Mapping of the seabed by NGU's interferometric sonar mounted onboard FF Seisma. Such information is used to examine environmental status, to find out how the seabed has changed over the past hundreds or thousands of years, and if changes are natural or anthropogenic.
Habitats and resources
The data are also used for mapping of seabed habitats, which depend on the relationships between seabed types (e.g., clay, sand, gravel or bedrock) and living organisms.
This is important information for ecosystem-based management of the seabed and oceans. We also map geological resources at and below the seabed, e.g. carbonate sand, and sand and gravel. Several Example of environmental data from the Oslofjord. In this sediment core, dating results and analyses of lead and zinc show that pollution was most intense in the period 1940-1970.of these topics were important in the Skagerrak Project (1990-1995).
Deep-water coral reefs on the continental shelf are amongst Norway's richest habitats. They provide spawning and growth areas for commercially important fish types such as haddock, bream and ling. However, these fragile coral reefs representa habitat at risk of destruction by bottom trawling with heavy equipment.
Fish farming in the coastal zone is expected to increase in the coming years which may also put pressure on seabed habitats. To ensure sustainable development and management of such resources there is an urgent need for more scientific knowledge about the seabed and associated marine habitats.
This need for better knowledge contributed to the development of the MAREANO programme (www.mareano.no), which started in 2005. MAREANO is a cooperative programme between the Institute of Marine Research, the Geological Survey of Norway and the Norwegian Mapping Authority.
The main aim of MAREANO is to provide scientific information about Norwegian coastal and ocean areas that can be used by public management, industry and research institutions. Such information is crucial for mapping of habitats and biological diversity, for environmental and pollution studies, and for the petroleum and fishery industries. Results are published regularly on www.mareano.no. MAREANO is aimedat providing answers to the following questions:
Moraine material with rich living communities on Malangsgrunnen outside Troms. Image from MAREANO 2007.
- Which landforms do we find on the Norwegian continental shelf?
- What does the seabed consist of?
- How are pollutants stored in the seabed sediments?
- Where are the important habitats?
- What is the biological diversity?
- What is the relationship between the physical environment and biological diversity?
Example of seabed map published on www.mareano.no.
Geodiversity and habitats
Over the past few years, NGU's Marine Geology group has been involved in several other projects on geodiversity, biodiversity and habitats, e.g. Hasut, Marmodell and Sushimap.
Ongoing projects include "Seabed maps and bottom trawling", where the aim is to show that geological knowledge can optimise bottom trawling, reduce damage of the seabed and fishing gear, and reduce costs.
The project "New marine base maps for the fisheries and fish-farming industry" is intended to develop tools and procedures for the fishing fleet to make use of detailed seabed data (bathymetry, bottom hardness, sediment type), and to use these during practical tests.
In the project "Mapping of marine biological diversity", NGU is responsible for mapping of coastal carbonate-sand deposits and marginal moraines. In the "Balance" project we have mapped and interpreted bottom types in the Hvaler area for habitat modeling.
Sub-sea pipeline route and cables
Detailed seabed data are needed for stability evaluations and risk analysis in connection with submarine constructions. Submarine slide scars and slide deposits on the seabed may indicate unstable seabed conditions. Similarly, sediment thickness and type are important parameters for construction purposes both in the coastal zone and offshore.
NGU has performed detailed investigations for a potential sub-sea gas pipeline route between Tjeldbergodden and Skogn. The seabed was investigated in detail by studying shallow seismic data, swath bathymetry, long boreholes, and cores. Similar investigations have been undertaken for the planning of laying electrical-power cables on the seabed between Norway and continental Europe.