Biological Impacts of Novel, Persistent, Oxygenated Fractions of Petroleum on Sentinel Species in Estuarine Environments

Sibel I. Karchner, Biology
Ann Tarrant, Biology
Chris Reddy, Marine Chemistry & Geochemistry
Mark E. Hahn, Biology

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2016 COI Funded Project

Abstract

Petroleum is a common contaminant in coastal marine environments.  Oil spills, especially large ones such as the Deepwater Horizon spill, generate intense interest immediately after the spill and stimulate research to understand the environmental fate of the spilled oil and its acute effects on biota.  Over time, however, the oil undergoes weathering (water washing, evaporation, photo-oxidation and biodegradation), leading to substantial changes in composition and the generation of persistent components whose impact is not well understood.  Recent studies from Reddy’s laboratory have shown that weathering (especially photo-oxidation) increases the formation and abundance of oxygenated, polar fractions [oxygenated hydrocarbons (OxHC)], which become >50% of the total mass of the weathered oil in just a few weeks.  These newly formed OxHCs appear to be more persistent than the well-studied saturated and aromatic compounds, but are difficult to analyze and thus have been overlooked in previous studies, which have focused almost exclusively on saturated or aromatic components such as alkanes and polycyclic aromatic hydrocarbons (PAHs), respectively.  Therefore, there is currently a major gap in our understanding of the biological impacts of these newly formed oxygenated fractions. 

We propose to begin to investigate the biological effects of these persistent oxygenated hydrocarbons on coastal marine animals.  We will use two complementary environmental sentinel species (species whose physiological status can be used as an indicator of environmental conditions): a vertebrate (the Atlantic killifish Fundulus heteroclitus) and an invertebrate (the sea anemone Nematostella vectensis).  In animals exposed to oxygenated and other fractions of weathered oil, we will assess toxicity and genome-wide changes in gene expression.  Three separate research groups are collaborating in this project, combining their expertise in petroleum chemistry, vertebrate and invertebrate biology, and toxicology.  This interdisciplinary collaboration is an excellent opportunity for expansion of our research at the interface of marine chemistry and biology.  It will generate preliminary data that will facilitate subsequent interdisciplinary proposals to federal agencies for research to provide a detailed assessment of the biological impacts of these previously overlooked but important components of weathered oil.