ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Late Quaternary glacier and sea‐ice history of northern Wijdefjorden, Svalbard (2020)
    In:  EPIC3Boreas, 49(3), pp. 417-437, ISSN: 0300-9483
    Details
    Publication Date: 2022-04-12
    Description: The deglaciation history and Holocene environmental evolution of northern Wijdefjorden, Svalbard, are reconstructed using sediment cores and acoustic data (multibeam swath bathymetry and sub-bottom profiler data). Results reveal that the fjord mouth was deglaciated prior to 14.5±0.3 cal. ka BP and deglaciation occurred stepwise. Biomarker analyses show rapid variations in water temperature and sea ice cover during the deglaciation, and cold conditions during the Younger Dryas, followed by minimum sea ice cover throughout the Early Holocene, until c. 7 cal. ka BP. Most of the glaciers in Wijdefjorden had retreated onto land by c. 7.6±0.2 cal. ka BP. Subsequently, the sea-ice extent increased and remained high throughout the last part of the Holocene. We interpret a high Late Holocene sediment accumulation rate in the northernmost core to reflect increased sediment flux to the site from the outlet of the adjacent lake Femmilsjøen, related to glacier growth in the Femmilsjøen catchment area. Furthermore, increased sea ice cover, lower water temperatures and the re-occurrence of ice-rafted debris indicate increased local glacier activity and overall cooler conditions in Wijdefjorden after c. 0.5 cal. ka BP. We summarize our findings in a conceptual model for the depositional environment in northern Wijdefjorden from the Late Weichselian until present.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Towards a continental drilling proposal for recovering Late Mesozoic to Cenozoic sedimentary strata from beneath the Ekström Ice Shelf, Weddell Sea, Antarctica (2022)
    In:  EPIC3Internationale Polartagung, Potsdam, 2022-05-01-2022-05-05
    Details
    Publication Date: 2022-04-24
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 3
    facet.materialart.
    Unknown
    MARINE ORGANIC CARBON AND RADIOCARBON—PRESENT AND FUTURE CHALLENGES (2022)
    In:  EPIC3Radiocarbon, pp. 1-17, ISSN: 0033-8222
    Details
    Publication Date: 2022-04-29
    Description: We discuss present and developing techniques for studying radiocarbon in marine organic carbon (C). Bulk DOC (dissolved organic C) Δ14C measurements reveal information about the cycling time and sources of DOC in the ocean, yet they are time consuming and need to be streamlined. To further elucidate the cycling of DOC, various fractions have been separated from bulk DOC, through solid phase extraction of DOC, and ultrafiltration of high and low molecular weight DOC. Research using 14C of DOC and particulate organic C separated into organic fractions revealed that the acid insoluble fraction is similar in 14C signature to that of the lipid fraction. Plans for utilizing this methodology are described. Studies using compound specific radiocarbon analyses to study the origin of biomarkers in the marine environment are reviewed and plans for the future are outlined. Development of ramped pyrolysis oxidation methods are discussed and scientific questions addressed. A modified elemental analysis (EA) combustion reactor is described that allows high particulate organic C sample throughput by direct coupling with the MIniCArbonDAtingSystem.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Performance of temperature and productivity proxies based on long-chain alkane-1, mid-chain diols at test: a 5-year sediment trap record from the Mauritanian upwelling (2022)
    In:  EPIC3Biogeosciences, 19(5), pp. 1587-1610, ISSN: 1726-4189
    Details
    Publication Date: 2022-04-29
    Description: Proxies based on long-chain alkane-1, mid-chain diols (diol for short) are obtaining increasing interest to reconstruct past upper ocean temperature and productivity. Here we evaluate performance of the sea surface temperature proxies (long-chain diol index (LDI), diol saturation index (DSI), and diol chain length index (DCI)), productivity and upwelling intensity proxies (two diol indices DIR and DIW and the combined diol index (CDI)), and the nutrient diol index (NDI) as a proxy for phosphate and nitrate levels. This evaluation is based on comparison of the diols in sediment trap samples from the upwelling region off NW Africa collected at 1.28 km water depth with daily satellite derived sea surface temperatures (SSTs), subsurface temperatures, productivity, the plankton composition from the trap location, monthly phosphate and nitrate concentrations, wind speed, and wind direction from the nearby Nouadhibou airport. The diol-based SST reconstructions are also compared the long-chain-alkenone-based SST reconstructions. The alkenone SSTs correlate best with satellite SST (r2 D0.60). Amplitude and absolute values agree very well as do the flux-corrected time series averages. For the diol proxies the situation is more complicated. Diol proxies including 1,14 diols lag trade wind speed by 30 d. Since wind is nearly always from the NNE to NNW and induces the upwelling, we relate the variability in these proxies to upwelling-induced processes. Correlation with the abundance of upwelling species and wind speed is best for.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    Evaluation of lipid biomarkers as proxies for sea ice and ocean temperatures along the Antarctic continental margin (2021)
    Copernicus GmbH
