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New results on nutrition levels in Gulf of Bothnia

Published: 17 November 2014

Low levels of phosphorus in the Gulf of Bothnia makes plankton and fish production low. Central Baltic Sea, part of the same ocean, is so rich in phosphorus that the environment is threatened by eutrophication.

Professor Johan Ingri, Luleå University of Technology, studying sediment cores from 6000 years back, in relation to measurements in streams, rivers and the Gulf of Bothnia, trying to explain the differences in the marine environment. 

Phosphorus is essential for all living organisms. Iron binds phosphorus in the so-called colloids and particles, thus preventing phosphorus from circulating in the ocean's food web. The result is that the water gets low in nutrients which affects fish stocks. To find out where these iron colloids and iron particles are formed, is important to clarify how it will affect the levels of phosphorus in the water.

More like sea then ocean

- Gulf of Bothnia is becoming more like a lake, says Johan Ingri, professor of environmental geochemistry. We compare the prevalence of different iron isotopes in streams, rivers and the Gulf of Bothnia, and have come up with entirely new results when it comes to track where the iron comes from. Our research shows that it is oxidized iron reacted with high concentrations of organic carbon in the forest landscape, that transports and binds phosphorus and organic carbon near the coast, making the Gulf of Bothnia poor in nutrients.

Luleå in the forefront

Research at Luleå University in the field iron isotopes and the iron isotope signatures is at the forefront. The results can be used to understand the metabolism of iron in the temperate zone of the northern hemisphere.  The Luleå research team collaborates with Oxford and other leading European universities in an EU-funded network.

The basic research conducted in Lulea can also be applied in the Arctic that exhibit similar prevalence of iron isotopes as the Gulf of Bothnia. Basic research around the iron isotopes at Luleå University is funded by the Swedish Research Council.