Influence of hydraulic conductivity on communities of microorganisms and invertebrates in porous media: a case study in drinking water slow sand filters

摘要

The impact of reduced hydraulic conductivity on the abundance and diversity of microorganisms and invertebrates was examined in an artificial ecosystem consisting of a slow sand-filter. Sand-filters processed pre-treated lake water under high flow rates and acted as small ecosystems inhabited by a complex community. The first trophic level consisting of microorganisms serves as a food source for a dense community of protists, micro- and macro-invertebrates. The reduction of hy- draulic conductivity due to the development of larger bacterial and fungal biomass induced a shift of the micro-bial community towards anaerobiosis that may increase clogging by carbonate precipitation. The presence of more bacterial prey seems to favour the development of higher trophic levels. Predation and bioturbation by eu-karyotes were not able to counteract the reduction of hydraulic conductivity due to prokaryotic clogging.