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Neutronenaktivierungsanalyse

Die NAA ist ein sehr leistungsfaehiges Verfahren zur Spuren- und Multielementbestimmung. Sie ist im Prinzip fuer alle Probenarten geeignet. Lediglich aus Sicherheitsgruenden werden die Proben in getrocknetem Zustand in den Reaktoren FRG-1 und FRG-2 bestrahlt. Die NAA wird hier hauptsaechlich in der Umwelt- und Meeresforschung eingesetzt. Da bei solchen Programmen sehr viele Proben zu bearbeiten sind, liegt ein Schwerpunkt der Arbeiten in der Automatisierung und Rationalisierung des Analysenganges. Ein weiterer Schwerpunkt liegt in der statistischen Verarbeitung der Datenflut. Dazu werden Programme zur statistischen Auswertung und Korrelationsanalyse verwendet und weiterentwickelt. Ein dritter Schwerpunkt der Arbeiten liegt in der Radiochemie. Denn neben der rein instrumentellen NAA muessen radiochemische Trennungen durchgefuehrt werden, um die Nachweisempfindlichkeit zu verbessern und stoerende Matrixaktivitaeten vor der Messung abzutrennen. In Einzelfaellen ist dann neben der Gamma-Spektroskopie die Alpha- und Beta-Spektroskopie die vorteilhafteste Methode. Es werden die deutschen Kuestenbereiche der Nord- und Ostsee und einzelne Flussmuendungen erprobt, um die Verteilg.und zeitl. Schwankungen der Schadstoffkonzentrationen zu ermitteln. Dazu werden systematisch Organismen und Sedimentproben genommen, analysiert und statistisch ausgewertet, ebenso Wasser- und Schwebstoffproben. Um aussagekraeftige Ergebnisse zu bekommen, muessen die natuerlichen jahreszeitlichen und langfristigen Aenderungen erfasst werden. Aus dem Spurenelementmuster sollen die Mechanismen der Schadstoffverteilungen aufgeklaert und moegliche Schadstoffquellen lokalisiert werden.

Ressortforschungsplan 2023, Naturschutzfachliche Begleitung Deutsche Allianz für Meeresforschung BfN-Vergabe-Nr. 3523521500

Planktondynamik im oligotrophen Ozean: Verbindungen zwischen dem mikrobiellen Nahrungsgewebe und höheren trophischen Ebenen im ultraoligotrophen Golf von Aqaba

Nährstoffarme Bereiche bilden die große Mehrheit des Ozeans, aber das Schicksal der dominierenden kleinen Autotrophen in diesen Bereichen ist wenig erforscht und noch weniger verstanden. Formen kleiner als 5 mym machen die große Mehrheit der Autotrophen in nährstoffarmen Systemen aus, und Protisten sind vermutlich die Haupträuber dieser Fraktion, aber besonders im Meer ist diese Verbindung wenig erforscht. Offene, grundlegende Fragen sind: Wie viel, und mit welcher Effizienz fließt Primärproduktion der kleinen Autotrophen in höhere trophische Ebenen? Sind kleine Ciliaten im Meer genauso wichtige Konsumenten kleiner Autotropher wie im Süßwasser oder sind heterotrophe Nanoflagellaten (HNF) die Haupträuber? Sind Synechococcus und Prochlorococcus, die beiden wichtigsten Vertreter der kleinen Autotrophen, in gleichem Masse frassempfindlich? Wie wichtig ist Nährstoff-Recycling durch Protisten, um Primärproduktion zu erhalten? Das vorgeschlagene Projekt wird im Golf von Aqaba stattfinden, einem oligroptrophen Tiefseesystem nicht weit vom Labor entfernt und deshalb logistisch für experimentelle Arbeit optimal geeignet. Das Projekt ist als Zusammenarbeit mit Prof. Anton Post, Eilat, Israel geplant. Experimente werden in Jahreszeiten durchgeführt, in denen unterschiedliche Autotrophe dominieren. Dabei werden Interaktionen zwischen gesamten trophischen Ebenen innerhalb der Planktongemeinschaft aber auch zwischen Arbeiten berücksichtigt, um allgemeine Vorhersagen für oligotrophe Systeme zu machen.

