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Publikationen

unserer Arbeitsgruppe
Collecting cores in the field – the start of every publication!
Foto: Roland Zech

38 Publikationen filtern

Die Publikationen filtern

Hervorgehobene Autoren sind Mitglieder der Forschungsgruppe.

  1. Validation of biomarker-based dual and coupled stable isotope approaches for reconstructing lake water evaporation in palaeohydrology

    Autoren
    M. Prochnow, L. Danius, B. Lemma, M. Zech, E. Bazarradnaa, P. Strobel
    Erscheinungsjahr
    Erschienen in:
    Palaeogeography, palaeoclimatology, palaeoecology
    Compound-specific stable hydrogen (δD) and oxygen (δ ¹⁸ O) isotopes of aquatic and terrestrial biomarkers in lake sediments are widely used to reconstruct palaeohydrology, recording variations in precipitation and evaporation. The two main approaches are the dual biomarker approach, based on the isotopic differences between δD of aquatic and terrestrial n-alkanes, and the coupled isotope approach, combining n-alkanes (δD n₋ₐlkₐnₑ ) with hemicellulose-derived sugars (δ ¹⁸ O sugₐr ) to reconstruct deuterium-excess (d-excess). Both are commonly applied in palaeohydrology, but so far, they were never directly compared to each other. We analysed δ ¹⁸ O sugₐr in surface sediments from Lake Khar Nuur, Mongolia, complementing an existing dual biomarker δD n₋ₐlkₐnₑ dataset. The sugar biomarker fucose was identified as an aquatic endmember in the sediments. The δ ¹⁸ O fucₒsₑ is therefore used as a proxy for δ ¹⁸ O lₐkₑ wₐtₑr , which is modulated by evaporative enrichment of lake water like δD n₋C₂₃ . Both isotopes significantly correlate and show high evaporative enrichment in the central basins. By coupling the aquatic endmembers δD n₋C₂₃ and δ ¹⁸ O fucₒsₑ , we calculated aquatic d-excess and precipitation δD and δ ¹⁸ O. Results closely match those from the dual biomarker approach and precisely align with the local isotopic signature of growing season precipitation. Similar results for d-excess and precipitation were obtained using a modified coupled isotope approach based on terrestrial δD n₋C₃₁ and aquatic δ ¹⁸ O fucₒsₑ . Overall, our results depict the sensitivity of biomarker compounds in the lake's sediment accumulation zone for environmental processes. The methodological comparison confirms the compatibility of dual and coupled isotope approaches and supports their application in molecular palaeohydrology.
    Universitätsbibliographie Jena:
    fsu_mods_00036621Externer Link

  2. The current natural ecological disturbance baseline of fire activity in the southern European Alps – climate or humans?

    Autoren
    L. Danius, H. von Suchodoletz, P. Strobel, M. Prochnow, R. Zech, F. Lechleitner, S. Szidat, M. Bliedtner
    Erscheinungsjahr
    Erschienen in:
    Ecological indicators : integrating monitoring, assessment and management
    Fire is a crucial disturbance agent in many ecosystems, such as in the Southern European Alps, where a considerable increase in fire activity is projected under anthropogenic climate change. However, currently it remains unclear whether natural or human factors mainly control the regional fire regime, since a current natural ecological disturbance baseline of regional fire activity is still missing. Therefore, we analyzed polycyclic aromatic hydrocarbons (PAHs) as a novel paleofire proxy on a well-dated ∼8 ka sediment record from Lake Pusiano in northern Italy. Fire activity was low during the Mid Holocene (ΣPAH of <1.8 ng g −¹ yr −¹ ) and increased since the Bronze Age (∼4 cal ka BP; average ΣPAH of 4.1 ng g −¹ yr −¹ ), being maximal during the Roman period (∼1.7 cal ka BP; ΣPAH of 10.8 ng g −¹ yr −¹ ). This agrees with multiple regional charcoal-based paleofire records, making the reconstruction of the regional paleofire history robust. The observed paleofire pattern contrasts with past climate changes and is instead highly consistent with human activities, indicating a human-driven fire regime. Therefore, without human influence, there should be little to no notable regional fire activity in the Southern Alpine ecosystems, which thus constitutes the current regional natural ecological disturbance baseline. During recent climate change, however, observed droughts increasingly exceed Holocene levels. Therefore, the naturally not fire-prone southern Alpine ecosystems may already be shifting towards a drought-driven fire regime. These findings offer an original perspective that may reshape the view on fire risk and management also for other sub-Mediterranean regions.
    Universitätsbibliographie Jena:
    fsu_mods_00036895Externer Link

