    Schlagwort(e): ddc:622.15
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 2
    facet.materialart.
    Unbekannt
    Mixed Layer Depth Promotes Trophic Amplification on a Seasonal Scale (2022)
    Details
    Publikationsdatum: 2022-10-06
    Beschreibung: The Humboldt Upwelling System is of global interest due to its importance to fisheries, though the origin of its high productivity remains elusive. In regional physical‐biogeochemical model simulations, the seasonal amplitude of mesozooplankton net production exceeds that of phytoplankton, indicating “seasonal trophic amplification.” An analytical approach identifies amplification to be driven by a seasonally varying trophic transfer efficiency due to mixed layer variations. The latter alters the vertical distribution of phytoplankton and thus the zooplankton and phytoplankton encounters, with lower encounters occurring in a deeper mixed layer where phytoplankton are diluted. In global model simulations, mixed layer depth appears to affect trophic transfer similarly in other productive regions. Our results highlight the importance of mixed layer depth for trophodynamics on a seasonal scale with potential significant implications, given mixed layer depth changes projected under climate change.
    Beschreibung: Plain Language Summary: The Humboldt Upwelling System is a fishery‐important region. A common assumption is that a certain amount of phytoplankton supports a proportional amount of fish. However, we find that a small seasonal change in phytoplankton can trigger a larger variation in zooplankton. This implies that one may underestimate changes in fish solely based on phytoplankton. Using ecosystem model simulations, we investigate why changes of phytoplankton are not proportionally reflected in zooplankton. The portion of phytoplankton that ends up in zooplankton is controlled by the changing depth of the surface ocean “mixed layer.” The “mixed layer” traps both the phytoplankton and zooplankton in a limited amount of space. When the “mixed layer” is shallow, zooplankton can feed more efficiently on phytoplankton as both are compressed in a comparatively smaller space. We conclude that in the Humboldt System, and other “food‐rich” regions, feeding efficiently, determined by the “mixed layer,” is more important than how much food is available.
    Beschreibung: Key Points: Environmental factors strongly affect plankton trophodynamics on a seasonal scale. Seasonal trophic amplification in the Humboldt system is driven by mixed layer dynamics. Mixed layer depth and food chain efficiency correlate also in other productive regions.
    Beschreibung: China Sponsorship Council
    Beschreibung: Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347
    Schlagwort(e): ddc:577.7
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 3
    facet.materialart.
    Unbekannt
    The Hidden Giant: How a rift pulse triggered a cascade of sector collapses and voluminous secondary mass‐transport events in the early evolution of Santorini (2022)
    Details
    Publikationsdatum: 2022-10-01
    Beschreibung: Volcanic island sector collapses have the potential to trigger devastating tsunamis and volcanic eruptions that threaten coastal communities and infrastructure. Considered one of the most hazardous volcano‐tectonic regions in the world, the Christiana‐Santorini‐Kolumbo Volcanic Field (CSKVF) lies in the South Aegean Sea in an active rift zone. Previous studies identified an enigmatic voluminous mass‐transport deposit west and east of Santorini emplaced during the early evolution of the edifice. However, the distribution and volume as well as the nature and emplacement dynamics of this deposit remained unknown up to now. In this study, we use an extensive dataset of high‐resolution seismic profiles to unravel the distribution and internal architecture of this deposit. We show that it is located in all basins surrounding Santorini and has a bulk volume of up to 125 km3, thus representing the largest known volcanic island mass‐transport deposit in the entire Mediterranean Sea. We propose that the deposit is the result of a complex geohazard cascade that was initiated by an intensive rift pulse. This rifting event triggered a series of smaller precursory mass‐transport events before large‐scale sector collapses occurred on the northeastern flank of the extinct Christiana Volcano and on the southeastern flank of the nascent Santorini. This was followed by the emplacement of large‐scale secondary sediment failures on the slopes of Santorini, which transitioned into debris and turbidity flows that traveled far into the neighboring rift basins. Following this cascade, a distinct change in the volcanic behaviour of the CSKVF occurred, suggesting a close relationship between crustal extension, mass transport and volcanism. Cascading geohazards seem to be more common in the evolution of marine volcanic systems than previously appreciated. Wider awareness and a better understanding of cascading effects are crucial for more holistic hazard assessments.
    Beschreibung: Schematic Reconstruction of the Santorini Mass‐Transport Cascade (SMTC): After a phase of volcanic quiescence (A), a rift pulse (B) triggered precursory mass‐wasting events (C), large‐scale sector collapses (D) and secondary sediment failures (E), which culminated in a change in the volcanic behaviour of the system (F).
    Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Schlagwort(e): ddc:551.21
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 4
    facet.materialart.
    Unbekannt
    Arctic – Atlantic Exchange of the Dissolved Micronutrients Iron, Manganese, Cobalt, Nickel, Copper and Zinc With a Focus on Fram Strait (2022)
    Details
    Publikationsdatum: 2022-10-04
    Beschreibung: The Arctic Ocean is considered a source of micronutrients to the Nordic Seas and the North Atlantic Ocean through the gateway of Fram Strait (FS). However, there is a paucity of trace element data from across the Arctic Ocean gateways, and so it remains unclear how Arctic and North Atlantic exchange shapes micronutrient availability in the two ocean basins. In 2015 and 2016, GEOTRACES cruises sampled the Barents Sea Opening (GN04, 2015) and FS (GN05, 2016) for dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) and zinc (dZn). Together with the most recent synopsis of Arctic‐Atlantic volume fluxes, the observed trace element distributions suggest that FS is the most important gateway for Arctic‐Atlantic dissolved micronutrient exchange as a consequence of Intermediate and Deep Water transport. Combining fluxes from FS and the Barents Sea Opening with estimates for Davis Strait (GN02, 2015) suggests an annual net southward flux of 2.7 ± 2.4 Gg·a−1 dFe, 0.3 ± 0.3 Gg·a−1 dCo, 15.0 ± 12.5 Gg·a−1 dNi and 14.2 ± 6.9 Gg·a−1 dCu from the Arctic toward the North Atlantic Ocean. Arctic‐Atlantic exchange of dMn and dZn were more balanced, with a net southbound flux of 2.8 ± 4.7 Gg·a−1 dMn and a net northbound flux of 3.0 ± 7.3 Gg·a−1 dZn. Our results suggest that ongoing changes to shelf inputs and sea ice dynamics in the Arctic, especially in Siberian shelf regions, affect micronutrient availability in FS and the high latitude North Atlantic Ocean.
    Beschreibung: Plain Language Summary: Recent studies have proposed that the Arctic Ocean is a source of micronutrients such as dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) and zinc (dZn) to the North Atlantic Ocean. However, data at the Arctic Ocean gateways including Fram Strait and the Barents Sea Opening have been missing to date and so the extent of Arctic micronutrient transport toward the Atlantic Ocean remains unquantified. Here, we show that Fram Strait is the most important gateway for Arctic‐Atlantic micronutrient exchange which is a result of deep water transport at depths 〉500 m. Combined with a flux estimate for Davis Strait, this study suggests that the Arctic Ocean is a net source of dFe, dNi and dCu, and possibly also dCo, toward the North Atlantic Ocean. Arctic‐Atlantic dMn and dZn exchange seems more balanced. Properties in the East Greenland Current showed substantial similarities to observations in the upstream Central Arctic Ocean, indicating that Fram Strait may export micronutrients from Siberian riverine discharge and shelf sediments 〉3,000 km away. Increasing Arctic river discharge, permafrost thaw and coastal erosion, all consequences of ongoing climate change, may therefore alter future Arctic Ocean micronutrient transport to the North Atlantic Ocean.
    Beschreibung: Key Points: Fram Strait is the major gateway for Arctic‐Atlantic exchange of the dissolved micronutrients Fe, Mn, Co, Ni, Cu and Zn. The Arctic is a net source of dissolved Fe, Co, Ni and Cu to the Nordic Seas and toward the North Atlantic; Mn and Zn exchange are balanced. Waters of the Central Arctic Ocean, including the Transpolar Drift, are the main drivers of gross Arctic micronutrient export.
    Beschreibung: German Research Foundation
    Beschreibung: Netherlands Organization for Scientific Research
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.859558
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.871030
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.868396
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.905347
    Beschreibung: https://dataportal.nioz.nl/doi/10.25850/nioz/7b.b.jc
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.933431
    Beschreibung: https://www.bco-dmo.org/dataset/718440
    Beschreibung: https://doi.org/10.1594/PANGAEA.936029
    Beschreibung: https://doi.org/10.1594/PANGAEA.936027
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.927429
    Schlagwort(e): ddc:551.9
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 5
    facet.materialart.