Multibeam bathymetry raw data (Kongsberg EM712 entire dataset) of RV MARIA S. MERIAN during cruise MSM99

Multibeam bathymetry raw data using the ship's own Kongsberg EM 712 multibeam echosounder was not continuously recorded during RV MARIA S. MERIAN cruise MSM99. Data was recorded on 16 days between 2021-02-26 and 2021-03-19. This dataset contains 13x survey lines (occasionally with some line crossing perpendicular to the track) in the Baltic Sea and Gulf of Bothnia. The approximate average depth of the entire dataset is around 150m, ranging from 280m to 22m. No ancillary sound velocity profiles (SVP) files from the cruise are added to this dataset. Data analysis of the multibeam raw data revealed that SVP has been changed several during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is rather good since the gridded hillshade data showed relatively few obstacles. Data can be processed e.g. with the open source software package MB-System (Caress et al. 2024, https://doi.org/10.5281/zenodo.6302801).

Glyptocephalus cynoglossus (Linnaeus, 1758) Hundszunge Meeresfische und -neunaugen Ungefährdet

Die Hundszunge wird weltweit als gefährdet (Vulnerable) eingestuft (IUCN 2023). NORDSEE: Die Art kommt hauptsächlich in den tieferen Bereichen der Nordsee vor; in der deutschen AWZ der Nordsee befindet sich die Randverbreitung der Art. Nach Einschätzung des Internationalen Rates für Meeresforschung (ICES Advice 2022) liegt die Laicherbestandsbiomasse der Hundszunge in Nordsee, Skagerrak, Kattegat und östlichem Ärmelkanal unterhalb des Referenzwertes (MSY Btrigger; zur Erläuterung siehe Glossar in Barz & Zimmermann 2024). Die fischereiliche Sterblichkeit liegt über dem Grenzwert (FMSY; zur Erläuterung siehe Glossar in Barz & Zimmermann 2024). OSTSEE: In der westlichen Ostsee scheint die Situation für die Art günstiger zu sein als im Nordseegebiet.

Photosynthetic efficiency and symbiont cover of Amphistegina lobifera measured by PAM fluorometry and CLSM during a menthol-DCMU bleaching experiment (Nov–Dec 2022, Bremen, Germany)

This dataset contains experimental data from a one-month aquarium-based bleaching experiment conducted on Large Benthic Foraminifera (Amphistegina lobifera) from 16 November to 16 December 2022 at the Marine Experimental Facility of the Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany. The aim of the experiment was to obtain symbiont-free A. lobifera individuals for future re-inoculation studies and symbiont switching experiments. The foraminifera were originally collected in May 2022 at the Interuniversity Institute for Marine Sciences (IUI) in Eilat, Israel (29°30'07.8N, 34°55'04.9E) and maintained in culture in Germany until the start of the experiment. To assess the effectiveness of two chemical agents—menthol and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)—in disrupting symbiosis, photosynthetic efficiency (measured as maximum quantum yield, Fv/Fm) was recorded every other day during the first week of the experiment using a Pulse-Amplitude-Modulated (PAM) fluorometer. Fv/Fm measurements were discontinued after the first week due to complete inhibition of photosynthesis. Symbiont coverage (%) was assessed on day one and then weekly until week four using Confocal Laser Scanning Microscopy (CLSM).

