Analysis of Organic Pollutants in Gulf of Mexico Gelatinous Zooplankton

Organic pollutants in gelatinous zooplankton species have yet to be studied as potential bioindicators for surface to bathypelagic depths in the Gulf of Mexico (GoM). These fauna could be used to assess water quality more accurately than vertebrate species (e.g., fishes) due to their thin integumentary system, lifestyle, and lack of xenobiotic-metabolic enzymes. Additionally, these organisms possess a mucus layer that can store organic chemicals, presenting an alternative method for coping with oil exposure. To test if gelatinous zooplankton accumulates more organic pollutants than fishes, we analyzed polycyclic aromatic hydrocarbons (PAHs) and pesticides in Atolla wyvillei, Aurelia aurita, and Sigmops elongatus. Samples were collected in the northern GoM in 2018 as part of the Deep Pelagic Nekton Dynamics Consortium (DEEPEND). Ultra-sonication and ASE extraction methods were utilized, followed by gas-chromatography analysis in reaction monitoring mode (GC/MS/MS-MRM). Statistically higher (~50 times) concentrations of organic compounds occurred in A. aurita as compared to A. wyvillei and S. elongatus. Also, high molecular weight PAHs (HMW PAHs) were 3.5 times higher in the two cnidarian species than in S. elongatus. However, no significant differences in low molecular weight PAHs (LMW PAHs) were found. These results showed that the medusae are unable to metabolize HMW PAHs as efficiently as S. elongatus. Therefore, these gelata can be used to assess bioavailability of chemicals in offshore waters due to their increased ability to accumulate organic contaminants as compared to vertebrates. In addition, we will present results for the tunicate Pyrosoma atlanticum collected before (2010) and after (2011, 2016, 2018) the Deepwater Horizon oil spill to better evaluate exposure, uptake, and storage capacity of hydrocarbons in deep-pelagic gelatinous zooplankton