On this basis, the benthic algal contribution in estuaries with high levels of suspended sediments is likely to be lower. Similarly, where the continental shelf is truncated or very steep sloping, combined with high energy coastline and tidal amplitude, there is little sea grass or turtle grass. Where shading is not excessive, mangrove prop root epiphytes may also be highly productive. Values for periphyton production on prop roots of 0.14 and 1.1 gcal/m2/d have been reported. (Lugo et al. 1975; Hoffman and Dawes, 1980). A generalized food web in mangrove ecosystem is depicted in the figure below.