O derramamento de óleo da Deepwater Horizon em 2010 foi o maior vazamento de óleo marinho da história dos EUA. O desastre foi causado pela explosão da plataforma de petróleo Deepwater Horizon, que não apenas tirou 11 vidas de cada vez, mas também liberou quase 210 milhões de galões de petróleo bruto no Golfo do México.
Doze anos depois, centenas de milhões de dólares foram gastos em resposta a esse evento catastrófico, e os cientistas estão trabalhando para entender onde todo esse petróleo vai parar, um conceito conhecido como destino ambiental.
Os destinos mais comumente discutidos de derramamentos de óleo no mar são a biodegradação (microrganismos consomem e quebram o óleo), evaporação (óleo líquido se transforma em gás) e adsorção depois que o óleo fica encalhado nas costas.
A team from the Woods Hole Oceanographic Institution (WHOI) has found that after the Deepwater Horizon disaster, nearly 10 percent of the oil floating in the Gulf was dissolved by sunlight into seawater - a process known as "photolysis". ". The findings are published today in the paper "Sunlight-driven dissolution is the main fate of offshore oil" in the journal Science Advances.
"During the 2010 Deepwater Horizon spill, the amount of oil that was converted by sunlight into compounds dissolved in seawater was different from what we usually know about the fate of oil (such as Biodegradation and stranding on shorelines) are comparable."
"One of the most fascinating aspects of this discovery is that it may affect our understanding of where oil is going elsewhere, and whether the outcome is good or bad," said lead author Danielle Haas Freeman, a student in the joint MIT/WHOI project. Say.
"If a significant portion of this oil is converted by sunlight and dissolved into seawater, it could mean that less oil ends up elsewhere, such as in sensitive coastal ecosystems. On the other hand, we have to consider the impact of these compounds on marine life. impact to determine whether the net result is positive or negative."
To make this important discovery, Freeman and Ward used a custom light-emitting diode (LED) reactor to measure how the velocity of this oil's fate changed under different types of light, such as ultraviolet and visible light.
"The process by which oil has been found to photolysis has actually been around for more than 50 years," Ward said. "But what's new here is that we understand how this process changes with the wavelength of light, which we determined using an LED reactor. This is key information that allows us to estimate the importance of this process during a leak."
Novos métodos de medição usando LEDs também oferecem uma oportunidade para determinar quais condições são mais importantes no controle do processo. A equipe criou cenários hipotéticos de derramamento com diferentes espessuras de manchas de óleo, diferentes épocas do ano, diferentes locais ao redor do mundo e diferentes tipos de luz. O que eles notaram foi que algumas dessas condições de mudança eram mais importantes do que outras.
Oil at the ocean's surface may have a new fate, a concept that has major implications for developing future oil spill research and spill response strategies. It is not known what the fate and potential toxicity of these sunlight-generated compounds are, making it challenging to assess the impact of this oil's fate. The researchers encourage the field to lean toward these gaps in knowledge.
"While our findings suggest that a significant portion of surface oil can dissolve into the ocean upon exposure to sunlight, the logical next step is to assess its persistence and potential harm to aquatic animals," Ward said.
