Hard rock aquifers and free‐living nematodes – an interdisciplinary approach based on two widely neglected components in groundwater research

Abstract

AbstractThe subterranean part of the water cycle takes place in three different types of groundwater bodies: (1) unconsolidated sediments, (2) karstic aquifers and (3) fractured hard rock aquifers. Basically, different aquifer types require different investigation methods. However, the physico‐chemical properties of groundwater can aid in the understanding of flow history and aquifer dynamics of each aquifer type. Although groundwater biology is sensitive to hydrochemistry, water temperature and flow velocity, the possible benefits of groundwater animals as ‘hydrogeological agents’ is still rarely considered by hydrogeologists. The main research focus of hydrogeologists and groundwater biologists is shallow groundwater bodies in unconsolidated sediments and karst aquifers. Fractured hard rock aquifers are still poorly considered by both disciplines. This commentary has three purposes: (1) to show the special characteristics of fractured hard rock aquifers in comparison to porous and karst groundwater bodies, and to describe the resulting methological gap hydrogeologists face when investigating such aquifer types; (2) to give an overview of current groundwater biological research with its focuses and shortcomings, including an introduction of rarely known but common groundwater inhabitants, namely free‐living nematodes; and (3) to suggest a combination of methods, supported by a hypothetical example, and the possible benefits this combined knowledge from hydrogeologists and groundwater biologists can bring to both disciplines. Copyright © 2014 John Wiley & Sons, Ltd.