The guano of penguins, other seabirds, and pinnipeds is an important source of phosphorus in the ecosystems of Antarctica. To study the vertical distribution of phosphorus in sediments influenced by penguins, we measu...The guano of penguins, other seabirds, and pinnipeds is an important source of phosphorus in the ecosystems of Antarctica. To study the vertical distribution of phosphorus in sediments influenced by penguins, we measured phosphorus forms in two sediment cores ((31 and Q2) from ephemeral ponds on Ardley Island. We also investigated the correlations between these phosphorus forms and physicochemical characteristics. Inorganic phosphorus was the main form of phosphorus in both cores. The vertical distribution patterns of phosphorus forms in G1 and Q2 differed, indicating different sedimentary sources. The GI sediment profile was more influenced by penguin guano than the Q2 profile, and as a result sediments in the G1 core had higher total phosphorus, non-apatite inorganic phosphorus, and apatite phosphorus content. The findings from two ephemeral ponds on Ardley Island indicate that the contribution of penguin guano to organic matter in G1 core has increased in recent times, while Q2 showed a relatively larger contribution from mosses in ancient times, evident from the lithology and the vertical trend in organic matter.展开更多
According to two cruises investigation information in summer and winter during 1998 and 1999, the phosphorous concentration distribution and changes of summer and winter were discussed primarily in the South China Sea...According to two cruises investigation information in summer and winter during 1998 and 1999, the phosphorous concentration distribution and changes of summer and winter were discussed primarily in the South China Sea. The results show that the phosphate concentration of surface seawater in summer is distinctly lower than that in winter, averaging 0.04 mumol/dm(3) in summer and 0.35 mumol/ dm(3) in winter. The organic phosphorous concentration of surface seawater in summer is higher than that in winter, averaging 0.12 mumol/dm(3) in summer and 0. 04 mumol/dm(3) in winter respectively. The seasonal changes of total phosphorus are similar to phosphate, averaging 0.22 mumol/dm(3) in summer and 0.61 mumol/dm(3) in winter respectively. In vertical direction, phosphate, TDP and TP content are the lowest in upper 50 m water column, and increase in linearity rapidly with water depth, increasing slowly under 500 m, reach to maximum about 1000 m, then decrease slightly with water depth increasing. The vertical distribution is typical in summer, and there is small dispersed for phosphorus concentration for the same depth of different stations. However, in winter there is a large disperse for phosphate, TDP and TP, specifically for phosphate at 200 m at which the concentration is maximum. This result indicates that there are large differences in hydrology and biology conditions that affect largely the chemical environment of the South China Sea. The organic phosphorus is the predominant in surface seawater of the South China Sea, but the inorganic phosphorus is the predominant in layers below depth of 150 m. The organic phosphorus concentration in deep water usually decreases with water depth increasing. The organic phosphorus in summer is remarkably more than that in winter because of the strong biology activities in summer.展开更多
An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic a...An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic apatite plus biogenic apatite plus CaCO 3- associated P (CFAP P), detrital apatite P (FAP P), and organic bound P (Org P) in suspended matter and surface sediments of the Huanghe River (Yellow River), its estuary and nearby shelf. The concentrations of dissolved inorganic and organic P in river water were also determined. A dissolved P flux of 1.6 billion grams per year, solubilized P flux of 281 billion grams per year, and buried P flux of 588 billion grams per year from the Huanghe River to the Bohai Sea were calculated using the concentrations of P determined in the water column, suspended matter and sediments. Due to the high suspended load and low discharge of the Huanghe River, the direct contribution of dissolved P carried in solution by it to the Bohai Sea is minor compared to the solubilized P released from the suspended matter and sediments. More than two thirds of the total P transported by the Huanghe River is deposited and buried in marine sediments. Decomposition of riverine organic matter which releases organic bound P is an essential source of dissolved/solubilized P in the sea.展开更多
The study was conducted to reveal P fractions and N forms changing characters during composting of pig manure with rice straw.During composting,the NH 4 +-N concentration decreased and reached at a relatively low va...The study was conducted to reveal P fractions and N forms changing characters during composting of pig manure with rice straw.During composting,the NH 4 +-N concentration decreased and reached at a relatively low value(〈400 mg kg-1) in the final compost,while the NO 3--N concentration increased.Total N losses mainly occurred during thermophilic phase due to the high temperature,the high NH 4 +-N concentration and the increase of pH value.Labile inorganic P was dominated in the pig manure and initial compost mixture.During composting,the proportion of labile inorganic P of total extracted P decreased,while the proportion of Fe+Al-bound P,Ca+Mg-bound P and residual P increased.The evolutions of the proportion of labile inorganic P,Fe+Al-bound P and Ca+Mg-bound P were well correlated with the changes of pH value,organic matter and C/N ratio.Therefore,composting could increase the concentration of N and P and decrease the presence of NH 4 +-N and labile P fractions which might cause environmental issues following land application.展开更多
