Phosphorus eutrophication

While many industrial wastes are so low in nitrogen and phosphorus that these must be added if biologically based treatment is to be used, others contain very high levels ofthese nutrients. For example, paint-production wastes are high in nitrogen, and detergent production wastes are high in phosphorus. Treatment for removal of these nutrients is required in areas where eutrophication is a problem. 

In this way, the near-linear chlorophyll-phosphorus relationship in lakes depends upon the outcome of a large number of interactive processes occurring in each one of the component systems in the model. One of the most intriguing aspects of those components is that the chlorophyll models do not need to take account of the species composition of the phytoplankton in which chlorophyll is a constituent. The development of blooms of potentially toxic cyanobacteria is associated with eutrophication and phosphorus concentration, yet it is not apparent that the yield of cyanobacterial biomass requires any more mass-specific contribution from phosphorus. The explanation for this paradox is not well understood, but it is extremely important to understand that it is a matter of dynamics. The bloom-forming cyanobacteria are among the slowest-growing and most light-sensitive members of the phytoplankton. ... 

This is the principal linkage between cyanobacterial blooms and eutrophication. Avoidance of cyanobacterial production does not necessarily depend upon eliminating all phosphorus inputs, but upon ensuring that optimum physical and chemical conditions for these organisms do not coincide. It is easy to understand why the biggest blooms in the UK have been in fertile lakes and reservoirs after prolonged spells of warm, dry weather in summer. 

Most lakes affected by eutrophication will also have significant amounts of phosphorus in their sediments, which can be recycled into the water column (Section 4). The control of this source can be achieved by treating the sediments with iron salts or calcite to bind the phosphorus more tightly into the sediments. These methods have been used to some effect, but consideration has to be given to the quality of the materials used and whether or not the lake can become de-oxygenated in the summer. In the latter case this can be overcome by artificial de-stratification. 

The most commonly used physical method for long-term eutrophication control in lakes is that of artificial destratification. This method is well tried and understood and uses either jetted water or compressed air bubbles to break down the lake stratification in the summer months. Algal growth is also affected by an increase in circulation. This is due to the artificial shading effect which results from the algae spending less time near the surface and consequently less time in the light. This technique also reduces the redox-dependent phosphorus release from sediments because the sediment surface remains aerobic. 

The above description of eutrophication has illustrated the complex nature of the problem, particularly in relation to the influence of nutrients, the multiplicity of sources of phosphorus and the spectrum of its bio-availability. Clearly, the most effective long-term solution to many of our eutrophication problems will be to reduce the nutrient load to affected waters. However, it has also been shown that, because the concentrations of available phosphorus required to impose a control on primary production is very low (e.g. 5-10/rgU total dissolved phosphorus), the reduction of nutrients from any one source alone is unlikely to be effective. 

With the passage of time, a wide array of environmental problems became evident, particularly cultural eutrophication due to excess phosphorus inputs. In... 

An unusual example of a process that produces a lot of waste is the intensive rearing of pigs. They need additional phosphorus in their feed for healthy growth, and this is usually added as inorganic phosphorus in the form of monocalcium phosphate (calcium dihydroxy-oxido-oxo-phosphorane). Unabsorbed phosphorus passes through into the manure, and if spread onto fields as a fertiliser can lead to excess phosphorus run-off into rivers and lakes leading to eutrophication. 

The only element that was discovered in body fluids (urine). This is plausible, as P plays a main role in all life processes. It is one of the five elements that make up DNA (besides C, H, N, and 0 evolution did not require anything else to code all life). The P-O-P bond, phosphoric acid anhydride, is the universal energy currency in cells. The skeletons of mammals consists of Ca phosphate (hydroxylapatite). The element is encountered in several allotropic modifications white phosphorus (soft, pyrophoric P4, very toxic), red phosphorus (nontoxic, used to make the striking surface of matchboxes), black phosphorus (formed under high pressures). Phosphates are indispensable as fertilizer, but less desirable in washing agents as the waste water is too concentrated with this substance (eutrophication). It has a rich chemistry, is the basis for powerful insecticides, but also for warfare agents. A versatile element. 