    In:  EPIC3Climate of the Past, Copernicus GmbH, 17(5), pp. 2305-2326
    Details
    Publication Date: 2022-03-17
    Description: The importance of Antarctic sea ice and Southern Ocean warming has come into the focus of polar research during the last couple of decades. Especially around West Antarctica, where warm water masses approach the continent and where sea ice has declined, the distribution and evolution of sea ice play a critical role in the stability of nearby ice shelves. Organic geochemical analyses of marine seafloor surface sediments from the Antarctic continental margin allow an evaluation of the applicability of biomarker-based sea-ice and ocean temperature reconstructions in these climate-sensitive areas. We analysed highly branched isoprenoids (HBIs), such as the sea-ice proxy IPSO25 and phytoplankton-derived HBI-trienes, as well as phytosterols and isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs), which are established tools for the assessment of primary productivity and ocean temperatures respectively. The combination of IPSO25 with a phytoplankton marker (i.e. the PIPSO25 index) permits semi-quantitative sea-ice reconstructions and avoids misleading over- or underestimations of sea-ice cover. Comparisons of the PIPSO25-based sea-ice distribution patterns and TEXL86- and RI-OH′-derived ocean temperatures with (1) sea-ice concentrations obtained from satellite observations and (2) instrument measurements of sea surface and subsurface temperatures corroborate the general capability of these proxies to determine oceanic key variables properly. This is further supported by model data. We also highlight specific aspects and limitations that need to be taken into account for the interpretation of such biomarker data and discuss the potential of IPSO25 as an indicator for the former occurrence of platelet ice and/or the export of ice-shelf water.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Rapid Atlantification along the Fram Strait at the beginning of the 20th century (2021)
    In:  EPIC3Science Advances, 7(48), ISSN: 2375-2548
    Details
    Publication Date: 2022-01-04
    Description: The recent expansion of Atlantic waters into the Arctic Ocean represents undisputable evidence of the rapid changes occurring in this region. Understanding the past variability of this “Atlantification” is thus crucial in providing a longer perspective on the modern Arctic changes. Here, we reconstruct the history of Atlantification along the eastern Fram Strait during the past 800 years using precisely dated paleoceanographic records based on organic biomarkers and benthic foraminiferal data. Our results show rapid changes in water mass properties that com-menced in the early 20th century—several decades before the documented Atlantification by instrumental records. Comparison with regional records suggests a poleward expansion of subtropical waters since the end of the Little Ice Age in response to a rapid hydrographic reorganization in the North Atlantic. Understanding of this mechanism will require further investigations using climate model simulations.INTRODUCTIONClimate reconstructions of the Common Era are fundamental bench-marks to place human-induced changes into the context of natural climatic change (1, 2). This is particularly relevant for the Arctic, which is currently warming faster than any other region (3). Arctic warming has been associated with rapid sea ice decline and expan-sion of Atlantic waters (AWs) into the Arctic basin (4, 5) — a phenomenon commonly referred to as “Atlantification” (6). While in situ observations and satellite images provide high-resolution records of anomalies in water mass properties and sea ice since the 1930s and 1980s (4, 7–10), respectively, little is known about this phenomenon in pre- and early-industrial times. Because natural archives preserve evidence of past climate variability, they can offer a longer-term perspective on Atlantification in this region.The Fram Strait represents an important oceanographic gateway that allows the exchange of Arctic and AW masses (11). Low-resolution paleoceanographic records suggest that the summer temperatures of the AW inflow moving along the eastern Fram Strait may have increased before the instrumental record (12). Although this change in AW properties hints at a possible early sign of Atlantification, the lack of a reliable chronology for these records limits the integration with regional high-resolution proxy reconstructions to determine the physical mechanisms at play. Recently, it has been argued that the Atlantic subpolar gyre (SPG) has weakened since the 20th century (13). This, in turn, might have conditioned the water masses routed toward the Arctic. However, a survey of the recent literature shows that our
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Particulate organic carbon deconstructed: molecular and chemical composition of particulate organic carbon in the ocean (2020)
    Frontiers Media
    Details
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kharbush, J. J., Close, H. G., Van Mooy, B. A. S., Arnosti, C., Smittenberg, R. H., Le Moigne, F. A. C., Mollenhauer, G., Scholz-Boettcher, B., Obreht, I., Koch, B. P., Becker, K. W., Iversen, M. H., & Mohr, W. Particulate organic carbon deconstructed: molecular and chemical composition of particulate organic carbon in the ocean. Frontiers in Marine Science, 7, (2020): 518, doi:10.3389/fmars.2020.00518.
