Chronic aquatic toxicity of perfluorooctane sulfonic acid (PFOS) to Ceriodaphnia dubia, Chironomus dilutus, Danio rerio, and Hyalella azteca.

Perfluorooctane sulfonic acid (PFOS) is a ubiquitous and persistent contaminant in aquatic ecosystems. Chronic toxicity information for aquatic organisms is limited, therefore we conducted chronic PFOS toxicity tests for four model organisms commonly used for freshwater toxicology assays: Chironomus dilutus (midge), Ceriodaphnia dubia (water flea), Hyalella azteca (amphipod) and Danio rerio (zebrafish). The 16-day survival test with C. dilutus resulted in the lowest PFOS exposure concentrations to cause significant impacts, with reduced survival at 1 µg/L, a LC50 of 7.5 µg/L, and a growth EC10 of 1.5 µg/L. D. rerio was the next most sensitive species, with a 30-day LC50 of 490 µg/L and reduced growth at 260 µg/L. Effects for C. dubia and H. azteca occurred at concentrations a thousand-fold higher than for C. dilutus. H. azteca had a 42-day LC50 of 15 mg/L, an EC50 of 3.8 mg/L for reproduction (neonates per female) and an EC50 of 4.7 mg/L for growth. C. dubia was similarly tolerant of PFOS, with a 6-day LC50 of 20 mg/L for survival and an EC50 of 7 mg/L for reproduction (neonates per adult). H. azteca, C. dubia, and, to a lesser extent, D. rerio, appear tolerant of PFOS concentrations typically found in the environment. However, in agreement with previous studies, C. dilutus was particularly sensitive to PFOS exposure, with lethal and sublethal effects occurring at concentration levels present at highly contaminated sites.

Novel microsatellite loci for Agave parryi and cross-amplification in Agave palmeri (Agavaceae).

PREMISE OF THE STUDY: To examine the foraging behavior of nectarivorous bats in southeastern Arizona, we developed microsatellite primers in Agave parryi. These markers were also tested for cross-amplification and applicability to assess patterns of genetic diversity and structure in A. palmeri. METHODS AND RESULTS: Utilizing DNA sequence data from 454 shotgun sequencing, we identified seven novel polymorphic microsatellite loci in A. parryi and screened them for cross-amplification in A. palmeri. These markers were characterized in two populations of 30 individuals each for each species. In A. parryi, all primers were polymorphic and amplified between three and 12 alleles per population. In A. palmeri, all primers amplified, six were polymorphic, and allelic diversity ranged from one to 16 alleles per population. CONCLUSIONS: Our results demonstrate the applicability of these microsatellite primers for population genetics studies in both A. parryi and A. palmeri.