The Scientific staff and crew onboard CCGS Louis S. St. Laurent (LSL) returned September the 10th, 2001 from a scientific expedition to the Nares Strait, the northernmost waterway connecting the Arctic and Atlantic oceans. The data format is Society of Exploration Geophysicists SEG Y. The ice conditions in the strait required the support of Canada's largest ice breaker. The ship was a versatile platform for 34 scientists to accomplish their marine investigation. The LSL has a history of supporting international scientific expeditions including an oceanographic transect of the Arctic Ocean in 1994 and a biological study of the Canadian Arctic Islands in 1999. Germany (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR) and Canada (Geological Survey of Canada) undertook a 5-week scientific cruise to study and explore the geological structure and evolution of the Nares Strait. The primary objective was the study of structural features relating to the formation of the Arctic Ocean and, in particular, the study of the Wegener Fault. This fault is a linear boundary between Greenland and Ellesmere Island which was noted by the German scientist Alfred Wegener in 1915 and later became the subject of a major scientific controversy. The co-operative cruise, which was planned over a period of 2 years, provided the basis for a wide range of scientific investigations, from marine seismic work and climate change studies through airborne magnetic investigations to geodetic survey measurements and geological sampling onshore. Systematic geophysical offshore studies in this key area had not been undertaken before. Where towing of seismic equipment was not possible because of ice coverage, magnetic maps were made using a helicopter-borne magnetic sensor system. Sediment and water samples taken during the cruise provide information on changes in climate and sea ice cover from the last ice-age to the present. An 11 m-long sediment core from outer Jones Sound is the longest core ever taken in the Canadian Arctic channels and holds clues to the detailed climate history of northern Baffin Bay.
The multidisciplinary marine geoscientific expedition ARK-25/3 was focused on the Greenland part of northern Baffin Bay and was aimed to acquire new geoscientific data to be used for modelling the evolution of the Greenland continental margin and its hydrocarbon prospective. The data format is Society of Exploration Geophysicists SEG Y. The cruise was performed under the direction of the Federal Institute for Geosciences and Natural Resources Hannover in cooperation with the Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven. Using 70 days of ship time onboard the research icebreaker R/V POLARSTERN a comprehensive data set was acquired along profiles extending from the deep oceanic basin in the central part of North Baffin Bay onto the Greenland continental margin in an area which was bordered by the Kane Basin in the North and Disko Island in the South. By means of multi-channel seismic, wide angle seismic, gravimetric and magnetic methods the structural inventory of the crust in the NW Baffin Bay was investigated. Additionally, heat flow data and sediment cores were collected along lines crossing the Greenland continental margin. The cores were extracted for geochemical and geomicrobiological analysis to be used for basin modelling, studying the hydrocarbon potential, and the hydrocarbon degradation by microorganisms under polar conditions. Geological sampling in the coastal area was done between Melville Bay and Washington Land. The collected rock material will be used to derive constraints on the erosion history of the coastal area. Aeromagnetic data was acquired covering a substantial part of the marine survey area to investigate magnetic signatures of the oceanic crust and the continental margin. This report summarizes the working programme and contains the documentation of acquired data and first results of the expedition.
Schulze, Tobias; Ricking, Mathias; Schröter-Kermani, Christa; Körner, Andrea; Denner, Hans-Dietrich; Weinfurtner, Karlheinz; Winkler, Andreas; Pekdeger, Asaf Journal of Soils and Sediments 7 (2007), 6, 361-367 Goal, Scope and Background. The European Water Framework Directive implies a risk based sediment management. In this approach sediments are recognised as secondary sources of contaminants, and suspended particulate matter (SPM) as the carrier. For that reason the concept of the German Environmental Specimen Bank (ESB) includes the establishment of these specimens. The ESB is characterised by a high quality assurance system of standard operation procedures (SOP) to preserve the integrity of the specimens under cryogenic conditions for transportation, storage and handling. The aim of this study was (1) the development and validation of SOPs for the collection of sediment and SPM, and (2) the adaptation and standardisation of sampling techniques for the ESB. This paper provides information about sediment and SPM as new specimens in the ESB. Methods. A redesigned freeze-coring device was tested and applied to collect unconsolidated sediments at the fresh water sampling sites of the German ESB. Liquid nitrogen was used as a cooling agent. Sediment cores were cut on site using a stainless steel saw or an angle grinder with a diamond blade, stored in stainless steel containers and transported to the depot of the ESB inside a nitrogen vapour freezer. SPM was collected using passive sedimentation boxes (SBs). The SBs were installed permanently in surface waters or monitoring stations. Sampling of SPM was performed monthly and the SPM was subsequently frozen on site, stored in stainless steel containers and transported to the depot of the ESB in a nitrogen vapour freezer. At two locations the comparability of this method with sampling using a continuous-flow centrifuge Padberg Z61 was investigated. Results and Discussion. The sediments at almost all fluvial sampling sites of the ESB are sapropel or Gyttja type. The use of a freeze-coring device allowed sampling of these unconsolidated sediments under the conditions of ESB. The device was not applicable at two locations due to tidal influence and fine-grained sediments, respectively due to the depth in case of Lake Belau (~28 m). In these cases piston corers were used for sediment sampling. The collection of time-integrated SPM samples using SBs achieves the approach of the ESB. In comparison, the Padberg Z61 provides only samples, which are representative for the short collection period of 8-10 h (snapshot). A shortcoming of SBs is a possible alteration of SPM during the sampling period of about 4 weeks. However, alteration of the samples is not as evident as shorter collection periods and usage of a Padberg Z61 causes technical and economic difficulties. Conclusions. The modified freeze-coring device and the sedimentation boxes are applicable for the collection of sediment and SPM samples within the framework of the ESB. The chosen sampling and handling techniques attain the requirements of the ESB. Consequently, routine collection and storage of sediment cores and SPM started in 2005. According to our knowledge, the German ESB is the first of all specimen banks worldwide that routinely collects and stores SPM and that applies in situ freeze-coring to collect sediment cores. Perspectives. The collection and storage of sediments and SPM as new specimens in the ESB enhances the possibilities to control the efficacy of the European Water Framework Directive, REACh, and similar regulations and to take further action. doi: 10.1065/jss2007.08.24
Wandernde Westwinde und warmes Tiefenwasser sind die treibenden Kräfte hinter dem zunehmenden Eismassenverlust in der Westantarktis. Zu diesem Ergebnis kommt ein internationales Geologenteam, dessen Studie am 5. Juli 2017 im Fachmagazin Nature erschienen ist. Die Wissenschaftler aus Deutschland, Großbritannien, Dänemark und Norwegen hatten mit Hilfe von Sedimentkernen das Zusammenspiel von Ozean und Eisströmen im Amundsenmeer für die zurückliegenden 11.000 Jahre rekonstruiert und deutliche Parallelen zwischen den aktuellen Ereignissen und großen Eisverlusten vor mehr als 7500 Jahren entdeckt. Die neuen Daten sollen nun helfen, die zukünftige Entwicklung des Westantarktischen Eisschildes besser vorherzusagen. Mit ihren neuen Erkenntnissen füllen die Wissenschaftler eine entscheidende Lücke in der Klima- und Eismodellierung. Für ihre Studie hatten die Wissenschaftler Sedimentkerne analysiert, die im Jahr 2010 auf einer Expedition des deutschen Forschungseisbrechers Polarstern in die Pine Island-Bucht des Amundsenmeeres geborgen worden waren. Die Bodenproben enthielten Überreste winziger Meeresorganismen, sogenannter Foraminiferen. Der geochemische Fingerabdruck ihrer Kalkschalen erlaubt Rückschlüsse auf die Umweltbedingungen zu Lebzeiten der Tiere. Auf diese Weise gelang es den Forschern, die Temperatur-, Strömungs- und Eisverhältnisse im Amundsenmeer für die zurückliegenden 11.000 Jahre zu rekonstruieren. Die in das Amundsenmeer mündenden Gletscher und Eisströme verlieren inzwischen so viel Eis, dass sie allein zehn Prozent des globalen Meeresspiegelanstieges verursachen. Weltweite Aufmerksamkeit erregen vor allem der Pine Island-Gletscher und der Thwaites-Gletscher. Beide haben ihr Fließtempo und ihre Rückzugsraten in den vergangenen Jahrzehnten enorm gesteigert. Zusammen genommen speichern die Eisströme der Region so viel Eis, dass sie im Falle ihres Abschmelzens den Meeresspiegel um 1,2 Meter ansteigen lassen könnten.
