Response of zooplankton communities to liquid creosote in freshwater microcosms

• Published in: Environmental toxicology and chemistry Vol. 20; no. 2; pp. 394 - 405
• Main Authors: Sibley, Paul K., Harris, Megan L., Bestari, Ketut T. (Jim), Steele, Tracey A., Robinson, Richard D., Gensemer, Robert W, Day, Kristen E., Solomon, Keith R.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Periodicals, Inc 01-02-2001; SETAC
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Cladocera; Community response; Copepoda; Creosote; Creosote - toxicity; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Fresh Water; Fundamental and applied biological sciences. Psychology; Microcosms; Principal response curves; Rotifera; Water Pollutants, Chemical - toxicity; Zooplankton; Zooplankton - drug effects; Community structure; Toxicity; Interspecific comparison; Creosote; Microcosm; Abundance; Time response relation; Polycyclic aromatic compound; Dose activity relation; Freshwater environment; Water pollution; Population recovery; Zooplankton; Species richness
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.5620200222

In this study, the response of zooplankton communities to single applications of liquid creosote in model aquatic ecosystems (microcosms) was evaluated. Liquid creosote was applied to 14 microcosms at concentrations ranging from 0.06 to 109 mg/L. Two microcosms served as controls. Zooplankton samples were collected from each microcosm on days 7 and 1 before treatment and on days 2, 5, 7, 14, 21, 28, 43, 55, and 83 following treatment. Temporal changes (response‐recovery) in composition of the zooplankton community were assessed using principal response curves (PRC). Creosote induced a rapid, concentrationdependent reduction in zooplankton abundance and number of taxa, with maximum response (50–100% reduction in population densities) occurring between 5 and 7 d after treatment. Taxa that dominated at the time of treatment experienced the greatest impact, as indicated by large, positive species weight values (>1) from the PRC analysis. Many of these taxa recovered to pretreatment or control levels during the posttreatment period, with the degree and duration of recovery being strongly dependent on concentration. Creosote had little effect on species composition at less than 1.1 mg/L, because changes in the types and relative proportion of species contributed from Cladocera, Rotifera, and Copepoda were comparable to those observed in control microcosms. However, a significant shift in species composition was observed at concentrations greater than 1.1 mg/L; these microcosms were generally dominated by low numbers of rotifers, some of which had not been collected before treatment. Community‐level effect concentrations (EC50s) were 44.6 and 46.6 μg/L at 5 and 7 d, respectively, based on nominal creosote. Corresponding no‐effect concentrations were 13.9 and 5.6 μg/L. The results of this field study indicate that creosote may pose a significant risk to zooplankton communities at environmental concentrations potentially encountered during spills and/or leaching events.