2010. aasta Deepwater Horizoni naftareostus oli suurim naftareostus merel USA ajaloos. Katastroofi põhjustas naftaplatvormi Deepwater Horizon plahvatus, mis mitte ainult ei nõudnud korraga 11 inimelu, vaid paiskas Mehhiko lahte ka ligi 210 miljonit gallonit toornaftat.
Kaheteistkümne aasta pärast on sellele katastroofilisele sündmusele reageerimiseks kulutatud sadu miljoneid dollareid ja teadlased töötavad selle nimel, et mõista, kuhu kogu see nafta jõuab. Seda mõistet nimetatakse keskkonnasaatuseks.
Enim arutatud naftareostuse saatused merel on biodegradatsioon (mikroorganismid tarbivad ja lagundavad õli), aurustumine (vedel õli muutub gaasiks) ja adsorptsioon pärast seda, kui nafta on kaldale sattunud.
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."
Uudsed LED-e kasutavad mõõtmismeetodid annavad ka võimaluse määrata, millised tingimused on protsessi juhtimisel kõige olulisemad. Meeskond lõi hüpoteetilisi lekkestsenaariume erineva õlilaigu paksuse, erinevate aastaaegade, erinevates kohtades üle maailma ja erinevat tüüpi valgusega. Nad märkasid, et mõned neist muutuvatest tingimustest olid olulisemad kui teised.
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.
