RAPID: Collaborative Research: Nematostella as an Estuarine Indicator Species for Assessing Molecular and Physiological Impacts of the Deepwater Horizon oil spill.

University Of Alabama Tuscaloosa, Tuscaloosa AL

Investigators

Abstract

As a result of the Deepwater Horizon oil spill, millions of gallons of oil have leaked into the Gulf of Mexico and much of that oil has and will continue to wash up along the Gulf Coast of the United States. In an attempt to minimize the amount of oil to reach the coast, an unprecedented of amount of dispersant has been used both on surface oil and at the source of the leak. The impact of this unprecedented use of dispersant on the marine environment, food webs and the bioavailability of oil remains to be investigated. Furthermore, the microbial degradation of oil and dispersed oil in the marine environment or estuarine marshes can produce very low oxygen levels (hypoxia) that will further stress marine and estuarine invertebrates. Unfortunately, very little information is available on the impact of oil or dispersed oil and additional abiotic stressors (hypoxia) on the physiology of marine and estuarine invertebrates. Nematostella vectensis is a sea anemone (an organism related to reef-building corals) found in salt marshes along the Gulf of Mexico and Atlantic coast of the United States. This project will use Nematostella as a model to address the urgent need to understand the physiological responses of estuarine invertebrates to oil exposure, combined exposure of oil and dispersant and possible synergism between oil exposure and hypoxia (low oxygen). First, Nematostella will be collected from Gulf Coast populations. Contaminant load, energetic stores and reproductive status will be quantified. Molecular techniques will be used to determine which genes are affected ("turned on" or "turned off") in anemones from oil-exposed sites. Second, laboratory experiments will be conducted to determine the effects of oil exposure and combined exposure to oil and dispersant under normal oxygen (normoxic) and hypoxic conditions. Brine shrimp will be reared in the presence of a range of concentrations of oil, dispersant, and oil with dispersant. These shrimp will be fed to Nematostella under normoxic and hypoxic conditions. Effects of exposure will be characterized by assessing changes in gene expression, lipid analysis, histological examination and biochemical assays. The results of these experiments will provide insight into the different molecular and cellular processes that are used to protect the organism from combinations of stressors that are associated with the oil spill and exposure to oil or dispersed oil. This project will also enable development of biomarkers that can be used to assess responses of organisms collected in the field. Broader Impacts: This project will provide insight into the ecological consequences of the Deepwater Horizon oil spill. Results from field sampling will be posted and linked with other emerging results (e.g., EPA sediment analysis). Gene expression and sequence data will be curated, and posted to publicly accessible databases. Two PhD students will be trained in lipid analysis and ecological genomics. This project will identify cellular and molecular responses of a cnidarian (sea anemone, related to reef-building corals) to oil exposure through an understudied route of exposure (feeding). In addition this project will provide direct measurements of gene expression, lipid stores and contaminant burdens an indicator species of anemones from potentially impacted populations along the Gulf Coast. The identification and characterization of various pathways being affected by oil exposure and related stressors (e.g., hypoxia) will assist in development of ecological forecasting tools to predict the physiological responses of organisms and subsequent impacts on local populations and ecosystems.