    Description: The dynamics of the particulate organic carbon (POC) pool in the ocean are central to the marine carbon cycle. POC is the link between surface primary production, the deep ocean, and sediments. The rate at which POC is degraded in the dark ocean can impact atmospheric CO2 concentration. Therefore, a central focus of marine organic geochemistry studies is to improve our understanding of POC distribution, composition, and cycling. The last few decades have seen improvements in analytical techniques that have greatly expanded what we can measure, both in terms of organic compound structural diversity and isotopic composition, and complementary molecular omics studies. Here we provide a brief overview of the autochthonous, allochthonous, and anthropogenic components comprising POC in the ocean. In addition, we highlight key needs for future research that will enable us to more effectively connect diverse data sources and link the identity and structural diversity of POC to its sources and transformation processes.
    Description: We thank the Hanse Institute for Advanced Studies (HWK) and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) project number 422798570, as well as the Geochemical Society, for funding which made the workshop possible. CA was additionally supported by OCE-1736772. BV was additionally supported by NSF OCE-1756254.
    Keywords: Marine particles ; Water column ; Phytoplankton ; Marine microbes ; Structural analysis ; Organic matter characterization ; Biomarkers
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    World Atlas of late Quaternary Foraminiferal Oxygen and Carbon Isotope Ratios (2022)
    Copernicus GmbH
    In:  EPIC3Earth System Science Data, Copernicus GmbH, 14(6), pp. 2553-2611, ISSN: 1866-3508
    Details
    Publication Date: 2022-11-02
    Description: 〈jats:p〉Abstract. We present a global atlas of downcore foraminiferal oxygen and carbon isotope ratios available at https://doi.org/10.1594/PANGAEA.936747 (Mulitza et al., 2021a). The database contains 2106 published and previously unpublished stable isotope downcore records with 361 949 stable isotope values of various planktic and benthic species of Foraminifera from 1265 sediment cores. Age constraints are provided by 6153 uncalibrated radiocarbon ages from 598 (47 %) of the cores. Each stable isotope and radiocarbon series is provided in a separate netCDF file containing fundamental metadata as attributes. The data set can be managed and explored with the free software tool PaleoDataView. The atlas will provide important data for paleoceanographic analyses and compilations, site surveys, or for teaching marine stratigraphy. The database can be updated with new records as they are generated, providing a live ongoing resource into the future. 〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    Burial and Origin of Permafrost‐Derived Carbon in the Nearshore Zone of the Southern Canadian Beaufort Sea (2020)
    In:  EPIC3Geophysical Research Letters, 47(3), ISSN: 0094-8276
    Details
    Publication Date: 2022-07-04
    Description: Detailed organic geochemical and carbon isotopic (δ13C and Δ14C) analyses are performed on permafrost deposits affected by coastal erosion (Herschel Island, Canadian Beaufort Sea) and adjacent marine sediments (Herschel Basin) to understand the fate of organic carbon in Arctic nearshore environments. We use an end‐member model based on the carbon isotopic composition of bulk organic matter to identify sources of organic carbon. Monte Carlo simulations are applied to quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget. The models suggest that ~40% of all carbon released by local coastal permafrost erosion is efficiently trapped and sequestered in the nearshore zone. This highlights the importance of sedimentary traps in environments such as basins, lagoons, troughs, and canyons for the carbon sequestration in previously poorly investigated, nearshore areas.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed , info:eu-repo/semantics/article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 10
    facet.materialart.
    Unknown
    Radiocarbon dating of methane (2022)
    In:  EPIC324th Radiocarbon Conference, Zurich, Switzerland, 2022-09-10-2022-09-16
    Details
    Publication Date: 2022-10-20
    Description: Methane (CH4) is the most abundant organic compound in the atmosphere and its influence on the global climate is subject to widespread and ongoing scientific discussion. Two sources of atmospheric methane are the release of methane from the ocean seafloor, as well as from thawing permafrost. In recent years the origin, sediment and water column processes and subsequent pathways of methane have received growing interest in the scientific community. 13C/12C ratio measurements can be used to determine the methane source (biogenic or thermogenic), but potential formation/alteration processes by microbes are not yet fully understood. Radiocarbon analysis can help to understand these carbon cycling processes. The presented method is a novel approach for the radiocarbon age determination of methane. A modified PreConn is used to separate methane from other gases such as CO2 in a gaseous sample. Afterwards, the purified methane is transferred to a furnace and oxidized to CO2. Subsequently, produced CO2 is concentrated on a custom-made zeolite trap, which can be connected to a novel sampling unit implemented into the GIS system (by Ionplus AG) for direct CO2 measurements on a MICADAS. The zeolite trap has ¼“ quick-fit connectors (Swagelok) that allow to detach the trap from the oxidation unit and to re-attach it in the GIS. Initial testing showed minimal blank carbon incorporation associated with sample storage, transfer and handling of the custom-build zeolite trap. Here we will present the setup of the method, first results of the blank determination as well as precision of common standard gases.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...