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  • 1
    Online Resource
    Online Resource
    New insights into fluid flow and seep processes : Case studies from the North Atlantic and offshore New Zealand (2015)
    Kiel
    Details Availability
    Keywords: Hochschulschrift ; Atlantischer Ozean Nord ; Pazifischer Ozean Süd ; Fluid
    Type of Medium: Online Resource
    Pages: Online-Ressource (PDF-Datei: 171 S., 58 MB)
    URL: http://macau.uni-kiel.de/receive/dissertation_diss_00017214
    URL: http://oceanrep.geomar.de/30980/
    URN: urn:nbn:de:gbv:8-diss-172146
    Language: English
    Location Call Number Limitation Availability
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    GEOMAR CATALOGUE
    Link to Library Catalog
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  • 2
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    Isotope analysis and heat flow measurements of Maria S. Merian cruise MSM21/4 on the western Svalbard margin (2014)
    PANGAEA
    In:  Supplement to: Berndt, Christian; Feseker, Tomas; Treude, Tina; Krastel, Sebastian; Liebetrau, Volker; Niemann, Helge; Bertics, Victoria J; Dumke, Ines; Dünnbier, Karolin; Ferre, Benedicte; Graves, Carolyn; Gross, Felix; Hissmann, Karen; Hühnerbach, Veit; Krause, Stefan; Lieser, Kathrin; Schauer, Jürgen; Steinle, Lea (2014): Temporal constraints on hydrate-controlled methane seepage off Svalbard. Published Online January 2 2014, Science, https://doi.org/10.1126/science.1246298
    Details
    Publication Date: 2023-03-03
    Description: Methane hydrate is an ice-like substance that is stable at high-pressure and low temperature in continental margin sediments. Since the discovery of a large number of gas flares at the landward termination of the gas hydrate stability zone off Svalbard, there has been concern that warming bottom waters have started to dissociate large amounts of gas hydrate and that the resulting methane release may possibly accelerate global warming. Here, we can corroborate that hydrates play a role in the observed seepage of gas, but we present evidence that seepage off Svalbard has been ongoing for at least three thousand years and that seasonal fluctuations of 1-2°C in the bottom-water temperature cause periodic gas hydrate formation and dissociation, which focus seepage at the observed sites.
    Keywords: Center for Marine Environmental Sciences; GEOMAR; Helmholtz Centre for Ocean Research Kiel; MARUM
    Type: Dataset
    Format: application/zip, 29 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 3
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    Hyperspectral imager (UHI) data files acquired on SONNE cruise SO242/2, ROV dive SO242/191-1 (2017)
    PANGAEA
    In:  Supplement to: Dumke, Ines; Nornes, Stein; Purser, Autun; Marcon, Yann; Ludvigsen, Martin; Ellefmo, Steinar L; Johnsen, Geir; Søreide, Fredrik (2018): First hyperspectral imaging survey of the deep seafloor: High-resolution mapping of manganese nodules. Remote Sensing of Environment, 209, 19-30, https://doi.org/10.1016/j.rse.2018.02.024
    Details
    Publication Date: 2023-03-03
    Description: Hyperspectral seafloor surveys using airborne or spaceborne sensors are generally limited to shallow coastal areas, due to the requirement for target illumination by sunlight. Deeper marine environments devoid of sunlight cannot be imaged by conventional hyperspectral imagers. Instead, a close-range, sunlight-independent hyperspectral survey approach is required. In this study, we present the first hyperspectral image data from the deep seafloor. The data were acquired in approximately 4200 m water depth using a new Underwater Hyperspectral Imager (UHI) mounted on a remotely operated vehicle (ROV). UHI data were recorded for 112 spectral bands between 378 nm and 805 nm, with a high spectral (4 nm) and spatial resolution (1 mm per image pixel). The study area was located in a manganese nodule field in the Peru Basin (SE Pacific), close to the DISCOL (DISturbance and reCOLonization) experimental area. To test whether underwater hyperspectral imaging can be used for detection and mapping of mineral deposits in potential deep-sea mining areas, we compared two supervised classification methods, the Support Vector Machine (SVM) and the Spectral Angle Mapper (SAM). The results show that SVM is superior to SAM and is able to accurately detect nodule surfaces. The UHI therefore represents a promising tool for high-resolution seafloor exploration and characterisation prior to resource exploitation.
