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2. Age of Himalayan bottom ice cores [2]

Author

Hou, S. G., Qin, D. H., Jouzel, J., Masson-Delmotte, V., Von Grafenstein, U., Landais, A., Caillon, N., Chappellaz, J., Hou, S. G., Qin, D. H., Jouzel, J., Masson-Delmotte, V., Von Grafenstein, U., Landais, A., Caillon, N., and Chappellaz, J.

Published
2022
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10. Evidence for higher-than-average air temperatures after the 8.2 ka event provided by a Central European δ18O record

Author

Andersen, N., Lauterbach, S., Erlenkeuser, H., Danielopol, D., Namiotko, T., Huels, M., Belmecheri, S., Dulski, P., Nantke, C., Meyer, Hanno, Chapligin, Bernhard, von Grafenstein, U., Brauer, A., Andersen, N., Lauterbach, S., Erlenkeuser, H., Danielopol, D., Namiotko, T., Huels, M., Belmecheri, S., Dulski, P., Nantke, C., Meyer, Hanno, Chapligin, Bernhard, von Grafenstein, U., and Brauer, A.

Abstract

The so-called 8.2 ka event represents one of the most prominent cold climate anomalies during the Holocene warm period. Accordingly, several studies have addressed its trigger mechanisms, absolute dating and regional characteristics so far. However, knowledge about subsequent climate recovery is still limited although this might be essential for the understanding of rapid climatic changes. Here we present a new sub-decadally resolved and precisely dated oxygen isotope (δ¹⁸O) record for the interval between 7.7 and 8.7 ka BP (10³ calendar years before AD 1950), derived from the calcareous valves of benthic ostracods preserved in the varved lake sediments of pre-Alpine Mondsee (Austria). Besides a clear reflection of the 8.2 ka event, showing a good agreement in timing, duration and magnitude with other regional stable isotope records, the high-resolution Mondsee lake sediment record provides evidence for a 75-year-long interval of higher-than-average δ¹⁸O values directly after the 8.2 ka event, possibly reflecting increased air temperatures in Central Europe. This observation is consistent with evidence from other proxy records in the North Atlantic realm, thus most probably reflecting a hemispheric-scale climate signal rather than a local phenomenon. As a possible trigger we suggest an enhanced resumption of the Atlantic meridional overturning circulation (AMOC), supporting assumptions from climate model simulations.

Published
2017

11. Preliminary results from excavations at Gueldaman Cave GLD1 (Akbou, Algeria)

Author

Raji, O., Dezileau, L., Von Grafenstein, U., Niazi, S., Snoussi, M., Martinez, P., Kherbouche, Farid, Hachi, Slimane, Abdessadok, Salah, Sehil, Nana, Merzoug, Souhila, Sari, Latifa, Benchernine, Redha, Chelli, Razika, Fontugne, Michel, Barbaza, Michel, Roubet, Colette, Travaux et recherches archéologiques sur les cultures, les espaces et les sociétés (TRACES), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), L'Homme préhistorique : son évolution, son milieu, ses activités, Université de la Méditerranée - Aix-Marseille 2-Muséum national d'Histoire naturelle (MNHN)-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), Centre National de Recherches Préhistoriques, Anthropologiques et Historiques (CNRPAH), Préhistoire et Technologie (PréTech), Université Paris Nanterre (UPN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Paléontologie du Muséum National d'Histoire Naturelle, Histoire naturelle de l'Homme préhistorique (HNHP), Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université MohammedV-Agdal, Rabat, Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Département des sciences de la Terre, Faculté des sciences de Rabat, Institut de Paléontologie Humaine (IPH), Fondation I.P.H-Centre National de la Recherche Scientifique (CNRS), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), L'homme préhistorique : son évolution, son milieu, ses activités, Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Nanterre (UPN), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Holocene, Socio-culturale, Excavation, Ornaments, preliminary results of excavation, Karst, Archaeology, law.invention, Sequence (geology), Paleontology, Cave, law, Gueldaman Cave GLD1, Algeria, preliminary results of excavation, Holocene, Algeria, Mammal, Radiocarbon dating, Gueldaman Cave GLD1, Domestication, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Geology, ComputingMilieux_MISCELLANEOUS, Earth-Surface Processes
Abstract

