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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of aquatic ecosystem stress and recovery 7 (2000), S. 299-315 
    ISSN: 1573-5141
    Keywords: deep-sea communities ; benthos ; disturbance ; environmental risk assessment ; monitoring ; large-scale experiment ; sewage contamination ; mineral mining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mining for mineral resources and the disposal of wastematerials are the major potential sources of environmental hazard for the deep-seasystem. Polymetallic nodules, manganese crusts, metalliferous sulphidic muds and massiveconsolidated sulphides might serve as exploitable sources of various metals, whilstphosporite deposits represent a further resource. The main types of waste targeted for deep-seadisposal are munitions, radioactive wastes, large offshore structures, sewage sludge anddredge spoils. Furthermore, it has recently been proposed to introduce hugequantities of carbon dioxide from industrial processes into the deep ocean in order tomitigate the greenhouse effect. A description of the different mineral resources and wastematerials is given, including information on the related technology and the status of thedumping and mining operations, respectively. The predicted effects of waste disposaland mining on the deep-seaenvironment are reviewed, possible impacts including removalof settling benthic substrate and mechanical stress exerted on soft bottomcommunities, plus impacts of sediment plumes, toxic materials and degradable organic matter.An overview of the major environmental studies in the deep sea is given. Twocategories of study can be discerned, research conducted after environmental impacts (e.g.,the monitoring of contamination by sewage sludge disposal off the New York Bight)and precautionary environmental studies on potential impacts threatening the deepsea environment in connection with its future human use (i.e., studies aiming toassess the possible effects of deep-sea mining). The development of large scale in-situexperiments was a new approach to the environmental risk assessment of nodule mining inthe deep sea. In the course of the DISCOL project in the south-east Pacific, the firstexperiment of this kind was implemented and monitored for three years. Another type oflarge-scale in-situexperimentation in the deep sea is represented by the BenthicImpact Experiments (BIEs) which have been conducted with similar experimental design by anumber of nations or multinational consortia. Since environmental impacts derivingfrom human penetration into the deep sea on an industrial scale are expected to besevere and long-lasting, a precautionary approach in the related environmental researchseems most appropriate. It is therefore proposed that environmental risk assessment in thedeep sea should rely on in-situ experiments which should start from a simulation ofsmall-scale impacts and proceed stepwise to the monitoring of a full-scale industrialoperation. At each stage impacts need to be evaluated thoroughly.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2013-04-10
    Type: Report , NonPeerReviewed
    Format: text
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  • 3
    Publication Date: 2014-06-11
    Description: Förderkennzeichen: 03R417 01F0010
    Type: Report , NonPeerReviewed
    Format: text
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  • 4
    Publication Date: 2014-11-07
    Type: Report , NonPeerReviewed
    Format: text
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  • 5
    Publication Date: 2017-01-27
    Description: Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1–2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Format: application/pdf
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  • 6
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
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  • 7
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    Unknown
    PANGAEA
    In:  Supplement to: Marcon, Yann; Sahling, Heiko; Borowski, Christian; dos Santos Ferreira, Christian; Thal, Janis; Bohrmann, Gerhard (2013): Megafaunal distribution and assessment of total methane and sulfide consumption by mussel beds at Menez Gwen hydrothermal vent, based on geo-referenced photomosaics. Deep Sea Research Part I: Oceanographic Research Papers, 75, 93-109, https://doi.org/10.1016/j.dsr.2013.01.008
    Publication Date: 2023-05-12
    Description: The Menez Gwen hydrothermal vents, located on the flanks of a small young volcanic structure in the axial valley of the Menez Gwen seamount, are the shallowest known vent systems on the Mid-Atlantic Ridge that host chemosynthetic communities. Although visited several times by research cruises, very few images have been published of the active sites, and their spatial dimensions and morphologies remain difficult to comprehend. We visited the vents on the eastern flank of the small Menez Gwen volcano during cruises with RV Poseidon (POS402, 2010) and RV Meteor (M82/3, 2010), and used new bathymetry and imagery data to provide first detailed information on the extents, surface morphologies, spatial patterns of the hydrothermal discharge and the distribution of dominant megafauna of five active sites. The investigated sites were mostly covered by soft sediments and abundant white precipitates, and bordered by basaltic pillows. The hydrothermally-influenced areas of the sites ranged from 59 to 200 m**2. Geo-referenced photomosaics and video data revealed that the symbiotic mussel Bathymodiolus azoricus was the dominant species and present at all sites. Using literature data on average body sizes and biomasses of Menez Gwen B. azoricus, we estimated that the B. azoricus populations inhabiting the eastern flank sites of the small volcano range between 28,640 and 50,120 individuals with a total biomass of 50 to 380 kg wet weight. Based on modeled rates of chemical consumption by the symbionts, the annual methane and sulfide consumption by B. azoricus could reach 1760 mol CH4 yr**-1 and 11,060 mol H2S yr**-1. We propose that the chemical consumption by B. azoricus over at the Menez Gwen sites is low compared to the natural release of methane and sulfide via venting fluids.