  3. Unprecedented Burning in Tropical Peatlands During the 20th Century Compared to the Previous Two Millennia

    Autoren
    Y. Wang, T. Feldpausch, G. Swindles, P. Moss, H. McGowan, T. Sim, P. Morris, A. Benfield, C. Courtney-Mustaphi, D. Wahl, E. Montoya, E. Githumbi, E. Honorio Coronado, F. Augustijns, G. Verstraeten, J. Jess O' Donnell, J. Tibby, J. Benavides, K. Hapsari, K. Schittek, K. Ramdzan, K. Bao, L. Cole, L. Anderson, M. Gałka, O. Akpo, P. Strobel, P. Bala, R. Dommain, R. Marchant, R. Sukumar, S. Chawchai, S. Kavil, S. Mooney, T. Kelly, Y. Gao, A. Voulgarakis, A. Boom, C. Burton, J. Berrio, K. Ribeiro, L. Anderson, M. Hardiman, M. Spater, S. Page, A. Gallego-Sala
    Erscheinungsjahr
    Erschienen in:
    Global Change Biology
    Tropical peatland wildfire incidence has risen in recent decades, driven by drainage for land use and intensified by severe droughts with global climate change. These disturbances have altered vegetation structure, disrupted ecosystem functioning, and increased carbon emissions, particularly in Southeast Asia. However, the long-term history and characteristics of wildfires in tropical peatlands remain largely unknown. Here, we compiled fifty-eight macro-charcoal records from peatlands across the tropics, ranging from lowland forested to montane peatlands, to assess millennia-scale changes and controlling factors of tropical peatland burning. We divided the datasets into four main sub-regions: Neotropical, Afrotropical, Indomalayan and Australasian ecoregions to explore regional variability. Tropical peatlands had high burning levels between 0 and 850 ce, followed by a relatively low and stable period until a marked increase during the 20th century. The general trend in tropical peatland burning follows changes in global temperature, and climate variables that control the length and severity of drought events have a notable influence on peat burning before 1900 ce. During the 20th century, regional differences were observed, with declining fire trends in the Neotropical and Afrotropical regions and increasing fire trends in the Indomalayan and Australasian regions. This difference is likely attributable to human activities, and such intervention is also evident in palm swamps and hardwood swamps under similar wet, weakly seasonal climates. With the increase in anthropogenic pressures on peatlands and greater climate variability, future wildfires in peatlands are likely to become more frequent and widespread across all tropical ecoregions. Conservation and sustainable land-use practices could be used to mitigate and control peatland burning and protect these carbon-rich sinks.
    Universitätsbibliographie Jena:
    fsu_mods_00035085Externer Link

  4. The Holocene formation of inland sand dunes in the North of Schleswig-Holstein (Northern Germany) and its palaeoenvironmental significance

    Autoren
    C. Stolz, R. Lehmann, A. Fülling, J. Meister, R. Zech
    Erscheinungsjahr
    Erschienen in:
    The Holocene : an interdisciplinary journal focusing on recent environmental change
    Universitätsbibliographie Jena:
    fsu_mods_00036399Externer Link