The limestone Adrar Gueldaman ridges of the northwestern Babors Mountains of the Tellian region (Northern Algeria) contain a large karst network with several caves. Inside one of them (GLD 1), first excavated in the 1920s, an Early Neolithic episode was identified. Since 2010, new investigations by the Centre National de Recherches Prehistoriques, Anthropologiques et Historiques, Algeria (CNRPAH), at GLD 1 and other newly discovered caves have revealed well-preserved anthropogenic deposits. The GLD1 deposits are more than 5 m deep. Four sectors (S1–S4) have been spatially defined, of which two (S2 and S3) were partially investigated. Eight samples of wood charcoal from these sectors were radiocarbon dated by AMS giving median dates ranging from 1484 cal BP to 17,031 cal BP. The main human occupation sequence at GLD1 is situated around the VI and VII millennia BP with virtually all of the archaeological deposits coming from these layers. Deeper occupation levels have not yet been investigated. Bio-archaeological remains are well preserved (mammal bones, mollusc shells and plant-remains) and linked with cultural material (ceramics, ornaments, lithic and bone tools). Multi-disciplinary analysis of this material is underway and here we report on the preliminary findings, which already bring new insights into the neolithisation process of this region. Evidence of sheep and goat domestication at more than 6 ka cal BP is particularly significant.

Published
2014
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14. Isotopic characterization of rapid climatic events during OIS 3 and OIS4 in Villars Cave stalagmites (SW-France) and correlation with Atlantic and Mediterranean pollen records

Author

Genty , Dominique, Combourieu-Nebout , Nathalie, Peyron , Odile, Blamart , Dominique, Wainer , Karine, Mansuri , F., Ghaleb , Bassam, Isabello , L., Dormoy , Isabelle, Von Grafenstein , U., Bonelli , S., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), GEOTOP UQAM, and Etat du Canada

Subjects
[ SDE.MCG ] Environmental Sciences/Global Changes, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2010

15. A 450-year record of spring/summer flood layers in annually laminated sediments from Lake Ammersee (Southern Germany)

Author

Czymzik, M., Dulski, P., Plessen, B., von Grafenstein, U., Naumann, R., and Brauer, A.

Subjects
550 - Earth sciences
Abstract

A 450-year spring/summer flood layer time series at seasonal resolution has been established from the varved sediment record of Lake Ammersee (Southern Germany) applying a novel methodological approach. The main results are (1) a precise chronology obtained by microscopic varve counting, (2) the identification of detrital layers representing flood2 triggered fluxes of catchment material into the lake, and (3) the recognition of the seasonality of these flood layers from their micro-stratigraphic position within a varve. Tracing flood layers in a proximal and a distal core and correlating them applying the precise chronology provided information on the depositional processes. Comparing the seasonal flood layer record with daily runoff data of the inflowing River Ammer for the period from 1926 to 1999 allowed defining an approximate threshold in flood magnitude above which the formation of flood layers becomes very likely. Moreover, it was for the first time possible to estimate the ‘completeness’ of the flood layer time series and to recognize that mainly floods in spring and summer representing the main flood seasons in this region are well preserved in the sediment archive. Their frequency distribution over the entire 450-year time series is not stationary, but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced. The observed spring/summer flood layer frequency further shows similar trends as the occurrence of flood-prone weather regimes since AD 1881, probably suggesting a causal link between solar variability and changes in mid-latitude atmospheric circulation patterns.

