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Ecotoxicology of Deep Ocean Spills
Citation:
Chiasson, S., A. Bejarano, AND M. Barron. Ecotoxicology of Deep Ocean Spills. Society of Environmental Toxicology and Chemistry (SETAC), Fort Worth, Texas, November 15 - 19, 2020.
Impact/Purpose:
The purpose of this presentation is to summarize the central issues in the ecotoxicology of deep ocean spills. The impact of this work is three fold: 1) deep ocean drilling in the Gulf of Mexico is likely to occur in the future, creating the potential for deep ocean oil spills, thus understanding the state of the science in ecotoxicology is important to better understand the potential impacts of future deep ocean spills. 2) EPA is responsible for regulating dispersants, and future use of dispersants in the deep ocean is probable, thus it is important to understand the state of the science in ecotoxicology. 3) This presentation will be part of a session on the 10th anniversary spill at an international science conference, thus providing a forum to communicating information and research needs to scientists, regulators and managers in the public and private sector.
Description:
Central issues in understanding impacts of oil spills in the deep ocean include the unknown sensitivity of species inhabiting aphotic zones and the complexity and diversity of habitats that may be affected as the oil enters euphotic offshore and coastal environments. Challenges in evaluating toxicity in deep ocean species comprise both unique physical conditions (low temperature, high pressure, low dissolved oxygen, no light) and biotic factors (e.g. chemosynthetic and bioluminescent species), and little is known about bioavailability of volatile hydrocarbons in deep hypersaline environments. Oil spilled in the deep ocean may also impact coastal and offshore ecosystems as the oil droplets enter the meso- and epipelagic zones, and could result in oiling of seabirds, turtles, marine mammals, and coastal wetlands. A spill coinciding with spawning seasons may elevate risk to sensitive life stages of pelagic species. Some approaches for estimating toxicity to deep ocean and other aquatic species includes using existing extrapolation tools, such as the species sensitivity distribution, toxicity databases (e.g. Chemical Aquatic Fate and Effects), and predictive models (e.g. Interspecies Correlation Estimate). This presentation reviews challenges, approaches, and limitations of toxicity estimates to deep ocean species, and is based primarily on information derived from the Gulf of Mexico and lessons learned from the Deepwater Horizon oil spill.
