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A method is developed for estimation of accelerated nutrient release rates into a soil from particulate fertiliser formulations, by carrying out release studies at elevated temperatures. This can provide time-saving targetting of samples to be subsequently used in field trials. The rate of total phosphorus leaching into water from a standard commercial fertiliser product embedded in grey, deep, sandy duplex soil was monitored using inductively coupled plasma-optical emission spectroscopy. The time dependence of phosphate concentration at a given temperature was found to obey simple first- order kinetics. These data fitted an Arrhenius relation within acceptable limits, enabling release rates at ambient field temperatures to be estimated significantly faster than by field experiment. A release rate calculated for the accelerated test, i.e. (1.2 ± 0.1) x [10.sup.-3]/min, when compared with a more standard-type pot-trial leaching rate for the corresponding temperature of 2.3 x [10.sup.-4]/min, gives a direct correlation of ~1 : 1 when corrected for concentration differences. Additional keywords: Arrhenius, ICP-OES, leaching, kinetics, phosphate, soil., Introduction Fertiliser loss to soil water seepage and surface runoff not only results in wastage of fertiliser resources but also contributes to algal blooms and eutrophication. In coastal waters, this [...]

Ultraviolet solar radiation (UVR) and atmospheric nutrient inputs associated with aerosols are major worldwide stressors that simultaneously affect species and the interaction among them. A 2 x 5 field experimental design was used to determine how variations in light regimes (presence and absence of UVR [+UVR and--UVR]) and nutrients might influence the strength of phytoplankton--zooplankton coupling (PZC). We observed unimodal curves for zooplankton biomass in response to increased food supply from nutrient enrichment. These results challenge the 'more is better (or at least never worse)' concept, since high food levels resulted in weakened PZC. The effect of UVR on zooplankton was nutrient dependent, significantly reducing zooplankton abundance at intermediate phosphorus (P) supplied levels but not at the two ends of the trophic gradient generated (control and highest P level). Neither food quantity nor food quality explained observed differences in zooplankton biomass between light treatments, suggesting a deleterious direct effect of UVR on zooplankton at intermediate food ranges, resulting in a weakening of PZC. The location of this lake in the Mediterranean region has shown an increasing intensity and frequency of aerosol depositions over the past three decades (1973-2003), resulting in higher phytoplankton biomass. A combination of these higher atmospheric dust depositions with the high UVR levels characteristic of high mountain lakes might underlie the interannual decoupling between phytoplankton and zooplankton dynamics observed in these oligotrophic ecosystems. doi: 10.4319/lo.2010.55.6.2549

Total phosphorus (TP) levels in many Canadian Shield lakes in central Ontario have declined over recent decades, despite increases in human activity in most watersheds. To investigate the contribution of changes in catchment export to long-term declines in lake TP, we examined temporal and spatial patterns in TP concentrations and export (1980-1981 to 2001-2002) across 11 subcatchments that drain into three lakes in which average ice-free TP levels have declined by approximately 35%. Annual stream export of TP decreased significantly by 30%-89% in eight of the 11 subcatchments, and decreases in export were driven by declines in TP concentration, not changes in stream flow. Annual average TP concentrations varied fivefold among adjacent subcatchments, and temporal patterns in annual average TP concentrations were poorly correlated. Seasonal patterns of TP concentration were most similar among streams in the spring (March-April-May), and TP export in the spring declined significantly in 10 of the 11 subcatchments. Because spring melt is the principal hydrologic event in these seasonally snow-covered basins, decreases in TP export during the spring were primarily responsible for declines observed in annual export. The drivers of changes in TP over time are unclear at this point but are the focus of current research. Les concentrations de phosphore total (TP) dans plusieurs lacs du Bouclier canadien du centre de l'Ontario ont diminue au cours des dernieres decennies, malgre l'augmentation des activites humaines dans la plupart des bassins versants. Afin d'etudier la contribution des changements dans l'exportation de TP des bassins versants aux declins a long terme du TP lacustre, nous examinons les patrons temporels et spatiaux de concentrations et d'exportation de TP (1980-1981 a 2001-2002) dans 11 sous-bassins qui se deversent dans trois lacs dans lesquels les concentrations de TP durant la periode sans glace ont chute d'environ 35 %. L'exportation annuelle de TP dans les cours d'eau a decru significativement de 30-89 % dans huit des 11 sous-bassins et les declins de l'exportation de TP s'expliquent par des diminutions des concentrations de TP et non par des changements de debit des cours d'eau. Les concentrations annuelles moyennes de TP varient par un facteur de cinq dans des sous-bassins adjacents et les patrons temporels des concentrations annuelles moyennes sont faiblement correles. Les patrons saisonniers des concentrations de TP entre les cours d'eau ont la similarite la plus forte au printemps (mars-avril-mai) et l'exportation de TP au printemps a diminue significativement dans 10 des 11 sousbassins versants. Parce que le degel printanier est l'evenement hydrologique principal dans ces bassins versants couverts de neige en saison, la diminution de l'exportation de TP au printemps est la cause principale des declins observes dans l'exportation annuelle. Le ou les facteurs explicatifs des changements de TP au cours du temps restent obscurs, mais font actuellement l'objet de recherches. [Traduit par la Redaction], Introduction Declining total phosphorus (TP) concentrations have been reported recently in a number of oligotrophic Canadian Shield lakes in south-central Ontario that are remote from agricultural, industrial, and urban sources [...]