Published
2010

17. Seasonal flood layer distribution of the last 450 years in annually laminated sediment from Lake Ammersee (Southern Germany)

Author

Czymzik, M., Brauer, A., Dulski, P., Plessen, B., Naumann, R., Zimmermann, J., von Grafenstein, U., German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 550 - Earth sciences, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Lakes can be utilized as long-term natural observatories of environmental and climate change in the human habitat because they act as ideal sediment traps accumulating continuous sediment records reaching far back in time. Especially from annually laminated lake sediment records detailed seasonal information can be obtained. Such long time series of high-resolution data ideally complement multi-scale observational data in order to achieve a comprehensive mechanistic understanding of climate and environmental variability. For this case study two short annually laminated sediment cores from Lake Ammersee (Southern Germany) have been studied using a combination of micro-facies analyses, high resolution element scanning ( -XRF) and stable isotope (^13C, ^18O) data. Our results provide a precise and independent chronology established by counting of calcite varves using a petrographic microscope and the identification of short-term fluxes of detrital matter into the lake. The seasonal occurrence of these detrital layers was determined by their micro-stratigraphic position within a varve. The record of detrital layers within the last 73 years is in good agreement with observed runoff data from the main tributary river (Ammer) and local precipitation data. This leads in combination with a proximal-distal pattern of detrital layer thicknesses to an interpretation as flood layers. Our data indicate maxima of spring and summer flood layers during solar minima in the Little Ice Age triggered by intensified snowmelt events and atmospheric circulation changes.

Published
2009

18. A multi-proxy record of Lateglacial climatic and environmental changes from Lake Mondsee (Upper Austria)

Author

Lauterbach, S., Brauer, A., Dulski, P., Schettler, G., Milecka, K., Hüls, M., Andersen, N., Namiotko, T., Danielopol, D. L., von Grafenstein, U., German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), University of Gdańsk (UG), Karl-Franzens-Universität [Graz, Autriche], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Karl-Franzens-Universität Graz, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Aptel, Florence

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Within the frame of the ESF EuroCLIMATE project DecLakes (Decadal Holocene and Lateglacial variability of the oxygen isotopic composition in precipitation over Europe reconstructed from deep-lake sediments), the sediment record of pre-alpine Lake Mondsee (Upper Austria) has been investigated with a special focus on the Lateglacial. The use of a multi-proxy approach, including microfacies analysis, high-resolution -XRF element scanning, stable isotope analyses on valves of benthic ostracods, carbon geochemistry and analysis of pollen and ostracods enables the identification of major climatic fluctuations during this period. Furthermore, the parallel sampling strategy allows direct comparison of sensitivity of different proxies to climatic and environmental changes. The basal clastic-detrital facies of the profile is dominated by proglacial varves. The gradual onset of biochemical calcite precipitation is paralleled by a rapid shift in oxygen isotope ratios of benthic ostracod valves which marks the abrupt warming at the onset of the Lateglacial Interstadial. However, the allochthonous sediment input from the catchment shows no rapid shift but a gradual decrease. During the Allerød biozone sedimentation is dominated by homogeneous endogenic calcite with a very low detrital component. At the onset of the Younger Dryas cold period a marked decrease in oxygen isotope ratios within ca. 100 years occurs, followed by a reduction in the amount of endogenic calcite and the increase of detrital flux with a lag of about 100 years. The clear vegetational shift towards higher proportions of herbs and Juniperus and the frequency increase of detrital event layers lag the ^18O signal by about 250 years. In contrast, the rapid Holocene warming within 20-30 years is well reflected by the parallel ^18O rise and the establishment of a vegetation adapted to a warmer climate with the onset of massive calcite precipitation and the cessation of detrital input lagging by only few decades. The Holocene climatic amelioration is also well reflected by changes in the ostracod assemblage of the profundal zone from an oligotrophic and psychrophilic fauna to one which favours benthic substrates with higher organic input. This study has been made possible thanks to the support from the European Science Foundation (EUROCORES Programme EuroCLIMATE, ESF project DecLakes no. 04-ECLIM-FP29) and the National Agencies FWF (Austria, project no. I35-B06), DFG (Germany) and CNRS (France).