Phosphorus(P) bioavailability is an important factor in alpine meadows and plays an important role in the response to climate change and the maintenance of ecosystem functioning.However,little is known about how envir...Phosphorus(P) bioavailability is an important factor in alpine meadows and plays an important role in the response to climate change and the maintenance of ecosystem functioning.However,little is known about how environmental factors,such as elevation and slope aspect,affect soil P bioavailability.We explored the effects of elevational gradient and slope aspect on different forms of P and P availability in the alpine meadows on the southern slope of the Tian Shan Mountain range.Total P was found to be 851.9-1556.7 mg·kg^(-1) at different elevational gradients and 437.5-1547.0 mg·kg^(-1) at different slope aspects,and highest at 3337 and 3652 m.a.s.l.,but little differences between slope aspects.Olsen P and Labile P linearly increased with the elevational gradient.The valley and the base of the shady slope had higher contents of H_2O-Po.NaHCO_3-Pi,and NaHCO_3-Po,and high-active organic P(NaHCO_3-Po,NaOH-Po,and H_2O-Po) was positively correlated with soil total carbon(TC),total nitrogen(TN),soil organic carbon(SOC),and aboveground biomass(AGB),but was negatively correlated with pH,aluminum(Al),and calcium(Ca) at different elevational gradients.High-active bioavailable P(H_2OPi,H_2O-Po,NaHCO_3-Pi,and NaHCO_3-Po) was positively correlated with soil SOC and AGB and was negatively correlated with pH at different slope aspects.Our results suggest that soil P availability in alpine meadows is significantly controlled by topographical factors and the valleys and base of shady slopes are reservoirs of high-active bioavailable P.展开更多
Chemical forms of phosphorus in the sediments of the Daya Bay, the Zhujiang River estuary , and the Xiamen Bay are measured with extraction solutions of MgCl2, NaOH, and HC1. Their availabilities to Chlorella sp. and ...Chemical forms of phosphorus in the sediments of the Daya Bay, the Zhujiang River estuary , and the Xiamen Bay are measured with extraction solutions of MgCl2, NaOH, and HC1. Their availabilities to Chlorella sp. and Isochrysis galbana are estimated by using sediments as the sole source of P in the bioassays. The results show that the contents of total phosphorus (TP) in these sediments are 449.3, 650.1 and 643.9 mg/kg, respectively. The contents of non-apatite inorganic P (NAIP) extracted with MgCl2 and NaOH from 3 sediments are 168.8, 146.6 and 118.1 mg/kg, respectively, and account for 18.3% -32.6% of TP. The phosphorus extracted with HC1 solution is greater than that extracted with NaOH solution and the lowest extracted P is MgCl2-extractable P. The greatest relative growth rates of Chlorella sp. and Isochrysis galbana cultured with sediments are in the range of 4.3% -26.9%. The increasing biomasses of these algae correspond to NAIP and AAPP (the estimated algal-available particulate P). AAPP accounts for 42.4% -78.2% of NAIP, 21.1 % - 27.1% of total inorganic P, and 11.8% - 20.3% of TP, respectively.展开更多
This paper takes the sediments of Dianchi Lake as the research object.The results show that the total phosphorus content in the sediments of Dianchi Lake is relatively high,and the spatial variation is large,ranging f...This paper takes the sediments of Dianchi Lake as the research object.The results show that the total phosphorus content in the sediments of Dianchi Lake is relatively high,and the spatial variation is large,ranging from 1,193.94 to 4,629.25 mg/kg.The spatial distribution characteristics of total phosphorus in the sediments of Dianchi Lake have obvious regional differences.The average content of total phosphorus in the sediments of Dianchi Lake is 2,184.39(+579.09 mg/kg),and the TP(Total Phosphorus)content in the areas over 60%of the lake is higher than 2,000 mg/kg,which is in heavily flat.By analyzing the distribution of phosphorus forms in surface sediments of different areas of Dianchi Lake,it can be concluded that the difference is significant.The relationship between the phosphorus contents of different forms is HCl-P>NaOH-rP>NaOH-nrP>Res-P>BD-P.Through summarizing the characteristics of different phosphorus distribution in the sediments of Dianchi Lake,this paper concludes that the sustained release of endogenous phosphorus load will be an important factor to delay the ecological health recovery time of Dianchi Lake and offset the effect of exogenous treatment.展开更多
Phosphorus is a key element and plays an important role in global biogeochemical cycles. The evolution of sedimentary environment is also influenced by phosphorus concentrations and fractions as well as phosphate sorp...Phosphorus is a key element and plays an important role in global biogeochemical cycles. The evolution of sedimentary environment is also influenced by phosphorus concentrations and fractions as well as phosphate sorption characteristics of the marine sediments. The geochemical characteristics of phosphorus and their environmental records were presented in Jiaozhou Bay sediments. Profiles of different forms of phosphorus were measured as well as the roles and vertical distributions of phosphorus forms in response to sedimentary environment changes were investigated. The results showed that inorganic phosphorus (IP) was the major fraction of total phosphorus (TP); phosphorus which is bound to calcium, iron and occluded phosphorus, as well as the exchangeable phosphorus were the main forms of IP, especially calcium - phosphorus, including detrital carbonate-bound