The Seawatch experiment is being set up and operated by the Norwegian marine research company Oceanor under Euromar, part of a European programme to encourage the development of advanced technologies.
The initial four-year trial is expected to improve understanding of the formation of blooms of toxic algae and to act as a pollution early warning system. Norway, France, Germany and the Netherlands are collaborating in the project.
Fifteen buoys will be moored in offshore waters around the North Sea by the end of 1992. Each will carry sensors for oxygen, nitrate, phosphate, radioactivity and particles. Optical sensors on the buoys can distinguish between the green, red and blue algae which can develop into toxic blooms. Oceanor hopes eventually to add sensors to detect heavy metals, but the technology is not yet sufficiently advanced to cope with the hostile offshore environment.
The buoys also carry instruments to measure meteorological data, currents, waves and temperature and salinity profiles. The aim is to provide information on the long-range transport of pollution and, in the words of Oceanor's Tore Audunson, to "provide the equivalent of a weather forecast for the ocean."
Information is transmitted to land by satellite. This should prove cheaper than the current practice of sampling from a boat, and the results will show important short-term variations which are missed by single "snapshot" measurements. Because the data are available almost in real time, the buoys could in principle be used to track a pollution incident.
Six buoys are already in place around the Norwegian and Danish coasts, where recent algal blooms have caused severe damage to marine life and fish farms. Information from the Seawatch project may help to settle the debate over the role of pollution in the formation of "red tides" - blooms of red algae which periodically appear in the area.
Buoys are also planned off the UK's east coast and in the English Channel. Some of these waters are affected by algal blooms. In both of the past two years, the Department of Health has issued warnings against the consumption of shellfish caught off the north-east coast which contained potentially fatal levels of algal toxins.