Competition: water plants contra algae

For some years, however, a phenomenon has been observed in the Old Danube that the Municipality now wants to counteract. Analyses of the water status show that the biomass of water plants dramatically decreased from 1987 to 1995 (from 721 tons to 1.3 tons dry substance) and that the status of clear water with rich stocks of underwater plants developed into a new stable condition marked by mass amounts of plankton algae and the ensuing turbidity. The declared aim of the clean-up is now to re-establish the macrophytes in such a way that they are able to bind the nutrients dissolved in the water. Thanks to previous measures the biomass content could be raised to 12.3 t (status summer 1998), but replanting progressed much slower than expected.

The renaturalisation project recently presented by the company Biotop Landschaftsgestaltung aims at promoting the growth of water plants even further. Since there is a competition between macrophytes and algae for nutrients, the algae will hopefully lose their nutrition basis.

The company can certainly rely on valuable experience in the field of algae growth reduction and earned an excellent reputation in the reduction of algae growth in swimming and garden ponds by means of the "Biotopkatalysator" it has developed. The Austrian and the US patent offices have already accepted this particularly environmentally friendly technology, the European patent is pending. This bio-catalytic converter does not simply kill the algae – their degradation would lead to a considerable oxygen depletion and thus probably to a further deterioration of the water fauna – but re-establishes a natural balance by reducing algae growth.(Source: aqua press Int. 4-5/2001)

Information & Contact:
Biotop Landschaftsgestaltung GmbH
DI Peter Petrich
Hauptstraße 285,
A–3411 Weidling
Phone +43 2243 30 406
Fax +43 2243 30 406-22