phosphorus (Det- P) and authigenic apatite-bound phosphorus (ACa- P), are the uppermost constituent of IP in Jiaozhou Bay sediments. Moreover, the lead-210 chronology technology was employed to estimate how much phosphorus was buried ultimately in sediments. And the research showed that the impacts of human activities have increased remarkably in recent years especially between the 1980s and 2000. According to research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages : ( 1 ) before the 1980s characterized by the relatively low sedimentation rate, weak land-derived phosphorus inputs and low anthropogenic impacts; (2) from the 1980s to around 2000, accelerating in the 1990s, during which high sedimentation rates, high phosphorus abundance and burial fluxes due to the severe human activities impacted on the whole environmental system ; ( 3 ) after 2000, the period of the improvement of environment, the whole system has been improved including the decreasing sedimentation rates, concentration and the burial fluxes of phosphorus.展开更多
There is a global concern about the depletion in phosphorus (P) resources in the near future. Some attempts for effective reuse of P, including recovery from municipal wastes, have been conducted. However, a strong so...There is a global concern about the depletion in phosphorus (P) resources in the near future. Some attempts for effective reuse of P, including recovery from municipal wastes, have been conducted. However, a strong sorption of P onto some minerals may result in low P availability for crops. Therefore, it is necessary to understand the speciation of the chemical forms of P and to elucidate the relationships between P availability and chemical forms of P in soil. This study focuses on the variation in P speciation and the chemical forms of available P in a paddy soil. Incubation experiments with/without drainage, simulating the situation in a paddy field, were performed at a laboratory scale to evaluate the variation in speciation and P availability in soil. The speciation of P was analyzed according to Wilson’s sequential extraction method and measured using Bray No. 2 and Truog methods. Two kinds of chemical forms, i.e. , Fe and Mn (oxy)hydroxides (Fe-Mn-P) and organic and biogenic P (Org-P) were predominant in the soil, and they were easily interconverted by changing soil redox conditions. Available P using the Bray No. 2 method was increased in 21 days owing to the anaerobic condition;thereafter, it reached a constant value by the end of both the incubation experiments. However, a drastic decrease was detected in available P, using Truog-P. It occurred owing to the drying of soil, which suggested that some chemical form(s) of P other than Truog-P might be generated. A comparison between the concentrations of available P and that of each chemical form showed that available P included some Org-P, which might be less absorbed by plants compared to the exchangeable and pore water fraction (Ex-P) and Fe-Mn-P. We conclude that anaerobic soil conditions play an important role in the efficient consumption of P.展开更多
Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,w...Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,which in turn depend on the sedimentary environment.Here,sediment samples from Baiyangdian(BYD)lake were collected and measured by the Standards,Measurements,and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy(31P NMR)to characterize different P forms and their relationships with sediment physicochemical properties.The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input.Inorganic P(334–916 mg/kg)was the dominant form of P.The 31P NMR results demonstrated that orthophosphate monoesters(16–110 mg/kg),which may be a source of P when redox conditions change,was the dominant form of organic P(20–305 mg/kg).The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities,and the regions affected by exogenous river input had a higher content of P and a higher risk of P release.Principal component analysis indicated that P bound to Fe,Al,and Mn oxides and hydroxides(NaOH-P)and organic P were mainly derived from industrial and agricultural pollution,respectively.Redundancy analysis indicated that increases in pH lead to the release of NaOH-P.Organic matter plays an important role in the organic P biogeochemical cycle,as it acts as a sink and source of organic P.展开更多
In this study,aluminum-based P-inactivation agent(Al-PIA)was used as a high-efficiency microbial carrier,and the biological Al-PIA(BA-PIA)was prepared by artificial aeration.Laboratory static experiments were conducte...In this study,aluminum-based P-inactivation agent(Al-PIA)was used as a high-efficiency microbial carrier,and the biological Al-PIA(BA-PIA)was prepared by artificial aeration.Laboratory static experiments were conducted to study the effect of BA-PIA on reducing nitrogen and phosphorus contents in water.Physicochemical characterization and isotope tracing method were applied to analyze the removal mechanism of nitrogen and phosphorus.High-throughput techniques were used to analyze the characteristic bacterial genus in the BA-PIA system.The nitrogen and phosphorus removal experiment was conducted for 30 days,and the removal rates of NH_(4)^(+)-N,TN and TP by BA-PIA were 81.87%,66.08%and 87.97%,respectively.The nitrogen removal pathways of BA-PIA were as follows:the nitrification reaction accounted for 59.0%(of which denitrification reaction accounted for 56.4%),microbial assimilation accounted for 18.1%,and the unreacted part accounted for 22.9%.The characteristic bacteria in the BA-PIA system were Streptomyces,Nocardioides,Saccharopolyspora,Nitrosomonas,and Marinobacter.The loading of microorganisms only changed the surface physical properties of Al-PIA(such as specific surface area,pore volume and pore size),without changing its surface chemical properties.The removal mechanism of nitrogen by BA-PIA is the conversion of NH_(4)^(+)-N into NO_(2)^(−)-N and NO_(3)^(−)-N by nitrifying bacteria,which are then reduced to nitrogen-containing gas by aerobic denitrifying bacteria.The phosphorus removal mechanism is that metal compounds(such as Al)on the surface of BA-PIA fix phosphorus through chemisorption processes,such as ligand exchange.Therefore,BA-PIA overcomes the deficiency of Al-PIA with only phosphorus removal ability,and has better application prospects.展开更多
