Deep-Sea Channel/Submarine-Yazoo System of the Labrador Sea: A New Deep-Water Facies Model (1)

Direct interaction between the atmosphere and the deep ocean basins takes place today only in the Southern Ocean near the Antarctic continent and in the northern extremity of the North Atlantic Ocean, notably in the Norwegian–Greenland Sea and Labrador Sea. Cooling and evaporation cause surface waters in the latter region to become dense and sink. At depth, further mixing occurs with Arctic water masses from adjacent polar shelves. Export of these water masses from the Norwegian–Greenland Sea (Norwegian Sea Overflow Water) to the North Atlantic basin occurs via two major gateways, the Denmark Strait system and the Faeroe– Shetland Channel and Faeroe Bank Channel system (e.g. Dickson et al. 1990; Fig.1). Deep convection in the Labrador Sea produces intermediate waters (Labrador Sea Water), which spreads across the North Atlantic. Deep waters thus formed in the North Atlantic (North Atlantic Deep Water) constitute an essential component of a global ‘conveyor’ belt extending from the North Atlantic via the Southern and Indian Oceans to the Pacific. Water masses return as a (warm) surface water flow. In the North Atlantic this is the Gulf Stream and the relatively warm and saline North Atlantic Current. Numerous palaeo-oceanographic studies have indicated that climatic changes in the North Atlantic region are closely related to changes in surface circulation and in the production of North Atlantic Deep Water. Abrupt shut-down of the ocean-overturning and subsequently of the conveyor belt is believed to represent a potential explanation for rapid climate deterioration at high latitudes, such as those that caused the Quaternary ice ages. Here it should be noted, that significant changes in deep convection in Greenland waters have also recently occurred. While in the Greenland Sea deep water formation over the last decade has drastically decreased, a strong increase of deep convection has simultaneously been observed in the Labrador Sea (Sy et al. 1997).

Download Full-text

Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽

10.3390/min11060653 ◽

2021 ◽

Vol 11 (6) ◽

pp. 653

Author(s):

Shereef Bankole ◽

Dorrik Stow ◽

Zeinab Smillie ◽

Jim Buckman ◽

Helen Lever

Keyword(s):

Grain Size ◽

Deep Water ◽

Sedimentary Facies ◽

X Ray Diffraction ◽

Weak Current ◽

Large Area ◽

Fine Grained ◽

Mean Size ◽

The Mean ◽

Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

Download Full-text

The Reproductive Biology of Ophiacantha Bidentata (Echinodermata: Ophiuroidea) From The Rockall Trough

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400020099 ◽

1982 ◽

Vol 62 (1) ◽

pp. 45-55 ◽

Cited By ~ 21

Author(s):

P. A. Tyler ◽

J. D. Gage

Keyword(s):

Reproductive Biology ◽

Deep Water ◽

Larval Stage ◽

North Pacific ◽

Deep Sea ◽

Direct Development ◽

The Arctic ◽

Shallow Waters ◽

Arctic Seas ◽

Rockall Trough

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

Study on the Characteristics of Well Completion Technology in Deepwater Oil and Gas Field Development

International Journal of Power and Energy Engineering ◽

10.53469/ijpee.2021.03(08).12 ◽

2021 ◽

Vol 3 (8) ◽

pp. 70-72

Author(s):

Jianbo Hu ◽

◽

Yifeng Di ◽

Qisheng Tang ◽

Ren Wen ◽

...

Keyword(s):

Deep Water ◽

Deep Sea ◽

Oil And Gas ◽

Gas Field ◽

Marine Research ◽

Field Development ◽

Research Technology ◽

Well Completion ◽

Development Capacity ◽

Exploration And Development

In recent years, China has made certain achievements in shallow sea petroleum geological exploration and development, but the exploration of deep water areas is still in the initial stage, and the water depth in the South China Sea is generally 500 to 2000 meters, which is a deep water operation area. Although China has made some progress in the field of deep-water development of petroleum technology research, but compared with the international advanced countries in marine science and technology, there is a large gap, in the international competition is at a disadvantage, marine research technology and equipment is relatively backward, deep-sea resources exploration and development capacity is insufficient, high-end technology to foreign dependence. In order to better develop China's deep-sea oil and gas resources, it is necessary to strengthen the development of drilling and completion technology in the oil industry drilling engineering. This paper briefly describes the research overview, technical difficulties, design principles and main contents of the completion technology in deepwater drilling and completion engineering. It is expected to have some significance for the development of deepwater oil and gas fields in China.