  5. Beryllium-10-derived denudation rates in the Roda Catchment, Germany

    Autoren
    L. Zhang, Y. Li, O. Marchhart, S. Merchel, A. Wieser, R. Zech
    Erscheinungsjahr
    Erschienen in:
    Quaternary Science Journal: an open-access journal by the German Quarternary Association
    Denudation is a key geomorphological process shaping landscapes. In-situ-produced cosmogenic ¹⁰ Be has been used to quantify millennial denudation rates worldwide. Long-term denudation rates in the European lowlands can provide valuable insights into the roles of periglacial processes and human activity in landscape evolution. Here, we quantify local and catchment-wide denudation rates in the Roda Catchment in Thuringia, central Germany. Specifically, we constrain 17 catchment-wide denudation rates based on ¹⁰ Be concentrations in river sediments and 5 local denudation rates based on ¹⁰ Be concentrations from soil samples on the flat catchment divides. Catchment-wide denudation rates vary between 23.8 ± 5.4 and 79 ± 18 mm kyr −¹ , and local denudation rates range from 23.4 ± 5.6 to 41.9 ± 9.8 mm kyr −¹ . These catchment-wide denudation rates are consistent with published European data, which are generally higher than those reported from other regions worldwide. This difference can be attributed to periglacial dynamics during the last glacial period. The ¹⁰ Be-derived long-term denudation rates in Europe are generally higher than recent, short-term erosion rates, despite vast human activities and intensive land use in recent decades. This could be due to past periglacial activity; large-scale forest clearance during the Roman and Medieval times; and the limitations of short-term measurements in capturing low-frequency, high-magnitude events. The observed differences between catchment-wide and local denudation rates suggest that denudation has led to changes in topographic relief in the Roda Catchment at a mean rate of 0–28 mm kyr −¹ over the past 10 ka.
    Universitätsbibliographie Jena:
    fsu_mods_00034340Externer Link

  6. Towards an ‘absolute’ timing of biostratigraphic and environmental phases from the Saalian late glacial to the Weichselian pleniglacial in central Europe: Insights from a lacustrine succession in Lichtenberg, northern Germany

    Autoren
    M. Hein, T. Kasper, A. Samudra, M. Theuerkauf, M. Fischer, N. Rahimzadeh, M. Proborukmi, S. Rigterink, A. Gruszczyńska, C. Zeeden, S. Parfitt, D. Horne, L. Roberts, D. White, L. Brogmus, H. von Suchodoletz, T. Lauer, M. Weiss, D. Tanner, B. Urban
    Erscheinungsjahr
    Erschienen in:
    Boreas: an international journal of quaternary research
    Palynological records are central to the biostratigraphic subdivision of the Late Pleistocene in central Europe. Yet many interglacial and interstadial phases—such as the Eemian, Brörup and Odderade—remain only poorly constrained in time due to limited numerical dating. This lack of robust chronologies hampers efforts to assess the synchronicity of climatic and ecological transitions across regions and to contextualise human occupations during this period. Here, we present a 21-m-long, high-resolution lacustrine sediment succession from northern Germany that spans the Saalian late glacial (late Marine Isotope Stage—MIS 6) to the Weichselian pleniglacial (MIS 4 to MIS 2). Using a multi-proxy approach combining palynology (partially automated), sedimentology, geochemistry, magnetic susceptibility and microfossil-based reconstructions, we develop a detailed palaeoenvironmental reconstruction for this period. This is supported by 25 luminescence samples incorporated into a previously published Bayesian age–depth model, thus offering one of the most continuous and well-resolved chronologies for this interval in the region. According to our findings, the Saalian late glacial pollen zones B and C occurred between ∼133–132 ka and ∼132–129 ka, respectively. The Eemian interglacial lasted ∼21 500 years (∼128.8–107.3 ka), significantly longer than previously estimated at the key reference site of Bispingen (∼15 000 years). The Brörup and Odderade interstadials are constrained to ∼100–88.2 and ∼77–72 ka, while three newly identified, short-lived interstadials (WP Li Os I–III) occurred during MIS 4 and MIS 2 (∼69, 61 and 25 ka). These findings reveal hydrological and ecological responses that were partly asynchronous with both North Atlantic climate signals and biostratigraphic zonation, suggesting regional lags in vegetation change and/or uncertainties in the age–depth model. By providing a high-resolution, and independently dated palaeoenvironmental framework, this study improves the chronological constraints of central European pollen zones and thus offers a new basis for archaeological interpretations of Neanderthal activity. Our results call for re-evaluation of assumed synchrony in climate–ecosystem transitions across Europe during the last interglacial/glacial cycle and underscore the need for further high-resolution, numerically anchored records across the region.
    Universitätsbibliographie Jena:
    fsu_mods_00036506Externer Link

  7. Warm and wet, cool and dry?: molecular paleohydrology based on biomarker δD and δ18O across Central Europe since the Late Glacial

