The 3He distribution in deep water over the Mid-Atlantic Ridge

1977 ◽  
Vol 24 (4) ◽  
pp. 283
Keyword(s):  
Deep Water ◽  
Mid Atlantic Ridge

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Deep Water ◽  
Stock Assessment ◽  
Data Availability ◽  
Biological Knowledge ◽  
Human Consumption ◽  
British Isles ◽  
The North ◽  
Mid Atlantic Ridge ◽  
Pros And Cons ◽  
A Minor

<em>Abstract</em>.—The biology and fisheries of macrourid species in the NE Atlantic are reviewed. Of about 30 species that occur within that area, the roundnose grenadier <em>Coryphaenoides rupestris </em>is one of the main target species of deep-water fisheries. Roughhead grenadier <em>Macrourus berglax </em>is a minor bycatch of other deep-water fisheries and an occasional target of some small fisheries. Other macrourid species are not commercially exploited because they are too small and/or in too deep waters, but some are also taken as accidental bycatch. There are three main fisheries for roundnose grenadier: north and west of the British Isles, Skagerrak, and Mid-Atlantic Ridge. The Skagerrak fishery is mainly for fish meal while the others are for human consumption. Due to data availability, a range of assessment methods has been trialled primarily for stocks to the north and west of the British Isles. Although uncertain, these assessments provide evidence that the stock has been severely depleted. Fisheries were largely unregulated until the early 2000s, but following repeated International Council for the Exploration of the Sea (ICES) advice, total allowable catches were introduced in 2003 together with effort and capacity regulations. Roundnose grenadier is the most studied species. It lives more than 50 years, compared to 30 years or more for roughhead grenadier. The limited knowledge of other species suggests a contrasting picture of maximum age ranging from 10 to 40 years. Taking into account the limited biological knowledge for these species, the pros and cons of the current management regime are discussed.

Biological and ecological aspects of the deep‐water red crab populations inhabiting isolated seamounts to the west of the Azores (Mid‐Atlantic Ridge)

2019 ◽  
Vol 28 (6) ◽  
pp. 723-734 ◽  
Author(s):  
Régis Santos ◽  
Mário Pinho ◽  
Octávio Melo ◽  
João Gonçalves ◽  
Ana Leocádio ◽  
...  
Keyword(s):  
Deep Water ◽  
The West ◽  
Ecological Aspects ◽  
Mid Atlantic Ridge

scholarly journals Fracture zones in the Mid Atlantic Ridge lead to alterations in prokaryotic and viral parameters in deep-water masses

2014 ◽  
Vol 5 ◽  
Author(s):  
Simone Muck ◽  
Thomas Griessler ◽  
Nicole Köstner ◽  
Adam Klimiuk ◽  
Christian Winter ◽  
...  
Keyword(s):  
Deep Water ◽  
Water Masses ◽  
Fracture Zones ◽  
Mid Atlantic Ridge

First reports of deep-water hermit crabs Parapagurus Smith, 1879 (Decapoda, Parapaguridae) and coelenterate associates from the Mid-Atlantic Ridge and South Atlantic

Crustaceana ◽  
2012 ◽  
Vol 85 (4-5) ◽  
pp. 591-600 ◽  
Author(s):  
Irene Cardoso ◽  
Rafael Lemaitre
Keyword(s):  
Deep Water ◽  
Deep Sea ◽  
South Atlantic ◽  
Open Ocean ◽  
Hermit Crabs ◽  
The South ◽  
Mid Atlantic Ridge ◽  
Seamount Chain ◽  
First Time ◽  
Important Habitat

Three species of deep water hermit crabs of the genus Parapagurus Smith, 1879, family Parapaguridae, were collected in the South Atlantic during studies of the fauna and ecology of the Mid-Atlantic Ridge, a seamount chain that is an important habitat, feeding ground, and site of reproduction for many open ocean and deep-sea species. The three species collected, P. abyssorum (Filhol, 1885), P. nudus (A. Milne-Edwards, 1891), and P. pilosimanus Smith, 1879, are known to range broadly in the Atlantic, but only one, P. pilosimanus, was previously reported from the South Atlantic. Thus, P. abyssorum and P. nudus are reported for the first time from the Mid-Atlantic Ridge and the South Atlantic. These three species live in association with zoanthids or actinians that produce carcinoecia and serve as housing. The carcinoecia found with the specimens are also reported.

