Lukkari,K., Leivuori,M. and Kotilainen,A.(2009): The chemical character and behaviour of phosphorus in poorly oxygenated sediments from open sea to organic-rich inner bay in the Baltic Sea. Biogeochemistry, 96, 25-48.

『バルト海の外洋から有機物に富む内湾までの貧酸素堆積物中のリンの化学的特性と挙動』


Abstract
 The chemical composition and vertical distribution of phosphorus (P) in poorly oxygenated sediments in a continuum extending from the open Baltic Sea towards an organic-rich inner bay were characterized by sequential extraction to examine the potential for release of sediment P. The chemical composition of P was related to chemical and physical characteristics of the sediments and the chemistry of pore water and near-bottom water to better understand the behaviour of P. Sediment P increased towards the inner bay, and the concentration of organic matter appeared to dictate its composition: the dominance of apatite-P turned to dominance of organic P (OP). Sediment P burial and, thus, release from sediment P reserves varied depending on the chemical composition of P. Dissolved species at the sediment-water interface suggested fluctuating redox conditions that affect P binding at short time scale. Redox-sensitive, iron (Fe)-bound P was usually relatively low because of poor oxygen (O2) conditions, which emphasized the role of OP in P release. The results indicate that, over the long term, the abundant organic P reserve may support a significant continuing P release from hypoxic sediments in the severely eutrophied Gulf of Finland (GoF) because capture of P into Fe oxyhydroxides at the sediment surface is restricted. The average long-term minimum annual rate of P release from poorly oxygenated sediments below about 60 m depth in the GoF was approximated on the basis of the vertical distribution of sedimentary P forms and estimates of sedimentation rate.

Keywords: Baltic Sea; Fractionation; Organic matter; Phosphorus; Sediment』

Introduction
Materials and methods
 Research area and sediment types at the sampling sites
 Sampling
 Analytical methods
  Water column and pore water samples
  Sediment
  P fractionation
 Statistical analyses
Results
 Water column and pore water
 Sediments
 P fractions
  Total elements in extracts
 Statistical analyses
Discussion
 Sediment properties
 Vertical and spatial distribution of P
  Immobile P
  Reactive P
 Dissolved species at the sediment-water interface
 Burial and potential for release of sediment P along the west-to-east transect
Conclusions
Acknowledgments
References


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