Wireless ocean monitoring in the Arctic

Three years ago the idea emerged of a wireless network of sensors to monitor the Arctic regions of the ocean. Today, the theory behind the concept has been tested and found to be watertight.

The background for the 2007 intervention on wireless communication was the lack of effective monitoring of the environment and ocean resources in the Arctic. Today, most monitoring is performed manually in the course of cost-intensive research cruises.

SINTEF scientists suggested that wireless sensor networks would be a much smarter way of covering a large area in order to rapidly gather large amounts of reliable information.

Kongsberg Maritime and SINTEF were joined by the Institute of Marine Research, Fugro Oceanor, Statoil and Western Geco, and were awarded NOK 7 million by the Research Council of Norway.

In December, a small group of scientists found themselves testing the technology on board a boat off Horten in the Oslofjord. With them, they had five yellow metre-long plastic tubes packed with electronics and batteries. The cylinders were dropped into the sea at intervals of several hundred metres. This gave the scientists a network of sensor nodes capable of both sending and receiving information.

'Such information centres can either be moored to the seabed or act as untethered current-driven floaters; the whole thing is rather like like building a subsea GSM system,' explains SINTEF scientist Tor Arne Reitan. 'For example, if one of the sensors registers a high concentration of a particular environmental toxin, it could trigger the whole network to monitor just the same chemical. This would provide more rapid and reliable mapping of such occurrences than would a single sensor that could only provide the same warning several weeks or months later.'

The tests showed that the network was capable of configuring itself, and that it automatically included new nodes as these were dropped into the sea. The scientists also managed to route the signals among the sensor nodes in such a way that they could send and receive information without 'talking over each other.'

Although the network of sensors could mean a cheaper and more reliable way of acquiring marine data, a network of five or six sensors is not going to cover much of the Barents Sea. Hundreds or even thousands of units might well be needed, and even then, we are still speaking of covering a limited area. For this reason, the scientists believe that the best solution would be to monitor particularly important areas and events. The units would not need to be moored in fixed positions, but could be released wherever they are needed.

'If there was an oil-spill in the Lofoten area, for example, 10 or 20 nodes could be dropped into the sea in order to monitor where the oil is being driven and how it breaks down. If we wish to measure the number of cod on their spawning migration to Lofoten, we could place a line of sensors across their migration route, for example off Tromso,' says Reitan. 'Or by connecting the sensors to an upward-looking echo-sounder, an entire current profile could be measured and studied.'

The research is now being taken a step further via two EU projects in which Kongsberg Marine and SINTEF are participating. SINTEF has also launched the Group Project known as Ocean Space Surveillance, in which data from subsea sensor networks are combined with sophisticated ocean models in order to improve the interpretation of the measurements. This technology will be highly relevant as an element of BarentsWatch, the Norwegian government's programme for an integrated monitoring system for the oceans of the Arctic region.