Published
2009

19. Lake Hańcza (northeast Poland) – A new multi-proxy record of Lateglacial and early Holocene climate and environmental change from the Eastern Baltic

Author

Lauterbach, S., Brauer, A., Plessen, B., Dulski, P., Zamelczyk, K., Milecka, K., Namiotko, T., Hüls, M., Andersen, N., von Grafenstein, U., Danielopol, D.L., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

23. Last glacial- Interglacial Cycle Palaeoclimatology and Palaeoecology Reconstruction: Ostracod Stable Isotope Records From Ohrid Lake and Palaeolake 'Les Echets'

Author

Belmecheri, S., Von Grafenstein, U., Bordon, A., Andersen, N., Lézine, A.-M., Mazaud, A., Andrieu-Ponel, V., Robert, Cédric, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Climat et Magnétisme (CLIMAG), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

25. Ein Lasermassenspektrometer zum Nachweis aromatischer Spurenstoffe

Author

Zimmermann, R. (Univ.-Prof. Dr. (Universität Augsburg)), Boesl-von Grafenstein, U. (Prof. Dr.), Kettrup, A. (Prof. Dr. Dr. h.c.), Hauler, Thorsten Erik, Zimmermann, R. (Univ.-Prof. Dr. (Universität Augsburg)), Boesl-von Grafenstein, U. (Prof. Dr.), Kettrup, A. (Prof. Dr. Dr. h.c.), and Hauler, Thorsten Erik

Abstract

Die Verbrennung von Holz und anderer Biomasse zum Heizen oder zur Stromgewinnung ist eine Hauptquelle für Schadstoffemissionen. Dabei spielen neben gasförmigen Verbindungen auch lungengängige Feinpartikel eine große Rolle. Zur Evaluation der Gesundheitsgefahren ist eine möglichst umfassende Abgasanalyse erforderlich. Zu diesem Zweck wurde im Rahmen dieser Arbeit ein Analysegerät zum Nachweis von gasförmigen und von auf festen Proben adsobierten Verbindungen entwickelt. Es wurden Messungen an verschiedenen Anlagen vom Hausofen bis zur industriellen Pilotanlage durchgeführt. Dabei konnte in der Gasphase die Emissionsdynamik von Verbrennungsprozessen detailliert verfolgt sowie durch Analyse gleichzeitig gesammelter Rußproben ein umfassendes Bild von Verbrennungsprozessen gewonnen werden., Wood and biomass combustion for heating or energy generation purposes are main sources for emission of pollutants in the lower atmosphere. Both gaseous emissions and respirable particulate matter contribute to possible health hazards. Therefore, a comprehensive analysis of emissions is required. A mobile instrument was built to serve this purpose by allowing for both components to be measured simultaneously. It was applied to four differently scaled combustion facilities, from a domestic kiln to industrial scale incinerators. Gas phase emission dynamics as well as particle-bound aromatic compounds were detected. Furthermore, a wide range of solid samples was analysed.

Published
2008

26. Extreme storms during the last 6,500 years from lagoonal sedimentary archives in Mar Menor (SE SPAIN).

Author

Dezileau, L., Pérez-Ruzafa, A., Blanchemanche, P., Degeai, J. P., Raji, O., Martinez, P., Marcos, C., and Von Grafenstein, U.

Abstract

Amongst the most devastating marine catastrophes that can occur in coastal areas, are storms and tsunamis, which may seriously endanger human society. Many such events are known and have been reported for the Mediterranean, a region where high-frequency occurrences of these extreme events coincides with some of the most densely populated coastal areas in the world. In a sediment core from Mar Menor Lagoon (SE Spain), we discovered eight coarse grained layers which document marine incursions during periods of intense storm activity or tsunami events. Based on radiocarbon dating, these extreme events occurred around 5250, 4000, 3600, 3010, 2300, 1350, 650 and 80 years cal B.P.. No comparable events have been observed during the 20th and 21th centuries. The results indicate little likehood of a tsunami origin for these coarse grained layers, although historical tsunami events are recorded in this region. These periods of surge events seem to coincide with the coldest periods in Europe during the late Holocene, suggesting a control by a climatic mechanism for periods of increased storm activity. Spectral analyses performed on the sand % revealed four major periodicities of 1228 ±327, 732 ±80, 562 ±58, and 319 ±16 yr. Amongst the well-known proxies that have revealed a millennial-scale climate variability during the Holocene, the ice-rafted debris (IRD) indices in North Atlantic developed by Bond et al. (1997, 2001) present a cyclicity of 1470 ±500 yr, which matches the 1228 ±327 yr periodicity evidenced in the Mar Menor lagoon, considering the respective uncertainties on the periodicities. Thus, an in-phase storm activity in Western Mediterranean is found with the coldest periods in Europe and to the North Atlantic thermohaline circulation. However, further investigations, such as additional coring, high-resolution coastal imagery, are needed to better constrain the main cause of these multiple-events. [ABSTRACT FROM AUTHOR]

