Oil within the Ocean Photooxidizes in Hours to Days, New Research Finds – Watts Up With That?
The study provides new details on the fate of oil spills in the marine environment and the effectiveness of chemical dispersants
UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF NAVY & ATMOSPHERE SCIENCE
Research news
IMAGE: SATELLITE IMAGE TAKEN ON MAY 9, 2010 FROM THE DEEPWATER HORIZON OIL SPILL SITE IN THE GULF OF MEXICO. Show more CREDIT: MODIS ON AQUA SATELLITE from NASA, MAY 9, 2010 @ 190848 UTC. DOWNLINK AND PROCESSED IN THE UM ROSENSTIEL SCHOOL CENTER FOR SOUTH EAST TROPICAL ADVANCED REMOTE DETECTION (CSTARS)
MIAMI – A new study by scientists from the Rosenstiel School of Marine and Atmospheric Science at the University of Miami (UM) shows that under realistic environmental conditions, oil in the ocean drifts after the DWH oil spill becomes persistent within hours to days Compounds have been photooxidized for long periods of time, as was believed during the 2010 Deepwater Horizon oil spill. This is the first model result to support the new paradigm of photooxidation that emerged from laboratory research.
After an oil spill, oil droplets on the ocean’s surface can be converted by a weathering process known as photo-oxidation, which causes crude oil to break down into new by-products over time through exposure to light and oxygen. Tar, a by-product of this weathering process, can remain in coastal areas for decades after being buried. Despite the significant consequences of this weathering pathway, photo-oxidation has not been factored into oil pollution models or oil budget calculations during the Deepwater Horizon spill.
The research team at UM Rosenstiel School developed the first algorithm for oil pollution models that tracks the dose of solar radiation that oil droplets receive as they rise from the deep sea and are transported to the surface of the sea. The authors found that weathering of oil droplets from sunlight occurred within hours to days, and that approximately 75 percent of the photooxidation during the Deepwater Horizon oil spill occurred in the same areas where chemical dispersants were sprayed from airplanes. It is known that photooxidized oil reduces the effectiveness of air dispersants.
“Understanding when and where this weathering process occurs is extremely important. said Claire Paris, a faculty at UM Rosenstiel School and lead author on the study. “It helps direct efforts and resources towards fresh oil while avoiding polluting the environment with chemical dispersants on oil that cannot be dispersed.”
“Photooxidized compounds like tar stay in the environment longer. Therefore, modeling the likelihood of photo-oxidation is critical not only in deciding what first response to an oil spill and how to recover it, but it must also be considered in risk assessments prior to exploration activities, ”added Ana Carolina Vaz, Research Associate at UM Cooperative Institute for Marine and Atmospheric Studies and lead author of the study.
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The study, entitled “A Lagrangian-Earth Coupled System Model for Predicting Oil Photooxidation,” was published online in Frontiers in Marine Science on February 19, 2021. The authors of the paper include: Ana Carolina Vaz, Claire Beatrix Paris, and Robin Faillettaz.
The study was supported by the Gulf of Mexico Research Initiative (GoMRI): C-IMAGE III (Center for Integrated Modeling and Analysis of the Gulf Ecosystem) and RECOVER 2 (Relationship of the Impact of Cardiac Outcomes in Fish to Validate Ecological Risk).
From EurekAlert!
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