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The Faroe Islands
The Faroe Islands are an archipelago at 62°N and 7°W consisting of 18 larger islands and a host of islets and skerries. The Faroes themselves and their shelf area are the remnants of a volcanic area evolved during the lower tertiary. The rock is basalt with intermittent layers of tufa. The Faroes constitute part of the ridge stretching from Scotland to Greenland, which again constitutes the border between the colder Norwegian Sea and the warmer Central Atlantic.
The exclusive economic zone stretching to 200 nautical miles or the mid-lines towards Iceland and the Shetland Islands comprises ab. 308.000 km².The Faroe shelf with depths less than 200 m comprises ab. 20.000 km² while depths less than 100 m only constitute ab. 5.400 km². Depth of less than 500 m comprise ab. 43.000 km².
To the SW of the Faroes there are banks, more or less shaped as seamounts. On the Faroe Bank, separated from the main shelf by the more than 800 m deep Faroe Bank Channel, are about 100 m deep. The Faroese Fisheries Research and BIOFAR specialists currently intensively study the Faroe Bank fauna. Further towards the SW are Bill Bailey´s Bank, about 200m and Lousey Bank, ab. 300 m.
Water masses and currents are equally diversified. In the upper regions three distinct water masses are recognized. In the deeper channels and north of the islands bottom temperatures are below zero, while the deep bottoms west of the islands are within the deep Atlantic regime.
The sea bottom is very varied from mud in fjords and sounds to bedrock, where strong currents prevail.
Bottom types
So far, we have no accurate map of bottom types around the Faroes, although official maps give some clues. Registrations in connection with sampling within the BIOFAR programme were published in the station list ( SARSIA, vol. 79, p. 165-180, 1994). From various new and old sources, the Kaldbak Laboratory is compiling material for a more complete overview of bottom types in order to be able to map these bottoms. A preliminary attempt is illustrated below
This much can be said by now, that as would be expected, the deeper sediments are mud, clay or silt, while coarser sediments are found on the "continental" slope and on the banks. Very rough bottom is found in several places, including stones, boulders and rock. No easy bottom to sample!
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Water masses and currents
Oceanographers have long studied water masses and currents around the Faroe Islands (see pre-BIOFAR history ), more recently especially Bogi Hansen from the Fisheries Laboratory of the Faroes. Several publications by him and collaborators are available, and his book in Faroese: ”Havið”, Føroya Skúlabókagrunnur, 2000, has many illustrative figures, which talk for themselves.
Water masses from a branch of the Gulf Stream, called North Atlantic Water (NAW), run NE between Iceland and the Shetlands, thus passing on both sides of the Faroes. This water mass is relatively warm - 5-11° C – and is carried into the northern North Sea and the Norwegian Sea. It reaches down to about 500 meters depth.
After cooling in arctic areas Deep Norwegian Sea Water (DNSW) sinks and enters the Faroe-Shetland Channel from the NE, passes south of the Faroes turning NW through the Faroe Bank Channel and along the southern slope of the Faroe-Iceland-Ridge. The temperature lies just below -1°C and its upper limit lies at around 5-600 meters depth.
North of Iceland and along the northern slope of the Faroe-Iceland-Ridge water masses of about 2-4°C (East-Iceland-Water, EIW) pass SE under the NAW, pass S east of the Faroes into a bend, that turns NE once again, but the bend is very variable in extent. And some of this water intermittently spills over the Faroe-Iceland-Ridge into the Atlantic.
This complicated pattern leads to great differences in bottom temperatures at the bottoms of the Faroe seas, and a special study by dr. Håkan Westerberg is accompanied by maps, see publication list and below.
On the Faroe Bank an anticyclonic gyre makes the water over the bank more or less stagnate for up to five summer months, but recent investigations show a complicated current pattern. A similar, but less pronounced gyre circumvents the island group itself.
Tidal currents, standing waves and water mass movements combined have a pronounced effect on the bottom environment. Dr. Håkan Westerberg has modelled the bottom currents at the sampling stations, and these velocities are included in the BIOFAR station list. One published paper by Frederiksen et.al. 1992 (see publication list) addresses the problems of currents and sedimentation along the boarders of the shelf and the banks.
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