Deepwater Horizon study could improve ocean oil cleanup

Dr Sabine Matallana-Surget carries out seawater filtration to collect marine bacteria in Florida.

Research into the Deepwater Horizon oil spill by an international team of scientists could lead to major improvements in marine oil spill cleanup processes.

The innovative study, led by researchers Dr Sabine Matallana-Surget at the University of Stirling in Scotland and Dr Wade Jeffrey of the University of West Florida, US, assessed the impact of the Deepwater Horizon oil spill on microscopic seawater bacteria that perform a significant role in ecosystem functioning. Dr Matallana-Surget used a pioneering technique more commonly employed in medical science during field work in the Gulf of Mexico.

In April 2010, an explosion at the Deepwater Horizon offshore oil rig killed 11 crew and caused the largest marine oil spill in history, when 4.9 million barrels released into the Gulf of Mexico. The findings show chemical oil dispersants used to mitigate the impact of the disaster worsened the stress response in bacteria, and those harmful effects were then intensified by exposure to sunlight. The event happened in the spring, a season characterised by extreme sunlight in the region.

"The study's implications extend to environmental conservation, influencing future strategies for mitigating the impact of such incidents and safeguarding marine ecosystems.”

Dr Sabine Matallana-Surget, University of Stirling

“We have demonstrated that dispersants exert a more profound impact on the regulation of microbial communities than the oil spill itself. In just 24 hours, these chemicals induce acute stress responses," said Matallana-Surget.

“Additionally, sunlight played a crucial role in intensifying dispersant toxicity. In the presence of sunlight and oil, the diversity of essential hydrocarbon-degrading bacteria significantly decreased.

“This suggests that sunlight can modify the chemical structure of oil, making it more toxic to specific bacterial species. Our study also revealed the impact of oil and dispersant on cyanobacterial photosynthesis, further emphasising the intricate interactions between contaminants, sunlight, and microbial communities in the Gulf of Mexico.”

The research has international significance for society and industry because it deepens understanding of the impact of oil spill responses.

Dr Matallana-Surget added: “By understanding how dispersants impact microbial communities in the presence of natural hydrocarbon degraders, we contribute to more effective oil spill cleanup strategies. The benefits extend globally, as marine ecosystems worldwide face similar challenges.

“The findings have the potential to influence environmental policies and cleanup procedures on an international scale. The study's implications extend to environmental conservation, influencing future strategies for mitigating the impact of such incidents and safeguarding marine ecosystems.”

The UK is among the countries that could benefit from the findings, Dr Matallana-Surget said, “The study primarily focuses on the impact of oil spills in the Gulf of Mexico, but its outcomes hold broader relevance for policymakers in regions facing similar challenges, such as Scotland, with crude oil seepages. The insights gained from our research could provide valuable guidance for crafting effective policies and response strategies in these comparable environments.”

The study saw researchers simulate oil spills in waters collected off Pensacola Beach in Florida. Crude oil was added with and without dispersant under sunlight and dark conditions, with larger organisms filtered out.

Dr Matallana-Surget, who has pioneered the technique, said, “This enables a more precise and comprehensive analysis of microbial communities' reactions to oil spills. These findings not only enhance our comprehension of environmental impacts but also underscore the capacity of employing state-of-the-art molecular tools to address crucial concerns in marine conservation.

“This innovative approach marks a transformative shift, elevating the precision and depth of oil spill investigations and guiding future endeavours to preserve the health of our oceans.”

The research was led by the University of Stirling working with scientists from the University of West Florida, Sorbonne University in France, the University of Mons, Belgium, and the University of Tübingen in Germany.