title: The use of ephyrae of a scyphozoan jellyfish, Aurelia aurita, in the aquatic toxicological assessment of Macondo oils from the Deepwater Horizon incident.
abstract: Ephyrae of the scyphozoan jellyfish, Aurelia aurita, were evaluated in 96-hr acute toxicity tests for lethal response to Macondo crude oils from the Deepwater Horizon (DWH) incident in the Gulf of Mexico (GOM), Corexit 9500, and oil-dispersant mixtures. Water accommodated fractions (WAFs) of weathered and unweathered Macondo crude oils were not acutely toxic to ephyrae (LC50s > 100% WAF). The total PAHs (TPAHs), measured as the sum of 46 PAHs, averaged 21.1and 152 µg TPAH/L for WAFs of weathered and unweathered oil, respectively. Mortality was significantly (p = <0.0001) higher in the three highest exposure concentrations (184-736 µg TPAH/L) of chemically dispersed WAFs (CEWAF) compared to controls. Dispersant only tests resulted in a mean LC50 of 32.3 µL/L, which is in the range of previously published LC50s for marine zooplankton. Changes in appearance and muscle contractions were observed in organisms exposed to CEWAF dilutions of 12.5 and 25%, as early as 24 h post-exposure. Based on the results of these tests, crude oil alone did not cause significant acute toxicity; however, the presence of chemical dispersant resulted in substantial mortality and physical and behavioral abnormalities either due to an increase in hydrocarbons or droplet exposure.
authors.affiliation: Southeast Environmental Research Center, Earth and Environment, Florida International University, North Miami, FL 33181, USA. Electronic address: bsechols@gmail.com.
authors.forename: B S
authors.initials: BS
authors.lastname: Echols
authors.affiliation: Southeast Environmental Research Center, Earth and Environment, Florida International University, North Miami, FL 33181, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Smith
authors.affiliation: Southeast Environmental Research Center, Department of Chemistry, Florida International University, North Miami, FL 33181, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Gardinali
authors.affiliation: Southeast Environmental Research Center, Earth and Environment, Florida International University, North Miami, FL 33181, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Rand
mesh_terms: D000059:Accidents; D000818:Animals; D054750:Ecotoxicology; D060851:Gulf of America; D008055:Lipids / Q000633:toxicity; D010578:Petroleum / Q000032:analysis*; D059392:Petroleum Pollution; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity; D037401:Scyphozoa / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D008055:Lipids; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; C470995:corexit 9500
keywords: Acute toxicity; Corexit 9500; Deepwater Horizon; Jellyfish; PAHs; Stress indicators