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Gorgon's head
Photo: MAREANO/IMR
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MAREANO's spring-cruise was finished in deep water at Storegga

Cruise report: The first MAREANO cruise this year has been successfully finished after a one month survey off Vesterålen/Nordland VI and off North-Trøndelag and Møre. The last 2-3 days were used for video filming in the northern part of the Storegga where both depth and fauna communities varied. In deep water the communities were affected by sub-zero temperatures and a thousands of years old underwater slide.

After 25 days at sea and a two-days return voyage to Tromsø, the research vessel "G.O. Sars" arrived Tromsø Tuesday May 22. In addition to the video filming of various faunal communities and unknown coral reefs off Trøndelag, we also made a visit to the picturesque village of Uthaug close to Ørlandet while waiting for better weather. A really nice place with white beaches and well-maintained older buildings.

After arriving to the Storegga May 19 we soon observed the contrast between the shallow bank area and the deep sea down the continental slope. While the shelf was diverse, and even with small sprigs of corals at the upper edge of the slope, the deep-water was (800-900 m) partly characterized by ridges of compact and hard sediments with fewer species.

Fauna that often thrive on hard stony bottom, such as sea lilies and the spectacular brittle star named Gorgon's head (see photos), was found in a number of dense populations of the obviously very compact and hard sediment parties. Thus, geological phenomena, in this case the massive undersea landslide that occurred thousands of years back in time at Storegga, affect the biological conditions by forming compact and hard "sediment waves" deep within the slide area.

As expected for the Norwegian Sea deep water, the temperature at these depths was measured to - 0.7 degrees, which is one of the reasons for the faunal differences between the deep water and shallow shelf areas.