Abstract The restoration of a small hypereutrophic urban lake in Baton Rouge, Louisiana was accom... more Abstract The restoration of a small hypereutrophic urban lake in Baton Rouge, Louisiana was accomplished by isolating the lake from its primary source of nutrient loading: a larger, connecting lake that was heavily contaminated by sewage. Restoration objectives were directed towards reducing phosphorus levels in the system to minimize chronic summer fish kills. Previous studies had identified a critical phosphorus level of 0.4 mg l −1 , below which no fish kills had been observed in this system. Above this level the kill frequency was a uniform 3.0%. Water quality data, consisting of 13 parameters, were collected over a four and one-quarter year period, representing conditions before, during and after the isolation. Evaluation of total phosphorus data indicated an approx. 90% reduction in estimated risk of summer fish kills as a result of the isolation. A general reduction in nutrient levels, as well as an increase in system stability, was also observed. Isolation of the lake proved to be a simple and economical means of attaining management objectives.
Page 1. A STOCHASTIC ADAPTATION OF THE VOLLENWEIDER PHOSPHORUS MODEL DANIEL G. BURDEN RONALD F. M... more Page 1. A STOCHASTIC ADAPTATION OF THE VOLLENWEIDER PHOSPHORUS MODEL DANIEL G. BURDEN RONALD F. MALONE Department of Civil Engineering Louisiana State University Baton Rouge, Louisiana CONSTANTINE ...
tion method when temperature, salinity, disease, water supply, land availability, or exotic speci... more tion method when temperature, salinity, disease, water supply, land availability, or exotic species /environmental regulations prevent more cost effective alternatives. A recirculating aquaculture system (RAS) can also be used to support traditional pond or net pen culture through broodstock or fingerling production. Recirculating systems have been widely used in research laboratories and universities across the country, but commercial use has been limited to relatively high value products. See SRAC Publication No. 456, A Spreadsheet Tool for the Economic Analysis of a Recirculation System for a discussion of the economics associated with recirculating aquaculture systems. The science and engineering of recirculating systems is well developed. The details of recirculating technologies have been exhaustively covered by Timmons and Ebeling (2007). This fact sheet summarizes the principal technological approaches being used in current commercial designs that may range in size from a few hundred gallons to nearly 100,000 gallons (1 to 400 m3). The technologies that support tank based culture must address five key issues; clarification, biofiltration, circulation, aerations, and degassing. Solids must be removed from the recirculating system through a clarification process. Dissolved organics and ammonia are then removed through a biofiltration process. The system must provide for circulation between the tank and filtration
Variability in total phosphorus concentrations in a small hypereutrophic lake are represented by ... more Variability in total phosphorus concentrations in a small hypereutrophic lake are represented by a stochastic modification to the basic Vollenweider model. Uncertainties arising from the definition of initial conditions and a lumped white noise parameter are used to project probability distributions of mean in‐lake total phosphorus concentrations. The resulting distributions of mean phosphorus values are modified by consideration of uncertainties associated with monitoring programs to permit comparison with the monitoring results. The model is calibrated using the results of an intensive monitoring program which included nearly five hundred total phosphorus observations from Crest Lake in southeastern Louisiana. The model is also compared against the results of a routine monitoring program. Calibration results indicate the potential usefulness of this modeling approach.
... Journal of Shellfish Research, 3, 175-82. Manthe, DP, Malone, R. E & Kumar (1984). ..... more ... Journal of Shellfish Research, 3, 175-82. Manthe, DP, Malone, R. E & Kumar (1984). ... In: Proceedings of the Blue Crab Colloquium, 1979, eds HM Perry & WA Van Engel, Gulf States Marine Fisheries Commission, No. 7, pp. 137-50. Spotte, S. (1979). ...
The shortening in molt interval and induced mortality due to crawfish eyestalk ablation are the m... more The shortening in molt interval and induced mortality due to crawfish eyestalk ablation are the main factors that need to be evaluated for the application of ablation technology in commercial softshell crawfish production. Effects of temperature on the ablation-to-molt interval and ...
