Enhanced experimental flexibility and control in ecotoxicological mesocosm experiments--a new outdoor and indoor pond and stream system.
METHODS
The German Federal Environmental Agency has put into operation a new modular mesocosm system consisting of eight outdoor and eight indoor ponds and streams in order to investigate fate and effects of chemicals and municipal wastewater in aquatic ecosystems. General design and special characteristics are given to demonstrate the wide range of possibilities for experimental research.


METHODS
Each of the 16 streams with riffle and pool sections can be varied in length up to 106 m. The streams can be run as circular or flow-through systems at a flow velocity of 0.02 to 0.6 m/s. Physico-chemical standard parameters are measured on-line. The 16 ponds, which can be connected to the stream systems, are equipped with drainage and pore water-sampling devices for simulating processes in the littoral zone including influent and effluent ground water flow.


CONCLUSIONS
Since the highly flexible and controllable construction also allows treating a wide range of hydrological and ecological experiments external institutions are invited to submit proposals.
Mohr
Silvia
S
Umweltbundesamt (Federal Environmental Agency), Versuchsfeld Marienfelde, Schichauweg 58, 12307 Berlin, Germany.
Feibicke
Michael
M
Ottenströer
Thomas
T
Meinecke
Stefan
S
Berghahn
Rüdiger
R
Schmidt
Ralf
R
D017753:Ecosystem; D005618:Fresh Water; D005858:Germany; D008962:Models, Theoretical; D018570:Risk Assessment; D014876:Water Pollution