Download Full-text

Zeiform mouthbrooding in the deepsea – dispelling a myth

10.31219/osf.io/rhk29 ◽

2020 ◽

Author(s):

Ralf ◽

G. David Johnson ◽

Kevin Conway

Keyword(s):

Deep Water ◽

Deep Sea ◽

Developmental Stages ◽

Extended Period ◽

Marine Fishes ◽

Early Developmental Stages ◽

Water Fish ◽

First Time ◽

Early Developmental ◽

Deep Sea Fauna

Mouthbrooding or oral incubation, the retention of early developmental stages inside of the mouth for an extended period of time, has evolved multiple times in bony fishes1,2. Though uncommon, this form of parental care has been documented and well-studied in several groups of freshwater fishes but is also known to occur in a small number of marine fishes, all inhabiting coastal waters1,2. A recent paper3, reported for the first time mouthbrooding in a deep-water fish species, the zeiform Parazen pacificus, which according to the authors “fills in a gap in the larval literature for this family of fishes and prompts further investigation into other novel reproductive modes of deep-sea fauna.”

Download Full-text

First records of marine tardigrades of the genus Coronarctus (Tardigrada, Heterotardigrada, Arthrotardigrada) from Mexico

Check List ◽

10.15560/16.1.1 ◽

2020 ◽

Vol 16 (1) ◽

pp. 1-7

Author(s):

Wilbert Andrés Pérez-Pech ◽

Jesper Guldberg Hansen ◽

Erica DeMilio ◽

Alberto de Jesús-Navarrete ◽

Ivonne Martínez Mendoza ◽

...

Keyword(s):

Gulf Of Mexico ◽

Deep Water ◽

Deep Sea ◽

Water Sampling ◽

Fold Belt ◽

Taxonomic Analysis

Deep-water sampling in the Perdido Fold Belt, Gulf of Mexico, Mexican Economic Exclusive Zone yielded five specimens of tardigrades belonging to the genus Coronarctus Renaud-Mornant, 1974. The specimens represent the first records of the genus for Mexico. Two two-clawed larvae and two four-clawed larvae of Coronarctus mexicus Romano, Gallo, D’Addabbo, Accogli, Baguley & Montagna, 2011 and a single four-clawed larval specimen of an undescribed Coronarctus species were identified. Taxonomic analysis of the specimens contributed to the knowledge of deep-sea and Mexican marine tardigrades, two data-poor areas of study.

Download Full-text

Glacial – interglacial atmospheric CO<sub>2</sub> change: a simple "hypsometric effect" on deep-ocean carbon sequestration?

Climate of the Past Discussions ◽

10.5194/cpd-2-711-2006 ◽

2006 ◽

Vol 2 (5) ◽

pp. 711-743 ◽

Cited By ~ 4

Author(s):

L. C. Skinner

Keyword(s):

Carbon Sequestration ◽

Carbon Storage ◽

Ocean Circulation ◽

Deep Water ◽

Deep Sea ◽

Storage Capacity ◽

Deep Ocean ◽

Contributing Factors ◽

Carbon Reservoir ◽

Ocean Carbon

Abstract. Given the magnitude and dynamism of the deep marine carbon reservoir, it is almost certain that past glacial – interglacial fluctuations in atmospheric CO2 have relied at least in part on changes in the carbon storage capacity of the deep sea. To date, physical ocean circulation mechanisms that have been proposed as viable explanations for glacial – interglacial CO2 change have focussed almost exclusively on dynamical or kinetic processes. Here, a simple mechanism is proposed for increasing the carbon storage capacity of the deep sea that operates via changes in the volume of southern-sourced deep-water filling the ocean basins, as dictated by the hypsometry of the ocean floor. It is proposed that a water-mass that occupies more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. Hence by filling this interval with southern-sourced deep-water (enriched in dissolved CO2 due to its particular mode of formation) the amount of carbon sequestered in the deep sea may be greatly increased. A simple box-model is used to test this hypothesis, and to investigate its implications. It is suggested that up to 70% of the observed glacial – interglacial CO2 change might be explained by the replacement of northern-sourced deep-water below 2.5 km water depth by its southern counterpart. Most importantly, it is found that an increase in the volume of southern-sourced deep-water allows glacial CO2 levels to be simulated easily with only modest changes in Southern Ocean biological export or overturning. If incorporated into the list of contributing factors to marine carbon sequestration, this mechanism may help to significantly reduce the "deficit" of explained glacial – interglacial CO2 change.

