Changes in the composition of phosphorus (P) compound groups in sediment and P in sediment pore water in a shallow eutrophic lake: a 31P NMR study

Shinohara, Ryuichiro; Imai, Akio; Kawasaki, Nobuyuki; Komatsu, Kazuhiro; Kohzu, Ayato; Miura, Shingo; Sano, Tomoharu; Satou, Takayuki; Tomioka, Noriko; Shimotori, Koichi

doi:10.1007/s10201-016-0497-4

Cited by 5 publications

(7 citation statements)

References 44 publications

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“…We studied Lake Kasumigaura, Japan. In previous research, our team clarified the vertical attenuation of organic P concentrations in the sediment using 31 P nuclear magnetic resonance [ Shinohara et al ., ]. We have also observed seasonal changes in the concentration of organic P in the sediment particles, and of MRP and MUP in the pore water.…”

Section: Introductionmentioning

confidence: 54%

“…Because phytoplankton blooms (cyanobacteria) sometimes occur in the spring in Lake Kasumigaura, it seems likely that the release of P from the sediment could promote the blooms by contributing P, which is a limiting nutrient for their growth. The transformation of organic P in the winter is likely to be a key process in Lake Kasumigaura [ Shinohara et al ., ].…”

Section: Discussionmentioning

confidence: 99%

“…Further improvement of our model is still needed to simulate P concentrations in sediment. To improve the model, the flux from orthophosphate diesters to orthophosphate must be quantified because of the large amounts of orthophosphate diesters in the sediment in Lake Kasumigaura [ Shinohara et al ., ]. For the rapid hydrolysis of phosphomonoesters, orthophosphate monoesters can be supplied from orthophosphate diesters.…”

Section: Discussionmentioning

confidence: 99%

“…We have also observed seasonal changes in the concentration of organic P in the sediment particles, and of MRP and MUP in the pore water. The results suggest that organic P in the sediment particles supplies MUP to the pore water [ Shinohara et al ., ]. Given these background results, Lake Kasumigaura is a good choice for research to clarify the mass balance of organic P in the sediment and MUP.…”

Section: Introductionmentioning

confidence: 99%

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Role of organic phosphorus in sediment in a shallow eutrophic lake

Shinohara

Hiroki

Kohzu

et al. 2017

Water Resources Research

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We tested the hypothesis that mineralization of molybdenum unreactive phosphorus (MUP) in pore water is the major pathway for the changes in the concentration of molybdenum‐reactive P (MRP) in pore water and inorganic P in sediment particles. The concentration of inorganic P in the sediment particles increased from December to April in Lake Kasumigaura, whereas concentrations of organic P in the sediment particles and MUP in pore water decreased. These results suggest that MUP mineralization plays a key role as the source of MRP, whereas desorption of inorganic P from the sediment particles into the pore water is a minor process. One‐dimensional numerical simulation of sediment particles and the pore water supported the hypothesis. Diffusive flux of MUP was small in pore water, even in near‐surface layers, so mineralization was the dominant process for changing the MUP concentration in the pore water. For MRP, diffusion was the dominant process in the surface layer, whereas adsorption onto the sediment was the dominant process in deeper layers. Researchers usually ignore organic P in the sediment, but organic P in sediment particles and the pore water is a key source of inorganic P in the sediment particles and pore water; our results suggest that in Lake Kasumigaura, organic P in the sediment is an important source, even at depths more than 1 cm below the sediment surface. In contrast, the large molecular size of MUP in pore water hampers diffusion of MUP from the sediment into the overlying water.

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Section: Introductionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Role of organic phosphorus in sediment in a shallow eutrophic lake

Shinohara

Hiroki

Kohzu

et al. 2017

Water Resources Research

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“…Finally, 31 P NMR indicates the presence of several organic P forms 69 in addition to the dominant inorganic orthophosphate form. Orthophosphate monoesters, diesters, and pyrophosphates (Fig.…”

Section: Vertical Distribution Of P Fe La and C In The Sedimentmentioning

confidence: 99%

Response of sediment phosphorus partitioning to lanthanum-modified clay amendment and porewater chemistry in a small eutrophic lake.

Neweshy

Planas

Tellier³

et al. 2022

Preprint

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Sustained eutrophication of the aquatic environment by the remobilization of legacy phosphorus (P) stored in soils and sediments is a prevailing issue worldwide. Fluxes of P from the sediments to the water column, referred to as internal P loading, often delays the recovery of water quality following a reduction in external P loads. Here, we report on the vertical distribution and geochemistry of P, lanthanum (La), iron (Fe) and carbon (C) in the culturally eutrophied Lake Bromont. This lake underwent remediation treatment using La- modified bentonite (LMB) commercially available as PhoslockTM. We investigated the effectiveness of LMB in decreasing soluble reactive phosphorus (SRP) availability in sediments and in reducing dissolved fluxes of P across the sediment-water interface. Sediment cores were retrieved before and after LMB treatment at three sites representing bottom sediment, sediment influenced by lakeside housing and finally littoral sediment influenced by the lake inflow. Sequential extractions were used to assess changes in P speciation. Depth profiles of dissolved porewater concentrations were obtained after LMB treatment at each site. Results indicate that SRP extracted from the sediments decreased at all sites, while total extracted P (PTOT) bound to redox-sensitive metal oxides increased. 31P NMR data on P extract reveals that 20-43% of total solid-phase P is in the form of organic P (Porg) susceptible to be released via microbial degradation. Geochemical modelling of porewater data provides evidence that LaPO4(s) mineral phases, such as rhabdophane and/or monazite, are likely forming. However, results also suggest that La3+ binding by dissolved organic carbon (DOC) hinders La-phosphate precipitation. We rely on thermodynamic modelling to suggest that high Fe2+ would bind to DOC instead of La3+, therefore promoting P sequestrations by LMB under anoxic conditions.

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