scholarly journals High-resolution characterization of labile phosphorus, iron, and manganese in sediments of different trophic waters in Lake Taihu, China

2017 ◽  
Vol 77 (2) ◽  
pp. 286-295 ◽  
Author(s):  
Liqing Zeng ◽  
Fan Yang ◽  
Changzhou Yan ◽  
Xinhong Wang

Abstract High-resolution combined ZrO-Chelex diffusive gradients in thin film (DGT) probes were arranged to synchronously monitor the characteristics of labile phosphorus (P), iron (Fe), and manganese (Mn) in sediments from regions of varying trophic levels in Lake Taihu, China. Results showed that P release was closely related to the lake region's trophic level. Labile P in sediments and the apparent diffusion flux (Fd) of P were higher in hyper-eutrophic algae-dominated regions than those in macrophyte-algae-dominated and macrophyte-dominated regions, indicating that P released from sediments may be facilitated in eutrophic environments. A positive correlation observed between DGT-labile P and Fe or Mn, which had similar regional spatial distributions to P, showed that reductive dissolution of Fe-Mn (oxyhydr)oxides (FeOOH-MnOOH) in sediments was responsible for internal P release, which was strengthened in eutrophic environments. Ratios of labile Fe or Mn/labile P (LFe/LP and LMn/LP) in sediments in algae-dominated regions showed lower values than those in macrophyte-algae-dominated and macrophyte-dominated regions, further confirming that FeOOH-MnOOH in algae-dominated regions were less able to fix P, which brought higher pollution risks for the overlying water. LFe/LP or LMn/LP also had a significantly positive correlation with Fd, further testament that labile Fe or Mn was much more relevant to the sediment P cycle.

2022 ◽  
Vol 9 ◽  
Author(s):  
Xu-Meng Dong ◽  
Shuo-Nan Ma ◽  
Hai-Jun Wang ◽  
Yuan-Yuan Li ◽  
Yan Li ◽  
...  

Increasing concentrations of dissolved organic carbon (DOC) have been observed in coastal ecosystems worldwide over the past decade, and tight coupling of the carbon (C) and phosphorus (P) biogeochemical cycle has been recognized in aquatic ecosystems. However, there is still no consensus regarding the potential effects of DOC loading on sediment P release. In a 2-month mesocosm experiment, we tested the effects of DOC enrichment on sediment P release in six glass aquariums. Two treatments were set: Control (without sodium acetate (Na(CH3COO)) addition) and Na(CH3COO) addition (equivalent to 5 mg C L−1). The results showed the following: 1) DOC loading stimulated sediment P mobilization and release, as indicated by increases in the labile P recorded for 7-cm-deep sediment using diffusive gradients in thin films, the flux of P across the sediment–water interface, and the total P concentrations in the overlying water; and 2) stimulated alkaline phosphatase activity, increased P-solubilizing bacteria proportion, and decreased dissolved oxygen concentration were likely the primary mechanisms behind the DOC-stimulated sediment P mobilization and release. These results provide insight into the promotion of sediment P release induced by C addition. Further studies investigating the quantitative relationships between DOC loadings and P release are needed to fully elucidate the coupled roles of C and P, especially those based on large-scale field investigations with broader C forms and loadings.


2014 ◽  
Vol 21 (22) ◽  
pp. 12989-12999 ◽  
Author(s):  
Shouliang Huo ◽  
Jingtian Zhang ◽  
Kevin M. Yeager ◽  
Beidou Xi ◽  
Jian Wang ◽  
...  

2017 ◽  
Vol 14 (1) ◽  
pp. 48 ◽  
Author(s):  
Tao Liang ◽  
Yali Tong ◽  
Xiahui Wang ◽  
Lingqing Wang

