Coastal communities are still reeling from a recent oil spill off Southern California that coated shorelines and marine life in black tar. Governor Gavin Newsom declared a state of emergency after a pipeline ruptured late last week, unleashing an oil slick spanning 8,320 acres on waters near some of California’s most iconic beaches. Officials are still investigating the cause of the spill but think that a cargo ship’s anchor might have snagged and tore through the pipeline, the Los Angeles Times reports.
It could take months to assess and clean up some of the mess, and longer for ecosystems to recover. To learn more about what to expect, The Verge spoke with Steve Murawski, a fisheries biologist and marine ecologist at the University of South Florida who studies the impact humans have on ocean ecosystems. Murawski was also the lead editor of the book Scenarios and Responses to Future Deep Oil Spills and previously served as chief scientist of the National Marine Fisheries Service.
I was hoping you could give me some context or a sense of scale when it comes to spills. How significant of a spill is the one off the coast of Southern California?
To put this in a little perspective, Deepwater Horizon, which was the largest accidental spill in global history, was about 2 million barrels. The Exxon Valdez spill was about 260,000 barrels. This one is about 3,400 barrels (about 144,000 gallons). Just in terms of volume, it’s a small percentage of what we would consider a catastrophic oil spill. That’s one perspective on it.
But it’s all about location. This is an oil spill of modest size; it’s in a very sensitive area. It’s only about four miles offshore. So just because it’s small, doesn’t mean it’s not significant. It’s very close to what we call amenity beaches, like Huntington Beach all the way down to Dana Point. Those are fully utilized for all kinds of recreation. That area in Southern California, you have a sort of persistent westward and southwestern wind. And so it only takes a few hours for that oil to be up on the beach. In the case of Deepwater Horizon, it was 50 miles offshore. It took weeks for the oil to actually come onto shore and so people could prepare for it. Here, there was no real preparation that you could do. It was up on the beach before people even knew you had a spill.
The other thing that you have to realize is, no two spills are exactly the same. It’s partially the geographic setup of the place, the wind, the tides, and all that. And it’s also the composition of the oil itself. Deepwater was what we would call Louisiana light sweet crude. I mean it was almost like cooking oil, it’s very light. This one, and all of the Southern California oils, are extremely heavy, dark, dense, oils. Heavy crude oils are higher in heavy components like asphaltenes, so they tend to be more toxic than the lighter ones.
So what risks might that oil pose to wildlife and people?
Oil is a conglomeration of about 40,000 different compounds. But the most problematic ones are the so called polycyclic aromatic hydrocarbons or PAH. These PAH can be both toxic, that is they poison things, and they are also carcinogenic.
There’s two major sets of ecological issues, not only with PAH’s, but other components as well. One is worker health and safety. I noticed most of the workers are wearing PPE; that’s great. In terms of toxicity in wildlife, the most critical early issues are for the air breathers. So this would be the marine mammals and birds.
You always see pictures of oiled birds in oil spills. It’s problematic for them because it’s hard for them to regulate their body temperatures when they get oil on their feathers and skin. You often see birds preening. What they’re doing is they’re fluffing out their feathers because that’s their protection. So when they get oiled they start preening. As they’re preening with their beaks they’re ingesting the oil. You see a lot of media showing birds being cleaned with detergents and what not. The prognosis for those birds is generally not very good. It’s partly because they’ve ingested oil as well as getting it on their skin.
With the air breathers, there’s different ways that oil gets into their bodies and one of them is basically aspirating the oil, which gets into the lungs and the circulatory system. Like dolphins that may be in that water, they don’t do a good job avoiding oil. You know, it’s not something they encounter all the time. That area down there has a number of large whale species. Luckily, some of the major migrations have already happened and return migrations haven’t started, but that’s certainly something to worry about.
In California, authorities are collecting oil on the surface of the water using mechanical equipment called skimmers. And they’ve set up barriers called booms to try to stop the oil from spreading. What else can be done to clean up the spill, especially after it reaches shore?
Of all the habitats where oil can get into, beaches are probably one of the least complex in order to actually mitigate the effects of the spill and pick up the oil. It’s not a very convoluted habitat and you can use machinery to groom those beaches, to get rid of tar balls and all that.
Particularly with this heavy crude oil, the oil comes in on waves and it gets mixed with beach sand. And so you get these patties that form, and they will persist at what we call the toe of the beach — that’s sort of where the waves break. And so I wouldn’t be surprised that as winter storms come, you’ll see tar balls cast on that beach all winter long.
The more problematic issue with the California spill is that there are several points of headlands there that enter into estuaries and marshes. Once oil enters the estuary and marsh habit, it cannot be cleaned up. I mean you can skim some oil at the surface, but once it gets entangled in all the wetlands vegetation, there’s no real way to mitigate that without causing more damage than the oil would itself.
One of the strategies for these habitats is to try to string booms across the mouths of these estuaries to intercept the oil that might be coming in. That can be effective if the weather and wave action cooperate. But if it’s bad weather, oil just hops over these booms which are not particularly high.
Once it’s in a habitat like this, there’s a lot of sediment that gets transported there until eventually the oil will be sequestered by the sediment. It’s sort of landfilled. Once it’s landfilled deep enough, oxygen will not get to it, and it’s the oxygen exposure and the sunlight that actually weathers oil. So once it’s below the oxygen line, it’ll degrade extremely slowly. It will probably be there for decades.
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