Document Author: James R. Payne

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.

Long Term Environmental Monitoring Program 2021 Summary Report

The Long-Term Environmental Monitoring Program (LTEMP), managed by the Prince William Sound Regional Citizens’ Advisory Council, is in its 28th year of monitoring hydrocarbons in the wake of the Exxon Valdez oil spill.

Through LTEMP, we are able to determine the source of hydrocarbons and the potential adverse effects on the ecosystem from Alyeska Pipeline Service Company’s Valdez Marine Terminal and tanker activity. These data have been insightful in understanding the influence of terminal and non-terminal sources of hydrocarbons and environmental factors on hydrocarbon dynamics across Prince William Sound and the Gulf of Alaska.

The following study presents the 2021 results from the LTEMP in Port Valdez and aims to determine:

  • The extent, if any, that the terminal and associated tankers’ hydrocarbon fingerprint is present in 2021 samples.
  • The potential environmental and toxicological risk posed by the measured hydrocarbon contribution from the terminal and tankers.
  • Other factors (e.g., environmental or anthropogenic) that may be influencing hydrocarbon presence and composition in 2021 samples and the toxicological relevance of these results.
  • How the 2021 data compare to historical LTEMP trends and whether new analysis supports previous conclusions.
  • Recommendations for future monitoring of petroleum hydrocarbons at the terminal and in Prince William Sound.

Prepared by: Morgan L. Bender. Contributors: James R. Payne and William B. Driskell

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.

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