    Keywords: Event label; File format; File name; File size; Hyperspectral Imager/Profiler; HYSP; JPI-OCEANS; JPI Oceans - Ecological Aspects of Deep-Sea Mining; JPIO-MiningImpact; Remote operated vehicle; ROV; SO242/2; SO242/2_191_HYSP-1; SO242/2_191_HYSP-10; SO242/2_191_HYSP-11; SO242/2_191_HYSP-12; SO242/2_191_HYSP-13; SO242/2_191_HYSP-14; SO242/2_191_HYSP-15; SO242/2_191_HYSP-2; SO242/2_191_HYSP-3; SO242/2_191_HYSP-4; SO242/2_191_HYSP-5; SO242/2_191_HYSP-6; SO242/2_191_HYSP-7; SO242/2_191_HYSP-8; SO242/2_191_HYSP-9; SO242/2_191-1; Sonne_2; South Pacific Ocean, Peru Basin; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 80 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 4
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    Seismic Data from MSM21/4 to Knipovich Ridge on the western Svalbard margin (2015)
    PANGAEA
    In:  Supplement to: Dumke, Ines; Burwicz, Ewa; Berndt, Christian; Klaeschen, Dirk; Feseker, Tomas; Geissler, Wolfram H; Sarkar, Sudipta (2016): Gas hydrate distribution and hydrocarbon maturation north of the Knipovich Ridge, western Svalbard margin. Journal of Geophysical Research: Solid Earth, 121(3), 1405-1424, https://doi.org/10.1002/2015JB012083
    Details
    Publication Date: 2024-02-16
    Description: The seismic data were acquired north of the Knipovich Ridge on the western Svalbard margin during cruise MSM21/4. They were recorded using a Geometrics GeoEel streamer of either 120 channels (profiles p100-p208) or 88 channels (profiles p300-p805) with a group spacing of 1.56 m and a sampling rate of 2 kHz. A GI-Gun (2×1.7 l) with a main frequency of ~150 Hz was used as a source and operated at a shot interval of 6-8 s. Processing of profiles p100-p208 and p600-p805: Positions for each channel were calculated by backtracking along the profiles from the GI-Gun GPS positions. The shot gathers were analyzed for abnormal amplitudes below the seafloor reflection by comparing neighboring traces in different frequency bands within sliding time windows. To suppress surface-generated water noise, a tau-p filter was applied in the shot gather domain. Common mid-point (CMP) profiles were then generated through crooked-line binning with a CMP spacing of 1.5625 m. A zero-phase band-pass filter with corner frequencies of 60 Hz and 360 Hz was applied to the data. Based on regional velocity information from MCS data [Sarkar, 2012], an interpolated and extrapolated 3D interval velocity model was created below the digitized seafloor reflection of the high-resolution streamer data. This velocity model was used to apply a CMP stack and an amplitude-preserving Kirchhoff post-stack time migration. Processing of profiles p400-p500: Data were sampled at 0.5 ms and sorted into common midpoint (CMP) domain with a bin spacing of 5 m. Normal move out correction was carried out with a velocity of 1500 m s-1 and an Ormsby bandpass filter with corner frequencies at 40, 80, 600 and 1000 Hz was applied. The data were time migrated using the water velocity.
    Keywords: Comment; Date/Time of event; Date/Time of event 2; Event label; File name; File size; Latitude of event; Latitude of event 2; Longitude of event; Longitude of event 2; Maria S. Merian; MSM21/4; MSM21/4_548-1; MSM21/4_562-1; MSM21/4_608-1; MSM21/4_619-1; MSM21/4_646-1; MSM21/4_651-1; North Greenland Sea; Seismic profile P100-P102; Seismic profile P200-P208; Seismic profile P400, P500; Seismic profile P600; Seismic profile P700-P706; Seismic profile P800-P805; Seismic reflection profile; SEISREFL; Uniform resource locator/link to sgy data file
    Type: Dataset
    Format: text/tab-separated-values, 32 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 5
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    First hyperspectral imaging survey of the deep seafloor: High-resolution mapping of manganese nodules (2018)
    In:  EPIC3Remote Sensing of Environment, 209, pp. 19-30, ISSN: 00344257
    Details
    Publication Date: 2018-02-23
    Description: Hyperspectral seafloor surveys using airborne or spaceborne sensors are generally limited to shallow coastal areas, due to the requirement for target illumination by sunlight. Deeper marine environments devoid of sunlight cannot be imaged by conventional hyperspectral imagers. Instead, a close-range, sunlight-independent hyperspectral survey approach is required. In this study, we present the first hyperspectral image data from the deep seafloor. The data were acquired in approximately 4200m water depth using a new Underwater Hyperspectral Imager (UHI) mounted on a remotely operated vehicle (ROV). UHI data were recorded for 112 spectral bands between 378 nm and 805 nm, with a high spectral (4 nm) and spatial resolution (1mm per