An experiment was conducted at the Experimental Lakes Area (ELA; Ontario, Canada) to investigate the effect of rainbow trout (Oncorhynchus mykiss) cage aquaculture on the phosphorus budget and productivity of a small Precam--brian Shield lake during the first three years of fish farming. Annual inputs of phosphorus to the experimental lake from aquaculture waste (67-100 kg) exceeded combined annual inputs from inflows and direct atmospheric deposition (4--18 kg). Compared with a reference lake, hypolimnetic dissolved oxygen concentrations in the aquaculture lake decreased by 36% and hypolimnetic ammonium and total phosphorus increased by 120% and 35%, respectively. However, compared with an epilimnion-fertilized lake, hypolimnetic dissolved oxygen in the aquaculture lake was 255% greater and epilimnetic suspended carbon and chlorophyll a was lower by 64% and 85%, respectively. Epilimnetic suspended carbon and hypolimnetic dissolved oxygen concentrations during aquaculture were more similar to concentrations measured in a hypolimnion-fertilized lake. Although the experimental lake remained oligotrophic during the initial three years of aquaculture, hypolimnetic dissolved oxygen decreased each year and hypolimnetic ammonium and total phosphorus increased each year, which suggests that the lake did not reach a steady state. Nous avons mene une experience dans la region des lacs experimentaux (ELA, Experimental Lakes Area, Ontario, Canada) afin d'evaluer l'effet de l'aquaculture en cage de la truite arc-en-ciel (Oncorhynchus mykiss) sur le bilan du phosphore et la productivite dans un petit lac du Bouclier precambrien durant les trois premieres annees de cette pisciculture. Les apports annuels de phosphore au lac experimental provenant des dechets d'aquaculture (67-100 kg) depassent les apports annuels combines des tributaires et des depots atmospheriques directs (4-18 kg). Par comparaison a un lac temoin, les concentrations d'oxygene dissous de l'hypolimnion du lac d'aquaculture ont diminue de 336 % et les concentrations hypolimnetiques d'ammonium et de phosphore total ont augmente respectivement de 120 % et de 35 %. Cependant, par rapport a un lac ayant subi une fertilisation de l'epilimnion, le lac d'aquacultue possede des concentrations hypolimnetiques d'oxygene dissous 255 % plus elevees et des concentrations epilimnetiques de carbone en suspension et de chlorophylle a plus basses respectivement de 64 % et de 85 %. Les concentrations epilimnetiques de carbone en suspension et hypolimne-tiques d'oxygene dissous durant l'aquaculture ressemblent plus a des concentrations mesurees dans un lac fertilise dans l'hypolimnion. Bien que le lac experimental soit demeure oligotrophe durant les trois premieres annees de l'aquaculture, les concentrations d'oxygene dissous dans l'hypolimnion ont diminue chaque annee et les concentrations hypolimnetiques d'ammonium et de phosphore total ont augmente chaque annee, ce qui indique que le lac n'a pas atteint l'etat d'equilibre. [Traduit par la Redaction], Introduction Cage aquaculture releases nutrients and organic wastes (e.g., fish excretion and small quantities of waste feed) into receiving aquatic ecosystems (Ackefors and Enell 1994; Enell 1995). In marine systems, [...]

Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume-grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus. Here we show that a new mechanism of overyielding, in which phosphorus mobilized by one crop species increases the growth of a second crop species grown in alternate rows, led to large yield increases on phosphorus-deficient soils. In 4 years of field experiments, maize (Zea mays L.) overyielded by 43% and faba bean (Vicia faba L.) overyielded by 26% when intercropped on a low-phosphorus but high-nitrogen soil. We found that overyielding of maize was attributable to below-ground interactions between faba bean and maize in another field experiment. Intercropping with faba bean improved maize grain yield significantly and above-ground biomass marginally significantly, compared with maize grown with wheat, at lower rates of P fertilizer application (112.5 kg of [P.sub.2][O.sub.5] per hectare). By using permeable and impermeable root barriers, we found that maize overyielding resulted from its uptake of phosphorus mobilized by the acidification of the rhizosphere via faba bean root release of organic acids and protons. Faba bean overyielded because its growth season and rooting depth differed from maize. The large increase in yields from intercropping on low-phosphorus soils is likely to be especially important on heavily weathered soils.

Ground water transport of P from the altered wetland soils of the Hula Valley may influence the water quality of Lake Kinneret, which provides up to 30% of the potable water for the slate of Israel. We hypothesized that land use change in these altered wetland soils is the cause for the reported increase in particulate P loading to the Jordan River, which empties to Lake Kinneret. To test this hypothesis we evaluated the P mobility from the Hula's wetland soils to waterways under various hydrological conditions using a field-scale experiment (0.8 [km.sup.2]) with well-monitored boundary conditions. The spatiotemporal changes in hydraulic head across the study area were measured using automated monitoring stations installed in eight observation wells. The hydraulic conductivity (K) of the near-surface peat/marl layers (179 m [d.sup.-1]) was significantly larger than the K values (0.001 to 0.03 m [d.sup.-1]) measured in the marl layers at 5 to 15 m below surface. The large K values of the near-surface layers result from the drainage of this wetland in the late 1950s followed by the oxidation of the peat layers and dissection of the lower peat and upper silt-clayey marl layers. Using a simple water-budget approach, the large field experiment yielded a discharge of 0.27 [Mm.sup.3] and a loading of 306 kg P transported from the altered peat soils to the waterways, in just 7 wk. Most of the P loading was in the form of particulate P (>0.45 [micro]m) rather than dissolved P.