The distribution and forms of phosphorus (P) were investigated in the tidal flat sediments of the Yangtze Estuary and coast. The total P contents in surface sediments range from 18.0 to 31.4 μmol · g-1 along the...The distribution and forms of phosphorus (P) were investigated in the tidal flat sediments of the Yangtze Estuary and coast. The total P contents in surface sediments range from 18.0 to 31.4 μmol · g-1 along the southern coast. The spatial and temporal distribution of P in tidal flats is closely related to the location and pollution resources, especially in association with the variation of hydrodynamic conditions. Significant variations in the forms of P in different sites were observed. P bonded with Ca(Ca-P) is the dominant mineral form in all surface sediments, organic P(Org-P) is lower. Most P is of unstable form, suggesting that P has larger potential activity. P accumulation is the main behavior process between water and sediment in the coastal environment of the Yangtze Estuary.展开更多
Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AA...Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest.However, content of ferric fraction phosphorus (Fe-P) was highest in 4-10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu.展开更多
Without the Lipschitz assumption and boundedness of K in arbitrary Banach spaces, the Ishikawa iteration {x n} ∞ n=1 defined byx 1∈K,\ x n+1 =(1-α n)x n+α nTy n,\ y n=(1-β n)x n+β n...Without the Lipschitz assumption and boundedness of K in arbitrary Banach spaces, the Ishikawa iteration {x n} ∞ n=1 defined byx 1∈K,\ x n+1 =(1-α n)x n+α nTy n,\ y n=(1-β n)x n+β nTx n,\ n≥1satisfying 0<α n,β n<1 ,for all n≥1;∑ ∞ n=1 α n=∞;α n→0,β n→0 as n→∞ is proved to converge strongly to the unique fixed point of T ,where T:K→K is a uniformly continuous strictly pseudo\|contractive operator with bounded range.展开更多
On March 16th, Clariant announced to establisha joint venture with Kunming GaohengHuagong Chemical Industry Co., Ltd. andPanchem International Trading and IndustrialCo. in Kunming, Yunnan province, in order tosecure s...On March 16th, Clariant announced to establisha joint venture with Kunming GaohengHuagong Chemical Industry Co., Ltd. andPanchem International Trading and IndustrialCo. in Kunming, Yunnan province, in order tosecure supply and meet the growing demandfor phosphorus pentoxide (P<sub>2</sub>O<sub>5</sub>).A state-of-the-art phosphorus pentoxideplant will be built and is scheduled to go onstream in the first quarter 2010.展开更多
Phosphatase may accelerate the process of lake eutrophication through improving phosphorus bioavailability. This mechanism was studied in three Chinese eutrophic shallow lakes (Lake Taihu, Lake Longyang and Lake Lianh...Phosphatase may accelerate the process of lake eutrophication through improving phosphorus bioavailability. This mechanism was studied in three Chinese eutrophic shallow lakes (Lake Taihu, Lake Longyang and Lake Lianhua). Phosphatase activity was related to the concentration of soluble reactive phosphorus (SRP) and chlorophyll a. Stability of dissolved phosphatase in reverse micelles may be attributed to molecular size, conformation and active residues of the enzyme.At the site with Microcystis bloomed in Lake Taihu, dissolved phosphatase activity was higher and more stable in micelles, SRP concentrations were lower in interstitial water, the contents of different forms of phosphorus and the amounts of aerobic bacteria were lower while respiration efficiency was higher in sediments. Phosphobacteria, both inorganic and organic and other microorganisms were abundant in surface water but rare in sediments. Therefore, internal phosphorus may substantially flux into water column by enzymatic hydrolysis and anaerobic release, together with mobility of bacteria,thereby initiating the bloom. In short, biological mechanism may act in concert with physical and chemical factors to drive the internal phosphorus release and accelerate lake eutrophication.展开更多
Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and ...Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and glycogen accumulating organisms(GAOs)in start-up stage.During the 34 days operation,SBR was set with temperature variation(0-5 d,22±1℃;6-13 d,29±1℃;14-34 d,14±1℃).PAOs and GAOs were analyzed by fluorescent in situ hybridization(FISH),and intracellular polyphosphate granules were stained by Neisser-stain.The results showed that the influence of temperature shock on PAOs’abundance was more serious than that on GAOs in the enriching process.Under sudden and substantially temperature variation,from 22±1℃ to 29±1℃ and then to 14±1℃,the domination of PAOs was deteriorated.After temperature shock,PAOs’competitive advantages at low temperature that concluded in other study did not appear in our study.As mesophilic,GAOs(indicated by Alphaproteobacteria and Gammaproteobacteria)were more temperature adaptive and better grew and took the domination at 14±1℃ in the end.In the competition process,organisms of tetrad forming organisms(TFOs)-like shape which were considered as typical GAOs,were observed.With the evidence of poly-P granules containing by Neisser-straining and result of FISH,these organisms of TFOs-like shape were better to be assumed as adaption state or a special self-protecting shape of PAOs.展开更多
