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  • 2020-2024  (30)
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  • 1
    Keywords: Forschungsreise
    Description / Table of Contents: The research cruise to the Eastern Mediterranean (GPF-18-2-40) originally planned on RV METEOR was relocated to RV SONNE (Fig. 1.2) due to the reduced number of scientists as part of the corona pandemic. The main objective of the Bremen Ocean Cluster expedition (DFG, EXC2077) was to investigate the interactions between the seabed and ocean water in Greek waters, whereby the plate tectonic constellation of a broad collision zone represents a special tectonic drive. A secondary goal was the sampling of the Sartori mud volcano, which is being processed in Italian waters as part of a separate DFG project and for which the GPF granted an additional permit for ship time (GPF 20-1_054). The expedition began on 12 October in Emden/Germany and ended on 01 December 2020, in Emden. Investigations on mud volcanoes were carried out divided into 3 working areas (Fig. 1.1, the Sartori mud volcano in the Calabrian arc, the so-called Cobblestone Area, the Olimpi mud volcano field including the United Nation Ridge). With the MARUM AUV SEAL (Fig. 1.3) 11 dives were successfully carried out to create high-resolution detailed maps of certain seafloor structures. A total of 38 gravity cores (Fig. 1.4), 30 multicorers (Fig. 1.5) and 4 minicorers were used for sampling sediments and 6 CTD stations for sampling methane in the water column. Furthermore, 10 profiles were carried out with the heat flow lance and 5 observation profiles with the on-board OFOS. In four different provinces, 16 mud volcanoes were examined, 10 of which are characterized by pore waters that show a distinct freshening, while three mud volcanoes, Napoli, Heraklion and Gelendzhik, are characterized by very high salt concentrations. The salt accumulations in these structures are derived from the Messinian salt deposits in the subbed, from which salty brines arise through subrosion, which interact in various ways with the mud volcanoes. The study areas were selected based on preliminary surveys and morphological structures and increased backscatter patterns from multibeam mapping carried out over 3580 nautical miles in Italian and Greek waters.
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (208 Seiten)
    Series Statement: Berichte aus dem MARUM und dem Fachbereich Geowissenschaften der Universität Bremen No. 326
    DDC: 551.23
    Language: English
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  • 2
    Description / Table of Contents: The research cruise to the Eastern Mediterranean (GPF-18-2-40) originally planned on RV METEOR was relocated to RV SONNE (Fig. 1.2) due to the reduced number of scientists as part of the corona pandemic. The main objective of the Bremen Ocean Cluster expedition (DFG, EXC2077) was to investigate the interactions between the seabed and ocean water in Greek waters, whereby the plate tectonic constellation of a broad collision zone represents a special tectonic drive. A secondary goal was the sampling of the Sartori mud volcano, which is being processed in Italian waters as part of a separate DFG project and for which the GPF granted an additional permit for ship time (GPF 20-1_054). The expedition began on 12 October in Emden/Germany and ended on 01 December 2020, in Emden. Investigations on mud volcanoes were carried out divided into 3 working areas (Fig. 1.1, the Sartori mud volcano in the Calabrian arc, the so-called Cobblestone Area, the Olimpi mud volcano field including the United Nation Ridge). With the MARUM AUV SEAL (Fig. 1.3) 11 dives were successfully carried out to create high-resolution detailed maps of certain seafloor structures. A total of 38 gravity cores (Fig. 1.4), 30 multicorers (Fig. 1.5) and 4 minicorers were used for sampling sediments and 6 CTD stations for sampling methane in the water column. Furthermore, 10 profiles were carried out with the heat flow lance and 5 observation profiles with the on-board OFOS. In four different provinces, 16 mud volcanoes were examined, 10 of which are characterized by pore waters that show a distinct freshening, while three mud volcanoes, Napoli, Heraklion and Gelendzhik, are characterized by very high salt concentrations. The salt accumulations in these structures are derived from the Messinian salt deposits in the subbed, from which salty brines arise through subrosion, which interact in various ways with the mud volcanoes. The study areas were selected based on preliminary surveys and morphological structures and increased backscatter patterns from multibeam mapping carried out over 3580 nautical miles in Italian and Greek waters.