Published
2016
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27. Rapid climate variability during warm and cold periods in polar regions and Europe

Author

Masson-Delmotte, V., Landais, A., Combourieu-Nebout, N., von Grafenstein, U., Jouzel, J., Caillon, N., Chappellaz, J., Stenni, B., Dahl-Jensen, Dorthe, Johnsen, Sigfus Johann, Masson-Delmotte, V., Landais, A., Combourieu-Nebout, N., von Grafenstein, U., Jouzel, J., Caillon, N., Chappellaz, J., Stenni, B., Dahl-Jensen, Dorthe, and Johnsen, Sigfus Johann

Abstract

Typical rapid climate events punctuating the last glacial period in Greenland, Europe and Antarctica are compared to two rapid events occurring under warmer conditions: (i) Dansgaard-Oeschger event 25, the first abrupt warming occurring during last glacial inception; (ii) 8.2 ka BP event, the only rapid cooling recorded during the Holocene in Greenland ice cores and in Ammersee, Germany. The rate of warming during previous warmer interglacial periods is estimated from polar ice cores to 1.5 °C per millennium, without abrupt changes. Climate change expected for the 21st century should however be at least 10 times faster. Udgivelsesdato: 23 May

Published
2005

31. Quantification of biotic responses to rapid climatic changes around the Younger Dryas – a synthesis.

Author

Amman, B., Birks, H.J.B., Brooks, S.J., Eicher, U., von Grafenstein, U., Hofmann, W., Lemdahl, Geoffrey, Schwander, J., Tobolski, K., Wick, L., Amman, B., Birks, H.J.B., Brooks, S.J., Eicher, U., von Grafenstein, U., Hofmann, W., Lemdahl, Geoffrey, Schwander, J., Tobolski, K., and Wick, L.

Abstract

To assess the presence or absence of lags in biotic responses to rapid climatic changes, we: (1) assume that the delta(18)O in biogenically precipitated carbonates record global or hemispheric climatic change at the beginning and at the end of the Younger Dryas without any lag at our two study sites of Gerzensee and Leysin, Switzerland; (2) derive a time scale by correlating the delta(18)O record from these two sites with the delta(18)O record of the GRIP ice core; (3) measure delta(18)O records in ostracods and molluscs to check the record in the bulk samples and to detect possible hydrological changes; (4) analyse at Gerzensee and Leysin as well as at two additional sites (that lack carbonates and hence a delta(18)O record) pollen, plant macrofossils, chironomids, beetles and other insects, and Cladocera; (5) estimate our sampling resolution using the GRIP time scale for the isotope stratigraphies and the biostratigraphies; and (6) summarise the major patterns of compositional change in the biostratigraphies by principal component analysis or correspondence analysis. We conclude that, at the major climatic shifts at the beginning and end of the Younger Dryas, hardly any biotic lags occur (within the sampling resolution of 8-30 years) and that upland vegetation responded as fast as aquatic invertebrates. We suggest that the minor climatic changes associated with the Gerzensee and Preboreal oscillations were weakly recorded in the biostratigraphies at the lowland site, but were more distinct at higher altitudes. Individualistic responses of plant and animal species to climatic change may reflect processes in individuals (e.g. productivity and phenology), in populations (e.g. population dynamics), in spatial distributions (e.g. migrations), and in ecosystems (e.g. trophic state). We suggest that biotic responses may be telescoped together into relatively short periods (50 to 150 years), perhaps disrupting functional interactions among species and thus destabilising e

Published
2000
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35. Rapid climate variability during warm and cold periods in polar regions and Europe [Variabilité climatique rapide pendant les périodes chaudes et froides aux pôles et en Europe]

Author

Masson-Delmotte, V., Landais, A., Combourieu-Nebout, N., von Grafenstein, U., Jouzel, J., Caillon, N., Chappellaz, J., Dahl-Jensen, D., Johnsen, S. J., and Stenni, B.

