title: Effects of salinity, pH and temperature on the re-establishment of bioluminescence and copper or SDS toxicity in the marine dinoflagellate Pyrocystis lunula using bioluminescence as an endpoint.
abstract: Pyrocystis lunula is a unicellular, marine, photoautotrophic, bioluminescent dinoflagellate. This organism is used in the Lumitox bioassay with inhibition of bioluminescence re-establishment as the endpoint. Experiments determined if acute changes in pH, salinity, or temperature had an effect on the organisms' ability to re-establish bioluminescence, or on the bioassay's potential to detect sodium dodecyl sulfate (SDS) and copper toxicity. The re-establishment of bioluminescence itself was not very sensitive to changes in pH within the pH 6-10 range, though reducing pH from 8 to levels below 6 decreased this capacity. Increasing the pH had little effect on Cu or SDS toxicity, but decreasing the pH below 7 virtually eliminated the toxicity of either compound in the bioassay. Lowering the salinity from 33 to 27 per thousandth or less resulted in a substantial decrease in re-establishment of bioluminescence, while increasing the salinity to 43 or 48 per thousandth resulted in a small decline. Salinity had little influence on the bioassay's quantification of Cu toxicity, while the data showed a weak negative relationship between SDS toxicity and salinity. Re-establishment of bioluminescence showed a direct dependence on temperature, but only at 10 degrees C did temperature have an obvious effect on the toxicity of Cu in this bioassay.
authors.affiliation: Department of Biology, University of Louisiana at Lafayette, PO Box 42451, Lafayette, LA 70504, USA. jaquelyn_craig@usgs.gov
authors.forename: Jaquelyn M
authors.initials: JM
authors.lastname: Craig
authors.forename: Paul L
authors.initials: PL
authors.lastname: Klerks
authors.forename: Kirsten
authors.initials: K
authors.lastname: Heimann
authors.forename: Juliann L
authors.initials: JL
authors.lastname: Waits
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods; D003300:Copper / Q000633:toxicity*; D004141:Dinoflagellida / Q000187:drug effects* / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D012965:Sodium Chloride / Q000032:analysis; D012967:Sodium Dodecyl Sulfate / Q000633:toxicity*; D013696:Temperature; D018675:Toxicity Tests / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D012967:Sodium Dodecyl Sulfate; D012965:Sodium Chloride; D003300:Copper