November 30th 2015

Discoveries in the Barents Sea in a new MAREANO book

The Demarcation Line Treaty with Russia opened up new areas of ocean for geological mapping. The new results from the Barents Sea are presented in the MAREANO programme’s updated book on the Norwegian sea floor. The book contains the results of 10 years mapping in the Norwegian and Barents seas.

The video shows some of the discoveries made by MAREANO on the bed of the Norwegian and Barents seas. Video: MAREANO/Havforskningsinstituttet.

Five years have passed since Jonas Gahr Støre, the Norwegian Foreign Minister at the time, signed the agreement on behalf of Norway. This event had great significance for MAREANO, the mapping programme in which NGU, the Norwegian Marine Research Institute and the Norwegian Mapping Authority are cooperating.

When the Norwegian areas were defined, the seabed scientists could begin the mapping. The results provide valuable information and updating for the management plan the authorities have drawn up for the Barents Sea. The business and industrial communities are also interested in the data from the floor of the Barents Sea.

Obvious connections

In recent years, MAREANO has been mapping in the southern part of the new Norwegian areas. The connections between geology and biology have become obvious here.

- In the parts of the Barents Sea we have mapped now, the seabed is mostly soft and consists of unconsolidated sediments. These mudflats may seem monotonous and barren, but down in the sediment they are in reality teeming with animal life. As soon as a harder bottom or coarse-grained ridges appear, where creatures can get a hold, pure oases arise that contain anemones and other beautiful species, says Lilja Rún Bjarnadóttir. She is NGU’s project manager and a member of the MAREANO field team.

PThe shallowest banks in the Barents Sea have “islands” where coarse sediments, including gravel and cobbles, give a foothold for anemones and other creatures. In addition to the sea anemones in the photograph, taken close to the extensive mudflats on the Thor Iversen Bank, we can see colony-forming sea squirts lowermost. Photo: MAREANO/Havforskningsinstituttet. 

The Barents Sea seabed also tells us about the geological processes that have affected the terrain.

- The soft sediments and the landscape we see on the seabed today are largely a result of the last Ice Age and the glaciers which covered this area until around 15 000 years ago. This influences where the organisms living there today can find suitable living conditions, says Lilja Rún Bjarnadóttir. 

Numerous ridges of moraine were pushed up by the ice covering the Barents Sea when it stood still or moved a little forward towards the end of the last Ice Age. Ill: MAREANO/NGU

Another feature which affects the appearance of the seabed is salt domes, pillars of salt which rise to the surface from deeper geological strata. This part of the Barents Sea has many salt domes and they can create special conditions on the seabed which, in turn, may affect the animal life on and around the domes. New knowledge about these structures is of interest for the petroleum industry because of the close link between oil and gas traps and salt domes. 

Figure a: The Helmet is a hump formed when a salt diapir intruded through the seabed. Figure b: Gravel with rose-coloured anemones on the top of The Helmet at a depth of about 170 m. Figure c: A solitary anemone on a soft, muddy bottom at the foot of The Helmet, at a depth of about 215 m. Figure d: The Petroleum Directorate’s seismic data from this area clearly show that The Helmet is the top of a salt diapir rising from depth and pressing the overlying sedimentary strata aside. Ill: MAREANO

The video shows the environment on the bed of the Barents Sea. Large parts of the seabed are so smooth and lacking a cover that the fish (a thorny skate) experiences problems when it encounters rocks. Photo: MAREANO/Havforskningsinstituttet

International interest 

As well as the discoveries in the Barents Sea, the new book about the MAREANO programme also describes the results of recent mapping performed in the Norwegian Sea.

“The Norwegian Sea Floor” updates the book, “To the bottom of the Barents Sea and the marine areas off Lofoten” published in Norwegian in 2010. The texts and results are now presented in English.

- Many requests for English texts have been received. The EU and many other nations are focusing strongly on preparing good atlases of the seabed. MAREANO means that Norway has already come a long way towards attaining this goal, much further than most other countries, and a great deal of international interest is therefore surrounding this project, says Lilja Rún Bjarnadottir.

IAn illustration from the seabed off central Norway. The orange patches on the left show previously observed coral reefs, while the yellow areas on the right-hand image include geological evidence of dead coral reefs (bioclastic sediments). The illustration is from the new MAREANO book “The Norwegian Sea Floor”. 

Focus on corals

The coral reefs on the floor of the Norwegian Sea are extensively described in the new book. Ever since the project started in 2005, there has been an expressed objective to find out where coral reefs occur and how large they are.

The biologists are mapping where live corals are found. NGU’s geologists, on the other hand, have focused on large mounds of dead corals, also called bioclastic sediments. In many places, large coral reefs often consist 90-95 % of bioclastic sediments, while the living part constitutes the rest. The biologists have shown that the coral reefs can be divided into several zones and the highest biodiversity (biological diversity) is found where there are blocks of dead coral, whereas there is comparatively low biodiversity in the zone where living corals are most abundant. This is described in detail in the new book.

- We have discovered that we can map coral reefs effectively by combining detailed marine primary data with geological knowledge. MAREANO’s mapping shows that there are probably far more coral reefs on the shelf off central Norway than has been known previously, and this is valuable information for management authorities, says Terje Thorsnes, an NGU scientist. 

Relaterte prosjekter

MAREANO
MAREANO maps the bathymetry, seafloor conditions, biodiversity, geodiversity and sedimentary contamination along the Norwegian coast and sea areas.