Download Full-text

The work of the Discovery Committee

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1950.0082 ◽

1950 ◽

Vol 202 (1068) ◽

pp. 1-16 ◽

Cited By ~ 2

Keyword(s):

Southern Ocean ◽

Deep Water ◽

Deep Sea ◽

Original Form ◽

The Past ◽

Scientific Staff ◽

Form Part ◽

Whaling Industry ◽

Major Industry ◽

Colonial Office

The geographical field in which most of the Discovery Committee’s work has been carried out during the past 25 years is the Southern Ocean. This zone of continuous deep water, very rich in marine fife, supports one major industry—the whaling industry—but is otherwise little developed as yet, and seldom visited. It is not easy to find a short descriptive label for the work itself, but nearly all of it comes under the headings of deep-sea oceanography, whales and whaling, or Antarctic geography, and much of it is concerned with the interrelations of these subjects. Since the beginning in 1924 the Discovery Committee has worked under the Colonial Office, but in 1949 the Committee’s functions, together with the scientific staff, the ships, and other assets, were taken over by the Admiralty, and now form part of the new National Institute of Oceanography. The Discovery Committee, in its original form, has been dissolved, but it is encouraging to know that the continuation of its work is assured.

Download Full-text

Labrador Sea bio-, tephro-, oxygen isotopic stratigraphy and Late Quaternary paleoceanographic trends

Canadian Journal of Earth Sciences ◽

10.1139/e80-083 ◽

1980 ◽

Vol 17 (7) ◽

pp. 831-854 ◽

Cited By ~ 53

Author(s):

R. H. Fillon ◽

J. C. Duplessy

Keyword(s):

Deep Water ◽

Late Quaternary ◽

Planktonic Foraminifera ◽

Open Water ◽

Labrador Sea ◽

Surface Cooling ◽

Stratigraphic Framework ◽

Stage 4 ◽

Oxygen Isotopic ◽

Stage 1

A stratigraphic framework for eastern Labrador Sea cores has been developed for the interval 0–90 000 years BP through analysis of oxygen isotopes, volcanic ash, benthonic foraminifera, and the radiolarian Diplocyclas davisiana. Benthonic and planktonic foraminiferal isotope stratigraphy and the time scale of Shackleton and Opdyke provide a basis for the approximate dating of a series of marker events which include ash zones at ca. 59 000 and ≤ 21 000 years BP; benthonic foraminiferal abundance maxima at ca. 83 000, 75 000, 60 000, 19 000, and 3000 years BP; and D. davisiana percentage maxima at ca. 90 000, 73 000, 64 000, 54 000, 45 000 – 32 000, and 10 000 years BP. Incursions of subpolar planktonic foraminifera into the area during parts of isotopic stage 2 (between about 13 000 and 25 000 years BP but probably excluding the 15 000–18 000 years BP glacial maximum interval) and during the isotopic stage 4/5a transition (around 75 000 years BP) suggest that the eastern Labrador Sea was free of sea ice, at least in summer during periods of rapid continental ice sheet growth which lead to the isotopic stage 4 and stage 2 glacial maxima. A larger than normal stage 1/stage 2 difference in the isotopic composition of benthonic foraminifera (1.8‰) implies that this open water and attendant surface cooling was a potential source for colder than modern deep water. In contrast the Norwegian Sea was a reservoir of warmer than modern deep water during the last glacial.

Download Full-text

Large multi-biotic cyanoliths from relatively deep-water facies in the early Serpukhovian of SW Spain

Facies ◽

10.1007/s10347-003-0023-0 ◽

2003 ◽

Vol 49 (1) ◽

pp. 31-48 ◽

Cited By ~ 10

Author(s):

Pedro Cózar ◽

Sergio Rodríguez ◽

Ian D. Somerville

Keyword(s):

Deep Water ◽

Sw Spain ◽

Water Facies

Download Full-text