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Groundwater is one of the largest and oldest limnic habitats populated by a rich and diverse fauna. Groundwater ecosystems are heterotrophic; subsequently the fauna depends on imports from the surface. Stygobiotic fauna has highly adapted to their living space tolerating very long periods without food. Oxygen is a limiting factor, but groundwater fauna tolerates periods with low oxygen concentrations, even anoxic conditions. Different adequate sampling methods are available. They are representative of the aquifer, however a suitable number of monitoring wells is required. In Finland, Iceland, Ireland, North America and Siberia and formerly glaciated Alpine regions first surveys were successful in glaciofluvial porous aquifers, especially eskers, in karstic aquifers as well as in the hyporheic zone. Surveys of the hyporheic zone in Sweden indicate a high probability for groundwater fauna in aquifers as well.
Groundwater fauna communities do in the main display the the intensity of surface water intrusion rather than the origin of the water (like the hydrochemical data). The information provided by groundwater fauna assemblages can therefore be used for an ecologically based assessment of contacts between different water bodies. Community structure of groundwater fauna permits reliable statements on the strength of the surface water impact and the vulnerability of the aquifer. Furthermore, groundwater fauna displays changes in contacts between different water masses very exact and fast.
Advances in applications and adjustments of environmental laws are in rapid progress. Ecologically based assessment is used for extraction wells and the quality management in drinking water abstraction (standards are still to be established). Groundwater fauna assessments also prove to be useful in management of wetlands and regulation under nature protection law. Impact assessment is proposed for construction works as tunnels or larger culverts. In this case a change in the vertical water flow of groundwater may result in altered contact to surface waters.
The lecture will be based on a technical report "Ecology and Living Conditions of Groundwater Fauna" on behalf of SKB AB (Swedish Nuclear Fuel and Waste Management Co).
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