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Importance of boreal rivers in providing iron to marine waters.

  • Emma Kritzberg
  • Ana Bedmar Villanueva
  • Marco Jung
  • Heather Reader
Publishing year: 2014
Language: English
Publication/Series: PLoS ONE
Volume: 9
Issue: 9
Document type: Journal article
Publisher: Public Library of Science

Abstract english

This study reports increasing iron concentrations in rivers draining into the Baltic Sea. Given the decisive role of iron to the structure and biogeochemical function of aquatic ecosystems, this trend is likely one with far reaching consequences to the receiving system. What those consequences may be depends on the fate of the iron in estuarine mixing. We here assess the stability of riverine iron by mixing water from seven boreal rivers with artificial sea salts. The results show a gradual loss of iron from suspension with increasing salinity. However, the capacity of the different river waters to maintain iron in suspension varied greatly, i.e. between 1 and 54% of iron was in suspension at a salinity of 30. The variability was best explained by iron:organic carbon ratios in the riverine waters - the lower the ratio the more iron remained in suspension. Water with an initially low iron:organic carbon ratio could keep even higher than ambient concentrations of Fe in suspension across the salinity gradient, as shown in experiments with iron amendments. Moreover, there was a positive relationship between the molecular size of the riverine organic matter and the amount of iron in suspension. In all, the results point towards a remarkably high transport capacity of iron from boreal rivers, suggesting that increasing concentrations of iron in river mouths may result in higher concentrations of potentially bioavailable iron in the marine system.


  • Ecology


  • MICCS - Molecular Interactions Controlling soil Carbon Sequestration
  • ISSN: 1932-6203
Emma Kritzberg
E-mail: emma [dot] kritzberg [at] biol [dot] lu [dot] se

Senior lecturer

Aquatic ecology

+46 46 222 40 79



Research group

Aquatic Ecology


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PhD students, main supervisor

PhD students, assistant supervisor

Post docs

Johanna Sjöstedt