Phosphorus enrichment

Froelich, P.N., L.W. Kaul, J.T. Byrd, M.O. Andreas, and K.K. Roe. 1985. Arsenic, barium, germanium, tin, dimethylsulfide and nutrient biogeochemistry in Charlotte Harbor, Florida, a phosphorus-enriched estuary. Estuar. Coastal Shelf Sci. 20 239-264. 

Beauchemin, S., Hesterberg, D., Chou, J., Beauchemin, M., Simard, R. S., and Sayers, D. E. (2003). Speciation of phosphorus in phosphorus-enriched agricultural soils using X-ray... 

Puglisi, M. P. and Paul, V. J., Intraspecific variation in the red algae Portieria homemannii monot-erpene concentrations are not influenced by nitrogen or phosphorus enrichment, Mar. Biol., 128, 161, 1997. 

The catalyst surface has a degree of phosphorus enrichment, and it is these surface layers that are directly involved in the catalysis. 

However, Coulsfon et al. (109) reported contradictory findings. In sum, they found thaf fhe surface P/V rafios of a number of pure vanadium phosphate phases and activated catalysts were all closer to that of the bulk than had been previously reported, leading to the claim that phosphorus enrichment noted by other groups was based on incorrect calibration of XPS insfruments. 

The surface has some phosphorus enrichment. Only the surface layers are directly involved in catalysis. 

Centi and coworkers [84] have suggested that, in addition to Lewis acidity, Br0nsted acidity plays an important role in the selective oxidation of butane to maleic anhydride. The surface phosphorus enrichment means that a number of P—OH groups are present on the catalyst surface. Centi offers three hypotheses for the role of Bronsted acidity the stabilization of reaction intermediates, the stabilization of an adsorbed oxygen species, or the generation of an organic surface species that is involved in oxygen activation or transport. 

In contrast, an open ocean phosphorus enrichment experiment (CYCLOPS) conducted in the eastern Mediterranean did find evidence for P limitation of N2 fixation in bulk water (Rees et ah, 2006). 

Snidvongs, A., and Kinzie, R. A. (1994). Effects on nitrogen and phosphorus enrichment on in vivo symbiotic zooxantheUae of Pocilllopora damicornis. Mar. Biol. 118, 705—711. 

There is —90 ppm of phosphorus in the silicate Earth (McDonough et al., 1985), and the bulk Earth is estimated to have — 0.1 wt.% phosphorus. Using the relationships in Figure 6 the core is thus estimated to have —0.20 wt.% phosphorus (Table 4). Thus, 90% of the planet s inventory of phosphorus is in the core (Table 6) and the core s metal/silicate phosphorus enrichment factor is —22. Similarly, the core hosts —90% of the planet s carbon budget, and has a metal/silicate enrichment factor only slightly lower at —17. 

Gatchalian RA, Popli A, Ejaz A A, Leehey DJ, Kjellstrand CM, Ing TS. Management of hypophosphatemia induced by high-flux hemodiafiltration for the treatment of vancomycin toxicity intravenous phosphorus therapy versus use of a phosphorus-enriched dialysate. Am J Kidney Dis 2000 36(6) 1262-6. 

Furthermore, the driving force for the phosphorus enrichment on the CV0)2P20 surface is not clear yet. In the study of Arnold and Sundaresan [10] on the influence of water on the catalytic properties of a non-equihbrated VPO catalyst the hydrophilicity of phosphorus was supposed to be a reason for it but this assumption has not yet been proven. It was found that the addition of water vapour to the feed lowers the overall activity towards butane oxidation and enhances the selectivity towards partial oxidation products. The addition of steam accelerated the formation of (V0)2P207 in the solid structure which originally contained approximately equal amounts of a-V0P04 and (V0)2P207 crystalline phases [10]. However, the (V0)2P207 phase is the only crystalline phase in an equilibrated VPO catalyst with a P V ratio of 1.1 as used in [10]. Recently Cavani and Trifiro emphasized [2] that only a study of equilibrated catalysts provides precise information on the relationships between activity and selectivity and the structural properties of vanadylpyrophosphate catalysts. 

Compared to the anoxic sediment, the oxic surface sediment is enriched in As (up to 345 nmol g-1). The enrichment is weak where the sedimentation rate is high, but enrichment becomes stronger with decreasing sedimentation rate. Phosphorus enrichment in the surface layer is evident only where the sedimentation rate is low. However, upon burial, both P and As are released from the solid phase to the pore water, irrespective of the sedimentation rate, and the distributions of both elements show subsurface maxima that correspond to the depth where the dissolution rates of solid phases of P and As are maximum. From the relative location of these maxima, it can be concluded that As is released to the pore water at shallower depths than at which phosphate is released. Mucci etal. (2000a) proposed that As is released upon the reduction of As(V) to soluble As(III), and that this takes place earlier than the reduction of Fe(III) to Fe(II) in the diagenetic sequence. In contrast, the... 

Escudey, M., Galindo, G., Forster, J.E., Salazar, I., Page, A.L. and Chang, A. (1997) Phosphorus-nuclear magnetic resonance analysis in extracts of a phosphorus-enriched volcanic soil of Chile. Communications in Soil Science and Plant Analysis28, 121-131. 

Reddy et al. (1999). In this study, the amount of total phosphorus lost during 4 years was similar to the amount of phosphorus exported with harvest products. Loss of total phosphorus in the Tanzanian trial after 3 years of cultivation translated into an annual loss of 83 kg P/ha, whereas after 15 years an additional phosphorus loss of only 44 kg P/ha was observed (Solomon and Lehmann, 2000). Clearly, other pathways of phosphorus loss, such as erosion of phosphorus-enriched topsoil after woodland clearing, must have been relevant. Likewise, annual phosphorus losses of 17—19 kg P/ha in a study from Ethiopia (Solomon et al., 2002) appear to be at the high end for phosphorus exports from unfertilized maize. In addition, significant reductions in total phosphorus under plantations of tea and Cupressus, despite low mineral fertilizer inputs, suggest that phosphorus loss through erosion and/or leaching occurred. 

FIGURE 8.55 Pore water ammonium profiles of select wetlands in Florida. WCA-2-F1 = water conservation area-phosphorus-enriched site WCA-2-217 = water conservation area-phosphorus-limited site Sunny Hill Farm = agricultural land converted to wetland ESA-TW = natrrral wetland used for wastewater treatment. 

FIGURE 9.4 Soil phosphorus enrichment in the northern Everglades resulting from point sources of external loading to a wetland. (From DeBusk et al., 2004.)... 

The EPCq can be used as an indicator of wetlands capacity to function as source or sink for phosphorus. Phosphorus loading can result in the loss of soil s buffering capacity to maintain low EPCq values (Eigure 9.24). The influence of soil phosphorus enrichment in WCA-2A soils of the Everglades on EPCq is shown in Eigure 9.25. 

Wetlands and aquatic systems are recipients of phosphorus loads from upland systems. Increased loading of phosphorus to a system can cause nitrogen limitations. The phosphorus enrichment of P-limited systems leads to eutrophication and ecosystem stress. The phosphorus cycle does not have a significant gaseous loss mechanism. Thus, most of the added P accumulates in the systems. 

U.S. Fish and Wildlife Service (USFWS). Rainfall is the primary water input, while other sources include phosphorus-enriched runoff from the EAA. Elevated soil total phosphorus levels have been observed in areas adjacent to water-inflow points. Typha dominates in phosphorus-impacted areas whereas Cladium, open sloughs, and tree islands are common in unimpacted interior areas. 

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