    Unbekannt
    Tides, Stratification, and Counter Rotation: The German Bight ROFI in Comparison to Other Regions of Freshwater Influence (2022)
    Details
    Publikationsdatum: 2022-10-01
    Beschreibung: The characteristics of tidal velocity profiles and their relation to stratification are investigated based on high‐resolution field data collected at four locations in the German Bight Region of Freshwater Influence (ROFI) in the North Sea. The deployments each include two to three tidal cycles and were conducted during field campaigns in August 2016 and May 2018. The depth‐averaged semidiurnal tidal motion is dominated by a standing wave directed toward the coast, but modified by a smaller, coast‐parallel progressive wave contribution. The time series of the tidal velocity profiles consistently show tidal asymmetries with higher flood than ebb velocities near the surface and counter‐clockwise rotation of the velocity trajectories at depth. Near the surface, phase‐locked periodic changes in the sense of rotation within the tidal cycle are evident for three deployments, resulting in periodic counter‐rotation of the upper and lower layer. During these episodes, stratification of the water column is observed. Counter‐rotation is initiated after a sudden decoupling developing from the surface downward, with subsequent rapid development of stratification and velocity shear. The observed decoupling is most likely triggered by advection of the plume‐induced lateral surface density gradient by weakly sheared ebb currents toward the study site. Due to the dominance of the standing wave in the German Bight ROFI, the observed intra‐tidal variations of stratification are more similar to the Liverpool Bay and differ significantly from the Rhine ROFI, where the tidal dynamics are controlled by a progressive Kelvin wave.
    Beschreibung: Plain Language Summary; The water velocities in the German Bight are strongly influenced by river freshwater input and semidiurnal tides. While the freshwater input from the rivers has a stratifying effect, tidal motion as well as wind and waves induce mixing. These forces compete in controlling the state of the water column in a complex manner. In theory, tidal motion should describe elliptical paths. However, in reality, these ellipses can be modified for example, by periodically occurring stratification. To assess the characteristics of the semidiurnal tidal velocity profile and its variability, four instruments to measure current velocity profiles were deployed in the German Bight during August 2016 and May 2018. Measurements were carried out for the duration of up to three tidal cycles, accompanied by parallel profiles of water temperature and salinity taken from the anchored ship nearby. Results show that periodic stratification related to the river freshwater plume is associated with periodically counter‐rotating tidal currents during the tidal cycle. The measurement position relative to the location of the density front of the plume appears to be critical for the occurrence of counter‐rotation. The observed dynamics are qualitatively compared to two other well‐studied coastal ocean regions of freshwater influence.
    Beschreibung: Key Points: High‐resolution velocity and density data from the German Bight Region of Freshwater Influence are used to assess M2 tidal properties and intra‐tidal variability. M2 tidal motion is a hybrid of standing and progressive waves, with the standing wave contribution dominating. Periodic counter‐rotation of upper‐ and lower‐layer current trajectories during the tidal cycle is related to water column stratification.
    Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Beschreibung: https://doi.org/10.1594/PANGAEA.919168
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.943958
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.943955
    Beschreibung: https://doi.org/10.1594/PANGAEA.897214
    Schlagwort(e): ddc:551.46
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 6
    facet.materialart.
    Unbekannt
    Tropical Instability Waves and Wind‐Forced Cross‐Equatorial Flow in the Central Atlantic Ocean (2022)
    Details
    Publikationsdatum: 2022-12-07
    Beschreibung: Based on velocity data from a long‐term moored observatory located at 0°N, 23°W we present evidence of a vertical asymmetry during the intraseasonal maxima of northward and southward upper‐ocean flow in the equatorial Atlantic Ocean. Periods of northward flow are characterized by a meridional velocity maximum close to the surface, while southward phases show a subsurface velocity maximum at about 40 m. We show that the observed asymmetry is caused by the local winds. Southerly wind stress at the equator drives northward flow near the surface and southward flow below that is superimposed on the Tropical Instability Wave (TIW) velocity field. This wind‐driven overturning cell, known as the Equatorial Roll, shows a distinct seasonal cycle linked to the seasonality of the meridional component of the south‐easterly trade winds. The superposition of vertical shear of the Equatorial Roll and TIWs causes asymmetric mixing during northward and southward TIW phases.