基金funded by the Chinese Polar Environment Comprehensive Investigation & Assessment Programs (Grant no. CHINARE2015-02-01)
文摘The guano of penguins, other seabirds, and pinnipeds is an important source of phosphorus in the ecosystems of Antarctica. To study the vertical distribution of phosphorus in sediments influenced by penguins, we measured phosphorus forms in two sediment cores ((31 and Q2) from ephemeral ponds on Ardley Island. We also investigated the correlations between these phosphorus forms and physicochemical characteristics. Inorganic phosphorus was the main form of phosphorus in both cores. The vertical distribution patterns of phosphorus forms in G1 and Q2 differed, indicating different sedimentary sources. The GI sediment profile was more influenced by penguin guano than the Q2 profile, and as a result sediments in the G1 core had higher total phosphorus, non-apatite inorganic phosphorus, and apatite phosphorus content. The findings from two ephemeral ponds on Ardley Island indicate that the contribution of penguin guano to organic matter in G1 core has increased in recent times, while Q2 showed a relatively larger contribution from mosses in ancient times, evident from the lithology and the vertical trend in organic matter.
基金National Basic Research Priorities Programme of China under contract No.G2000078500.
文摘According to two cruises investigation information in summer and winter during 1998 and 1999, the phosphorous concentration distribution and changes of summer and winter were discussed primarily in the South China Sea. The results show that the phosphate concentration of surface seawater in summer is distinctly lower than that in winter, averaging 0.04 mumol/dm(3) in summer and 0.35 mumol/ dm(3) in winter. The organic phosphorous concentration of surface seawater in summer is higher than that in winter, averaging 0.12 mumol/dm(3) in summer and 0. 04 mumol/dm(3) in winter respectively. The seasonal changes of total phosphorus are similar to phosphate, averaging 0.22 mumol/dm(3) in summer and 0.61 mumol/dm(3) in winter respectively. In vertical direction, phosphate, TDP and TP content are the lowest in upper 50 m water column, and increase in linearity rapidly with water depth, increasing slowly under 500 m, reach to maximum about 1000 m, then decrease slightly with water depth increasing. The vertical distribution is typical in summer, and there is small dispersed for phosphorus concentration for the same depth of different stations. However, in winter there is a large disperse for phosphate, TDP and TP, specifically for phosphate at 200 m at which the concentration is maximum. This result indicates that there are large differences in hydrology and biology conditions that affect largely the chemical environment of the South China Sea. The organic phosphorus is the predominant in surface seawater of the South China Sea, but the inorganic phosphorus is the predominant in layers below depth of 150 m. The organic phosphorus concentration in deep water usually decreases with water depth increasing. The organic phosphorus in summer is remarkably more than that in winter because of the strong biology activities in summer.
文摘An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic apatite plus biogenic apatite plus CaCO 3- associated P (CFAP P), detrital apatite P (FAP P), and organic bound P (Org P) in suspended matter and surface sediments of the Huanghe River (Yellow River), its estuary and nearby shelf. The concentrations of dissolved inorganic and organic P in river water were also determined. A dissolved P flux of 1.6 billion grams per year, solubilized P flux of 281 billion grams per year, and buried P flux of 588 billion grams per year from the Huanghe River to the Bohai Sea were calculated using the concentrations of P determined in the water column, suspended matter and sediments. Due to the high suspended load and low discharge of the Huanghe River, the direct contribution of dissolved P carried in solution by it to the Bohai Sea is minor compared to the solubilized P released from the suspended matter and sediments. More than two thirds of the total P transported by the Huanghe River is deposited and buried in marine sediments. Decomposition of riverine organic matter which releases organic bound P is an essential source of dissolved/solubilized P in the sea.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment (2012ZX07201004)Jilin Provincial Research Foundation for Basic Research, China (201105033)
文摘The study was conducted to reveal P fractions and N forms changing characters during composting of pig manure with rice straw.During composting,the NH 4 +-N concentration decreased and reached at a relatively low value(〈400 mg kg-1) in the final compost,while the NO 3--N concentration increased.Total N losses mainly occurred during thermophilic phase due to the high temperature,the high NH 4 +-N concentration and the increase of pH value.Labile inorganic P was dominated in the pig manure and initial compost mixture.During composting,the proportion of labile inorganic P of total extracted P decreased,while the proportion of Fe+Al-bound P,Ca+Mg-bound P and residual P increased.The evolutions of the proportion of labile inorganic P,Fe+Al-bound P and Ca+Mg-bound P were well correlated with the changes of pH value,organic matter and C/N ratio.Therefore,composting could increase the concentration of N and P and decrease the presence of NH 4 +-N and labile P fractions which might cause environmental issues following land application.
