150 years in the Norwegian Sea

In 1876 the steamship «Vøringen» left Bergen for the first of three summer research cruises. The meteorologist and oceanographer Henrik Mohn and the biologist Georg Ossian Sars had been inspired by the British expedition with the corvette HMS Challenger.

During a three and a half years’ long yourney, British scientists had circumnavigated the world, the first global marine research expedition. They had traveled in southern waters. Mohn and Sars wished to explore the ocean to the west and north of Norway.

«The expedition demanded extensive cooperation,» says Svein Østerhus.

Østerhus is an oceanographic researcher at NORCE and the Bjerknes Centre for Climate Research. Tomorrow he will give the opening talk during an international conferance about the northern ocean regions.

The more than one hundred marine researchers gathered in Bergen will get to hear the history of the exploration of the Nordic Seas as well as about the most significant variations observed in these regions since around 1900.

The tempting ocean

Where did cod and schools of herring come from? Why was there sometimes loads of fish right off the Norwegian coast, and in other years far less? And, who was entitled to the fish stocks in waters farther away? The motivation behind the Northern Seas expedition was not merely scientific.

These questions were of major importance for the nation’s economy. In addition to the mapping of new fish banks, exploring the ocean could be a way of marking territory. Mohn and Sars were supported by the Department of Domestic Affairs, also responsible for trade and shipping.

While HMS Challenger carried more than two hunded men, Vøringen brought five scientists and an artist in addition to the ship’ captain and a crew of nearly thirty.

Following the expedition, Henrik Mohn declared that it would be eligible to call the ocean off Norway «Det norske Hav», meaning the Norwegian ocean, not just because Norwegian sailors had sailed there through all times, but because the nation now had carried out a scientific exploration of the this ocean. 

This way, Norway took ownership of the Norwegian Sea.

Ocean currents were mapped early

Extensive reports written after the Northern Seas expedition made the foundation for the development of fishery biology and oceanography in the following decades.

In 1909 the marine researchers Bjørn Helland-Hansen and Fridtjof Nansen published a major work titled The Norwegian Sea, including a detailed map of ocean currents in the Nordic Seas. 

Neither Helland-Hansen nor Nansen had visited or measured anything in many of the regions covered by the map. Still, the map is realistic, Svein Østerhus concludes.

«The picture Helland-Hansen and Nansen gave of the ocean circulation in the Norwegian Sea, can hardly be drawn better today,» he says.

The two scientists had spoken to fishermen and sailors who knew the ocean currents. Some features of the moving water could also be estimated, while in other regions they must have guessed at a result that is surprisingly close to the real ocean.

New instruments were decisive

Svein Østerhus believes technology has shaped the development of science. What anyone would be able to find out, has at all times depended on the accuracy of available instruments.

By the time "Vøringen" left the dock in Bergen in 1876, the thermometer as an instrument was well developed, but the procedures for measuring temperatur at great depths were still primitive. Neither was measuring the salinity of sea water simple, and the expedition's participants worked hard to develop new methods.

Toward the turn of the century, Nordic marine researchers collaborated on the development of instruments and methodology. Fridtjof Nansen was among those driving this, and he demanded highly accurate thermometers.

"Combined with many research cruises, the new methods formed the basis for Nansen's and Helland-Hansen's success with The Norwegian Sea," says Svein Østerhus.

In the 1960s the Aanderaa current meter, developed in Bergen, was quickly put into use in the global ocean. New technology permitted new ways of recording and storing data. 

"Newly developed semi-conductors" were truly a prerequisite for the development of the Aanderaa current meter," says Østerhus.

National and international cooperation

As the development of the field of oceanography has followed developments in meteorology and fishery science, cooperation between scientists working in these disciplines has always been normal, Svein Østerhus tells.

As a student he was involved in an international oceanographic organization and got an extensive network. The meetings added faces to his exam curriculum.

"I had had beers with everyone on my reading list," the oceanographer says.

As a young researcher in the 1980s, Svein Østerhus startet a measurement series that took a decade to get running. First, he and his colleagues had to make the instruments work. Then they had to wait for data to analyze.

Today new projects often demand quick results, and he advises young scientists to go for data that have already been collected.

"Existing measurements contain information no one has yet exploited," he says. 

Even though the hunt for the secrets of the abyss still requires research cruises, analyzing old numbers and measurements can provide valuable insights. Possibly, new northern seas expeditions may be carried out without leaving the dock.