Hard substrate ichnocoenoses and their relations to light intensity and marine bathymetry

Studies on traces of boring algae, fungi and bacteria in sedimentary basins of different age (Silurian, Devonian, Triassic, Jurassic, Cretaceous and Tertiary) and the comparison of these traces with modern ones and the light adaptation of their producers resulted in a first attempt to characterize the vertical sequence of marine zones of decreasing light intensity (3 different parts of the euphotic zone, the dysphotic and the aphotic zone) by hard substrate ichnocoenoses. The observations in the Upper Jurassic and Lower Tertiary basins accord closely with each other and - with some restrictions - the characterization can also be applied for the Silurian and Triassic basins. Devonian and Upper Cretaceous endolith associations create problems.