Environmental Monitoring and Assessment, May 25, 2012
Load duration curves were developed using the Hydrological Simulation Program FORTRAN (HSPF) for ... more Load duration curves were developed using the Hydrological Simulation Program FORTRAN (HSPF) for dissolved oxygen (DO) for the Amite River in Louisiana, USA. The concept of 'dissolved oxygen reserve', defined as the total quantity of DO, is introduced. The effect of temporal resolution on duration curves of DO reserve was examined using duration curves developed based on daily, weekly, biweekly, and monthly average data. Duration curves for DO exhibited high variability in the load estimated using daily data as compared to those based on biweekly and monthly data. A seasonal analysis revealed the trend in the DO reserve. The daily DO reserve for the Amite River at Port Vincent was 44,049.31 kg when daily summer data were used and 74,255.15 kg for daily annual data. A surplus of 10,691 kg of DO reserve was shown in the monthly data during critical summer months. The coefficient of variation (CV), used to define the temporal scale-induced uncertainty, was found to be linearly and inversely correlated with the logarithm of the time scale. Regression equations were developed to extrapolate near real-time flow and water quality data, greatly simplifying flow and water quality monitoring and reducing the cost involved in flow and water quality monitoring.
Abstract The supply of dissolved oxygen for the bacteria has been observed to be the principal fa... more Abstract The supply of dissolved oxygen for the bacteria has been observed to be the principal factor limiting the carrying capacity of submerged rock filters used in high density recirculating culture systems. Oxygen concentrations in a submerged rock filter must not fall below 2 mg liter−1 if complete nitrification is to be assured. A mass balance on oxygen is used to develop relationships defining the rock volume and flow rates required for the nitrification beds used in blue crab (Callinectus sapidus Rathbun) shedding systems. These relationships are used to examine the impact of various filter configurations on performance. Of the six designs evaluated, those employing recirculation with supplemental aeration are shown to be the most successful. Under the conditions imposed in this analysis, it was observed experimentally that 1 m3 of 2 cm limestone could support bacterial consumption of 1·2 kg O2 day−1 without limitations from other parameters. Elimination of oxygen limitation leads to filter failure by physical clogging or pH decline. Further improvements in carrying capacity can be realized by solids removal which is shown to reduce oxygen demand in a submerged rock filter tested on blue crabs by approximately 30%. The criterion developed is applicable to a wide variety of culture systems.
The operation of soft-shell crawfish culture is based upon crawfish molting behavior. Mean molt i... more The operation of soft-shell crawfish culture is based upon crawfish molting behavior. Mean molt interval and molting percentage are the main factors determining the production rate of a culture facility. Effects of temperature on mean molt interval and molting percentage of red ...
Abstract The restoration of a small hypereutrophic urban lake in Baton Rouge, Louisiana was accom... more Abstract The restoration of a small hypereutrophic urban lake in Baton Rouge, Louisiana was accomplished by isolating the lake from its primary source of nutrient loading: a larger, connecting lake that was heavily contaminated by sewage. Restoration objectives were directed towards reducing phosphorus levels in the system to minimize chronic summer fish kills. Previous studies had identified a critical phosphorus level of 0.4 mg l −1 , below which no fish kills had been observed in this system. Above this level the kill frequency was a uniform 3.0%. Water quality data, consisting of 13 parameters, were collected over a four and one-quarter year period, representing conditions before, during and after the isolation. Evaluation of total phosphorus data indicated an approx. 90% reduction in estimated risk of summer fish kills as a result of the isolation. A general reduction in nutrient levels, as well as an increase in system stability, was also observed. Isolation of the lake proved to be a simple and economical means of attaining management objectives.
Page 1. A STOCHASTIC ADAPTATION OF THE VOLLENWEIDER PHOSPHORUS MODEL DANIEL G. BURDEN RONALD F. M... more Page 1. A STOCHASTIC ADAPTATION OF THE VOLLENWEIDER PHOSPHORUS MODEL DANIEL G. BURDEN RONALD F. MALONE Department of Civil Engineering Louisiana State University Baton Rouge, Louisiana CONSTANTINE ...
