Toxicant Responses and Culturing Characteristics of Long-Term Laboratory-Reared and Field Populations of Ceriodaphnia dubia.

Ceriodaphnia dubia is a standardized test organism for regulatory toxicity testing of surface waters and commercial chemicals because of its simplicity to culture and responsiveness to toxicants. For testing convenience, C. dubia is often cultured for extended periods in the laboratory with little knowledge of the impact on subsequent generations.

Silver Inhibits Growth at High Initial Frond Densities.

Silver nanoparticles (AgNPs) are the most popular engineered nanomaterials in consumer products due to their antimicrobial properties. They enter aquatic ecosystems via insufficient purified wastewaters from manufacturers or consumers. AgNPs inhibit growth of aquatic plants, including duckweeds.

Recessivity of pyrethroid resistance and limited interspecies hybridization across Hyalella clades supports rapid and independent origins of resistance.

Several populations of the amphipod, Hyalella azteca, have developed resistance to pyrethroid insecticides due to non-target exposure, but the dominance of the resistance trait is unknown. The current study investigated the dominance level of point mutations in natural populations of insecticide-resistant H. azteca and determined whether H.