Maximizing P removal with cropping can increase regulated P-based manuring rates or reduce soil test P in manure-enriched soils. The potential for increased P removal with winter forage-corn silage double cropping was evaluated in a 3-yr study at Parma, ID. Winter barley (Hordeum vulgare L.), and both winter and spring genotypes of wheat (Triticum aestivum L.) and triticale (x Triticosecale Wittmack) were fall planted at three seeding rates (112, 168, or 224 kg [ha.sup.-1]) and followed with silage corn (Zea mays L.). Corn alone and a noncropped treatment were included. Winter forages were harvested near boot stage. Seeding rates of 168 kg [ha.sup.-1] were necessary for maximizing winter forage production but had little effect on P uptake. Winter forage production and P content were highly year dependent due largely to appredable winterkill of spring wheat and winter barley in 1999. Winter forage P concentrations, unlike those for corn, decreased with successive harvests. Cumulative P uptake ranged as high as 65.7 kg [ha.sup.-1] for winter triticale. Winter forages reduced corn yields in 2 of 3 yr and corn P uptake in 1 yr. Compared to corn alone, double cropping increased cumulative forage production from 8.4 to 15.9% and total P removal by 29.8 to 42.2%. Soil test P concentrations after 3 yr decreased more with double cropping than with corn alone. Half of the P decline was unrelated to P uptake and removal. Double cropping can increase total forage production, P removal, and hasten soil test P decline.

Phytic acid (PA; myo-inositol 1,2,3,4,5,6 hexakisphosphate) in soybean [Glycine max (L.) merr.] meal is a major source of P in animal excreta, a serious environmental pollutant. Genetic mutants in which seed PA is reduced by 60% have been developed. The objectives were to assess (i) natural variation in seed PA-P and inorganic phosphorus ([P.sub.i]) concentrations in soybean breeding lines and cultivars of Maturity Groups (MGs) V, VI, and VII; (ii) genotype x environment (G x E) interactions for [P.sub.i] and PA-P, and (iii) relations among PA-P, [P.sub.i], and seed protein concentrations. Three sets of cultivars and breeding lines were tested separately in two or three environments. Variation among lines was highly significant, ranging from 3.77 to 5.07 g [kg.sup.-1] PA-P and from 0.19 to 0.37 g [kg.sup.-1] [P.sub.i]. The G x E interactions were highly significant for [P.sub.i] concentration, but significant variation for PA-P concentration was observed only among cultivars, not across environments nor as G x E interactions. Rank correlation coefficients for [P.sub.i] concentrations between environments were large (0.65-0.88), suggesting that the G x E interactions were due to differences in average [P.sub.i] concentration in various environments. Variation in seed protein was highly significant in all three sets, but protein was not correlated with PA-P and was correlated with [P.sub.i] (r = 0.56) only in the MG V breeding lines test. Therefore, genetic relationships between protein and either PA-P or [P.sub.i] could not be established. Significant natural genetic variation indicates that PA level of potential adapted parents may be useful in breeding low-PA soybeans., MUCH OF THE PHOSPHORUS in soybean seeds, between 68 and 78%, is stored as PA (Raboy et al., 1984). Phytic acid P is not bioavailable to either livestock or human [...]

A laboratory scale enhanced biological phosphorus removal process was operated in the University of Cape Town configuration to study the variations in alpha and oxygen transfer efficiency ([OTE.sub.f]) under different process conditions. As part of this investigation, process oxygen transfer parameters were determined using the steady state oxygen uptake rate (OUR) and the nonsteady state hydrogen peroxide addition (HPA) methods, as per the American Society of Civil Engineers guidelines. The results indicated that the oxygen transfer parameters [volumetric mass transfer coefficient ([K.sub.L][a.sub.f]), oxygen transfer rate ([OTR.sub.f]), ct and [OTE.sub.f])] were higher when both methods were applied on the same day, compared to the subsequent period, when only the steady state OUR method was employed, under similar operating conditions. The difference in the oxygen transfer parameters appears to be due to the addition of [H.sub.2][O.sub.2] that generates reactive oxygen species in the nonsteady state HPA test. Based on the findings, it was concluded that the HPA test was not a suitable technique to measure oxygen transfer under process conditions. Further, a conceptual model hypothesizing the impacts of [H.sub.2][O.sub.2] addition on activated sludge process is presented. DOI: 10.1061/(ASCE)0733-9372(2005)131:12(1684) CE Database subject headings: Phosphorus; Oxygen transfer; Abatement and removal; Biological treatment; Activated sludge.

Phosphorus (P) has been increasingly designated as the limiting nutrient in freshwater systems (Carpenter et. al., 1998; Brown et. al., 1999). Excess P inputs into aquatic systems lead to eutrophication, [...]

