The use of ephyrae of a scyphozoan jellyfish, Aurelia aurita, in the aquatic toxicological assessment of Macondo oils from the Deepwater Horizon incident

Chemosphere. 2016 Feb;144:1893-900. doi: 10.1016/j.chemosphere.2015.10.082. Epub 2015 Nov 11.


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.

Keywords: Acute toxicity; Corexit 9500; Deepwater Horizon; Jellyfish; PAHs; Stress indicators.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accidents*
  • Animals
  • Ecotoxicology*
  • Gulf of Mexico
  • Lipids / toxicity
  • Petroleum / analysis*
  • Petroleum Pollution*
  • Polycyclic Aromatic Hydrocarbons / toxicity
  • Scyphozoa / drug effects*
  • Water Pollutants, Chemical / toxicity


  • Lipids
  • Petroleum
  • Polycyclic Aromatic Hydrocarbons
  • Water Pollutants, Chemical
  • corexit 9500