Labile organic carbon regulates phosphorus release from eroded soil transported into anaerobic coastal systems

Jouni Lehtoranta*, Petri Ekholm, Stella Wahlström, Petra Tallberg, Risto Uusitalo

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

10 Citations (Scopus)

Abstract

Coastal eutrophication is expected to increase due to expanding and intensifying agriculture which causes a large amount of soil-associated P to be transported into aquatic systems. We performed anaerobic long-term incubations on field soil to mimic the conditions that eroded soil encounters in brackish sediments. The release of P from soil increased with the amount of labile organic C (acetate) addition and decreased with the soil/solution ratio. We deduce that in less-productive brackish systems, microbial Fe reduction allows for the maintenance of the coupled cycling of Fe and P and restricts the amount of P entering the oxic water. In more eutrophic systems, the formation of Fe sulfides as a result of SO4 reduction inactivates Fe, and leads to a higher release of P, thus generating an adverse feedback effect. The dependence of the fate of soil-bound Fe and P on the trophic status of the receiving water should be recognized in eutrophication management.

Original languageEnglish
Pages (from-to)S263-S273
Number of pages11
JournalAmbio
Volume44
Issue numberSupplement 2
DOIs
Publication statusPublished - Mar 2015
MoE publication typeA1 Journal article-refereed
EventInternational Phosphorus Workshop - Uppsala, Sweden
Duration: 9 Sep 201313 Sep 2013
Conference number: 7

Keywords

  • Coastal waters
  • Agriculture
  • Sediment
  • Eutrophication
  • Fe oxides
  • Redox reactions
  • SEDIMENT MICROBIAL PROCESSES
  • ALGAL-AVAILABLE PHOSPHORUS
  • BALTIC SEA
  • BIOAVAILABLE PHOSPHORUS
  • PHOSPHATE RELEASE
  • MARINE SEDIMENT
  • WATER
  • RUNOFF
  • IRON
  • EUTROPHICATION

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