Previous models for filtration of oyster beds were useful in their simplicity of gathering data in the field but completely disregard any other effects that could be attributed to turbulent diffusion. This would explain some of the previous discrepancies in hydrodynamic effects to oyster filtration noted by others
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noted in her numerical mass balance model that the inclusion of diffusion had a significant impact on the profile of seston concentration across an oyster reef. This result validated previous observations of particle gradients and food limitation across reefs
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Upweller aquaculture systems are particularly influenced by flow that regulates food, oxygen, and water quality within the bed of oysters being cultured . Upweller systems have reported superficial velocities that range from 0.5 to 7.1 cm s-1 . In practice, higher current velocities are desirable because they increase delivery of food to the oysters, improve water quality, and enhance dispersal of biodeposits . This presentation summarizes the findings of previous studies and provides preliminary results of hydrodynamic model considering effects on feeding of juvenile oysters within a packed bed. This model relates axial diffusion and packed bed reactor theory to the oyster aquaculture system.
A series of experiments were conducted using upflow tubes constructed from 2-inch (5 cm) polycarbonate tubes packed with juvenile oysters (1-2 cm) that were subjected to 6 superficial velocities (0.5, 1, 2, 4, 8, 16 cm s-1). The upflow tubes were designed to create a predictable and repeatable flow within a porous packed bed of solid material. The tubes had sampling ports along the porous bed zone which double as ports for measurement (i.e. differential pressure). The results from the physical and physical-biological experiments were used to calibrate axial dispersion models developed from packed bed reactor theory. The development of the axial dispersion parameters will allow for the design and optimization of upweller aquaculture systems. This presentation summarizes the findings of previous studies, details experiment methodology, model development and calibration, and provides results of engineering parameter calibration for juvenile oysters within a packed bed.