Das Projekt "Ein Beitrag zur Oekologie des Tiefbeckens des Weissen Meeres" wird vom Umweltbundesamt gefördert und von Stiftung Alfred-Wegener-Institut für Polar- und Meeresforschung e.V. (AWI) durchgeführt. General Information: The deep water ecosystem of the White Sea is exposed to perennial Arctic water temperatures and covered by winter sea ice. It will be studied as an example of Arctic seas emphasizing the relationships between the different sub-systems (coupling of ice biota, pelagos and benthos) and focussing on the question, how a presumably oligotrophic deep water fauna is sustained and regulated by input of particulate organic matter during the limited productive season. For this, the whole biotic system will be analysed from spring till autumn (primary producers including ice-algae, pelagic consumers including remineralising micro-organisms, larger copepods and near-bottom zooplankton, and the main macro-and meio-benthos groups). Oceanographic conditions and plant nutrients will be monitored, and the vertical particle flux be measured by short and longer term exposures of sediment traps. Benthic responses to food input will be investigated by life cycle analyses (e.g. gonad maturation, spawning and spat fall of macrofauna), composition of the meiofauna (e.g. dominances of different feeding types) and also changes in diversity patterns. The overall benthic respiration (oxygen uptake rates) will be obtained from sediment core incubations, which will allow estimates of remineralisation activities of the bulk small fauna and micro-organisms. From these measurements and consumption estimates of the larger animals from their biomass and laboratory/literature data about metabolic rates, benthic budgets of energy flow will be derived. The benthic demands will be compared with the data obtained about primary production, pelagic consumption and from the vertical fluxes estimated by the sediment trap exposures. As the White Sea is well accessable even during winter, additional studies (e.g. on ice organisms and on winter metabolism of selected bottom fauna) are intended to better understand biological activities during the non-productive season. Such data as well as investigations of the entire ecosystem during the whole productive season are lacking for Arctic seas, for which the Deep water White Sea system will be regarded as a model. Prime Contractor: Alfred Wegener Institut for Polar and Marine Research, Sektion Biology I, Arctic Benthos Ecology Group; Bremerhaven; Germany.
Das Projekt "Daphnia hybrids" wird vom Umweltbundesamt gefördert und von Universität Konstanz, Limnologisches Institut durchgeführt. Hybrids of the water flea Daphnia occur in many lakes. However, little is known about the factors that cause the success of Daphnia hybrids. In a joint project of two laboratories we study the possible role of biotic interactions in the maintenance of a Daphnia hybrid complex. Daphnia hyalina, D. galeata and their hybrids occur in Bodensee and in Greifensee. The parent species are more abundant in Lake Constance, while hybrids dominate in Greifensee. Both lakes differ in important aspects (morphometry, trophic state), which is reflected by different biotic influences con Daphnia. Compared to Lake Constance, Daphnia in Greifensee are more often exposed to low quality food (toxic blue-greens) and have less of a refuge from fish predation (due the anoxic hypolimnion). Differences between both lakes in the invertebrate predation regime and in the parasite load of Daphnia are very probable. Besides field sampling programmes, we want to establish a collection of about 50 Daphnia clones from both lakes (parent species and hybrids, recent clones and old clones hatched from sediment cores). These clones will be used for life history experiments in the laboratory to test the influences of low quality food, of fish kairomones, of invertebrate predator kairomones and of a protozoan parasite. Food quality and invertebrate predator experiments will be done in Konstanz; parasite and fish experiments will be done in Dübendorf.
Das Projekt "Sub project: What ends an Interglacial? Feedbacks between tropical rainfall, Atlantic climate and ice sheets during the Last Interglacial (EndLIG)" wird vom Umweltbundesamt gefördert und von Universität Bremen, Fachbereich 5 Geowissenschaften, Fachgebiet Geosystem Modellierung durchgeführt. When and how the present interglacial will end remains an open question. With a relatively wellknown climate, the Last Interglacial (LIG) and following glacial inception can shed some light on the climate mechanisms leading to the establishment of a new ice age. Two key questions arise from the chain of climate events known to end the LIG: (1) Did the interglacial North Atlantic warmth, prolonged by an active thermohaline circulation (THC), favor or delay the growth of northern ice sheets? (2) Did reorganizations in South American moisture contribute to prolong the North Atlantic warmth by maintaining a salty North Atlantic and active THC at the end of the LIG, as suggested by tropical moisture feedbacks observed during glacial times? To address these questions, we propose here to combine new paleoclimate reconstructions with climate model experiments. First, we will reconstruct the detailed evolution of the South American rainbelt during the last glacial inception, by applying complementary proxies on a transect of marine sediment cores. Second, we will assess the impact of tropical hydrologic changes on tropical Atlantic sea surface salinities (SSS) and the Atlantic THC, by comparing tropical Atlantic SSS and deep-water properties with model sensitivity experiments where we will vary the tropical freshwater forcing. Finally, we will perform a transient climate/ice-sheet model run for the last glacial inception, and a sensitivity study, in which different ocean heat fluxes will be imposed to investigate the effect of prolonged North Atlantic warmth on ice sheet growth.