Schachtman DP, Reid RJ, Ayling SM (1998) Phosphorus uptake by plants from soil to cell. Plant Physiol 116 447-453. doi http //www.plantphysiol.org Schindler DW (1974) Eutrophication and recovery in experimental lakes implications for lake management. Science 184 897-899. doi http //www.sciencemag.org/cgi/content/abstract/184/4139/897 Schindler DW, Hecky RE, Findlay DL, Stainton MP, Parker BR, Paterson MJ, Beaty KG, Lyng M, Kasian SEM (2008) Eutrophication of lakes cannot be controlled by reducing nitrogen input results of a 37-year whole-ecosystem experiment. Proc Natl Acad Sci USA 105 11254-11258. doi http //www.pnas.org/content/105/32/l 1254.abstract Scott JT, Condron LM (2003) Dynamics and availability of phosphorus in the rhizosphere of a temperate silvopastoral system. Biol Fert Soils 39 65-73 Shane MW, Lambers H (2005) Cluster roots a curiosity in context. Plant Soil 274 101-125. doi http //dx.doi.org/10.1007/s 11104-004-2725-7... 

The excessive amounts of nitrogen and phosphorus as well as heavy metals migrate with water fluxes and enter into surface waters. This is accompanied by eutrophication of surface water bodies. 

Increases in phosphorus export from agricultural landscapes have been measured after the application of phosphorus. Phosphorus losses are influenced by the rate, time, and method of phosphorus application, form of fertilizer or manure applied, amount and time of rainfall after application, and land cover. These losses are often small from the standpoint of farmers (generally less than 200 kg P km-2) and represent a minor proportion of fertilizer or manure phosphorus applied (generally less than 5%). Thus, these losses are not of economic importance to farmers in terms of irreplaceable fertility. However, they can contribute to eutrophication of downstream aquatic ecosystems. 

While phosphorus export from agricultural systems is usually dominated by surface runoff, important exceptions occur in sandy, acid organic, or peaty soils that have low phosphorus adsorption capacities and in soils where the preferential flow of water can occur rapidly through macropores (Sharpley et al., 1998 Sims et al., 1998). Soils that allow substantial subsurface exports of dissolved phosphorus are common on parts of the Atlantic coastal plain and Honda, and are thus important to consider in the management of coastal eutrophication in these regions. 

Dobolyi and Bidlo [76] determined the phosphorus-containing minerals in Balatien lake sediment, and thus the forms in which the phosphorus responsible for the accelerating eutrophication of the lake are present. Samples were subjected to chemical, electron microscope and X-ray analysis. Hydroxylapatite was identified, but no proof of the presence of other phosphorus minerals was obtained. 

The experimental aspects of this study were focussed on two hard-water lakes in Switzerland, namely, the northern basin of Lake Zurich and Lake Sempach. The hydraulic residence time of Lake Zurich is 1.2 years. Most of the particles in the lake are produced directly or indirectly by biological processes within the lake itself (e.g., photosynthesis, CaC03 precipitation). Phosphorus removal has been implemented in recent years at all wastewater treatment plants discharging into the lake at present Lake Zurich can be described as between meso- and eutrophic. Lake Sempach has an average hydraulic residence time of 15.8 years as in Lake Zurich, particles in the lake waters are primarily autochthonous. Phosphorus concentrations have increased substantially and the lake is eutrophic. 

The ultimate sources of nitrogen and phosphorus causing cultural eutrophication are industrial N2 fixation, fossil-fuel burning, and the mining of phosphorite. The nitrogen and phosphorus used as fertilizer have three possible 6tes they either enter the food chain, become part of the soil, or are washed off the land by stormwater runoff The nutrients that enter the food chain eventually end up as either animal wastes or dead biomass. Animal wastes include human sewage, livestock manure, and pet feces. Sanitary... 

Hombeiger GM, Spear RC. 1980. Eutrophication in Peel Inlet, I, problem-defining behavior and a mathematical model for the phosphorus scenario. Water Res 14 29-42. 

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