Subjects
climate change, polar region
Abstract

Typical rapid climate events punctuating the last glacial period in Greenland, Europe and Antarctica are compared to two rapid events occurring under warmer conditions: (i) Dansgaard-Oeschger event 25, the first abrupt warming occurring during last glacial inception; (ii) 8.2 ka BP event, the only rapid cooling recorded during the Holocene in Greenland ice cores and in Ammersee, Germany. The rate of warming during previous warmer interglacial periods is estimated from polar ice cores to 1.5 °C per millennium, without abrupt changes. Climate change expected for the 21st century should however be at least 10 times faster. © Académie des sciences. Published by Elsevier SAS. All rights reserved.

36. Interactive comment on "Spatial structure of the 8200 cal yr BP event in Northern Europe" by H. Seppä et al.

Author

Von Grafenstein, U.

Abstract

The author comments on the article "Spatial Structure of the 8200 cal yr BP Event in Northern Europe," by H. Seppä and colleagues. The manuscript described a synthesis of existing early to mid Holocene pollen and stable isotope records, which points to a south-north decrease of the reaction of those two proxies to the 8.2-kiloyear event.

Published
2007

38. Reconstruction of past precipitation δ 18O using tree-ring cellulose δ 18O and δ 13C: A calibration study near Lac d'Annecy, France

Author

Danis, P.A., Masson-Delmotte, V., Stievenard, M., Guillemin, M.T., Daux, V., Naveau, Ph., and von Grafenstein, U.

Subjects
*CELLULOSE, *OXYGEN, *CARBON, *HUMIDITY
Abstract

Abstract: Two sets of living oaks (Quercus R.) growing under different hydrological situations were sampled near Lac d''Annecy, France. The stable isotope composition of the latewood cellulose was analysed in terms of oxygen and carbon isotopic composition for the period 1971–2001 and compared to the nearby monthly meteorological (temperature, relative humidity) and isotopic composition of precipitation records. A linear regression shows that 60% of the cellulose oxygen isotopic composition inter-annual variations are due to changes in precipitation isotopic composition and relative humidity. The small slope between cellulose versus precipitation oxygen isotopic composition suggests a significant contribution of local continental recycling and questions the common assumption that vapour oxygen isotopic composition is at equilibrium with precipitation isotopic composition in Europe during the growing season. Finally, the combined use of tree-ring oxygen and carbon isotopic composition records enables to account for leaf water enrichment due to stomata stress and to provide a reconstruction (R 2 =0.64) of the summer precipitation isotopic composition. [Copyright &y& Elsevier]

Published
2006
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39. Ein Lasermassenspektrometer zum Nachweis aromatischer Spurenstoffe

Author

Hauler, Thorsten Erik, Zimmermann, R. (Univ.-Prof. Dr. (Universität Augsburg)), Boesl-von Grafenstein, U. (Prof. Dr.), and Kettrup, A. (Prof. Dr. Dr. h.c.)

Subjects
Lasermassenspektrometrie, Laserdesorption, TOF-Ionenquelle, Biomasseverbrennung, on line-Analytik, chemische Analyseverfahren, ddc:540, Chemie, laser mass spectrometry, laser desorption, TOF ion source, biomass combustion, on-line monitoring, chemical analysis, ddc:620, Ingenieurswissenschaften
Abstract