image pixel). The study area was located in a manganese nodule field in the Peru Basin (SE Pacific), close to the DISCOL (DISturbance and reCOLonization) experimental area. To test whether underwater hyperspectral imaging can be used for detection and mapping of mineral deposits in potential deep-sea mining areas, we compared two supervised classification methods, the Support Vector Machine (SVM) and the Spectral Angle Mapper (SAM). The results show that SVM is superior to SAM and is able to accurately detect nodule surfaces. The UHI therefore represents a promising tool for high-resolution seafloor exploration and characterisation prior to resource exploitation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
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    PAPER (OA)
  • 6
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    Underwater hyperspectral imaging as an in situ taxonomic tool for deep-sea megafauna (2018)
    In:  EPIC3Scientific Reports, 8(1), ISSN: 2045-2322
    Details
    Publication Date: 2018-09-11
    Description: Identification of benthic megafauna is commonly based on analysis of physical samples or imagery acquired by cameras mounted on underwater platforms. Physical collection of samples is difficult, particularly from the deep sea, and identification of taxonomic morphotypes from imagery depends on resolution and investigator experience. Here, we show how an Underwater Hyperspectral Imager (UHI) can be used as an alternative in situ taxonomic tool for benthic megafauna. A UHI provides a much higher spectral resolution than standard RGB imagery, allowing marine organisms to be identified based on specific optical fingerprints. A set of reference spectra from identified organisms is established and supervised classification performed to identify benthic megafauna semi-autonomously. The UHI data provide an increased detection rate for small megafauna difficult to resolve in standard RGB imagery. In addition, seafloor anomalies with distinct spectral signatures are also detectable. In the region investigated, sediment anomalies (spectral reflectance minimum at ~675 nm) unclear in RGB imagery were indicative of chlorophyll a on the seafloor. Underwater hyperspectral imaging therefore has a great potential in seafloor habitat mapping and monitoring, with areas of application ranging from shallow coastal areas to the deep sea.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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    PAPER (OA)
  • 7
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    Gas hydrate distribution and hydrocarbon maturation north of the Knipovich Ridge, western Svalbard margin (2016)
    Wiley
    In:  EPIC3Journal of Geophysical Research-Solid Earth, Wiley, ISSN: 0148-0227
    Details
    Publication Date: 2016-02-02
    Description: A bottom-simulating reflector (BSR) occurs west of Svalbard in water depths exceeding 600 m, indicating that gas hydrate occurrence in marine sediments is more widespread in this region than anywhere else on the eastern North Atlantic margin. Regional BSR mapping shows the presence of hydrate and free gas in several areas, with the largest area located north of the Knipovich Ridge, a slow-spreading ridge segment of the Mid Atlantic Ridge system. Here, heat flow is high (up to 330 mW m-2), increasing towards the ridge axis. The coinciding maxima in across-margin BSR width and heat flow suggest that the Knipovich Ridge influenced methane generation in this area. This is supported by recent finds of thermogenic methane at cold seeps north of the ridge termination. To evaluate the source rock potential on the western Svalbard margin, we applied 1D petroleum system modeling at three sites. The modeling shows that temperature and burial conditions near the ridge were sufficient to produce hydrocarbons. The bulk petroleum mass produced since the Eocene is at least 5 kt and could be as high as ~0.2 Mt. Most likely, source rocks are Miocene organic-rich sediments and a potential Eocene source rock that may exist in the area if early rifting created sufficiently deep depocenters. Thermogenic methane production could thus explain the more widespread presence of gas hydrates north of the Knipovich Ridge. The presence of microbial methane on the upper continental slope and shelf indicates that the origin of methane on the Svalbard margin varies spatially.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 8
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    Giant depressions on the Chatham Rise offshore New Zealand – Morphology, structure and possible relation to fluid expulsion and bottom currents (2018)
    Elsevier
    In:  Marine Geology, 399 . pp. 158-169.