tion method when temperature, salinity, disease, water supply, land availability, or exotic speci... more tion method when temperature, salinity, disease, water supply, land availability, or exotic species /environmental regulations prevent more cost effective alternatives. A recirculating aquaculture system (RAS) can also be used to support traditional pond or net pen culture through broodstock or fingerling production. Recirculating systems have been widely used in research laboratories and universities across the country, but commercial use has been limited to relatively high value products. See SRAC Publication No. 456, A Spreadsheet Tool for the Economic Analysis of a Recirculation System for a discussion of the economics associated with recirculating aquaculture systems. The science and engineering of recirculating systems is well developed. The details of recirculating technologies have been exhaustively covered by Timmons and Ebeling (2007). This fact sheet summarizes the principal technological approaches being used in current commercial designs that may range in size from a few hundred gallons to nearly 100,000 gallons (1 to 400 m3). The technologies that support tank based culture must address five key issues; clarification, biofiltration, circulation, aerations, and degassing. Solids must be removed from the recirculating system through a clarification process. Dissolved organics and ammonia are then removed through a biofiltration process. The system must provide for circulation between the tank and filtration
Variability in total phosphorus concentrations in a small hypereutrophic lake are represented by ... more Variability in total phosphorus concentrations in a small hypereutrophic lake are represented by a stochastic modification to the basic Vollenweider model. Uncertainties arising from the definition of initial conditions and a lumped white noise parameter are used to project probability distributions of mean in‐lake total phosphorus concentrations. The resulting distributions of mean phosphorus values are modified by consideration of uncertainties associated with monitoring programs to permit comparison with the monitoring results. The model is calibrated using the results of an intensive monitoring program which included nearly five hundred total phosphorus observations from Crest Lake in southeastern Louisiana. The model is also compared against the results of a routine monitoring program. Calibration results indicate the potential usefulness of this modeling approach.
... Journal of Shellfish Research, 3, 175-82. Manthe, DP, Malone, R. E & Kumar (1984). ..... more ... Journal of Shellfish Research, 3, 175-82. Manthe, DP, Malone, R. E & Kumar (1984). ... In: Proceedings of the Blue Crab Colloquium, 1979, eds HM Perry & WA Van Engel, Gulf States Marine Fisheries Commission, No. 7, pp. 137-50. Spotte, S. (1979). ...
The shortening in molt interval and induced mortality due to crawfish eyestalk ablation are the m... more The shortening in molt interval and induced mortality due to crawfish eyestalk ablation are the main factors that need to be evaluated for the application of ablation technology in commercial softshell crawfish production. Effects of temperature on the ablation-to-molt interval and ...
Environmental Monitoring and Assessment, May 25, 2012
Load duration curves were developed using the Hydrological Simulation Program FORTRAN (HSPF) for ... more Load duration curves were developed using the Hydrological Simulation Program FORTRAN (HSPF) for dissolved oxygen (DO) for the Amite River in Louisiana, USA. The concept of 'dissolved oxygen reserve', defined as the total quantity of DO, is introduced. The effect of temporal resolution on duration curves of DO reserve was examined using duration curves developed based on daily, weekly, biweekly, and monthly average data. Duration curves for DO exhibited high variability in the load estimated using daily data as compared to those based on biweekly and monthly data. A seasonal analysis revealed the trend in the DO reserve. The daily DO reserve for the Amite River at Port Vincent was 44,049.31 kg when daily summer data were used and 74,255.15 kg for daily annual data. A surplus of 10,691 kg of DO reserve was shown in the monthly data during critical summer months. The coefficient of variation (CV), used to define the temporal scale-induced uncertainty, was found to be linearly and inversely correlated with the logarithm of the time scale. Regression equations were developed to extrapolate near real-time flow and water quality data, greatly simplifying flow and water quality monitoring and reducing the cost involved in flow and water quality monitoring.
Abstract The supply of dissolved oxygen for the bacteria has been observed to be the principal fa... more Abstract The supply of dissolved oxygen for the bacteria has been observed to be the principal factor limiting the carrying capacity of submerged rock filters used in high density recirculating culture systems. Oxygen concentrations in a submerged rock filter must not fall below 2 mg liter−1 if complete nitrification is to be assured. A mass balance on oxygen is used to develop relationships defining the rock volume and flow rates required for the nitrification beds used in blue crab (Callinectus sapidus Rathbun) shedding systems. These relationships are used to examine the impact of various filter configurations on performance. Of the six designs evaluated, those employing recirculation with supplemental aeration are shown to be the most successful. Under the conditions imposed in this analysis, it was observed experimentally that 1 m3 of 2 cm limestone could support bacterial consumption of 1·2 kg O2 day−1 without limitations from other parameters. Elimination of oxygen limitation leads to filter failure by physical clogging or pH decline. Further improvements in carrying capacity can be realized by solids removal which is shown to reduce oxygen demand in a submerged rock filter tested on blue crabs by approximately 30%. The criterion developed is applicable to a wide variety of culture systems.
The operation of soft-shell crawfish culture is based upon crawfish molting behavior. Mean molt i... more The operation of soft-shell crawfish culture is based upon crawfish molting behavior. Mean molt interval and molting percentage are the main factors determining the production rate of a culture facility. Effects of temperature on mean molt interval and molting percentage of red ...
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