scholarly journals Population structure of a deep-water squaloid shark, the Portuguese dogfish (Centroscymnus coelolepis)

2011 ◽  
Vol 68 (3) ◽  
pp. 555-563 ◽  
Author(s):  
Ana Veríssimo ◽  
Jan R. McDowell ◽  
John E. Graves
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Deep Water ◽  
Large Scale ◽  
Maturity Stage ◽  
Genetic Population ◽  
High Dispersal ◽  
Sampling Locations ◽  
Nuclear Microsatellite ◽  
Mid Atlantic Ridge

Abstract Veríssimo, A., McDowell, J. R., and Graves, J. E. 2011. Population structure of a deep-water squaloid shark, the Portuguese dogfish (Centroscymnus coelolepis). – ICES Journal of Marine Science, 68: . The genetic population structure of the deep-water squaloid Centroscymnus coelolepis (the Portuguese dogfish) in the eastern Atlantic was investigated using eight polymorphic nuclear microsatellite markers and a 496-bp fragment of the mitochondrial DNA control region (mtDNA CR). Samples (20–50 individuals per location) were collected off Ireland, Portugal, Madeira, Mauritania, South Africa, and the Azores (Mid-Atlantic Ridge). High levels of genetic diversity were found at the nuclear microsatellite loci (mean A = 17.3; overall Ho = 0.77), although there was low diversity at the mtDNA CR (h = 0.65, π = 0.0018). Genetic diversity for the Portuguese dogfish was homogeneously distributed among sampling locations, resulting in low and non-significant indices of genetic differentiation (e.g. FST = −0.0013 to 0.0096, ΦST = −0.017 to 0.033; p > 0.5), consistent with the absence of population structure within the area sampled. The results indicate that C. coelolepis has a high dispersal potential within the eastern Atlantic, and its apparent spatial segregation by size and maturity stage suggest large-scale migration associated with the reproductive cycle.

scholarly journals Centromedon zoe (Crustacea: Amphipoda: Lysianassoidea: Uristidae), a new deep-water scavenger species from the North Atlantic, with a key to the genus Centromedon

Zootaxa ◽  
2011 ◽  
Vol 2869 (1) ◽  
pp. 54 ◽  
Author(s):  
TAMMY HORTON ◽  
MICHAEL THURSTON
Keyword(s):  
New Species ◽  
North Atlantic ◽  
Deep Water ◽  
The North ◽  
Baited Traps ◽  
Mid Atlantic Ridge ◽  
The North Atlantic ◽  
A New Species

A new species of Centromedon Sars, 1891 is described based on abundant material collected in baited traps at 2500 m on the Mid-Atlantic Ridge. The species can be distinguished from the most closely allied species, Centromedon typhlops (Sars, 1879), Centromedon mediator (Barnard, 1962) comb. nov. and Centromedon laevis (Bonnier, 1896) comb. nov., by the form of the gnathopods, and characters of the mouthparts. A key to the eight species in the genus is provided. The differences between the closely allied genera Uristes Dana, 1849 and Centromedon are discussed.

Vesicularity of Mid-Oceanic Pillow Lavas

1971 ◽  
Vol 8 (10) ◽  
pp. 1315-1319 ◽  
Author(s):  
F. Aumento
Keyword(s):  
Hydrostatic Pressure ◽  
Marine Environment ◽  
Deep Water ◽  
High Hydrostatic Pressure ◽  
Vertical Movements ◽  
Vesicle Size ◽  
Pillow Lavas ◽  
Mid Atlantic Ridge ◽  
Radiogenic Argon ◽  
Block Faulting

In contrast to pillow lavas from the marine environment around Iceland and Hawaii, tholeiitic pillow lavas from the Mid-Atlantic Ridge at 45° N do not show a correlation between vesicle size and depth of recovery. Post-eruptive vertical block faulting may have displaced the lavas from their original extrusion depth by as much as 1500 m, explaining in part the lack of correlation. Calculation of the original depth of extrusion by compensation for these vertical movements indicates that many of the basalts now high on the Crest Mountains were extruded in deep water (2900–3500 m), possibly within the floor of the Median Valley. Nevertheless, they were able to produce numerous, comparatively large vesicles, permitting the basalts to outgas radiogenic argon trapped in the magmas.Bulk chemical differences between the 45? N basalts and those of Iceland and Hawaii cannot explain why those from 45? N are able to outgas under high hydrostatic pressure. Different histories prior to extrusion may contribute to these varying characteristics.

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