    Keywords: Atos_10; Cage_site; Center for Marine Environmental Sciences; Event label; File name; File size; MARUM; MULT; Multiple investigations; Uniform resource locator/link to image; Uniform resource locator/link to thumbnail; White_flames; Woody_site
    Type: Dataset
    Format: text/tab-separated-values, 16 data points
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  • 8
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    Unknown
    PANGAEA
    In:  Supplement to: Zielinski, Frank; Gennerich, Hans-Hermann; Borowski, Christian; Wenzhöfer, Frank; Dubilier, Nicole (2011): In situ measurements of hydrogen sulfide, oxygen, and temperature in diffuse fluids of an ultramafic-hosted hydrothermal vent field (Logatchev, 14°45'N, Mid-Atlantic Ridge): Implications for chemosymbiotic bathymodiolin mussels. Geochemistry, Geophysics, Geosystems, 12, Q0AE04, https://doi.org/10.1029/2011GC003632
    Publication Date: 2023-10-28
    Description: The Logatchev hydrothermal vent field (14°45'N, Mid-Atlantic Ridge) is located in a ridge segment characterized by mantle-derived ultramafic outcrops. Compared to basalt-hosted vents, Logatchev high temperature fluids are relatively low in sulfide indicating that the diffuse, low temperature fluids of this vent field may not contain sufficient sulfide concentrations to support a chemosymbiotic invertebrate community. However, the high abundances of bathymodiolin mussels with bacterial symbionts related to free-living sulfur oxidizing bacteria suggested that bioavailable sulfide is present at Logatchev. To clarify if diffuse fluids above mussel beds of Bathymodiolus puteoserpentis provide the reductants and oxidants needed by their symbionts for aerobic sulfide oxidation, in situ microsensor measurements of dissolved hydrogen sulfide and oxygen were combined with simultaneous temperature measurements. High temporal fluctuations of all three parameters were measured above the mussel beds. H2S and O2 co-existed with mean concentrations between 9-31 µM (H2S) and 216-228 µM (O2). Temperature maxima (〈= 7.4°C) were generally concurrent with H2S maxima (〈= 156 µM) and O2 minima (〉= 142 µM). Long-term measurements for 250 days using temperature as a proxy for oxygen and sulfide concentrations indicated that the mussels were neither oxygen- nor sulfide-limited. Our in situ measurements at Logatchev indicate that sulfide may also be bioavailable in diffuse fluids from other ultramafic-hosted vents along slow- and ultraslow-spreading ridges.
    Keywords: 8-Channel Temperature Lance; 8-CTL; DERIDGE; From Mantle to Ocean: Energy-, Material- and Life-cycles at Spreading Axes; HYDROMAR1; HYDROMAR2; M60/3; M60/3-29-ROV; M60/3-38-ROV; M60/3-66-ROV; M64/2; M64/2-283-ROV-3b; Meteor (1986); Mid-Atlantic Ridge at 10-15°N; Mid-Atlantic Ridge at 15°N; MSM04/3-258-ROV_J2; Remote operated vehicle; ROV
    Type: Dataset
    Format: application/zip, 12 datasets
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  • 9
    Publication Date: 2024-01-12
    Keywords: CTD, Sea-Bird, SBE 9; CTD/Rosette; CTD-RO; DEPTH, water; HE191; HE191/791; Heincke; Methane Flux Control in Ocean Margin Sediments; METROL; Pressure, water; Salinity; Temperature, water
    Type: Dataset
    Format: text/tab-separated-values, 3984 data points
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  • 10
    Publication Date: 2024-01-12
    Keywords: CTD, Sea-Bird, SBE 9; CTD/Rosette; CTD-RO; DEPTH, water; HE191; HE191/762; Heincke; Methane Flux Control in Ocean Margin Sediments; METROL; Pressure, water; Salinity; Temperature, water
    Type: Dataset
    Format: text/tab-separated-values, 846 data points
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