Die Verbrennung von Holz und anderer Biomasse zum Heizen oder zur Stromgewinnung ist eine Hauptquelle für Schadstoffemissionen. Dabei spielen neben gasförmigen Verbindungen auch lungengängige Feinpartikel eine große Rolle. Zur Evaluation der Gesundheitsgefahren ist eine möglichst umfassende Abgasanalyse erforderlich. Zu diesem Zweck wurde im Rahmen dieser Arbeit ein Analysegerät zum Nachweis von gasförmigen und von auf festen Proben adsobierten Verbindungen entwickelt. Es wurden Messungen an verschiedenen Anlagen vom Hausofen bis zur industriellen Pilotanlage durchgeführt. Dabei konnte in der Gasphase die Emissionsdynamik von Verbrennungsprozessen detailliert verfolgt sowie durch Analyse gleichzeitig gesammelter Rußproben ein umfassendes Bild von Verbrennungsprozessen gewonnen werden. Wood and biomass combustion for heating or energy generation purposes are main sources for emission of pollutants in the lower atmosphere. Both gaseous emissions and respirable particulate matter contribute to possible health hazards. Therefore, a comprehensive analysis of emissions is required. A mobile instrument was built to serve this purpose by allowing for both components to be measured simultaneously. It was applied to four differently scaled combustion facilities, from a domestic kiln to industrial scale incinerators. Gas phase emission dynamics as well as particle-bound aromatic compounds were detected. Furthermore, a wide range of solid samples was analysed.

Published
2008

40. Rapid climate variability during warm and cold periods in polar regions and Europe

Author

Sigfus J Johnsen, Nicolas Caillon, Ulrich von Grafenstein, Amaelle Landais, Nathalie Combourieu-Nebout, Jean Jouzel, Jérôme Chappellaz, Dorthe Dahl-Jensen, Valérie Masson-Delmotte, Barbara Stenni, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institute of Earth Sciences, Hebrew University, Géochrononologie Traceurs Archéométrie (GEOTRAC), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Geophysics and Water Resources, Section for Geology [Copenhagen], Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Dipartimento di Scienze Geologiche [Trieste], Università degli studi di Trieste = University of Trieste, European Commission, Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Università degli studi di Trieste, Masson Delmotte, V., Landais, A., Combourieu Nebout, N., von Grafenstein, U., Jouzel, J., Caillon, N., Chappellaz, J., Dahl Jensen, D., Johnsen, S. J., Stenni, Barbara, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)

Subjects
010506 paleontology, 010504 meteorology & atmospheric sciences, Climate change, polar ice core, Palaeoclimate, 01 natural sciences, Lake, interglacials, Ice core, Dansgaard–Oeschger event, Rapid climate event, Glacial period, lake record, Holocene, 0105 earth and related environmental sciences, Global and Planetary Change, polar ice cores, Rapid climate events, Dansgaard–Oeschger events, Ice-sheet model, lake records, Settore GEO/08 - Geochimica e Vulcanologia, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Ice cores, Interglacial, Abrupt climate change, General Earth and Planetary Sciences, Polar, Pollen, Geology
Abstract

Typical rapid climate events punctuating the last glacial period in Greenland, Europe and Antarctica are compared to two rapid events occurring under warmer conditions: ( i ) Dansgaard–Oeschger event 25, the first abrupt warming occurring during last glacial inception; ( ii ) 8.2 ka BP event, the only rapid cooling recorded during the Holocene in Greenland ice cores and in Ammersee, Germany. The rate of warming during previous warmer interglacial periods is estimated from polar ice cores to 1.5 °C per millennium, without abrupt changes. Climate change expected for the 21st century should however be at least 10 times faster. To cite this article: V. Masson-Delmotte et al., C. R. Geoscience 337 (2005).

Published
2005
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41. Long-term sediment records reveal over three thousand years of heavy metal inputs in the Mar Menor coastal lagoon (SE Spain).

Author

Pérez-Ruzafa A, Dezileau L, Martínez-Sánchez MJ, Pérez-Sirvent C, Pérez-Marcos M, von Grafenstein U, and Marcos C

Subjects
Humans, Ecosystem, Spain, Geologic Sediments chemistry, Environmental Monitoring, Food Chain, Water Pollutants, Chemical analysis, Metals, Heavy analysis
Abstract