The total syntheses of antiinflammatory marine sponge metabolites (+)-cacospongionolide B and E are described. The activity of the synthetic analogues against bee venom phospholipase A(sub 2) suggest that the cacospongionolides have enantiospecific interactions with the enzyme that may be independent of the gamma-hydroxybutenolide moiety.

During an intense (up to 33 x [10.sup.6] cells [L.sup.-1]) Alexandrium minutum bloom in the Penze estuary (France), total N[O.sub.3], N[H.sub.4], and P[O.sub.4] requirements of the bloom were, respectively, 184, 25, and 20 [micro]mol [L.sup.-1], with peak uptake rates of 43, 6, and 4.8 [micro]mol [L.sup.-1] [d.sup.-1]. The measured ambient concentrations of N[H.sub.4] and P[O.sub.4] were far short of this peak demand, whereas those of N[O.sub.3] were far in excess, indicating that N[O.sub.3] supply is important for sustaining the bloom. Comparison of the measured N[O.sub.3] uptake rates with advective fluxes indicates that a reduction of N[O.sub.3] concentrations in river waters to

Previous studies have suggested that Mediterranean surface water becomes phosphorus limited for both bacteria and phytoplankton during stratified periods and that orthophosphate uptake in these situations was close to diffusion limitation for both cyanobacteria and autotrophic nanoflagellates. In order to better understand vertical and seasonal variations of this system, we measured orthophosphate uptake by bacteria and phytoplankton in Villefranche Bay (northwestern Mediterranean) monthly for the 0-75-m layer and weekly or biweekly at 10 m from June to December 2002. Turnover time of orthophosphate was relatively short (30 h) in the deeper layer during the stratified period and in the whole water column during the mixing period. Short-term fluctuations in turnover time were repeatedly observed from the stratified through the mixing periods. The dominance of P[O.sub.4] uptake drastically shifted from both bacteria and cyanobacteria to cyanobacteria when there were slight increases in turnover time (1-10 h). Compared to the theoretical maximum calculated for diffusion limitation, mean affinity constants at 10 m were similar for autotrophic nanoflagellates and greater for cyanobacteria in situations with turnover time

The reaction of KP(H)Si(super t)Bu3 with GaCl3 in a molar ratio of 3:1 yielded the title compound with a central Ga2P2 cycle. This allyl moiety is bridged by a (trialkylsily)phosphanidyl substituent.

When beef cattle (Bos taurus) are red grain of maize (Zea mays L.) in which the concentration of phosphorus (P) exceeds the animal's need for this element, the excess P is excreted in the feces. Spreading this manure on cropland increases the potential for P pollution of surface waters by run-off. Experiments were undertaken to determine the relative magnitudes of genotypic and nongenotypic variances of P concentration in maize grain (P-Gr) to assess the ability to select maize genotypes in which this trait more closely marches the dietary need of beef cattle. Genetic variability was found in a population developed from a cross of Illinois High Protein (IHP) x Illinois Low Protein (ILP). Because of few low P-Gr segregates, the IHP x ILP population was not considered a good breeding source for this trait. Nongenetic sources of variance were significant but small compared with genotypic variances. Broad-sense heritability (H) for P-Gr among [S.sub.1] family means in the IHP x ILP population was estimated at 0.82. This high value suggested that this trait would respond to selection. A comparison of mean values of [S.sub.1] families selected on the basis of performance in 2000 of in 2001 alone to those selected on the basis of 2-yr data suggested that the loss in efficiency resulting from selecting on 1-yr data would be only approximately 5%., MAIZE IS THE PRIMARY GRAIN used in the diets of many livestock animals in the USA. Because the grain of maize is approximately 75 % starch and primarily is used [...]

Byline: A. G. Vlessidis (1), M. E. Kotti (1), N. P. Evmiridis (1) Abstract: A study for the validation of orthophosphate determination using an FI-manifold/spectrophotometric detection set-up is made. Under optimized conditions, the method with the largest valid range (0--50 mg L.sup.--1), with the possibility of extending it even higher) is the molybdate/ascorbic acid method its reproducibility and interferences are similar to other tested methods. A study among the conventional digestion methods is then made to test the adaptability of the method to FI systems. The persulfate digestion method was found to be more suitable for use with flow systems. The persulfate digester was connected in-line with the FI-manifold under optimized conditions, the sensitivity of the method is decreased, especially when used with organic phosphorus compounds, but it is still reasonable for use. The sensitivity is also dependent on the nature of the phosphate species attached to the organic residue. In addition, it was found that colloid precipitate phase in the sample decreases the sensitivity. Finally, real wastewater samples were tested using the UV radiation-assisted, persulfate digester-implemented FI-system method, and using the batch method. It was found from the correlation of the two methods that the fraction of P-recovery in the FIA system was 2/3 of the total phosphate, suggesting that the rest was due to the polyphosphate content. Author Affiliation: (1) Laboratory of Analytical Chemistry, University of Ioannina, Ioannina, 45110, Greece Article History: Registration Date: 06/10/2004