    Autor
    M. Prochnow
    Erscheinungsjahr
    A warmer climate is often described as a wetter climate, as warmer air can hold more moisture, leading to increased precipitation. However, the simple notion of “warm and wet” or “cool and dry” can be misleading, as seasonal changes in precipitation and evaporation are important for ecosystems. In Central Europe, summer droughts are becoming more severe, while heavy precipitation events are increasing simultaneously. This seasonal interplay of hydrological processes strongly affects ecosystems worldwide, and understanding them is essential for assessing future climate change. This thesis applies molecular paleohydrology to investigate the relationship between temperature and hydroclimate using four lake sediment records from Central Europe. Two records cover the Late Glacial–Early Holocene transition (16 until 11 cal. ka BP; Bergsee, Bichlersee), and two span the Mid to Late Holocene (last 7000 years; Moossee, Schliersee). Molecular paleohydrology is applied using compound-specific stable isotope analyses (δ18O and δD) of aquatic and terrestrial hemicellulose sugars and n-alkanes, enabling the application of the dual biomarker and coupled isotope approach to reconstruct past evapo(transpi)ration. The synthesis of all four biomarker records shows that wetter or drier conditions primarily depend on seasonality and hydrological settings. As the biomarker proxies are summer-sensitive, the results indicate that warmer periods were characterized by drier summers and enhanced evapo(transpi)ration in Central Europe. This contrasts with the common assumption that warmer climates are generally more humid. For future climate change, these proxy-based findings suggest more severe summer droughts, alongside an increased risk of extreme precipitation events such as localized convective rainfall and flooding. Molecular paleohydrology using biomarkers and compound-specific δ18O and δD analyses thus provides powerful tools to explore such relationships in detail.
    Universitätsbibliographie Jena:
    fsu_mods_00030192Externer Link

  8. Wetter or drier? Paleohydrological evidence from a 30-year resolution Holocene biomarker δD record from Moossee, Switzerland

    Autoren
    M. Prochnow, L. Danius, P. Strobel, F. Rey, L. Rittmeier, M. Zech, W. Tinner, R. Zech
    Erscheinungsjahr
    Erschienen in:
    Quaternary science reviews : the international multidisciplinary research and review journal
    The hydrological cycle intensifies under global warming, causing humid areas to become wetter. However, rising temperatures also amplify seasonal ecosystem dryness, complicating the link between temperature and hydroclimate. Such divergent mechanisms challenge generalizations like 'warm and wet' in paleoclimatology on a global scale. On a regional scale, knowledge about evapotranspiration in response to past warming and cooling is still limited, but highly relevant to understand future hydroclimate. Here, we analyse the hydrogen isotope composition (δD) of aquatic and terrestrial biomarkers in varved sediments from Moossee, Switzerland, covering the past 7300 years at a temporal resolution of 30 years. Based on a dual biomarker approach, we reconstruct evapotranspiration at Moossee. Our data suggests that cool and wet conditions repeatedly favored rising lake levels and advancing glaciers in the Alps but lowered treelines, e.g. at the onset of the Neoglacial, dated to ∼5.5 cal ka BP. In contrast, warmer periods like the Mid Holocene or the Roman Warm Period were associated with dryness. Short-term hydrological fluctuations are partly explained by volcanic and solar forcings. Aside from an increased risk of strong convective rainfall and floods, paleohydrology provides robust evidence that an intensified hydrological cycle under global warming will substantially favor summer drought in Central Europe.
    Universitätsbibliographie Jena:
    fsu_mods_00027545Externer Link

  9. Pleistocene glacial geomorphology and chronology of the Nahuel Huapi-Limay and Traful catchments, northern Patagonia

    Autoren
    I. Mizerit, E. Morabito, F. Bechis, C. Terrizzano, A. Groos, G. Rugel, S. Merchel, R. Zech
    Erscheinungsjahr
    Erschienen in:
    Geomorphology: an international journal on pure and applied geomorphology
    Universitätsbibliographie Jena:
    fsu_mods_00025293Externer Link

  10. A Late Glacial and Holocene sugar biomarker-based δ¹⁸O paleoclimate record from the Afro-alpine Central Lake, Bale Mountains, Ethiopia