    Beschreibung: Plain Language Summary; Tropical Instability Waves (TIWs) are clear in satellite measurements of sea surface temperature as horizontal undulations with wavelength of the order of 1,000 km in equatorial regions of both Atlantic and Pacific Oceans. TIWs are characterized by their distinctive upper‐ocean meridional velocity structure. TIWs amplify vertical shear and thus contribute to the generation of turbulence which in turn leads to the mixing of heat and freshwater downward into the deeper ocean. In this study we show that the prevailing southerly winds in the central equatorial Atlantic drive near‐surface northward and subsurface southward flows, which are superposed on the meridional TIW velocity field. The strength of this wind driven cell is linked to the seasonal cycle of the northward component of the trade winds, peaking in boreal fall when TIWs reach their maximum amplitude. The overturning cell affects the vertical structure of the meridional velocity field and thus has impact on the generation of current shear and turbulence. We show that the overturning reduces/enhances shear during northward/southward TIW flow, an asymmetry that is consistent with independent measurements showing asymmetric mixing.
    Beschreibung: Key Points: Composites of Tropical Instability Waves at 0°N, 23°W show a surface (subsurface) velocity maximum during northward (southward) phases. Meridional wind stress forces a seasonally‐varying, shallow cross‐equatorial overturning cell‐the Equatorial Roll. The superposition of Tropical Instability Waves and Equatorial Roll causes asymmetric mixing during north‐ and southward phases.
    Beschreibung: EU H2020
    Beschreibung: Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347
    Beschreibung: US NSF
    Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Beschreibung: National Oceanic and Atmospheric Administration http://dx.doi.org/10.13039/100000192
    Beschreibung: National Academy of Sciences http://dx.doi.org/10.13039/100000209
    Beschreibung: National Science Foundation http://dx.doi.org/10.13039/100000001
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.941042
    Beschreibung: https://www.pmel.noaa.gov/tao/drupal/disdel/
    Schlagwort(e): ddc:551.5 ; tropical instability waves ; equatorial Atlantic ; equatorial roll ; moored velocity data ; ocean mixing ; ocean observations
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 7
    facet.materialart.
    Unbekannt
    Representation of hydrological processes in a rural lowland catchment in Northern Germany using SWAT and SWAT+ (2022)
    John Wiley & Sons, Inc. | Hoboken, USA
    Details
    Publikationsdatum: 2022-10-04
    Beschreibung: The latest version of the Soil and Water Assessment Tool (SWAT+) features several improvements compared with previous versions of the model, for example, the definition of landscape units that allow for a better representation of spatio‐temporal dynamics. To evaluate the new model capabilities in lowland catchments characterized by near‐surface groundwater tables and extensive tile drainage, we assess the performance of two SWAT+ model setups in comparison to a setup based on a previous SWAT model version (SWAT3S with a modified three groundwater storage model) in the Kielstau catchment in Northern Germany. The Kielstau catchment has an area of about 50 km2, is dominated by agricultural land use, and has been thoroughly monitored since 2005. In both SWAT+ setups, the catchment is divided into upland areas and floodplains, but in the first SWAT+ model setup, runoff from the hydrologic response units is summed up at landscape unit level and added directly to the stream. In the second SWAT+ model setup, runoff is routed across the landscape before it reaches the streams. Model results are compared with regard to (i) model performance for stream flow at the outlet of the catchment and (ii) aggregated as well as temporally and spatially distributed water balance components. All three model setups show a very good performance at the catchment outlet. In comparison to a previous version of the SWAT model that produced more groundwater flow, the SWAT+ model produced more tile drainage flow and surface runoff. Results from the new SWAT+ model confirm that the representation of routing processes from uplands to floodplains in the model further improved the representation of hydrological processes. Particularly, the stronger spatial heterogeneity that can be related to characteristics of the landscape, is very promising for a better understanding and model representation of hydrological fluxes in lowland areas. The outcomes of this study are expected to further prove the applicability of SWAT+ and provide useful information for future model development.
    Beschreibung: The model performance of all three model setups was very good, but the SWAT+ model setup with runoff routing between landscape units performed best. Moreover, the SWAT+ model applications predicted a greater spatial heterogeneity of the water balance components. The representation of hydrological fluxes particularly with regard to groundwater flow, surface runoff, and tile drainage flow differed considerably between the SWAT and SWAT+ model setups.
    Schlagwort(e): ddc:551.48
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 8
    facet.materialart.
