Only healthy groundwater ecosystems provide clean groundwater

Two thirds of drinking water in Germany is obtained from groundwater. At the same time groundwater is in no way a lifeless resource with at least 2,000 known species and numerous microorganisms mainly helping to clean the groundwater and improve the quality of drinking water. However, the protection of this habitat has not yet been established in law. The Institute for Environmental Sciences of the University of Koblenz-Landau has now presented a draft for the geographical classification of groundwater fauna, which could be used as an important step for the evaluation of the environmental status of groundwater. Its aim is the long-overdue establishment of suitable measures for the sustainable, ecologically-oriented management of groundwater.

European groundwater is bustling with at least 2,000 highly adapted, often very rare species such as turbellaria, rotifiers, water mites, fresh water amphipods and olms. Groundwater therefore provides one of the largest continental and oldest habitats in Europe. The so-called ecosystem services provided by groundwater creatures are highly relevant: the species-rich bacteria and fauna clean the water in the subsoil by decomposing organic material which has fallen from the surface to the bottom.

The creatures are also particularly suitable as bioindicators: due to their specialisation to the habitat, they are particularly susceptible to changes such as infiltration of surface water, fertilisers and pollutants such as metals and temperature fluctuations.

Compared to chemical analysis methods, they can provide a much earlier indication of changes in the water and in so doing make a significant contribution towards ensuring the quality of groundwater and therefore drinking water.

With the publication of the essay “Stygoregions – a promising approach to a bioregional classification of groundwater systems”, the research team led by associate lecturer Dr. Hans Jürgen Hahn of the Institute for Environmental Sciences of the University of Koblenz-Landau together with Dr. Christian Griebler of the Institute of Groundwater Ecology of the Helmholtz Centre, Munich, has developed a proposal for the biogeographical classification of groundwater habitats in Germany. For this publication, data from the project “Development of biological evaluation methods and criteria for groundwater ecosystems” commissioned by the Federal Environment Agency (UBA) and the LAWA (the German Working Group on water issues of the Federal States and the Federal Government represented by the Federal Environment Ministry) as well as numerous other studies by the University of Koblenz-Landau was evaluated. This is the first ever proposal for a definition of ecological references for groundwater over a wide area. These may provide an important basis for defining whether the environmental status of groundwater is good.

“Binding criteria and limits for the evaluation and sustainable protection of groundwater ecosystems can only be established on such a basis,” stresses Hahn. These already existed for surface water, however studies by the University of Koblenz-Landau have shown that this classification does not hold up for groundwater.

The scientists proposed a groundwater-specific classification with four potential so-called stygoregions for groundwater, taking Germany as an example. “Sustainable groundwater management is only possible if the groundwater ecology is taken fully into consideration,” explains Hahn. “Fortunately those responsible for water management and water supply are open minded about this issue, because they too know that only healthy groundwater ecosystems provide clean groundwater.”

Ultimately it is the politicians who are challenged to define the legal status of groundwater ecosytems. Although there are passages in laws such as the EU Groundwater Directive and the German Water Management Act in which groundwater is defined as waters and waterways and is therefore subject to the general principles of waterway management with all of its consequences and protective laws, to date there is no legal opinion or relevant precedent which would clarify the inconsistent legal situation and provide momentum to its implementation.

The Groundwater Ecology Department of the University of Koblenz-Landau is one of only a few organisations in Europe, alongside in particular the BUND in Germany, that has for years been committed to the extensive research and sustainable protection of groundwater ecosystems. To date there has been little research on this habitat and the current state of knowledge is roughly comparable with that of fauna in surface waters 50 to 100 years ago. According to Hahn, groundwater fauna and microbiological communities are a scientific treasure of immeasurable value. Many are “living fossils” as they descend from terrestrial species which died out millions of years ago.

Reference:
Stygoregions – a promising approach to a bioregional classification of groundwater systems, Heide Stein, Christian Griebler, Sven Berkhoff, Dirk Matzke, Andreas Fuchs, Hans Jürgen Hahn.Scientific Reports 2, Article number: 673 doi:10.1038/srep00673