    Type of Medium: Book
    Pages: 208 Seiten , Illustrationen, Diagramme, Karten
    Series Statement: Berichte aus dem MARUM und dem Fachbereich Geowissenschaften der Universität Bremen No. 326
    Language: English
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  • 3
    Publication Date: 2024-02-07
    Description: Seabed methane gas emissions occur worldwide at cold seeps located along most continental margins. Fluxes of methane gas released from the seabed in the form of bubbles can be extremely variable even over short time intervals. Some factors controlling the variability are still poorly understood. Here, we report on the results of continuous long-term sonar monitoring of bubble emissions at a depth of 1,260 m on the Clayoquot Slope, northern Cascadia margin. With a total monitoring duration of 4 years and a sampling period of 1 h, this is by far the longest high temporal resolution monitoring of seabed methane gas release ever conducted. Our results provide evidence that the diurnal and semi-diurnal tides influence the timing of the onset and cessation of bubble emissions. However, gas emissions within the monitoring area are active more than 84% of the time, indicating that tides alone are not sufficient to make venting pause. We hypothesize that the gas fluxes are transient but generally sufficiently high to maintain ebullition independently of the tidally-induced bottom pressure variations. Results also show that the tides do not seem to modulate the vigor of active gas emissions.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
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  • 4
    Publication Date: 2024-02-07
    Description: Hydroacoustic surveys at the accretionary wedge southwest of Taiwan reveal a confined active hydrocarbon seepage area of ~ 49,000 m 2 in ~ 1350 m water depth on the northern crest of the Four-Way Closure Ridge, which we call Yam Seep. In this study, multibeam and side-scan sonar data acquired during surveys with an autonomous underwater vehicle during an expedition with R/V Ocean Researcher I in 2017 showed that the area is characterized by rough topography and high seafloor backscatter. Seafloor observations with a video sled and sediment sampling with gravity corers and the MeBo seafloor drill rig during an expedition with R/V SONNE in 2018 revealed that the area is almost entirely covered by intensely fractured methane-derived carbonates, which indicate that seepage has been ongoing for thousands of years. Hydroacoustic anomalies (‘flares’) in the water column indicated the presence of several gas bubble emission sites mostly at the center and eastern flank of the area in 2019. Drilling through massive carbonates in the northwestern part of Yam Seep induced free gas escape from a depth of ~ 5.1 m. This suggests the presence of gas hydrates in the subsurface as the seep area is located well within the gas hydrate stability zone. The inter-disciplinary investigations of the Yam Seep demonstrate that upward migration of light hydrocarbons and seafloor discharge has a considerable influence on the seabed properties.
    Type: Article , PeerReviewed
    Format: text
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  • 5
    Publication Date: 2024-02-07
    Description: Highlights • Extensive asphalt deposits and asphalt volcanism at Mictlan Knoll in the southern Gulf of Mexico. • A novel type of active hydrocarbon seepage system in the southern GoM. • High-resolution seafloor mapping and seafloor manifestation of heterogeneous hydrocarbon seepage system. • Mapping, quantification and monitoring of gas emission sites in the southern GoM. • Mictlan Knoll hosts the most extensive asphalt deposits known to date in the GoM. Abstract Hydrocarbon seepage plays an essential role in defining seafloor morphology and increasing habitat heterogeneity in the deep sea whereby asphalt volcanism ranks among the most complex and proliferous hydrocarbon discharge systems that have been described to date. In this study, seepage of hydrocarbon gas and oil as well as asphalt deposits were investigated at Mictlan Knoll in the southern Gulf of Mexico. A multi-disciplinary approach was used including hydroacoustic surveys and visual seafloor observations to study the seafloor manifestations of hydrocarbon seepage. Mictlan Knoll is an asphalt volcano characterized by a crater-like depression surrounded by an elevated rim. Asphalt deposits are widespread in the depression where a large area of extensive asphalt deposits correlates with a high backscatter area (~75,000 m2). Numerous asphalt deposits appear relatively fresh and probably extruded recently, as oil bubbles were seen to emanate locally within areas covered by extensive asphalt deposits. An area of more irregular seafloor morphology occurring in the northern part of the depression is interpreted to be related to the active extrusion of asphalt below or within older surficial deposits. Additionally, 25 hydroacoustic anomalies indicative for gas bubble emissions were detected. Gas volume quantifications conducted during seafloor inspections with a remotely-operated vehicle (ROV) at a single gas escape site situated above a gas hydrate outcrop revealed up to 0.1 × 106 mol CH4/yr. Gas emission at this site, monitored by an autonomous scanning sonar device, indicated a highly variable bubble release activity. Based on our findings, it is proposed that Mictlan Knoll hosts the most extensive asphalt deposits known to date in the Gulf of Mexico.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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  • 6
    Publication Date: 2024-05-17
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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    Format: other
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  • 7
    Publication Date: 2023-03-03
    Description: The permanently cold sediments of South Georgia were investigated in this study to identify the geochemical parameters that are linked to microbial community composition. To identify these parameters, pore water profiles of sulfate, sulfide, dissolved iron, ammonium, silicate, dissolved inorganic carbon, and phosphate were analysed. The results presented here were obtained during the RV METEOR M134 expedition (January - March, 2017) and contribute to our understanding of microbial community composition in surface sediments of South Georgia.