基金grants from the National Natural Science Foundation of China(U1703244)
文摘Phosphorus(P) bioavailability is an important factor in alpine meadows and plays an important role in the response to climate change and the maintenance of ecosystem functioning.However,little is known about how environmental factors,such as elevation and slope aspect,affect soil P bioavailability.We explored the effects of elevational gradient and slope aspect on different forms of P and P availability in the alpine meadows on the southern slope of the Tian Shan Mountain range.Total P was found to be 851.9-1556.7 mg·kg^(-1) at different elevational gradients and 437.5-1547.0 mg·kg^(-1) at different slope aspects,and highest at 3337 and 3652 m.a.s.l.,but little differences between slope aspects.Olsen P and Labile P linearly increased with the elevational gradient.The valley and the base of the shady slope had higher contents of H_2O-Po.NaHCO_3-Pi,and NaHCO_3-Po,and high-active organic P(NaHCO_3-Po,NaOH-Po,and H_2O-Po) was positively correlated with soil total carbon(TC),total nitrogen(TN),soil organic carbon(SOC),and aboveground biomass(AGB),but was negatively correlated with pH,aluminum(Al),and calcium(Ca) at different elevational gradients.High-active bioavailable P(H_2OPi,H_2O-Po,NaHCO_3-Pi,and NaHCO_3-Po) was positively correlated with soil SOC and AGB and was negatively correlated with pH at different slope aspects.Our results suggest that soil P availability in alpine meadows is significantly controlled by topographical factors and the valleys and base of shady slopes are reservoirs of high-active bioavailable P.
文摘Chemical forms of phosphorus in the sediments of the Daya Bay, the Zhujiang River estuary , and the Xiamen Bay are measured with extraction solutions of MgCl2, NaOH, and HC1. Their availabilities to Chlorella sp. and Isochrysis galbana are estimated by using sediments as the sole source of P in the bioassays. The results show that the contents of total phosphorus (TP) in these sediments are 449.3, 650.1 and 643.9 mg/kg, respectively. The contents of non-apatite inorganic P (NAIP) extracted with MgCl2 and NaOH from 3 sediments are 168.8, 146.6 and 118.1 mg/kg, respectively, and account for 18.3% -32.6% of TP. The phosphorus extracted with HC1 solution is greater than that extracted with NaOH solution and the lowest extracted P is MgCl2-extractable P. The greatest relative growth rates of Chlorella sp. and Isochrysis galbana cultured with sediments are in the range of 4.3% -26.9%. The increasing biomasses of these algae correspond to NAIP and AAPP (the estimated algal-available particulate P). AAPP accounts for 42.4% -78.2% of NAIP, 21.1 % - 27.1% of total inorganic P, and 11.8% - 20.3% of TP, respectively.
文摘This paper takes the sediments of Dianchi Lake as the research object.The results show that the total phosphorus content in the sediments of Dianchi Lake is relatively high,and the spatial variation is large,ranging from 1,193.94 to 4,629.25 mg/kg.The spatial distribution characteristics of total phosphorus in the sediments of Dianchi Lake have obvious regional differences.The average content of total phosphorus in the sediments of Dianchi Lake is 2,184.39(+579.09 mg/kg),and the TP(Total Phosphorus)content in the areas over 60%of the lake is higher than 2,000 mg/kg,which is in heavily flat.By analyzing the distribution of phosphorus forms in surface sediments of different areas of Dianchi Lake,it can be concluded that the difference is significant.The relationship between the phosphorus contents of different forms is HCl-P>NaOH-rP>NaOH-nrP>Res-P>BD-P.Through summarizing the characteristics of different phosphorus distribution in the sediments of Dianchi Lake,this paper concludes that the sustained release of endogenous phosphorus load will be an important factor to delay the ecological health recovery time of Dianchi Lake and offset the effect of exogenous treatment.
文摘Phosphorus is a key element and plays an important role in global biogeochemical cycles. The evolution of sedimentary environment is also influenced by phosphorus concentrations and fractions as well as phosphate sorption characteristics of the marine sediments. The geochemical characteristics of phosphorus and their environmental records were presented in Jiaozhou Bay sediments. Profiles of different forms of phosphorus were measured as well as the roles and vertical distributions of phosphorus forms in response to sedimentary environment changes were investigated. The results showed that inorganic phosphorus (IP) was the major fraction of total phosphorus (TP); phosphorus which is bound to calcium, iron and occluded phosphorus, as well as the exchangeable phosphorus were the main forms of IP, especially calcium - phosphorus, including detrital carbonate-bound phosphorus (Det- P) and authigenic apatite-bound phosphorus (ACa- P), are the uppermost constituent of IP in Jiaozhou Bay sediments. Moreover, the lead-210 chronology technology was employed to estimate how much phosphorus was buried ultimately in sediments. And the research showed that the impacts of human activities have increased remarkably in recent years especially between the 1980s and 2000. According to research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages : ( 1 ) before the 1980s characterized by the relatively low sedimentation rate, weak land-derived phosphorus inputs and low anthropogenic impacts; (2) from the 1980s to around 2000, accelerating in the 1990s, during which high sedimentation rates, high phosphorus abundance and burial fluxes due to the severe human activities impacted on the whole environmental system ; ( 3 ) after 2000, the period of the improvement of environment, the whole system has been improved including the decreasing sedimentation rates, concentration and the burial fluxes of phosphorus.
