chlorophyll-a and 3-4-dichloroaniline

The fate and effects of single doses of 3,4-dichloroaniline (DCA) on North Sea coastal plankton communities enclosed by large plastic bags (contents 1.5 m3) were studied in two experiments lasting 5 and 6 weeks, respectively. The biodegradation of DCA was also studied in laboratory experiments, which were carried out simultaneously, using water from the enclosed model ecosystems. DCA was not degraded in the laboratory tests and probably also not degraded in the enclosed plankton communities, although concentrations in the water decreased during the experiments. This decrease appeared to be partly caused by diffusion of DCA through the walls of the enclosures. After the addition of single doses of 2, 10, and 25 microgram liter-1 DCA no effects on the enclosed plankton community could be detected. The addition of 0.1 mg liter-1 DCA had a clear influence on the species composition and the biomass development of the phytoplankton, changed the relative species composition of the zooplankton, and resulted in lower numbers of bacteria. In addition to these effects 1 mg liter-1 DCA limited the phytoplankton growth and resulted in mortality and inhibition of growth of the copepods.

Topics: Aniline Compounds; Animals; Bacteria; Chlorophyll; Plankton; Water Pollutants; Water Pollutants, Chemical