The fate and effects of a single dose of 0.3 and 1.0 mg of 5-nitrofuroic acid-2 (NFA) per litre on a marine plankton community enclosed in large plastic bags (contents 1.5 m³) were studied. The plankton community was derived from North Sea coastal waters, and the model ecosystems were anchored in the harbor of Den Helder, the Netherlands, where they were exposed to a natural light and temperature regimen. Two experimental units were polluted with NFA; a third served as a control.

During four weeks the development of the phytoplankton, zooplankton, and bacteria was followed, as were a set of physicochemical parameters including nutrients, light, and temperature.

The nitro group was removed from the NFA within about one day of the addition of the compound to the model ecosystems, probably as a result of the exposure to light. The intact NFA inhibited the phytoplankton slightly; the remaining molecule produced no detectable effects in the system. The development of the enclosed community was very similar in the different bags.