The efficiency of broadcast and band P and K placement methods for ridge tilled soybean [Glycine Max (L.) Merr.] has not been extensively researched. This study evaluated grain yield, early plant growth, and nutrient uptake (V5-V6 stages), and soil-test responses to broadcast and deep-band (15-20 cm below the ridge surface) placements in 14 trials. Fertilizer rates were 0, 14, and 56 kg P [ha.sup.-1] and 0, 33, and 132 kg K [ha.sup.-1]. A randomized complete-block design was used. Soil-test P (STP) was 7 to 61 mg [kg.sup.-1] (Bray-[P.sub.1] test, 15-cm depth) and soil-test K (STK) was 100 to 197 mg [kg.sup.-1] (ammonium acetate test). Phosphorus increased yield (P [less than or equal to] 0.1) at four sites. Band P was better at one site (30 kg [ha.sup.-1] and broadcast P was better (40 kg [ha.sup.-1]) at another site. Both P placements increased dry weight (DW) at two sites. Yield and DW responses to P were observed when STP was

Phosphorus (P) exported from pastures following fertiliser application contributes to the nutrients and associated problems ill the streams and rivers of south-eastern Australia. This laboratory study examined whether attributes of P fertilisers may affect P exports soon after their application to field soils: 3 commercial fertilisers [diammonium phosphate (DAP), single superphosphate (SSP), and sulfur-coated single superphosphate (CSSP)] were applied to 2 repacked soils (Arawata and Ellinbank) at 5 moisture contents. Soil type was the most important factor affecting water-extractable P (expressed as a percentage of the P added as fertiliser), accounting for 30% of the total variation. The majority of this variation is explained by the water-extractable P concentrations in the Arawata low moisture treatments. These treatments [7, 6, and 6% soil moisture when equilibrated at 99, 95, and 86.5% relative humidity (RH), respectively] contained water-extractable P concentrations c. 3 times higher than the high moisture (c. 20 and 25% soil moisture) or the Ellinbank treatments. This result probably reflects differences in soil properties including the extent of water repellency and P adsorption. Fertilizer type explained only 6.9% (P < 0.001) of the total variation in water-extractable P, partially as a result of the 86.5% RH (a low moisture) Arawata treatment. In this Arawata low moisture treatment, the mean extractable P was similar for both DAP aud SSP, 13.1% [least significant interval (l.s.i.) 16.7-10.3] and 11.3% (l.s.i.. 14.3-8.9), respectively, but for SSP, water-extractable P increased over time unlike any other treatment. Water-extractable P from DAP was approximately double that from SSP for the Ellinbank and high moisture treatments. The higher water-extractable P following DAP application is explained in terms of its chemical properties and reaction products. Sulfur coating the SSP granules (CSSP) increased water-extractable P, as did higher soil moisture. This study suggests that under conditions present in most pastures in south-eastern Australia and depending on soil hydrology, water-extractable P and P export from fertilisers may increase in the order DAP > CSSP > SSP if overland flow occurs soon after their application. Additional keywords: diammonium phosphate, single superphosphate., Introduction Nutrient enrichment of surface waters contributes to the increasing incidence of cyanobacteria blooms, as well as other less noxious algal species in south-eastern Australia (Environment Protection Authority 1995). The [...]

The crystal and molecular structures of three new phosphorochromones determined by the X-ray diffraction method are presented. The results on model system stated that bifurcated H bonds were weak and the binding energies were equal to 2.9-3.5 kcal/mol.

The capacity for sequential and specific exchange of single peptides from coiled-coil heterotrimers is investigated. Dual hydrophobic-hydrophylic interface systems permit iterative cycles of pH-triggered strand exchange that can specifically replace the initial trimer components, resulting in new complexes that are either resistant to or capable of further exchange.

********** Phosphorus is an essential macronutrient for crop and livestock production. However, applications of commercial and manure phosphorus on cropland often exceed crop uptake requirements (National Research Council, 1993; Heathwaite [...]

A new efficient method for the highly disasteroselective formation of internucleotidic phosphorothioate linkages is developed. The new oxazaphosphholidine method using a new activator helps to produce stereoregulated Ps-ODNs.

A simplified framework for considering variability and uncertainty in developing lake phosphorus total maximum daily loads (TMDLs) is demonstrated. Explicit consideration of these factors can increase the probability that TMDL implementation will meet a defined water quality goal at an acceptable frequency. Although a lake goal is typically expressed as a seasonal or yearly average phosphorus concentration, effects of temporal variations can be captured by correlating average phosphorus concentrations with the frequency of algal blooms (defined by extreme values of chlorophyll a) or the frequency of exceeding numeric water quality standards that are directly linked to algal blooms, such as hydrogen ion concentration or transparency. The margin of safety (MOS) required to achieve the lake goal at a defined frequency and with a defined confidence level can be estimated by including stochastic terms in the phosphorus balance equation to reflect variability and uncertainty. Given limitations in the data and models typically used in developing TMDLs, the cost of the MOS, expressed in terms of percent of the total allocated load or safety factors in the design of control measures, can be large. The MOS would be expected to increase with the percent load reduction required under the TMDL, as the forecast loads become increasingly dependent on assumptions regarding the performance of best management practices or other measures for reducing loads. The magnitude and cost of the MOS can be reduced by implementing TMDLs in an iterative fashion with ongoing data collection, and model refinement to reduce uncertainties associated with forecasting the performance of phosphorus load controls and lake responses. DOI: 10.1061/(ASCE)0733-9496(2003)129:4(337) CE Database subject headings: Phosphorus; Water quality; Lakes.