    Details
    Publication Date: 2021-02-08
    Description: Highlights • Large seafloor depressions with diameters of up 10 km across have been mapped on the southern Chatham Rise, New Zealand. • Seismic reflection data show scarce indications for vertical fluid flow but no clear link between fluid flow and depressions. • Methane gas or methane hydrates appear to be absent on the southern Chatham Rise. • Seismic evidence suggests that vertical fluid flow was likely fuelled by polygonal faulting and silica diagenesis • The depressions are the results of erosion and sediment drift deposition of bottom currents associated with the Subtropical Front. Abstract Several giant seafloor depressions were investigated on the Chatham Rise offshore New Zealand using mainly bathymetric and seismic data, supplemented by sediment cores and reported porewater geochemistry data. The depressions have diameters of up to 11 km and occur on the southern flank of the Chatham Rise in water depths between 600 and 900 m, i.e. roughly underneath the location of the strongest thermal gradients of the Subtropical Front (STF) and characterized by eastward flowing currents. With up to 150 m of relief the depressions cut into post-Miocene deposits. Some of the depressions are partially filled with drift deposits that have similar seismic characteristics as the surrounding sediments and consist of alternations of silty muds and silts. Seismic profiles also show completely filled depressions that no longer have a bathymetric expression. Despite several pipe structures indicating vertical fluid flow, neither active fluid seepage nor indications for past fluid seepage are present at the seafloor of the Chatham Rise. Also, both pore water geochemistry and geophysical data do not show indications for an existing or past gas hydrate system in the area. Instead, seismic data suggest widespread polygonal faulting and the presence of silica diagenetic fronts. The release of mineral-bound water during silica diagenesis or fluid expulsion during sediment compaction can explain the presence of vertical fluid flow features but not the giant depressions themselves. Instead, the depressions are interpreted as the result of scouring by strong bottom currents for which fluid venting may have created the nucleation points.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.1016/j.margeo.2018.02.011
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    Underwater hyperspectral imaging as an in situ taxonomic tool for deep-sea megafauna (2018)
    Nature Research
    In:  Scientific Reports, 8 (12860).
    Details
    Publication Date: 2021-03-19
    Description: Identification of benthic megafauna is commonly based on analysis of physical samples or imagery acquired by cameras mounted on underwater platforms. Physical collection of samples is difficult, particularly from the deep sea, and identification of taxonomic morphotypes from imagery depends on resolution and investigator experience. Here, we show how an Underwater Hyperspectral Imager (UHI) can be used as an alternative in situ taxonomic tool for benthic megafauna. A UHI provides a much higher spectral resolution than standard RGB imagery, allowing marine organisms to be identified based on specific optical fingerprints. A set of reference spectra from identified organisms is established and supervised classification performed to identify benthic megafauna semi-autonomously. The UHI data provide an increased detection rate for small megafauna difficult to resolve in standard RGB imagery. In addition, seafloor anomalies with distinct spectral signatures are also detectable. In the region investigated, sediment anomalies (spectral reflectance minimum at ~675 nm) unclear in RGB imagery were indicative of chlorophyll a on the seafloor. Underwater hyperspectral imaging therefore has a great potential in seafloor habitat mapping and monitoring, with areas of application ranging from shallow coastal areas to the deep sea.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.1038/s41598-018-31261-4
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
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    First hyperspectral imaging survey of the deep seafloor: high-resolution mapping of manganese nodules (2018)
    Elsevier
    In:  Remote Sensing of Environment, 209 . pp. 19-30.
    Details
    Publication Date: 2021-03-19
    Description: Highlights: • We present the first hyperspectral image data from the deep seafloor. • The data were acquired with a new UHI in 4200 m water depth. • Supervised classification is able to detect manganese nodules and fauna. • The UHI is a promising tool for high-resolution seafloor exploration and monitoring. Abstract: Hyperspectral seafloor surveys using airborne or spaceborne sensors are generally limited to shallow coastal areas, due to the requirement for target illumination by sunlight. Deeper marine environments devoid of sunlight cannot be imaged by conventional hyperspectral imagers. Instead, a close-range, sunlight-independent hyperspectral survey approach is required. In this study, we present the first hyperspectral image data from the deep seafloor. The data were acquired in approximately 4200 m water depth using a new Underwater Hyperspectral Imager (UHI) mounted on a remotely operated vehicle (ROV). UHI data were recorded for 112 spectral bands between 378 nm and 805 nm, with a high spectral (4 nm) and spatial resolution (1 mm per image pixel). The study area was located in a manganese nodule field in the Peru Basin (SE Pacific), close to the DISCOL (DISturbance and reCOLonization) experimental area. To test whether underwater hyperspectral imaging can be used for detection and mapping of mineral deposits in potential deep-sea mining areas, we compared two supervised classification methods, the Support Vector Machine (SVM) and the Spectral Angle Mapper (SAM). The results show that SVM is superior to SAM and is able to accurately detect nodule surfaces. The UHI therefore represents a promising tool for high-resolution seafloor exploration and characterisation prior to resource exploitation.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.rse.2018.02.024
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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