文摘There is a global concern about the depletion in phosphorus (P) resources in the near future. Some attempts for effective reuse of P, including recovery from municipal wastes, have been conducted. However, a strong sorption of P onto some minerals may result in low P availability for crops. Therefore, it is necessary to understand the speciation of the chemical forms of P and to elucidate the relationships between P availability and chemical forms of P in soil. This study focuses on the variation in P speciation and the chemical forms of available P in a paddy soil. Incubation experiments with/without drainage, simulating the situation in a paddy field, were performed at a laboratory scale to evaluate the variation in speciation and P availability in soil. The speciation of P was analyzed according to Wilson’s sequential extraction method and measured using Bray No. 2 and Truog methods. Two kinds of chemical forms, i.e. , Fe and Mn (oxy)hydroxides (Fe-Mn-P) and organic and biogenic P (Org-P) were predominant in the soil, and they were easily interconverted by changing soil redox conditions. Available P using the Bray No. 2 method was increased in 21 days owing to the anaerobic condition;thereafter, it reached a constant value by the end of both the incubation experiments. However, a drastic decrease was detected in available P, using Truog-P. It occurred owing to the drying of soil, which suggested that some chemical form(s) of P other than Truog-P might be generated. A comparison between the concentrations of available P and that of each chemical form showed that available P included some Org-P, which might be less absorbed by plants compared to the exchangeable and pore water fraction (Ex-P) and Fe-Mn-P. We conclude that anaerobic soil conditions play an important role in the efficient consumption of P.
基金supported by the Beijing Municipal Science and Technology Plan Project (No. Z181100005518005)the National Natural Science Foundation of China (Nos. 51579009, 51879012)the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2018ZX07110004)
文摘Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,which in turn depend on the sedimentary environment.Here,sediment samples from Baiyangdian(BYD)lake were collected and measured by the Standards,Measurements,and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy(31P NMR)to characterize different P forms and their relationships with sediment physicochemical properties.The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input.Inorganic P(334–916 mg/kg)was the dominant form of P.The 31P NMR results demonstrated that orthophosphate monoesters(16–110 mg/kg),which may be a source of P when redox conditions change,was the dominant form of organic P(20–305 mg/kg).The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities,and the regions affected by exogenous river input had a higher content of P and a higher risk of P release.Principal component analysis indicated that P bound to Fe,Al,and Mn oxides and hydroxides(NaOH-P)and organic P were mainly derived from industrial and agricultural pollution,respectively.Redundancy analysis indicated that increases in pH lead to the release of NaOH-P.Organic matter plays an important role in the organic P biogeochemical cycle,as it acts as a sink and source of organic P.
基金supported by the National Natural Science Fund of China(No.51878300)the Natural Science Foundation of Fujian Province of China(No.2019J01052)the Science and Technology Project Foundation of Xiamen City(No.3502Z20203044).
文摘In this study,aluminum-based P-inactivation agent(Al-PIA)was used as a high-efficiency microbial carrier,and the biological Al-PIA(BA-PIA)was prepared by artificial aeration.Laboratory static experiments were conducted to study the effect of BA-PIA on reducing nitrogen and phosphorus contents in water.Physicochemical characterization and isotope tracing method were applied to analyze the removal mechanism of nitrogen and phosphorus.High-throughput techniques were used to analyze the characteristic bacterial genus in the BA-PIA system.The nitrogen and phosphorus removal experiment was conducted for 30 days,and the removal rates of NH_(4)^(+)-N,TN and TP by BA-PIA were 81.87%,66.08%and 87.97%,respectively.The nitrogen removal pathways of BA-PIA were as follows:the nitrification reaction accounted for 59.0%(of which denitrification reaction accounted for 56.4%),microbial assimilation accounted for 18.1%,and the unreacted part accounted for 22.9%.The characteristic bacteria in the BA-PIA system were Streptomyces,Nocardioides,Saccharopolyspora,Nitrosomonas,and Marinobacter.The loading of microorganisms only changed the surface physical properties of Al-PIA(such as specific surface area,pore volume and pore size),without changing its surface chemical properties.The removal mechanism of nitrogen by BA-PIA is the conversion of NH_(4)^(+)-N into NO_(2)^(−)-N and NO_(3)^(−)-N by nitrifying bacteria,which are then reduced to nitrogen-containing gas by aerobic denitrifying bacteria.The phosphorus removal mechanism is that metal compounds(such as Al)on the surface of BA-PIA fix phosphorus through chemisorption processes,such as ligand exchange.Therefore,BA-PIA overcomes the deficiency of Al-PIA with only phosphorus removal ability,and has better application prospects.
