Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic

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).

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Change in the North Atlantic circulation associated with the mid-Pleistocene transition

Climate of the Past ◽

10.5194/cp-14-1639-2018 ◽

2018 ◽

Vol 14 (11) ◽

pp. 1639-1651 ◽

Cited By ~ 3

Author(s):

Gloria M. Martin-Garcia ◽

Francisco J. Sierro ◽

José A. Flores ◽

Fátima Abrantes

Keyword(s):

North Atlantic ◽

Major Change ◽

Water Masses ◽

Meridional Overturning Circulation ◽

The Arctic ◽

North Atlantic Current ◽

The North ◽

Oceanic Fronts ◽

Surface Circulation ◽

The North Atlantic

Abstract. The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37∘34.285′ N, 10∘7.562′ W; 2585 m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55∘ N, basin-wide paleoceanographic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south–north, and east–west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles.

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C14 content of recent molluscs from Scoresby Sund, central East Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v75.7460 ◽

1975 ◽

Vol 75 ◽

pp. 95-99

Author(s):

H Tauber ◽

S Funder

Keyword(s):

North Atlantic ◽

East Coast ◽

Marine Organisms ◽

Water Masses ◽

Lower Activity ◽

Terrestrial Plants ◽

East Greenland ◽

The North ◽

The North Atlantic ◽

Turn Over

C14 dating of subfossil marine shelIs presupposes a knowledge of the original C14 activity of the organisms while living. Due to the slow turn over of water masses, the C14 activity of marine bicarbonate and marine organisms is not the same in all parts of the oceans, but may show marked deficiencies in certain oceanic areas, especially at southern latitudes. In large areas of the North Atlantic the C14 activity seems to be fairly uniform and equal to or only slightly lower than that of 'pre-industrial' terrestrial plants (Broecker et al., 1960; Mangerud, 1972; Krog & Tauber, 1974). In certain areas, however, a somewhat lower activity seems to occur; trus has been noted for areas along the east coast of Greenland (Fonselius & Ostlund, 1959; Hjort, 1973).

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Distinct flavobacterial communities in contrasting water masses of the North Atlantic Ocean

The ISME Journal ◽

10.1038/ismej.2009.142 ◽

2010 ◽

Vol 4 (4) ◽

pp. 472-487 ◽

Cited By ~ 105

Author(s):

Paola R Gómez-Pereira ◽

Bernhard M Fuchs ◽

Cecilia Alonso ◽

Matthew J Oliver ◽

Justus E E van Beusekom ◽

...

Keyword(s):

Atlantic Ocean ◽

North Atlantic ◽

North Atlantic Ocean ◽

Water Masses ◽

The North ◽

The North Atlantic

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Preliminary report on the North Atlantic deep-sea cores taken by the Geophysical Laboratory, Carnegie Institution

Transactions American Geophysical Union ◽

10.1029/tr018i001p00224 ◽

1937 ◽

Vol 18 (1) ◽

pp. 224

Author(s):

W. H. Bradley ◽

M. N. Bramlette ◽

J. A. Cushman ◽

L. G. Henbest ◽

K. E. Lahman ◽

...

Keyword(s):

North Atlantic ◽

Deep Sea ◽

Preliminary Report ◽

Carnegie Institution ◽

The North ◽

The North Atlantic

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A barotolerant ciliate isolated from the abyssal deep sea of the North Atlantic: Euplotes dominicanus sp. n. (Ciliophora, Euplotia)

European Journal of Protistology ◽

10.1016/j.ejop.2019.125664 ◽

2020 ◽

Vol 73 ◽

pp. 125664 ◽

Cited By ~ 3

Author(s):

Suzana Živaljić ◽

Anja Scherwass ◽

Alexandra Schoenle ◽

Manon Hohlfeld ◽

Pablo Quintela-Alonso ◽

...

Keyword(s):

North Atlantic ◽

Deep Sea ◽

The North ◽

The North Atlantic

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New species, occurrence records and observations of predation by deep-sea Asteroidea (Echinodermata) from the North Atlantic by NOAA ship Okeanos Explorer

Zootaxa ◽

10.11646/zootaxa.4766.2.1 ◽

2020 ◽

Vol 4766 (2) ◽

pp. 201-260 ◽

Cited By ~ 2

Author(s):

CHRISTOPHER L. MAH

Keyword(s):

North Atlantic ◽

Deep Sea ◽

Substantial Contribution ◽

The North ◽

In Situ Observations ◽

The North Atlantic ◽

Feeding Observations ◽

Occurrence Records ◽

In Situ Feeding

Exploratory cruises by the NOAA Ship Okeanos Explorer have resulted in a substantial contribution in our understanding of deep-sea echinoderm biodiversity, biology, and ecology in the North Atlantic. This includes the description and in situ feeding observations of two, new corallivorous goniasterid species, Evoplosoma nizinskiae n. sp. and Sibogaster bathyheuretor n. sp. Significant in situ observations include a synchronous feeding event including multiple goniasterid asteroids and a cidaroid urchin on a large demosponge, providing new data for understanding echinoderm feeding behavior, including agonistic behavior, in deep-sea settings and new, in situ feeding observations for 28 deep-sea species including the myxasterid Pythonaster atlantidis, the korethrasterid Remaster palmatus and the poorly understood hippasterine goniasterids, Gilbertaster caribaea and Sthenaster emmae.

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