Seismic imaging of variable water layer sound speed in Rockall Trough, NE Atlantic and implications for seismic surveying in deep water

INTRODUCTIONOphiacantha bidentata (Retzius) is a widespread arctic-boreal ophiuroid with a circumpolar distribution in the shallow waters of the Arctic seas and penetrating into the deep sea of the.North Atlantic and North Pacific (Mortensen, 1927, 1933a; D'yakonov, 1954). Early observations of this species were confined to defining zoogeo-graphical and taxonomic criteria including the separation of deep water specimens as the variety fraterna (Farran, 1912; Grieg, 1921; Mortensen, 1933a). Mortensen (1910) and Thorson (1936, pp. 18–26) noted the large eggs (o.8 mm diameter) in specimens from Greenland and Thorson (1936) proposed that this species had ‘big eggs rich in yolk, shed directly into the sea. Much reduced larval stage or direct development’. This evidence is supported by observations of O. bidentata from the White and Barents Seas (Semenova, Mileikovsky & Nesis, 1964; Kaufman, 1974)..

Download Full-text

Bottom-current variability during the last glacial-deglacial transition, Northern Rockall Trough and Faroe Bank Channel, NE Atlantic

Scottish Journal of Geology ◽

10.1144/0036-9276/01-375 ◽

2009 ◽

Vol 45 (1) ◽

pp. 43-57 ◽

Cited By ~ 6

Author(s):

Kate L. McIntyre ◽

John A. Howe

Keyword(s):

Bottom Current ◽

Ne Atlantic ◽

Last Glacial ◽

Rockall Trough ◽

The Last Glacial

Download Full-text

Catch and post-release mortalities of deep-water sharks caught by bottom longlines in the Cantabrian Sea (NE Atlantic)

Journal of Sea Research ◽

10.1016/j.seares.2017.04.004 ◽

2017 ◽

Vol 130 ◽

pp. 248-255 ◽

Cited By ~ 4

Author(s):

Cristina Rodríguez-Cabello ◽

Francisco Sánchez

Keyword(s):

Deep Water ◽

Ne Atlantic

Download Full-text

Sensitivity of matched‐field processing to sound‐speed profile mismatch for vertical arrays in a deep water Pacific environment

The Journal of the Acoustical Society of America ◽

10.1121/1.2026048 ◽

1988 ◽

Vol 84 (S1) ◽

pp. S18-S18

Author(s):

A. Tolstoy

Keyword(s):

Deep Water ◽

Sound Speed ◽

Speed Profile ◽

Sound Speed Profile ◽

Matched Field Processing ◽

Vertical Arrays

Download Full-text

Laonicespecies (Polychaeta, Spionidae) from the Whittard Canyon (NE Atlantic) with descriptions of two new species

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315417000480 ◽

2017 ◽

Vol 97 (5) ◽

pp. 961-973 ◽

Cited By ~ 2

Author(s):

Andrey Sikorski ◽

Laetitia M. Gunton ◽

Lyudmila Pavlova

Keyword(s):

New Species ◽

North Atlantic ◽

Deep Water ◽

The Body ◽

Identification Key ◽

The Other ◽

Ne Atlantic ◽

Two New Species ◽

Generic Groups ◽

Number Of Segments

Four species ofLaonice(Annelida: Spionidae) were collected from the lower bathyal depths (3300–3700 m) in the Whittard Canyon, NE Atlantic. Two are herewith described as new species:Laonice whittardensissp. nov. andLaonice nataesp. nov. The other two areLaonice blakeiSikorski & Jirkov, 1988 andLaonice magnacristataMaciolek, 2000.Laonice whittardensishas genital pouches appearing from chaetiger 3, prostomium free of peristomium and bidentate hooks.Laonice nataebelongs to the subgenusAppelloefianov. with prostomium distinct from the peristomium, more than two vertical rows of capillaries in several anterior chaetigers, genital pouches present on a limited number of segments or totally absent. However, the absence of pronounced anterior widening of the body together with anterior branchiae, which are remarkably (nearly twice) longer than the notopodial postchaetal lobes, the narrow lanceolate notopodial postchaetal lobes, the pronounced pointedness of all postchaetal lobes (both notopodial and neuropodial) in the anterior half of body at least, and absence of genital pouches and the size of the body all distinguishL. nataefrom other species belonging to this subgenus. An identification key to all nine known deep-water (>400 m depth)Laonicespecies in North Atlantic is given and four previously recognized sub-generic groups are formally named:Laonice, Sarsianasubgen. nov.,Appelloefiasubgen. nov.,Norgensiasubgen. nov.

Download Full-text

Foraminifera associated with phytodetritus deposits at a bathyal site in the northern Rockall Trough (NE Atlantic): seasonal contrasts and a comparison of stained and dead assemblages

Marine Micropaleontology ◽

10.1016/s0377-8398(02)00050-6 ◽

2002 ◽

Vol 46 (1-2) ◽

pp. 83-110 ◽

Cited By ~ 97

Author(s):

Andrew J. Gooday ◽

J.Alan Hughes

Keyword(s):

Ne Atlantic ◽

Rockall Trough

Download Full-text

Assessing the stability of the AMOC during past warm climates

10.5194/egusphere-egu21-15298 ◽

2021 ◽

Author(s):

Megan Murphy O' Connor ◽

Christophe Colin ◽

Audrey Morley

Keyword(s):

North Atlantic ◽

Deep Water ◽

Meridional Overturning Circulation ◽

Labrador Sea ◽

Deep Water Formation ◽

Nordic Seas ◽

Water Formation ◽

Rockall Trough ◽

Eastern North Atlantic ◽

Warm Climates

There is emergent evidence that abrupt shifts of the Atlantic Meridional Overturning Circulation (AMOC) have occurred during interglacial periods, with recent observations and model simulations showing that we may have over-estimated its stability during warm climates. In this study, we present a multi-proxy reconstruction of deep-water characteristics from the Rockall Trough in the Eastern North Atlantic to assess the variability of Nordic seas and Labrador Sea deep-water formation during past interglacial periods MIS 1, 5, 11, and 19. To test the warm climate stability hypothesis and to constrain the variability of deep-water formation for past warm climates, we performed geochemical analysis on planktic (Nd isotopes) and benthic foraminifera (&#948;18O and &#948;13C) along with sedimentological analysis. This approach allows us to reconstruct paleocurrent flow strength, as well as the origin and contribution of different water masses to one of the deep-water components of the AMOC in the Rockall Trough. We found that deep-water properties varied considerably during each of our chosen periods. For example during the Holocene &#949;Nd variability is smaller (1.8 per mil) when compared to variability during MIS 19 (3.3 per mil), an interglacial that experienced very similar orbital boundary conditions. Our results confirm that deep-water variability in the eastern North Atlantic basin was more variable in previous interglacial periods when compared to our current Holocene and provide new insight into the relative contribution of Nordic Seas Deep Water and Labrador Sea Water in the Rockall trough.

Download Full-text