Environmental contextEutrophication caused by excessive inputs of phosphorus is a prevalent global environmental problem. Reactive phosphorus released from sediments was measured by two new in situ passive sampling techniques capable of high-resolution measurements of phosphorus concentration. The methods provide the scientific evidence for solving the problems associated with deteriorating surface water quality. AbstractInternal phosphorus (P) loading is regarded as a major eutrophication factor and may prevent improvements in lake water quality. Two new in situ passive sampling techniques, high-resolution pore-water equilibrators (HR-Peeper) and zirconium oxide-based diffusive gradients in thin films (Zr-oxide DGT), were combined to measure dissolved reactive phosphorus (DRP) (CPeeper) and labile phosphorus (CDGT) at five sites in South Dongting and West Dongting Lakes. The vertical distribution of CPeeper and CDGT displayed similarity, which demonstrated that the buffering capacity of the labile P in sediments was similar at different depths. The diffusion flux of P from the sediments at the sediment–water interface ranged from 1.9 to 88ng m–2 day–1, with an average value of 38ng m–2 day–1. The P flux at the entrances to the Yuan, Li and Zi Rivers was fairly large at all five sites. The sediments at the five sites released P into overlying water, indicating that the sediments are an important source of P for Dongting Lake.


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3232
Author(s):  
Qingqing Sun ◽  
Fujun Yue ◽  
Jingan Chen ◽  
Jingfu Wang ◽  
Yulin Li ◽  
...  

Nitrogen and phosphorus are key elements in controlling eutrophication in the aquatic system. Water and sediment samples were collected from Hongfeng Lake, a seasonally stratified reservoir in southwest China, in winter and summer. Diffusion fluxes of NH4+, NO3−, and labile P in summer using diffusive gradients in thin films technology were 3.4, −37.2, and 0.9 mg m−2 day−1, respectively, based on Fick’s first law. The diffusion flux of labile P was 2.05 mg m−2 day−1 in winter. The contributions fraction of the labile P diffusion flux from sediment to the overlying water were higher in winter than those in summer, because of the relatively lower external input, concentrations and higher diffusion fluxes in winter. After the external input decreased, all of the three diffusion fluxes were lower than the previous record. To understand the influence effect of hydrodynamics, environmental fluid dynamics code modeling was used to simulate the flow and temperature field in winter and summer. Modeling results showed that velocity in summer was higher than that in winter due to concentrated rainfall within the catchment. Moreover, the velocity and temperature in the euphotic zone were higher than that of the hypolimnion in summer. Less variation of velocity and temperature in vertical profile in winter than that in summer was observed, which may be attributable to the high specific heat capacity and the low heat conductivity of water. There was no significant correlation among velocity, hydrochemistry, nitrogen, and phosphorus concentrations. Hydrodynamics, solar radiation, and water depth affect the position of the thermocline, which was consequently to water temperature, hydrochemistry, dissolved nitrogen, and phosphorus concentration. Correlation analysis suggested that the higher bottom velocity and total bed shear may accelerate labile P, NH4+, and NO3− diffusion fluxes. These results provide evidence and suggestions for preventing and controlling reservoir eutrophication and water safety management.


2015 ◽  
Vol 24 (2) ◽  
pp. 297-308
Author(s):  
A. Barbaro

The changes in labile phosphorus compounds content during germination of wheat were investigated. These compounds were determined in acid-soluble germ extracts separated into fractions according to the solubility of their barium salts. Low germination temperature was found to raise the labile phosphorus content in the fraction of insoluble barium salts. If we assume that labile P of this fraction consisted mainly of adenosinedi- and triphosphates, it would seem that the rise, in the ATP and ADP level under the influence of low temperature may be essential for initiating flowering in winter varieties.


2021 ◽  
Author(s):  
Bereket Ayenew Alemu ◽  
Asmare Melese

Abstract Background: In acid soils, soluble inorganic phosphorus is fixed by aluminum and iron, so that phosphorous availability to plant would be inhibited. Thus, an incubation study was conducted to evaluate the effects of lime, vermicompost, and mineral P fertilizer on the distribution of P fractions and oxalate and dithionite extractable aluminum and iron. The treatments consisted of three rates of phosphorous (0, 74.51 and 149.01 kg P ha-1), three rates of vermicompost (0, 5 and 10 ton VC ha-1) and four rates of lime (0, 5.70, 9.20, and 11.50 ton CaCO3 ha-1). The experiment was laid out as a complete randomized design in a factorial arrangement. Results: Combined application of lime, vermicompost and mineral P significantly increased (p<0.05) labile phosphorus fractions and decreased potential sorption capacities of the soil. As the increased soil pH, reduced exchangeable acidity and oxalate extractable Fe and Al the integrated applications of these amendments fixed aluminum and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool compared to sole application of the amendments. Conclusions: Combined applications of lime, vermicompost and inorganic P to acidic soils of Goha-1 in Cheha district could convey enhanced amount of available P and ensures the maintenance of higher levels of labile P. It might also contribute towards meeting crop P requirements.