Processed seismic data of Cruise MSM9/3

The cruise leg MSM09/3 was conducted as a cooperative project between the Alfred Wegener Institute for Polar and Marine Research (AWI), the Federal Institute for Geosciences and Resources (BGR), the Geological Survey of Denmark and Greenland (GEUS) and Dalhousie University. The data format is Society of Exploration Geophysicists SEG Y. A geophysical survey covered areas of Baffin Bay and Davis Strait between Greenland and the Canadian Baffin Island. A component of the IPY 2007/08 Lead Project Plate Tectonics and Polar Gateways in the Earth System (PLATES & GATES), this project DAVIS GATE is aimed to develop a tectonic and sedimentary reconstruction of the opening process of this oceanic gateway. Baffin Bay and Davis Strait play an important role in the shallow water exchange from the Arctic to the Atlantic Ocean. The plate-tectonic evolution as well as the magmatic history of this region has been sparsely known and required a careful geophysical investigation in order to construct a set of gridded detailed paleotopographic maps for a complete geodynamic reconstruction of this gateway. With a set of three seismic refraction/wide-angle reflection profiles, using ocean-bottom seismometers on 62 stations, as well as multi-channel reflection seismic recordings with a 3000-m long streamer, data were acquired from the sedimentary cover to the deep crust and even from parts of the uppermost mantle. Additional seismic data supplement these profiles and provide insights into the structures of the basement and dominant fault zones such as the Ungava fault system. A parallel running magnetic survey aimed to resolve the temporal evolution of the oceanic crust of Baffin Bay. The extension and subsidence of the continental and transitional crust in the Davis Strait and the evolution of oceanic crust in the Labrador Sea and Baffin Bay could be investigated with dataset to which continuously recorded gravity anomaly data and sub-bottom profiler data also contribute. This dataset provides the basis of geometrical and physical properties of the crust required for a realistic geodynamic model which will describe the break-up and the ocean basin evolution between Greenland and Canada in terms of detailed paleo-topography.

Fixed-wing Magnetics NOGRAM I + II

In 1998, as part of the expedition NOGRAM I (Northern Gravity, Radio Echo Sounding and Magnetics), a flight campaign was carried out over the Lincoln Sea north of Greenland with the Polar 2 aircraft (Dornier 228-100) in cooperation with the Alfred Wegener Institute Helmholtz Center for Polar and Marine Research. A second flight campaign NOGRAM II took place in 2011 with the Polar 5 (Basler BT-67) over the Wandel Sea north of Greenland. The aim of the research was the structure and architecture of the upper Earth’s crust underneath the ice-covered offshore areas of the Morris Jesup Plateau and coastal waters north of Greenland. The airborne magnetic surveys were carried out with a flight line spacing of 3 km, and control profiles were flown every 30 km. During the two expeditions, 33000 km of line data were collected (16000 km in 1998, and 17000 km in 2011).

Multibeam bathymetry raw data (Kongsberg EM 712 transit dataset) of RV MARIA S. MERIAN during cruise MSM98

Multibeam bathymetry raw data was recorded in the North Sea during cruise MSM98 that took place between 2021-01-08 and 2021-01-23. The data was collected using the ship's own Kongsberg EM 712. This data is part of the DAM (German Marine Research Alliance) underway research data project.

Multibeam bathymetry raw data (R2Sonic SONIC 2024 entire dataset) of RV ELISABETH MANN BORGESE during cruise EMB304

Multibeam bathymetry raw data using the ship's own R2Sonic SONIC 2024 Wideband multibeam echosounder was not continuously recorded during RV ELISABETH MANN BORGESE (EMB) cruise EMB304. Data was recorded on 3 separate days (2022-10-25, 2022-10-29, 2017-10-30. This dataset contains a survey in the Baltic Sea. The system settings of the device were set prior to the cruise and data acquisition was not entirely monitored during the survey time. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). This dataset is considered to be a test dataset for the incorporation of data from EMB into PANGAEA. The software QINSy from QPS was used for data recording. Data is stored with the regular QINSy data format .db and the auxiliary .xtf data format. Data are not compatible with the open source software package MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, http://www.mbari.org/products/research-software/mb-system/, 2022), therefore - as up to this publication date – professional software like CARIS HIPS/SIPS or QPS QIMERA is needed the post-process the data. Thus, individual data files could not be georeferenced by reading out the files itself using open-source software. Data files contained empty spaces " " in the file names. All files had to be renamed using underscores "_", since PANGAEA database does not allow the usage of spaces " " in file names. Data are unprocessed and therefore contain incorrect depth measurements (artifacts). Note that refraction errors can be expected due to the lack of accurate sound velocity profiles (SVP). Overall, it appears that the data quality differs. The gridded hillshade from data acquired on 2022-10-25 showed relatively many obstacles at the slant beams (bad data quality). Data acquired on 2022-10-29 show in general relatively less obstacles (very good data quality) with elongated structures on the seafloor without a distinct pattern. Data acquired on 2022-10-30 show in general a few obstacles (moderate data quality).

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