Effect of hydrodynamic factors on benthic communities in Lake Kinneret

The hypothesis of the study states that two fluxes of bottom sediments, with opposite direction (to the shore and from it), are formed under the influence of hydrodynamic factors, first of all, the wave flow turbulence and energy of the waves. Under conditions of high hydrodynamic activity, this can cause redistribution of different size fractions of bottom sediments along the bottom slope. One can suppose that the effect may be proven for both nonliving particles and sessile living organisms. Experimental studies were carried out in the littoral zone of Lake Kinneret (Israel). The major factors affecting the benthic community (i.e. bottom sediments balance, variability of their granulometric size-composition in space and time, bottom turbulence, structure of waves and currents) were analyzed. The theoretical description and experimental evidence demonstrated that several parameters controlling sedimentation and resuspension had an effect on bottom community composition, and a consequent conceptual model was developed. The model describes the size fractionation of particles along the bottom slope, in connection with the slope steepness and height of the waves. The model forecasts are in a good agreement with the empirically evidenced distributions of both gravel sediments and inhabiting them molluscs. The results obtained provide an insight into the size structure and diversity of the benthic communities in Lake Kinneret, and their relationship to several components of the aquatic system.