This report is the executive summary of the full report titled: Transcriptomic responses to an Alaskan oil spill over time reveal a dynamic multisystem involvement in exposed mussels (Mytilus trossulus).
Document Author: Austin Love
Transcriptomic responses to an Alaskan oil spill over time reveal a dynamic multisystem involvement in exposed mussels (Mytilus trossulus)
Whole tissues analyzed for the full suite of forensic oil hydrocarbons revealed weathering patterns and purging processes. The transcriptome of adductor muscle tissue showed multi-pathway effects and timing in gene activities related to the detoxification and recovery processes.
In multiple pathways, gene activities did not return to reference-site levels, suggesting that recovery from hydrocarbons was not complete by the final sampling. This may have been due to residual sheening prolonging recovery.
Genes that could potentially distinguish between ANS crude oil and harbor contaminants (pyrogenics and diesel) were identified with the goal of developing more robust monitoring tools.
Utilizing Numerical Simulation to Estimate the Volume of Oil Leaked Through a Damaged Secondary Containment Liner
Field testing has revealed that a component of the ETF’s secondary containment systems, known as the catalytically blown asphalt (CBA) liner, likely has unrepaired holes in it that could allow oil to reach groundwater in the event of a spill, but the secondary containment systems are required to protect groundwater from oil spill contamination.
Alyeska’s spill response activities (e.g. times and recovery/processing rates) were modelled based on their stated capacities. To simulate how much oil could leak through a damaged CBA liner, this analysis considered the following key factors, among others: full storage volume of Tank 11, area of Tank 11’s secondary containment system, hydraulic conductivity or permeability of the earthen fill above the buried CBA liner, depth of that earthen fill, rate which spilled oil could be drained from the secondary containment area, time estimate for spill cleanup, and an estimate of the percentage of CBA liner damage (i.e., holes).
The results of the simulation indicate that the earthen fill above the CBA liner will be fully saturated with oil in under 8 minutes. Assuming a value of 0.1% liner damage, the standing oil will be drained in approximately 2.8 days; however, 38,000 barrels of oil will have leaked from secondary containment during this time period. Over the entire 30-day clean-up window, the simulation estimates that approximately 125,000 barrels of oil will be discharged through damage in the CBA liner.
Full Report: Mussel Chemistry and Transcriptomic Response after a Minor Alaskan Oil Spill
When a mussel is exposed to a chemical irritant such as crude oil, certain genes respond, triggering mRNA to carry a message to the mussel’s cells. That message tells the cells how to deal with the irritant. Every irritant triggers a different pattern of genes. The scientists looked for the genetic and chemical response patterns unique to crude oil.
Their analysis showed that both oil concentrations and gene response spiked then decreased with time, however the genetic response peaked at a later time.
This document is the full report. See also: Executive Summary.