The first predesigned self-assembled triangles utilizing a unique 60-degree ditopic, metal-containing corner is reported. The characterization of the supramoleuclar triangles by multinuclear NMR, elemental analysis, and electrospary mass spectrometry is presented.

Chemical sequential extraction is widely used to divide soil phosphorus (P) into different inorganic ([P.sub.i]) and organic ([P.sub.o]) fractions, but the assignment of these fractions to pools of differing plant availability, especially for low P tropical soils, is still matter of discussion. To improve this assignment, the effect of land-use systems and related P fertilizer inputs on size of P fractions and their isotopic exchangeability was investigated. A Colombian Oxisol, sampled from a long-term field experiment with contrasting management treatments, was labeled with carrier free [sup.33]P and extracted after incubation times of 4 h, 1, and 2 wk. Phosphorus concentrations and [sup.33]P recovery in fractions sequentially extracted with anion exchange resin ([P.sub.i]), 0.5 M NaHC[O.sub.3] (Bic-[P.sub.i], Bic-[P.sub.o]), 0.1 M NaOH ([P.sub.i], [P.sub.o]), hot concentrated HCl ([P.sub.i], [P.sub.o]), and residual P were measured for each incubation time. Resin-[P.sub.i], Bic-[P.sub.i], NaOH-[P.sub.i], and hot HCl-[P.sub.i] were increased with P fertilization, with the highest increase for NaOH-[P.sub.i]. The recovery of [sup.33]P in the treatments with annual P fertilization clearly exceeding P outputs indicate that resin-[P.sub.i], Bic-[P.sub.i], and NaOH-[P.sub.i] represented most of the exchangeable P. In these treatments, label P transformed with increasing incubation time from the resin to the Bic-[P.sub.i] and NaOH-[P.sub.i] fractions. The organic or recalcitrant inorganic fractions contained almost no exchangeable P. in contrast, in soils with low or no P fertilization, more than 14% of the [sup.33]P was recovered in NaOH-[P.sub.o] and HCl-[P.sub.o] fractions 2 wk after labeling, showing that organic P dynamics are important when soil [P.sub.i] reserves are limited.

A method of detection of ultratrace phosphorus and sulfur that uses reaction with [O.sub.2] in a dynamic reaction cell (DRC) to oxidize [S.sup.+] and [P.sup.+] to allow their detection as S[O.sup.+] and P[O.sup.+] is described. The method reduces the effect of polyatomic isobaric interferences at m/z = 31 and 32 by detecting [P.sup.+] and [S.sup.+] as the product oxide ions that are less interfered. Use of an axial field in the DRC improves transmission of the product oxide ions 4-6 times. With no axial field, detection limits (3[sigma], 5-s integration) of 0.20 and 0.52 ng/mL, with background equivalent concentrations of 0.53 and 4.8 ng/mL, respectively, are achieved. At an optimum axial field potential (200 V), the detection limits are 0.06 ng/mL for P and 0.2 ng/mL for S, respectively. The method is used for determining the degree of phosphorylation of [beta]-casein, and regular and dephosphorylated [alpha]-caseins at 10-1000 fmol/[micro]L concentration, with 5-10% v/v organic sample matrix (acetonitrile, formic acid, ammonium bicarbonate). The measured degree of phosphorylation for [beta]-casein (4.9 phosphorus atoms/molecule) and regular [alpha]-casein (8.8 phosphorus atoms/molecule) are in good agreement with the structural data for the proteins. The P/S ratio for regular [alpha]-casein (1.58) is in good agreement with the ratio of the number of phosphorylation sites to the number of sulfur-containing amino acid residues cysteine and methionine. The P/S ratio for commercially available dephosphorylated [alpha]-casein is measured at 0.41 (~26% residual phosphate).

The successive one-electron reduction of a two-phosphinines-containing macrocycle results in the formation of a phosphorus-phosphorus bond.

Research has been conducted on the ammonium salt of the 1:1 complex Ce(III). The preparation and characterization of this salt via elemental analysis, vibrational and NMR spectroscopy, cyclic voltammetry and single-crystal X-ray analysis are described.

The preparation of a novel phosphorous species has enabled the specific triphosphorylation of histidine at its 3-position. The alkylation of 3-triphosphohistidine by phenacyl bromine servers as a model for the introduction of labeling the probe reagents into histidine phosphorothioate containing proteins.

Synthesis of 3,3-bis(diphenylphospino)-1,1'-dimethyl-2,2`biindole (N-Me-2-BINP) and 3,3-bis(diphenylphospino)-1,1'-bis(methoxymethyl)-2,2`-biindole (N-Me-2-BINP) is investigated. Reactions were found to be fast and enantioselection quite good.

The effects of manganese oxides and phosphorus on soil lead bioavailability in five contaminated soils are studied in order to find a technique for in situ soil amendment that will replace the tradition method of soil excavation. The study is described.