    Keywords: Annenkov Trough; Center for Marine Environmental Sciences; Church Trough; Cumberland Bay; Drygalski Trough; M134; marine sediment; MARUM; MultiCorer; pore water; RV Meteor; South Georgia; sub-Antarctic sediment
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 8
    Publication Date: 2023-03-03
    Keywords: Ammonium; Annenkov Trough; Carbon, inorganic, dissolved; Center for Marine Environmental Sciences; Church Trough; Cumberland Bay; DEPTH, sediment/rock; Drygalski Trough; GeoB22015-1; Ion chromatography (Metrohm Compact IC 761); Iron 2+; M134; M134/1; M134/1_123-1; marine sediment; MARUM; Meteor (1986); MUC; MultiCorer; Optional event label; Phosphate; Photometer, molybdene blue; Photometrically using autoanalyzer QUAATRO; pore water; RV Meteor; SEAL Analytica, flow analyser, ortho-phtalaldehyde (OPA); SEAL Analytical, continuous flow analyser QuAAtro; Silicon dioxide; South Atlantic Ocean; South Georgia; Spectral photometry, ferrospectral solution at 565 nm wavelength; sub-Antarctic sediment; Sulfate
    Type: Dataset
    Format: text/tab-separated-values, 126 data points
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  • 9
    Publication Date: 2023-03-03
    Keywords: Ammonium; Annenkov Trough; Carbon, inorganic, dissolved; Center for Marine Environmental Sciences; Church Trough; Cumberland Bay; DEPTH, sediment/rock; Drygalski Trough; GeoB22031-1; Hydrogen sulfide; Ion chromatography (Metrohm Compact IC 761); Iron 2+; M134; M134/1; M134/1_139-1; marine sediment; MARUM; Meteor (1986); MUC; MultiCorer; Optional event label; Phosphate; Photometer, methylene blue (Cline 1969); Photometer, molybdene blue; Photometrically using autoanalyzer QUAATRO; pore water; RV Meteor; SEAL Analytica, flow analyser, ortho-phtalaldehyde (OPA); SEAL Analytical, continuous flow analyser QuAAtro; Silicon dioxide; South Atlantic Ocean; South Georgia; Spectral photometry, ferrospectral solution at 565 nm wavelength; sub-Antarctic sediment; Sulfate
    Type: Dataset
    Format: text/tab-separated-values, 121 data points
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  • 10
    Publication Date: 2023-03-03
    Keywords: Ammonium; Annenkov Trough; Carbon, inorganic, dissolved; Center for Marine Environmental Sciences; Church Trough; Cumberland Bay; DEPTH, sediment/rock; Drygalski Trough; GeoB22046-1; Ion chromatography (Metrohm Compact IC 761); Iron 2+; M134; M134/1; M134/1_154-1; marine sediment; MARUM; Meteor (1986); MUC; MultiCorer; Optional event label; Phosphate; Photometer, molybdene blue; Photometrically using autoanalyzer QUAATRO; pore water; RV Meteor; SEAL Analytica, flow analyser, ortho-phtalaldehyde (OPA); SEAL Analytical, continuous flow analyser QuAAtro; Silicon dioxide; South Atlantic Ocean; South Georgia; Spectral photometry, ferrospectral solution at 565 nm wavelength; sub-Antarctic sediment; Sulfate
    Type: Dataset
    Format: text/tab-separated-values, 141 data points
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