Phosphorus forms and reactive iron in lateglacial, postglacial and brackish-water sediments of the Archipelago Sea, northern Baltic Sea

Virtasalo, Joonas J.; Kotilainen, Aarno

doi:10.1016/j.margeo.2008.03.008

Cited by 20 publications

(11 citation statements)

References 55 publications

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“…Aigars (2001) reported for the Gulf of Riga that redox-sensitive P dominated in the topmost sediment and inorganic P was higher than OP. In contrast to this, Virtasalo et al (2005) found that in surface sediments at Archipelago Sea, OP dominated followed by detrital apatite-P, and redoxsensitive P was slightly higher than authigenic apatite-P. Another study in the Archipelago Sea showed high variation in P forms during the development of the sea area after the deglaciation (Virtasalo and Kotilainen 2008). Łukawska-Matuszewska and Bolałek (2008) reported very high and variable P contents in different sediment types in the Gulf of Gdansk, southern Baltic, as well as dominance of OP, followed by Al-bound P.…”

Section: Introductionmentioning

confidence: 87%

The chemical character and behaviour of phosphorus in poorly oxygenated sediments from open sea to organic-rich inner bay in the Baltic Sea

Lukkari¹,

Leivuori²,

Kotilainen

2009

Biogeochemistry

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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 (O 2 ) 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.

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Section: Introductionmentioning

confidence: 87%

The chemical character and behaviour of phosphorus in poorly oxygenated sediments from open sea to organic-rich inner bay in the Baltic Sea

Lukkari¹,

Leivuori²,

Kotilainen

2009

Biogeochemistry

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“…Furthermore, Virtasalo and Kotilainen (2008) showed that in the surface sediments of the AS, authigenic apatite-P was about six times lower than detrital apatite-P. Detrital apatite-P is a fairly inert P form, which can also be concluded from the more or less stable vertical distribution of apatite-P fraction (Fig. 3) (Jensen and Thamdrup 1993;Lukkari et al 2008).…”

Section: Immobile Pmentioning

confidence: 94%

The chemical character and burial of phosphorus in shallow coastal sediments in the northeastern Baltic Sea

Lukkari¹,

Leivuori²,

Vallius

et al. 2009

Biogeochemistry

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The chemical composition and vertical distribution of sediment phosphorus (P) in shallow coastal sediments of the northeastern Baltic Sea (BS) were characterized by sequential extraction. Different P forms were related to chemical and physical properties of the sediments and the chemistry of pore water and near-bottom water. Sediment P composition varied among the sampling sites located in the Archipelago Sea (AS) and along the northern coast of the Gulf of Finland (GoF): the organic rich sites were high in organic P (OP), while apatite-P dominated in the area affected by sediment transportation. Although the near-bottom water was oxic, the sediments released P. Release of P was most pronounced at the site with high sediment OP and reduced conditions in the sediment-water interface, indicating that P had its origins in organic sources as well as in reducible iron (Fe) oxyhydroxides. The results suggest that even though these coastal areas are shallow enough to lack salinity stratification typical for the brackish BS, they are vulnerable to seasonal oxygen (O 2 ) depletion and P release because of their patchy bottom topography, which restricts mixing of water. Furthermore, coastal basins accumulate organic matter (OM) and OP, degradation of which further diminishes O 2 and creates the potential for P release from the sediment. In these conditions, an abundance of labile OP may cause marked efflux of P from sediment reserves in the long-term.

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“…Vivianite is also likely present in Ancylus Lake sediments in the coastal Bothnian Sea (Dijkstra et al, 2017a) and may explain the enrichments in CDB-extractable P (Fe-bound P) in lake sediments from the Archipelago Sea in the northern Baltic Sea (Virtasalo and Kotilainen, 2008) and the large centimeter-scale blue aggregates observed in Ancylus Lake sediments in the Little Figure 14. Simplified schematic of methane (CH 4 ), sulfur (S), iron (Fe) and phosphorus (P) diagenesis in Baltic Sea (Bornholm Basin) and Black Sea sediments (see Sect.…”

Section: Implications For Sedimentary P Recordsmentioning

confidence: 99%

Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

et al. 2018

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Abstract. Phosphorus (P) concentrations in sediments are frequently used to reconstruct past environmental conditions in freshwater and marine systems, with high values thought to be indicative of a high biological productivity. Recent studies suggest that the post-depositional formation of vivianite, an iron(II)-phosphate mineral, might significantly alter trends in P with sediment depth. To assess its importance, we investigate a sediment record from the Bornholm Basin that was retrieved during the Integrated Ocean Drilling Program (IODP) Baltic Sea Paleoenvironment Expedition 347 in 2013, consisting of lake sediments overlain by brackish-marine deposits. Combining bulk sediment geochemistry with microanalysis using scanning electron microscope energy dispersive spectroscopy (SEM-EDS) and synchrotron-based X-ray absorption spectroscopy (XAS), we demonstrate that vivianite-type minerals rich in manganese and magnesium are present in the lake deposits just below the transition to the brackish-marine sediments (at 11.5 to 12 m sediment depth). In this depth interval, phosphate that diffuses down from the organic-rich, brackish-marine sediments meets porewaters rich in dissolved iron in the lake sediments, resulting in the precipitation of iron(II) phosphate. Results from a reactive transport model suggest that the peak in iron(II) phosphate originally occurred at the lake-marine transition (9 to 10 m) and moved downwards due to changes in the depth of a sulfidization front. However, its current position relative to the lake-marine transition is stable as the vivianite-type minerals and active sulfidization fronts have been spatially separated over time. Experiments in which vivianite was subjected to sulfidic conditions demonstrate that incorporation of manganese or magnesium in vivianite does not affect its susceptibility to sulfide-induced dissolution. Our work highlights that post-depositional formation of iron(II) phosphates such as vivianite has the potential to strongly alter sedimentary P records particularly in systems that are subject to environmental perturbation, such as a change in primary productivity, which can be associated with a lake-marine transition.

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Phosphorus forms and reactive iron in lateglacial, postglacial and brackish-water sediments of the Archipelago Sea, northern Baltic Sea

Cited by 20 publications

References 55 publications

The chemical character and behaviour of phosphorus in poorly oxygenated sediments from open sea to organic-rich inner bay in the Baltic Sea

The chemical character and behaviour of phosphorus in poorly oxygenated sediments from open sea to organic-rich inner bay in the Baltic Sea

The chemical character and burial of phosphorus in shallow coastal sediments in the northeastern Baltic Sea

Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

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