title: Labile organic carbon regulates phosphorus release from eroded soil transported into anaerobic coastal systems.
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.
authors: Finnish Environment Institute (SYKE), P.O. Box 140, 00251, Helsinki, Finland, jouni.lehtoranta@environment.fi.
authors: Jouni
authors: J
authors: Lehtoranta
authors: Petri
authors: P
authors: Ekholm
authors: Stella
authors: S
authors: Wahlström
authors: Petra
authors: P
authors: Tallberg
authors: Risto
authors: R
authors: Uusitalo
mesh_terms: D001421:Bacteria, Anaerobic; D002244:Carbon / Q000032:analysis; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D010758:Phosphorus; D002244:Carbon