The changing role of terrestrial and autochthonous organic matter in newly flooded lakes

Examination of the gut contents of mud-dwelling animals in three newly flooded lakes shows terrestrial organic matter to be a major component, particularly during filling of the lake basin. After filling is complete, a fall-off in total biomass of fauna is usually accompanied by significant reduction in the proportion of terrestrial detritus in favour of algal food. It is concluded that newly formed lakes pass through two phases. During flooding they are dependent on the terrestrial ecosystem. This is followed by a switch, immediately after filling, to more self-sustained autochthonous-based food chains.