P(MeNCH2CH2)(sub 3)N unlike its acyclic analogue P(NMe2)(sub 3) was found to be a highly selective reagent providing epoxides from aryl aldehydes with trns/cis ratios as high as 99/1. The phosphorus atom in P(MeNCH2CH2)(sub 3)N seemed to be more nucleophilic than that in P(NMe2)(sub 3) to produce faster reactions.

Theoretical and experimental data on the products from the reaction of laser-abalated red phosphorus and dioxygen are presented.

We conducted two studies to determine the bioavailability and apparent digestibility of P in a low-phytate corn hybrid (.28% total P, .10% phytate P) genetically modified to be homozygous for the 1pal-1 allele and a nearly isogenic corn hybrid (normal) (.25% total P, .20% phytate P). Additionally, we conducted an in vitro assay involving a peptic and pancreatin digestion to estimate P availability. The first study used 50 individually penned pigs (initial body weight 9 kg) and 10 treatments in a randomized complete block design. A cornstarch-soybean meal basal diet (.6% Ca, .2% P) was used. Treatments consisted of the basal diet and the basal diet plus .05, .10, or .15% P from monosodium phosphate (MSP), low-phytate corn, or normal corn. After a 35-d feeding period, pigs were killed to collect the fourth metacarpal for measurements of ash and breaking load. Breaking load was regressed on added P intake, and the bioavailability of P was determined by the slope ratio method. The bioavailabilities of P (relative to MSP) for low-phytate and normal corn were 62 and 9%, respectively. These were similar to the determined in vitro values of 57 and 11% for low-phytate and normal corn, respectively. In the second study, 20 pigs (initial BW 20 kg) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Two corn lines (low-phytate and normal) and two levels of supplemental P (0 and .2%) from dicalcium phosphate were used. Diets with no added P were formulated to contain .9% lysine, .6% Ca, and .34% P. Apparent nutrient digestibilities were calculated from total collection of urine and feces for 5 d. There were no differences among treatments for energy and nitrogen digestibility. Pigs fed low-phytate corn with no added P had increased digestibility and retention of P and reduced total P excretion (P < .05). We conclude that low-phytate corn contains at least five times as much available P as normal corn. The use of low-phytate corn greatly reduced the amount of P excreted by the pig and increased the N:P ratio in the manure. Key Words: Pigs, Phosphorus, Phytic Acid, Pig Manures, Maize

Several bioassays were conducted with young chicks and pigs fed phosphorus (P)-deficient corn-soybean meal diets. With diets for chicks containing .62% Ca and .42% P (.10% available P), graded doses of a citric acid + sodium citrate (1:1, wt:wt) mixture (0, 1, 2, 4, or 6% of diet) resulted in linear (P < .01) increases in both weight gain and tibia ash. Relative to chicks fed no citric acid, tibia ash (%) and weight gain (g/d) were increased by 43 and 22%, respectively, in chicks fed 6% citric acid. Additional chick trials showed that 6% citric acid alone or sodium citrate alone was as efficacious as the citric acid + sodium citrate mixture and that 1,450 U/kg of phytase produced a positive response in bone ash and weight gain in chicks fed a diet containing 6% citrate. Varying the Ca:available P ratio with and without citrate supplementation indicated that citric acid primarily affected phytate-P utilization, not Ca, in chicks. Moreover, chicks did not respond to citrate supplementation when fed a P-deficient (.13% available P), phytate-free casein-dextrose diet. Young pigs averaging 10 to 11 kg also were used to evaluate citric acid efficacy in two experiments. A P-deficient corn-soybean meal basal diet was used to construct five treatment diets that contained 1) no additive, 2) 3% citric acid, 3) 6% citric acid, 4) 1,450 U/kg phytase, and 5) 6% citric acid + 1,450 U/kg phytase. Phytase supplementation increased (P < .01) weight gain, gain:feed, and metatarsal ash, whereas citric acid addition increased only gain:feed (P < .05) and metatarsal ash (P < .08). A subsequent 22-d pig experiment was conducted to evaluate the effect of lower levels of citric acid (0, 1, 2, or 3%) or 1,450 U/kg phytase addition to a P-deficient corn-soybean meal diet. Phytase supplementation improved (P < .01) all criteria measured. Weight gain and gain:feed data suggested a response to citric acid addition, but this was not supported by fibula ash results (P > .10). The positive responses to phytase were much greater than those to citric acid in both pig experiments. Thus, dietary citric acid effectively improved phytate P utilization in chicks but had a much smaller effect in pigs. Key Words: Phosphorus Bioavailability, Citric Acid, Phytase, Chicks, Pigs