1986 ◽  
Vol 66 (2) ◽  
pp. 303-313 ◽  
Author(s):  
J. F. DORMAAR ◽  
T. G. SOMMERFELDT

A long-term field experiment was initiated in 1973 to determine the safe loading capacity of a Lethbridge loam (Dark Brown Chernozemic) with feedlot manure. The effect of 10 yr of feedlot manure loading was examined by analyzing a number of inorganic and organic matter constituents of the Ap horizon. Although soil C, P, and enzyme activities increased as feedlot manure additions to the soil increased, these increases diminished at triple the recommended loading regimes. Phosphatase activity was checked by increased labile phosphorus levels. Levels of adenosine 5′-triphosphate increased but fluctuated with time under various moisture regimes. The C:N ratios, percent monosaccharide C of total soil C, and the ratio of deoxyhexoses to pentoses remained constant while the percentage of manure C retained decreased as feedlot manure loading increased. The distribution between pentoses and hexoses was strongly affected by feedlot manure levels while the deoxyhexose percentage of the sum of the eight monosaccharides determined remained about the same. Feedlot manure additions, at triple the recommended level, increased the labile P as a percentage of total soil P to around 50%. Although mineralization did not keep pace with the quantities applied, the presence of undecomposed manure did not seem to have harmful agronomic effects. Key words: ATP, feedlot manure, labile phosphorus, monosaccharides, organic matter


2020 ◽  
Vol 20 (4) ◽  
pp. 1241-1252
Author(s):  
Han Wang ◽  
Yuping Han ◽  
Lide Pan

Abstract Based on overlying water and sediment sample collection from 15 sites during July, September, November 2018 and January 2019 in the hydro-fluctuation belt of Danjiangkou reservoir China, the variation of nitrogen (N) was studied. And the concentrations of NH4+-N, NO3−-N and NO2−-N in the sediment, pore water and overlying water were determined to evaluate the diffusion flux across the water–sediment interface. The results showed that the lowest sediment N concentration was 36.54 mg/L in July, and the highest one was 145.93 mg/L in November. Spatially, the sediment N concentrations were higher in tidal soil and loam than in sandy soil. According to the diffusion fluxes of NH4+, NO3− and NO2−, sediments at all sites tend to release N to the overlying water except in the sampling month of November, when the sediment acts as a sink of NO3−. The highest release rates of NH4+-N and NO3−-N were 17.66 mg m−2·d−1 and 80.15 mg m−2·d−1, respectively, which are much higher than the release rate of NO2−-N (0.29 mg m−2·d−1). The findings indicate that hydro-fluctuation belt sediment contributes a lot to the nitrogen contents in the overlying water, and internal pollution is a main reason for the water quality deterioration and even eutrophication.


2014 ◽  
Vol 69 (5) ◽  
pp. 1052-1058 ◽  
Author(s):  
Lichun Dai ◽  
Gang Pan

A natural red soil and a lanthanum-modified soil (LMS) were tested to compare their phosphorus (P) adsorption capacities and their effectiveness in removing P from the water column and reducing P release from sediment. The equilibrium of P adsorption demonstrated that the maximum P adsorption for the soil was 1.29 and 2.22 mg g−1 at pH 8.5 and 5.5, respectively, and for the LMS these were increased by 45.6 and 77.6% at pH 8.5 and 5.5, respectively, indicating that the soil was effective in P adsorption and the doping of lanthanum could substantially increase P adsorption. The sediment–water column incubation showed that, due to the P adsorption of the soil and LMS, the total P in the water column decreased by 58.5, 60.6, 68.2 and 77.2% for 180 g m−2 soil, 900 g m−2 soil, 180 g m−2 LMS and 900 g m−2 LMS treated systems, respectively, in a short time (6 h), and the capping layer substantially reduced the P release from sediment during column incubation, indicating that the soils were effective in reducing internal P load. However, considering the cost of LMS, the natural soil was suggested to be a cost-effective material to control internal P load.


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