    Autoren
    S. Chernet, L. Bittner, G. Gil-Romera, B. Lemma, M. Bliedtner, R. Zech, B. Glaser, T. Bromm, S. Szidat, W. Zech, M. Zech
    Erscheinungsjahr
    Erschienen in:
    Global and planetary change: a daughter journal of palaeogeography, palaeoclimatology, palaeoecology
    The Eastern African region is an amalgamation of complex climate systems nestled in contrasting topographic barriers. Although rift basins are prime targets for studying the climate of the past, high-altitude climate archives in the context of paleoclimate research also offer invaluable insight and have yet to be fully explored. Here, we present a 17 kyr hydroclimate history of the Afro-alpine (4121 m a.s.l) Central Lake using a δ¹⁸O record established by analyzing hemicellulose-derived sugar biomarkers. The sugar biomarker patterns with a dominance of fucose indicate the predominance of autochthonous sedimentary organic matter. Therefore, the oxygen isotopic variability of the sugar biomarkers in general and of fucose in particular (δ¹⁸Ofucₒsₑ) reflects δ¹⁸Olₐkₑ wₐtₑr being controlled by climatic conditions, particularly lake water ¹⁸O enrichment by evaporation. Our δ¹⁸Ofucₒsₑ record from Central Lake indicates strong enrichment during the Late Glacial. Around 15 cal kyr BP, the onset of more humid climate marks the beginning of the African Humid Period (AHP) in the Bale Mountains. The AHP was interrupted by an arid period during the Late Glacial – Holocene transition roughly coinciding with the Younger Dryas (YD). After the YD, humid climatic conditions prevailed again until the Late Holocene when a gradual shift towards drier climate started. Our δ¹⁸Ofucₒsₑ record and interpretation agree well with the findings from adjacent low-altitude archives of Eastern Africa, the Indian Ocean paleoclimate records and the Asian Monsoon Domain, which suggests region-wide hydro-climatic teleconnections.
    Universitätsbibliographie Jena:
    fsu_mods_00026113Externer Link

  11. Comparing recent and buried Chernozems/Phaeozems in Central Germany: Soil transformation and human impact since 3.8 ka

    Autoren
    H. von Suchodoletz, B. Schneider, A. Skokan, T. Nitz, B. Glaser, S. Polivka, K. Wiedner, F. Schlütz, T. Schunke, P. Kühn
    Erscheinungsjahr
    Erschienen in:
    Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution
    Universitätsbibliographie Jena:
    fsu_mods_00026016Externer Link

  12. Paleoclimate, paleoenvironment, and human impact over the last 400 years based on lipid biomarkers from Lake Höglwörth, Germany

    Autoren
    S. Acharya, P. Strobel, M. Prochnow, S. Taut, M. Zech, A. Schwalb, R. Zech
    Erscheinungsjahr
    Erschienen in:
    Quaternary Science Advances
    Lipid biomarkers are valuable proxies for reconstructing paleoclimate and paleoenvironmental changes as well as human impact. However, little attention has been paid on evaluating how the combination of biomarkers can be used to reconstruct various aspects of local paleoenvironmental conditions. This study presents a suite of lipid biomarker records from a sediment core from Lake Höglwörth, southern Germany, covering the past 400 years. Compound-specific hydrogen isotopic compositions (δD) of terrestrial n-alkanes (n-C₂₉₋ₐlkₐnₑ) and n-alkanoic acids (n-C₃₀₋ₐcid) indicate minor changes in isotopic composition of precipitation. The δD of n-C₂₂₋ₐcid is interpreted to record the isotopic composition of the lake water and evaporative enrichment, which drops after 1700 CE, coinciding with the construction of a mill and the related rerouting of a creek into Lake Höglwörth. The δD of n-C₂₅₋ₐlkₐnₑ is also enriched but decoupled from the reconstructed isotopic composition of precipitation and lake water. Therefore, we suggest that δD of n-C₂₅₋ₐlkₐnₑ reflects the leaf water isotopic composition of Sphagnum, which is present in the catchment and undergoes transpirative enrichment. Both short-chain compounds have become more enriched over the last century, maybe related to increasing temperature associated with anthropogenic climate warming. The faecal biomarkers record the changes in human population, partly related to the history of the local Monastery, the World Wars I and II as well as the intensive farming after the mid-20th century. Polycyclic aromatic hydrocarbons (PAHs) reveal a significant change in combustion activities associated with human activities such as the industrial revolution, biomass burning, and environmental cleanup as well as the implementation of emission standards. Our study demonstrates that the combination of plant wax compounds, faecal biomarkers, and PAHs from lacustrine sediment serves as a valuable tool to reconstruct and distinguish various aspects of paleoclimate and paleoenvironmental changes including human impacts.
    Universitätsbibliographie Jena:
    fsu_mods_00016348Externer Link
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