Description: <DIV STYLE="text-align:Left;font-size:12pt"><P STYLE="margin:0 0 11 0;"><SPAN><SPAN>Hydrodynamic disturbance at the seafloor can influence distribution patterns of sediments and organic material, light penetration, oxygen and nutrients effecting productivity, and the composition of marine species as well as the functional structure of benthic ecosystems. Higher hydrodynamic flow allows larger particles to settle out, while smaller, less dense particles can only settle in areas of low flow. Shallow subtidal areas with high wave action, erosion and resuspension of sediments favour infaunal and burrowing species. Suspension feeders are most associated with hydrodynamically active areas with high oxygen concentrations and resuspended food particles. Highly exposed sites can also have higher densities of mobile benthic fauna, while areas with less hydrodynamic activity favour surface deposit feeders, and subsurface deposit feeders are associated with areas with the least hydrodynamic disturbance. Despite intense disturbances and damage, such as those caused by major storms, benthic communities can generally recover leading to general temporal stability. One-year mean value of friction velocity (m/s) derived from (1) hourly estimates of surface wave statistics (significant wave height, peak wave period) from outputs of the NZWAVE_NZLAM wave forecast, at 8-km resolution, (2) median grain size (d50), at 250 m resolution, (3) water depth, at 25 m resolution. Overall resolution is at 250 m.</SPAN></SPAN></P><P STYLE="margin:0 0 11 0;"><SPAN><SPAN>Limitations/assumptions: Bed shear stress or friction velocity can be considered an appropriate measure of "benthic disturbance." Benthic sediment disturbance from wave action was assumed to be zero where depth ≥ 200m. </SPAN></SPAN></P></DIV>
Service Item Id: b804b618944b424abffddecd94a1818d
Copyright Text: The National Institute of Water and Atmospheric Research (NIWA)
Swart, D. H. (1974), Offshore sediment transport and equilibrium beach profiles, Delft Hydraul. Lab. Publ. 131, Delft.