. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Distance (m) Figure 3. Seabed bathymetry over a 2-m distance at the study site, showing variations of up to m. the surface in significant numbers over the spatial scales considered. Defined hetl level. The velocity of all particles was set to zero in the region below "mean bed level," within one roughness length (:0 = m) of the bed where the velocity profile is undefined. Zero net current in this zone is probably a reasonable approximation because of the sheltering induced by the coral. However, beca
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Distance (m) Figure 3. Seabed bathymetry over a 2-m distance at the study site, showing variations of up to m. the surface in significant numbers over the spatial scales considered. Defined hetl level. The velocity of all particles was set to zero in the region below "mean bed level," within one roughness length (:0 = m) of the bed where the velocity profile is undefined. Zero net current in this zone is probably a reasonable approximation because of the sheltering induced by the coral. However, because the coral is porous, some water movement may still occur, particularly when waves are present. Consequently, ran- dom movement was retained below : = :0. The lowest pumps were estimated to be about m above the minimum bed level (: = 0) in the model. The pumps were m above the base of the pump array frame while the bed profile at the study site exhibited variations of up to m (Fig. 3), and the pump frame base was generally located on the crests of the undulations. Mean bed level is expected to be at an elevation dependent on the magnitude of the roughness length. However, the frame was moved often and there remains some uncer- tainty, of the order of m, in the defined position of the bed in the field data relative to the model. Bowularv conditions. At the surface, a zero flux bound- ary condition was imposed by reflecting any particles that attempted to move through the surface by diffusion. The bottom boundary condition is best described as a "settling or trapping" condition, established to investigate the entry of particles into the bed matrix. In this paper, "settlement" is used in the sediment transport sense to denote contact with the seabed. A square grid covering the seabed was established in the model with sides, so that the surface area of each cell was equal to the area of the substrate traps ( nr). Particles we
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
