Eutrophication modeling

Thomann ( 1 1 ) discusses various model verification measures and demonstrates their application to eutrophication model results. Studies by Ambrose and Roesch (J 2), Hartigan et. al. (13),... 

Early approaches to lake eutrophication modelling did not distinguish between inorganic, organic, particulate or dissolved phosphorus (Vollenweider, 1975, 1976). These models consist of a mass balance for total phosphorus in the lake by considering inflow, outflow and sedimentation. They are usually combined with a hydraulic model representing the lake as a well-mixed compartment and, despite their simplicity, are able to describe the major phosphorus mass fluxes in lakes. 

Table 16.16. Process table of the lake eutrophication model by Imboden and Gachter (1978). ...

Table 7.1 Formal components of the lake eutrophication model.

Jelinski Moranda s de-eutrophication model (1972) Schick and Wolverton s model (1973)... 

Times between failures models Jelinski and Moranda (JM) de-eutrophication model... 

Estrada, V., Parodi, E., and Diaz, M.S. (2009) Determination of biogeochemical parameters in eutrophication models as large scale dynamic parameter estimation problems. Computers Chemical Engineering, 33, 1760-1769. 

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. ... 

Mechanistic Approaches. Adequate and appropriate river-quality assessment must provide predictive information on the possible consequences of water and land development. This requires an understanding of the relevant cause and effect relationships and suitable data to develop predictive models for basin management. This understanding may be achieved through qualitative, semi-quantitative or quantitative approaches. When quantitative or semi-quantitative methods are not available the qualitative approach must be applied. Qualitative assessments involve knowledge of how basin activities may affect river quality. This requires the use of various descriptive methods. An example of this kind of assessment is laboratory evaluation of the extent to which increases in plant nutrients, temperature or flow may lead to accelerated eutrophication with consequent reduction of water quality. 

Aquatic safety factors ranged from 5.5 X 107 for rainbow trout in ponds to 9.3 X 108 for daphnia in lakes. These data emphasize that exposure levels of CGA-72662 are low and must be taken into account for a risk assessment. Although the persistence of CGA-72662 in eutrophic lakes is relatively long, the exposure is extremely low and of no environmental consequence. Overall, use of SWRRB runoff and EXAMS models show CGA-72662 to be very safe in aquatic habitats when used on vegetables in Florida muck soil. 

Oxidation half-lives predicted by one compartment model t,/2 = 38 h in stream, eutrophic pond or lake and oligotrophic lake based on peroxy radical concentration of 10-9 M (Smith et al. 1978) aquatic fate rate k = 5 x 103 M-1 s-1 with t,/2 = 38 h (Callahan et al. 1979) ... 

Leonov, A. V., Stygar, O. V. (2001). Mathematical modeling of organogenic material biotransformation processes for studying the conditions of water eutrophication in the Caspian Sea surface layer. Water Resources, 28(5), 532-555... 

Emerson S. 1975. Chemically enhanced CO2 gas exchange in a eutrophic lake a general model. Limnology and Oceanography 20 743-753. 

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. 

His 40+ publications have dealt with biogeochemical processes that control the alkalinity of surface waters, the geochemisty of dilute seepage lakes, sediment chemistry, the interpretation of water-quality trends, regional analysis of water quality, modeling lake eutrophication, lake management, reservoir water quality, and nonpoint source pollution. He recently joined the faculty of the Department of Civil Engineering at Arizona State University. 

On the basis of this model, Lovley et al. (17) argued that reductive dissolution of ferric oxides must be a microbiological process because the zone of sulfide generation is distinct from the zone of maximum ferric oxide reduction. Highly eutrophic environments would be an exception. In these systems the zone of decomposition with oxygen as terminal electron acceptor directly overlies the zone of sulfate reduction. 

Volatilization t,/2 = 7000 h in stream, t,A = 35000 h in eutrophic pond and t,A = 28000 h in eutrophic lake and oligotrophic lake, based on transformation and transport of quinoline predicted by the one-compartment model (Smith et al. 1978). 

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