We have recently expressed a new phytase enzyme in a yeast system. Three experiments with a total of 140 weanling crossbred pigs were conducted to examine the efficacy of this enzyme in improving the bioavailability of phytate-P in corn-soybean meal diets to young pigs. Experiment 1 compared the efficacy of this new phytase with a commercially available phytase (Natuphos, BASF) for 4 wk at an inclusion level of 1,200 U/kg of diet. Experiment 2 compared the responses of pigs to four doses of the new phytase supplementation (300, 600,900, and 1,200 U/kg of diet) for 4 wk. Experiment 3 compared the efficacy of this new phytase and Natuphos at a marginally optimal dose (700 U/kg of diet) for 5 wk. A group of pigs were fed the P-deficient basal diet as a negative control in Exp. 1, and a group of pigs were fed the basal diet plus. 17 or .22% inorganic P as a positive control in all experiments. In Exp. 1, pigs fed the two sources of phytase had similar ADG (564 vs 567 g), gain/feed (.597 vs .589), plasma inorganic P concentrations (8.9 vs 8.4 mg/dL), and mobility scores (4.25 vs 4.46) that were higher (P < .05) than those of the negative control. In Exp. 2, plasma inorganic P concentration was a fairly linear response to the phytase dose (r > .83) at wk 1 and 2. Overall ADG of pigs also tended to increase with the phytase dose (P = .15). In Exp. 3, pigs fed the two sources of phytase had ADG (483 vs 506 g) similar to that of the positive control (508 g). These two groups also had similar plasma inorganic P concentrations (7.7 vs 7.4 mg/dL) that were lower (P < .05) than those of the positive control group (9.7 mg/dL). There was no significant effect of dietary treatments on ADFI in all three experiments. In conclusion, our new phytase was as effective as Natuphos, at the inclusion level of 700 or 1,200 U/kg of a P-deficient, corn-soybean meal diet, in improving phytate-P utilization by young pigs. Key Words: Phytase, Phosphorus, Pigs

Research has been conducted on the MutT enzyme that catalyzes triphosphate nucleoside hydrolysis to NMP and PP (sub)i. The nucleophilic substitution at the beta-phosphorus is described.

The preparation and study of unstable tris(bidentate) hexacoordinated phosphorus compounds is discussed. The use of NMR and X-ray crystallography is analyzed.

A synthesis of the phosphorus-donor ligands has been reported. Results reveal that their diazaphospholidine structure consists of monodentate and bidentate derivatives.

Segregation and diffusion of P from doped Si1-xGex epitaxial films into silicon were examined.

Research is presented illustrating the characteristics of low-valence derivatives (monohydrides and monofluorides) of phosphorus and nitrogen (group 15 of the periodic system), and aluminum and boron (group 13 of the periodic system).

Research has been conducted on the construction of the phosphorus, germanium and tin phorphyrin-based hybrid trimers. The use of a new building block approach is discussed.

Research has been conducted on the silicon-phosphorus multiple bond compounds and hydrogen-bridged species. Compound stability has been investigated and relative energies have been computed using a G2 theory level modification.

Research was conducted to examine the field emission properties for P-doped polycrystalline diamond films. It is indicated that the internal electron emission is relevant to the field emission properties of the P-doped diamond films. Results reveal that behaviors of the field emission characteristics, which rely on the P doping concentration, measurement temperature and the cathode metal, are consistently explained by the internal electron emission.

Research has been conducted on the C (sub)60 and acetylenes reaction with phosphines. Introduction of phosphorus substituents onto C (sub)60 is discussed.

The microorganism Beauveria bassiana was used to synthesize and subsequently microbially hydroxylate representative novel phosphorus-containing azabicyclic substrates in fair to good yields. Other N-subtituents and related functionalities have included several amides, lactams, N-carbamoyl and N-acetyl groups. Results illustrate that N-phosphinyl groups are good facilitators of hydroxylation reactions with B. bassiana.

A simple model could resolve the long-standing debate between oceanographers about whether nitrogen or phosphorus has overall control on oceanic primary production. A two-box global model of oceanic nitrogen and phosphorus cycles gave a representation of the competition between nitrogen-fixing and other phytoplankton. Homeostatic regulation of nitrate and phosphate results in external phosphate inputs have longer-term control of primary production in the global ocean.

Research was conducted to examine a new mechanism for the preparation of upper-rim functionalized calix(4)arenes bearing distal P-containing substituents. It comprises the starting point for the synthesis of entire families of calixarenes having metals across the upper rim. The dinuclear rhodium complex was found to exhibit useful catalytic activity for the hydroformylation of olefins.

1 A factorial fertilizer experiment was conducted in a 15-year-old coastal barrier salt marsh with a low soil nitrogen content, and in an older 100-year-old marsh with a higher nitrogen content. Plots were fertilized at high and low marsh elevations in both marshes. Nitrogen and phosphorus were applied at low and high concentrations both separately and in combination in each of 3 successive years. 2 Nitrogen limited above-ground plant growth in both young and old salt marshes in all years. Phosphorus limitation of plant growth was apparent in the first year in the young marsh and in the last year in both marshes. In young marshes with low soil organic matter, phosphorus limitation may occur. In addition, phosphorus limitation occurs at both successional stages when a marsh is saturated with nitrogen. 3 Plant species that are typical of nitrogen-rich habitats and late successional stages significantly increased in biomass after fertilization. Limonium vulgare, a low stature species of early and intermediate successional stages, decreased in biomass, whereas the taller Elymus pycnanthus and Artemisia maritima increased. After 3 years of fertilization, plant species composition in a young marsh was similar to the species composition in an unfertilized older marsh. Fertilization of a 100-year-old marsh, however, still resulted in a change in plant species composition, suggesting that succession was still occurring and that, overall, plants in marshes of different age are similar in their response to fertilization. Keywords: fertilization experiment, herbivory, nitrogen, plant-species interactions, plant succession