Das Projekt "Element cycles in mountain regions under various land use" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Geowissenschaften, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Agrarökosystemforschung durchgeführt. Research question: What is the role of agricultural land use in changes of nutrient cycles and losses dependingon surface slope and climate? Approach: Annual balance of main nutrients for 3-4 main agricultural farms based on fertilizer input, partitioning of nutrients in above and below ground plant parts, output with harvest, losses with DOM and erosion (in collaboration with other TP). The balances will be done depending on agricultural practices in Eger and Haean Catchment and will be compared with adjacent grassland and forest. Obtained element cycles will be upscaled from farm area to the level of both catchments basins depending on specific land use, surface slope and climate. Research question: Can we reconstruct previous erosion and nutrient losses and separate them under forest and under agricultural use? Approach: Undisturbed sediment cores (7 for Eger and 7 for Haean) will be taken from the lakes and soils of landscapes subordinated to agricultural fields. Three radiocarbon data of wood particles at increasing depth for each sediment core will be used as references. The age of the bottom sediment layer should be less than 1000 years. The total content of C, N, P, K, Mg, Ca, Si will be analyzed in individual laminae or sediment layers. Conclusions will be drawn based on the thickness of the laminae, their elements content and the ratio between nutrients and Si. The conclusions will be proven by 13C (vegetation change) and 15N (N input by fertilizers) of individual laminae. Research question: What are the best management practices for sloping uplands? Approach: Measured element cycles and losses under various agriculture practice will be analysed and practices with the least nutrient losses and erosion will be selected. The best management practices for landscapes with different slopes will be elaborated.
Das Projekt "ESR (Elektronen-Spin-Resonanz) und Th/U Datierungen von Karbonaten" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. Mineralogische und geochemische sowie ESR Untersuchungen an marinen Karbonaten werden durchgefuehrt. Schwerpunkte des Vorhabens sind: a) die Datierung von Foraminiferen aus dem Sedimentkernen aus Ostatlantik und Arktis. Dabei sollen die Methoden verfeinert werden hinsichtlich der Aufloesung und der Grenzen der Datierbarkeit. b) Ein weiterer Schwerpunkt besteht darin, die Zuverlaessigkeit der Th/U und der ESR-Datierung fuer fossile Muschelschalen zu untersuchen.
Das Projekt "Teilprojekt: Bestimmung der Transportwege von 10Be in der Wassersäule im Südpolarmeer, Sites 1089 und 1093, ODP Leg 177" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. Die geplanten Untersuchungen an den Sedimentkernen 1089 und 1093 des ODP Leg 177 aus dem Südpolarmeer sollen Aufschluß über Änderungen der Paläoproduktivität, des Sauerstoffgehalts des Bodenwassers, der 10Be Transport- und Sedimentationsprozesse geben, sowie eine 10Be-Stratigraphie liefern. Die vorgenommenen Arbeiten beinhalten: a) die Bestimmung der 231Paex/230Thex Verhältnisse für die letzten 150 ka; b) die Modellierung des diagenetischen Verhaltens von Mangan, Eisen und Uran im Sediment und c) die Erstellung von 10Be Tiefenprofilen.Mittels der 231Paex/230Thaex Verhältnisse soll die Paläoproduktivität im Südpolarmeer und die damit in Verbindung stehende Veränderung der geographischen Lage der Antarktischen Polarfrontzone untersucht werden. Die Lokationen der zu untersuchenden Sedimentkerne wurden so gewählt, daß sie sich nördlich und südlich der heutigen Polarfrontzone befinden. Die Modellierung des diagenetischen Verhaltens von Mangan, Eisen und Uran (234U, 238U) in der Sedimentsäule liefert Rückschlüsse auf Diagenese, den Sauerstoffgehalt des Bodenwassers und den Fluß von organischem Material ins Sediment.Die 10Be Stratigraphie dient der Überprüfung der Magnetostratigraphie, wobei sie eine höhere zeitliche Auflösung für die letzten 800 ka liefert. Der Vergleich der 10Be Depositionsflußdichte mit dem atmosphärischen Eintrag läßt Rückschlüsse auf Zeiten von erhöhtem oder erniedrigtem Eintrag von Trägermaterial (terrigen/biogen) zu. Der terrigene Anteil kann durch die Bestimmung der 9Be Konzentrationen ermittelt werden.
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