    Unbekannt
    Millimetre scale aeration of the rhizosphere and drilosphere (2022)
    Blackwell Publishing Ltd | Oxford, UK
    Details
    Publikationsdatum: 2022-10-04
    Beschreibung: Soil aeration is a critical factor for oxygen‐limited subsoil processes, as transport by diffusion and advection is restricted by the long distance to the free atmosphere. Oxygen transport into the soil matrix is highly dependent on its connectivity to larger pore channels like earthworm and root colonised biopores. Here we hypothesize that the soil matrix around biopores represents different connectivity depending on biopore genesis and actual coloniser. We analysed the soil pore system of undisturbed soil core samples around biopores generated or colonised by roots and earthworms and compared them with the pore system of soil, not in the immediacy of a biopore. Oxygen partial pressure profiles and gas relative diffusion was measured in the rhizosphere and drilosphere from the biopore wall into the bulk soil with microelectrodes. The measurements were linked with structural features such as porosity and connectivity obtained from X‐ray tomography and image analysis. Aeration was enhanced in the soil matrix surrounding biopores in comparison to the bulk soil, shown by higher oxygen concentrations and higher relative diffusion coefficients. Biopores colonised by roots presented more connected lateral pores than earthworm colonised ones, which resulted in enhanced aeration of the rhizosphere compared to the drilosphere. This has influenced biotic processes (microbial turnover/mineralization or root respiration) at biopore interfaces and highlights the importance of microstructural features for soil processes and their dependency on the biopore's coloniser.
    Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Schlagwort(e): ddc:631.4
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 9
    facet.materialart.
    Unbekannt
    Variability in the Concentration of Lithium in the Indo‐Pacific Ocean (2022)
    Details
    Publikationsdatum: 2022-10-04
    Beschreibung: Lithium has limited biological activity and can readily replace aluminium, magnesium and iron ions in aluminosilicates, making it a proxy for the inorganic silicate cycle and its potential link to the carbon cycle. Data from the North Pacific Ocean, tropical Indian Ocean, Southern Ocean and Red Sea suggest that salinity normalized dissolved lithium concentrations vary by up to 2%–3% in the Indo‐Pacific Ocean. The highest lithium concentrations were measured in surface waters of remote North Pacific and Indian Ocean stations that receive relatively high fluxes of dust. The lowest dissolved lithium concentrations were measured just below the surface mixed layer of the stations with highest surface water concentrations, consistent with removal into freshly forming aluminium rich phases and manganese oxides. In the North Pacific, water from depths 〉2,000 m is slightly depleted in lithium compared to the initial composition of Antarctic Bottom Water, likely due to uptake of lithium by authigenically forming aluminosilicates. The results of this study suggest that the residence time of lithium in the ocean may be significantly shorter than calculated from riverine and hydrothermal fluxes.
    Beschreibung: Key Points: Li/Na ratios vary by up to 2%–3% in the Indian and Pacific Oceans. Authigenic formation of aluminosilicates slightly deplete deep‐water lithium concentrations in the North Pacific. The residence time of lithium in the ocean is 240,000 ± 70,000 years, based on removal from North Pacific deep‐water.
    Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Beschreibung: MoES, Indian National Centre for Ocean Information Services http://dx.doi.org/10.13039/501100004814
    Beschreibung: National Science Foundation USA
    Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.941888
    Schlagwort(e): ddc:551
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    CITATION GEO-LEO
  • 10
    facet.materialart.
    Unbekannt
    The Miocene: The Future of the Past (2021)
    In:  EPIC3Paleoceanography and Paleoclimatology, 36(4), ISSN: 2572-4517
    Details
    Publikationsdatum: 2022-02-15
    Beschreibung: The Miocene epoch (23.03–5.33 Ma) was a time interval of global warmth, relative to today. Continental configurations and mountain topography transitioned toward modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a ∼2 Myr greenhouse interval—the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO2, and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO2 (∼400–600 ppm), the MCO has been suggested as a particularly appropriate analog for future climate scenarios, and for assessing the predictive accuracy of numerical climate models—the same models that are used to simulate future climate. Yet, Miocene conditions have proved difficult to reconcile with models. This implies either missing positive feedbacks in the models, a lack of knowledge of past climate forcings, or the need for re-interpretation of proxies, which might mitigate the model-data discrepancy. Our understanding of Miocene climatic, biogeochemical, and oceanic changes on broad spatial and temporal scales is still developing. New records documenting the physical, chemical, and biotic aspects of the Earth system are emerging, and together provide a more comprehensive understanding of this important time interval. Here, we review the state-of-the-art in Miocene climate, ocean circulation, biogeochemical cycling, ice sheet dynamics, and biotic adaptation research as inferred through proxy observations and modeling studies.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    ARTIKEL (OA)
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...