Land Use and Hydrogeological Characteristics Influence Groundwater Invertebrate Communities.

We examine the influence of land use and hydrogeological characteristics on the abundance, composition and structure of groundwater invertebrate communities in a loessic aquifer from Argentina. Seven wells, selected according to surrounding land use and hydrogeological characteristics, were sampled twice. Groundwater was characterized as sodium bicarbonate, bicarbonate sulfate or sulfate type. NO3(-) was detected in all samples. Land use in the area surrounding the well, unsaturated zone thickness and geochemical characteristics of groundwater influenced the abundance, composition and community structure of groundwater invertebrates. Copepoda, Oligochaeta, Cladocera, Ostracoda and Amphipoda were highly influenced by land use, particularly by point pollution sources that produced higher abundance and changes in taxonomic composition. The lowest invertebrate abundance was observed at the wells situated in areas with the thickest unsaturated zone. Groundwater salinity and geochemical type influenced the presence of certain species, particularly Stygonitocrella sp.