Comparing the sensitivity of algal, cyanobacterial and bacterial bioassays to different groups of antibiotics.

Antibiotics may affect both primary producers and decomposers, potentially disrupting ecosystem processes. Hence, it is essential to assess the impact of antibiotics on aquatic ecosystems. The aim of the present study was therefore to evaluate the potential of a recently developed test for detecting antibiotics in animal tissue, the Nouws Antibiotic Test (NAT), as a sensitive bioassay to assess the effects of antibiotics in water.

Life-history characteristics of Daphnia exposed to dissolved microcystin-LR and to the cyanobacterium Microcystis aeruginosa with and without microcystins.

In the current study, the role of microcystin(MC)-LR in inhibiting Daphnia growth was examined. Somatic growth, time to first reproduction, number of newborns, mortality, and population growth were measured in Daphnia fed mixtures of the cyanobacterium Microcystis aeruginosa (with and without microcystin) with a high quality green algal food (Scenedesmus obliquus) to avoid nutritional deficiency. Microcystin-LR-containing cells caused a dramatic reduction in growth and resulted in death of the animals, but the addition of purified toxin (microcystin-LR) had no effect on Daphnia growth.

Development of photosynthetic biofilms affected by dissolved and sorbed copper in a eutrophic river.

Photosynthetic biofilms are capable of immobilizing important concentrations of metals, therefore reducing bioavailability to organisms. But also metal pollution is believed to produce changes in the microalgal species composition of biofilms. We investigated the changes undergone by natural photosynthetic biofilms from the River Meuse, The Netherlands, under chronic copper (Cu) exposure.