The Deepwater Horizon oil leak in the Gulf of Mexico in 2010 was the world’s greatest marine oil spill. The rig has been leaking oil and gas for months, with nearly 5 million barrels thought to have spilled into the water. Half of the oil was confined deep underground, while the other half ascended to the surface, immortalized in photographs, and even made it to the coast. Some of the projected surface oil vanished before it could be cleaned, according to estimates, and researchers believe that sunlight may have had a part in this.
According to Danielle Haas Freeman and Collin Ward of the Woods Hole Oceanographic Institution, photo-dissolution could have cleared away as little as 3% to as much as 17% of the oil floating in the Gulf of Mexico, according to a study published in Science Advances. “Where did all of this oil go, in the big picture? Despite over a decade of investigation, there are still unanswered issues about the spilt oil’s environmental fate “IFLScience spoke with Hass Freeman and Ward.
”Biodegradation, in which bacteria eat the oil, evaporation, in which the oil transforms into a gas and is released into the atmosphere, and stranding, in which oil washes up on coasts, are the three most widely mentioned fates. We predicted that the oil could also undergo a process known as photo-dissolution, in which it absorbs sunlight and transforms into molecules that dissolve in seawater.” Until date, photo-dissociation has not been properly investigated in relation to spill models, yet light can break oil molecules into other organic substances.
Haas Freeman and Ward discovered that UV light and modest doses of sunshine are the most effective strategies to get rid of the oil after examining different wavelengths of light and varied amounts of sunlight received. “We discovered that following sunshine exposure, approximately 10% of the floating oil in the Gulf of Mexico after the Deepwater Horizon spill dissolved into saltwater, a quantity that equals other oil environmental outcomes including biodegradation and stranding,” they added.
“We also performed a sensitivity analysis to establish which parameters are most significant in limiting the rate of photo-dissolution at sea under hypothetical spill scenarios,” they added. “For example, we discovered that photo-dissolution rates in the Arctic may be similar to or even greater than those in lower-latitude waters during the summer months.” This finding is significant because cargo ship traffic in the Arctic is rising as sea ice melts, and with increased traffic comes a greater risk of oil spills.
This understanding may help us better understand how oil spills evolve, but they both emphasize that much more research is needed to fully comprehend the role of photo-dissociation, as well as investigations into any potential detrimental implications. “One implication of our findings is that photo-dissolution could lower the amount of material that responders need to burn, skim, and chemically scatter at sea, or physically remove from fragile coastal ecosystems,” they told IFLScience.
“On the other hand, the oil spill science community must also examine the possible implications of dissolved transformation products on marine ecosystems.” If the solar transformation products are persistent and poisonous to aquatic species, this process could have negative consequences. The durability and toxicity of these compounds, on the other hand, are mainly unknown. We believe that these knowledge gaps should be prioritized by the community in the future.”
Is it possible to apply this method to improve clean-up efforts? According to Haas Freeman and Ward, incorporating this technique into oil spill models should allow for more precise predictions of the volume of oil spills and their location, as well as refining estimates for other environmental processes. This could lead to “more judicious resource allocation throughout the spill response phase,” especially when resources are limited and environmental agencies must make decisions about what to protect and how to protect certain places.
