Deepwater Horizon olíulekinn 2010 var stærsti sjávarolíuslys í sögu Bandaríkjanna. Hamfarirnar urðu vegna sprengingarinnar í Deepwater Horizon olíuborpallinum, sem kostaði ekki aðeins 11 mannslíf í einu, heldur losaði hann einnig nærri 210 milljón lítra af hráolíu í Mexíkóflóa.
Tólf árum síðar hefur hundruðum milljóna dollara verið varið til að bregðast við þessum hörmulega atburði og vísindamenn vinna að því að skilja hvar öll þessi olía endar, hugtak sem kallast örlög í umhverfinu.
Algengustu afdrif olíuleka á sjó eru lífræn niðurbrot (örverur neyta og brjóta niður olíuna), uppgufun (fljótandi olía breytist í gas) og aðsog eftir að olían strandar á strandlengjum.
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."
Nýjar mælingaraðferðir sem nota LED gefa einnig tækifæri til að ákvarða hvaða aðstæður eru mikilvægastar við að stjórna ferlinu. Teymið bjó til ímyndaðar lekasviðsmyndir með mismunandi olíuþykktum, mismunandi árstímum, mismunandi stöðum um allan heim og mismunandi tegundum ljóss. Það sem þeir tóku eftir var að sumar þessara breyttu aðstæðna voru mikilvægari en aðrar.
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.
