Relationships among invertebrate communities and groundwater properties in an unconfined aquifer in Argentine

Abstract

The paper evaluates the relationships among invertebrate communities, land uses and chemical and microbiological groundwater properties, in a loessic unconfined aquifer in Argentina. Two surveys were conducted and seven wells were selected based on land use and unsaturated zone (USZ) thickness. Groundwater was characterized mainly as freshwater of sodium bicarbonate type. Invertebrates collected belong to Crustacea, Acari, Insecta, Collembola, Oligochaeta, Collembola, Pauropoda, and Nematoda. Crustacea was the most abundant group. The wells differed in terms of invertebrate composition and abundance. The lowest abundance was observed at sites with thickest USZ. No direct relationship was found between invertebrate abundance and any particular physicochemical parameter. In the only well where bacteria were detected, total invertebrate abundance, especially of copepods, was high in both surveys. Both USZ thickness and land use have a significant influence on abundance and composition of invertebrate communities in terms of organic matter inputs into the aquifer.