基金This work was supported by National Natural Science Foundation of China (Grant Nos. 49901015and 49771011) the State Key Laboratory of Estuary and Coast.
文摘The distribution and forms of phosphorus (P) were investigated in the tidal flat sediments of the Yangtze Estuary and coast. The total P contents in surface sediments range from 18.0 to 31.4 μmol · g-1 along the southern coast. The spatial and temporal distribution of P in tidal flats is closely related to the location and pollution resources, especially in association with the variation of hydrodynamic conditions. Significant variations in the forms of P in different sites were observed. P bonded with Ca(Ca-P) is the dominant mineral form in all surface sediments, organic P(Org-P) is lower. Most P is of unstable form, suggesting that P has larger potential activity. P accumulation is the main behavior process between water and sediment in the coastal environment of the Yangtze Estuary.
基金This work was supported by the Chinese Academy of Sciences(Grant No.KZCX1-SW-12)the National Natural Science Foundation of China(grant No.40203007)+1 种基金the Ministry of Science and Technology of China(Grant No.2002AA601011)Director Foundation of Nanjing Institute of Geography and Limnology,CAS.
文摘Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest.However, content of ferric fraction phosphorus (Fe-P) was highest in 4-10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu.
文摘Without the Lipschitz assumption and boundedness of K in arbitrary Banach spaces, the Ishikawa iteration {x n} ∞ n=1 defined byx 1∈K,\ x n+1 =(1-α n)x n+α nTy n,\ y n=(1-β n)x n+β nTx n,\ n≥1satisfying 0<α n,β n<1 ,for all n≥1;∑ ∞ n=1 α n=∞;α n→0,β n→0 as n→∞ is proved to converge strongly to the unique fixed point of T ,where T:K→K is a uniformly continuous strictly pseudo\|contractive operator with bounded range.
文摘On March 16th, Clariant announced to establisha joint venture with Kunming GaohengHuagong Chemical Industry Co., Ltd. andPanchem International Trading and IndustrialCo. in Kunming, Yunnan province, in order tosecure supply and meet the growing demandfor phosphorus pentoxide (P<sub>2</sub>O<sub>5</sub>).A state-of-the-art phosphorus pentoxideplant will be built and is scheduled to go onstream in the first quarter 2010.
基金supported by the Chinese Academy of Sciences(CAS)(Grant No.KZCX1-SW-12-Ⅱ-02-02)the National Natural Basic Research Program of China(Grant No.2002CB412304)+1 种基金the National Natural Science Foundation of China(Grant No.20177033)the funds(Grant No.2002AA601013).
文摘Phosphatase may accelerate the process of lake eutrophication through improving phosphorus bioavailability. This mechanism was studied in three Chinese eutrophic shallow lakes (Lake Taihu, Lake Longyang and Lake Lianhua). Phosphatase activity was related to the concentration of soluble reactive phosphorus (SRP) and chlorophyll a. Stability of dissolved phosphatase in reverse micelles may be attributed to molecular size, conformation and active residues of the enzyme.At the site with Microcystis bloomed in Lake Taihu, dissolved phosphatase activity was higher and more stable in micelles, SRP concentrations were lower in interstitial water, the contents of different forms of phosphorus and the amounts of aerobic bacteria were lower while respiration efficiency was higher in sediments. Phosphobacteria, both inorganic and organic and other microorganisms were abundant in surface water but rare in sediments. Therefore, internal phosphorus may substantially flux into water column by enzymatic hydrolysis and anaerobic release, together with mobility of bacteria,thereby initiating the bloom. In short, biological mechanism may act in concert with physical and chemical factors to drive the internal phosphorus release and accelerate lake eutrophication.
基金This research was supported by the National Nature Science Foundation of China(Grant No.50821002,National Creative Research Groups)Mega-Projects of Science Research for Water(No.2008ZX07207-005-003)the National Natural Science Foundation of China(Grant No.50638020).
文摘Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and glycogen accumulating organisms(GAOs)in start-up stage.During the 34 days operation,SBR was set with temperature variation(0-5 d,22±1℃;6-13 d,29±1℃;14-34 d,14±1℃).PAOs and GAOs were analyzed by fluorescent in situ hybridization(FISH),and intracellular polyphosphate granules were stained by Neisser-stain.The results showed that the influence of temperature shock on PAOs’abundance was more serious than that on GAOs in the enriching process.Under sudden and substantially temperature variation,from 22±1℃ to 29±1℃ and then to 14±1℃,the domination of PAOs was deteriorated.After temperature shock,PAOs’competitive advantages at low temperature that concluded in other study did not appear in our study.As mesophilic,GAOs(indicated by Alphaproteobacteria and Gammaproteobacteria)were more temperature adaptive and better grew and took the domination at 14±1℃ in the end.In the competition process,organisms of tetrad forming organisms(TFOs)-like shape which were considered as typical GAOs,were observed.With the evidence of poly-P granules containing by Neisser-straining and result of FISH,these organisms of TFOs-like shape were better to be assumed as adaption state or a special self-protecting shape of PAOs.