The Mar Menor lagoon combined high biological production and environmental quality, making it an important economic engine. However, the pressure of human activities put its ecological integrity at risk, the oldest environmental impact being mining activity recorded since Roman times, about 3500 years ago, reaching its maximum intensity in the 20th century, contributing heavy metals to the lagoon sediments for almost 30 centuries. This work reviews the spatiotemporal evolution of the main heavy metals in this coastal lagoon using data from 272 surface sediment samples obtained during the last 40 years and two deep cores covering the total history of the lagoon (c. 6500 yrs BP), so as their incidence in the lagoon trophic web. The observed patterns in sedimentation, sediment characteristics and heavy metal content respond to the complex interaction, sometimes synergistic and sometimes opposing, between climatic conditions, biological production and human activities, with mining being mainly responsible for Pb, Zn and Cd inputs and port activities for Cu. High Fe/Al, Ti/Al and Zr/Al ratios identify periods of mining activity, while periods of arid climatic conditions and deforestation that increase erosion processes in the drainage basin and silt concentration in the lagoon sediments are determined by high Zr/Rb and, to a lesser extent, Zr/Al and Si/Al ratios. After the cessation of direct discharges into the lagoon in the 1950s, the recent evolution of heavy metals concentration and its spatial redistribution would be determined by hydrographic and biogeochemical processes, solubility of different elements, and coastal works in harbours and on beaches. The bioconcentration factor decreases along the trophic levels of the food web, suggesting that the lagoon ecosystem provides an important service by retaining heavy metals in the sediment, largely preventing their bioavailability, but actions involving resuspension or changes in sediment conditions would pose a risk to organisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Published
2023
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42. On the Leptocytheridae Ostracods of the Long-Lived Lake Ohrid: A Reappraisal of their Taxonomic Assignment and Biogeographic Origin.

Author

Namiotko T, Danielopol DL, Belmecheri S, Gross M, and Von Grafenstein U

Abstract

Leptocythere karamani Klie, one of few non-marine species of the family Leptocytheridae (Ostracoda), is redescribed from specimens recently collected from the long-lived Lake Ohrid on the Albanian-Macedonian border. Detailed morphologies of valves and limbs of this species were compared with those of other Ohrid-Prespa leptocytherids, of some recent marine representatives of the genera Leptocythere Sars and Callistocythere Ruggieri from the Mediterranean, Irish and Baltic seas as well as with that of fossil non-marine species from the Miocene palaeo-Lake Pannon belonging to the genera Amnicythere Devoto and Euxinocythere Stancheva. Comparison with other species of Leptocytheridae inhabiting fresh to brackish waters of the Black-Azov, Caspian and Aral seas were also carried out using descriptions provided in the literature. Based on the comparative morphological studies it is shown that L. karamani and other Ohrid leptocytherids have a number of characters distinguishing them from other members of the genus Leptocythere but demonstrating a relationship with species of the genus Amnicythere . The most reliable of these characters are: a) anterior valve vestibulum from where mostly uni-ramified pore canals start, b) the entomodont hinge type with a strong anterior anti-slip tooth, a smooth posterior anti-slip bar on the left valve, and c) the hemipenis with underdeveloped lateral lobe and reduced clasping organ. From this strong evidence, the Ohrid leptocytherid species are allocated to the genus Amnicythere . Finally, a biogeographic scenario on the origin of the Ohrid leptocytherids is proposed which matches the "Lake Pannon derivate hypothesis". Close relationship of the Ohrid Amnicythere species with the non-marine leptocytherid taxa from the Neogene lakes of Central and Eastern Europe and with extant taxa from the Black and Caspian seas may indicate that the Ohrid Amnicythere derived from Lake Pannon species which were able to colonise lakes in Southern Europe through a stepping-stone process and subsequently to adapt to freshwater environment.

Published
2012
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44. A mid-european decadal isotope-climate record from 15,500 to 5000 years B.P

Author

von Grafenstein U, Erlenkeuser H, Brauer A, Jouzel J, and Johnsen SJ

Abstract

Oxygen-isotope ratios of precipitation (delta18OP) inferred from deep-lake ostracods from the Ammersee (southern Germany) provide a climate record with decadal resolution. The record in detail shows many of the rapid climate shifts seen in central Greenland ice cores between 15,000 and 5000 years before the present (B.P.). Negative excursions in the estimated delta18OP from both of these records likely reflect short weakenings of the thermohaline circulation caused by episodic discharges of continental freshwater into the North Atlantic. Deviating millennial-scale trends, however, indicate that climate gradients between Europe and Greenland changed systematically, reflecting a gradual rearrangement of North Atlantic circulation during deglaciation.

Published
1999
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