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  • 1
    ISSN: 1432-1793
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Initial ecological observations at Broken Spur in 1993 suggested a low biomass relative to other deep-water vent communities known along the Mid-Atlantic Ridge. The persistence of a low shrimp biomass over 15 mo at Broken Spur vents appears to refute the hypothesis that the community is expanding through reproduction and immigration to occupy habitat vacated during a recent period of hydrothermal quiescence or catastrophe. Although the absence of “swarms” of shrimp similar to those found at the hydrothermal mounds of TAG (26°N) and Snake Pit (23°N) is a visually striking feature of the majority of venting structures known at Broken Spur, the biomass of fauna other than shrimp may not be significantly less than that of other Mid-Atlantic sites. The discovery of “swarms” of shrimp at Bogdanov Site, visited for the first time in 1994, suggests that availability of substratum exposed to the flow of hydrothermal fluids, which is a function of the topography of venting structures, may be a prerequisite for the development of these dense aggregations. Two testable predictions arise from this hypothesis. Firstly, dense aggregations of Rimicaris exoculata should occur at any other structures with a morphology similar to Bogdanov Site that may be discovered in the Broken Spur vent field, and should not occur at other isolated chimney structures that may be found. Secondly, “swarms” of shrimp should appear at any Broken Spur chimneys that develop into structures with a morphology more similar to that of Bogdanov Site in future.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [s.l.] : Macmillian Magazines Ltd.
    Nature 407 (2000), S. 177-179 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The oxidation of the global ocean by cyanobacterial oxygenic photosynthesis, about 2,100 Myr ago, is presumed to have limited anoxygenic bacterial photosynthesis to oceanic regions that are both anoxic and illuminated. The discovery of oxygen-requiring photosynthetic bacteria about 20 ...
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    ISSN: 1432-1793
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Swarms of the pardaliscid amphipod Halice hesmonectes were sampled at low-temperature hydrothermal vents in the Venture Hydrothermal Fields of the East Pacific Rise. In excess of 3000 individuals were collected from a range of sites/habitats, and at two points in time (December 1991 and March 1994). The structure of swarms was described in terms of growth stages, the development of primary and secondary sex characteristics and the accumulation of nutritional reserves. The results demonstrated that swarms contained a wide range of growth stages, but that small juveniles and mature males and females were absent. Swarm structure was interpreted as an equilibrium dependent on the relative proportion of time spent by each growth stage in the swarm habitat. This equilibrium swarm structure was very similar at different sites and times. Swarms dominated by small juveniles occurred at the northern sites in December 1991 following a period of eruption and new venting in April 1991. Equilibrium swarm structure had become re-established at these sites by March 1994. The function of swarming was considered. The results indicated that swarming was not associated with reproductive activity. The available evidence, though not conclusive, suggested that swarms were associated with feeding.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Publikationsdatum: 2021-02-08
    Beschreibung: Highlights • Active hydrothermal vent ecosystems are extremely rare. • Vent ecosystems are recognized as vulnerable by international organizations. • Mineral resources at active vents would not contribute significantly to the global metal supply. • Effective networks that protect representative active vents cannot be ensured. • A prohibition on mining active vents is consistent with obligations for conservation. Abstract There is increasing interest in mining minerals on the seabed, including seafloor massive sulfide deposits that form at hydrothermal vents. The International Seabed Authority is currently drafting a Mining Code, including environmental regulations, for polymetallic sulfides and other mineral exploitation on the seabed in the area beyond national jurisdictions. This paper summarizes 1) the ecological vulnerability of active vent ecosystems and aspects of this vulnerability that remain subject to conjecture, 2) evidence for limited mineral resource opportunity at active vents, 3) non-extractive values of active vent ecosystems, 4) precedents and international obligations for protection of hydrothermal vents, and 5) obligations of the International Seabed Authority under the UN Convention on the Law of the Sea for protection of the marine environment from the impacts of mining. Heterogeneity of active vent ecosystems makes it extremely challenging to identify “representative” systems for any regional, area-based management approach to conservation. Protection of active vent ecosystems from mining impacts (direct and indirect) would set aside only a small fraction of the international seabed and its mineral resources, would contribute to international obligations for marine conservation, would have non-extractive benefits, and would be a precautionary approach.
    Materialart: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Publikationsdatum: 2017-09-12
    Beschreibung: From the moment of their discovery, chemosynthetic ecosystems in the deep sea have held intrinsic scientific value. At the same time that the scientific community is studying chemosynthetic ecosystems other sectors are either engaged in, or planning for, activities that may adversely impact these ecosystems. There is a need and opportunity now to develop conservation strategies for networks of chemosynthetic ecosystem reserves in national and international waters through collaboration among concerned stakeholders.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    facet.materialart.
    Unbekannt
    AGU (American Geophysical Union)
    In:  Eos, Transactions American Geophysical Union, 75 . pp. 44-45.
    Publikationsdatum: 2016-01-22
    Materialart: Article , NonPeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Publikationsdatum: 2013-06-29
    Beschreibung: We present the first evidence for widespread seabed methane venting along the southeastern United States Atlantic margin beyond the well-known Blake Ridge diapir seep. Recent ship- and autonomous underwater vehicle (AUV)–collected data resolve multiple water-column anomalies (〉1000 m height) and extensive new chemosynthetic seep communities at the Blake Ridge and Cape Fear diapirs. These results indicate that multiple, highly localized fluid conduits punctuate the areally extensive Blake Ridge gas hydrate province, and enable the delivery of significant amounts of methane to the water column. Thus, there appears to be an abundance of seabed fluid flux not previously ascribed to the Atlantic margin of the United States.
    Print ISSN: 0091-7613
    Digitale ISSN: 1943-2682
    Thema: Geologie und Paläontologie
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    Publikationsdatum: 2018-07-05
    Beschreibung: Mineral exploitation has spread from land to shallow coastal waters and is now planned for the offshore, deep seabed. Large seafloor areas are being approved for exploration for seafloor mineral deposits, creating an urgent need for regional environmental management plans. Networks of areas where mining and mining impacts are prohibited are key elements of these plans. We adapt marine reserve design principles to the distinctive biophysical environment of mid-ocean ridges, offer a framework for design and evaluation of these networks to support conservation of benthic ecosystems on mid-ocean ridges, and introduce projected climate-induced changes in the deep sea to the evaluation of reserve design. We enumerate a suite of metrics to measure network performance against conservation targets and network design criteria promulgated by the Convention on Biological Diversity. We apply these metrics to network scenarios on the northern and equatorial Mid-Atlantic Ridge, where contractors are exploring for seafloor massive sulfide (SMS) deposits. A latitudinally distributed network of areas performs well at (i) capturing ecologically important areas and 30 to 50% of the spreading ridge areas, (ii) replicating representative areas, (iii) maintaining along-ridge population connectivity, and (iv) protecting areas potentially less affected by climate-related changes. Critically, the network design is adaptive, allowing for refinement based on new knowledge and the location of mining sites, provided that design principles and conservation targets are maintained. This framework can be applied along the global mid-ocean ridge system as a precautionary measure to protect biodiversity and ecosystem function from impacts of SMS mining.
    Digitale ISSN: 2375-2548
    Thema: Allgemeine Naturwissenschaft
    Standort Signatur Einschränkungen Verfügbarkeit
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