Oil Disasters Through History: Ninth of Ten

In the days leading up to the 6th month anniversary of the BP deepwater drilling disaster, GRN is highlighting nine previous oil disasters, to give historic context to what the Gulf of Mexico is experiencing, and will experience for years to come.Prestige, 2002 In 2002, only eight years ago, Spain experienced the largest scale disturbance ever to occur in Europe. On November 13, 2002, off the coast of Galicia, Spain, the Prestige oil tanker was located 30 miles out and made a distress call. Two days later, the vessel was towed offshore having already lost 1,500 tones of oil and at 133 miles off the coast, while still carrying over 60,000 tons of oil, completely sank. Oil continued to leak from the Prestige until robots were sent down to seal the cracks and remove the oil.Because Galicia, Spain is economically and culturally tied to the marine environment, more information can be found regarding this oil spill’s affect on the marine organisms and the fishing industry. In a review by Abad et al. regarding the oil spill’s affect on the Spanish fisheries, he states “one of the first handicaps we had to overcome when facing the Prestige oil spill is the lack of contrasted and peer-reviewed information on the effect of oil spills on industrial fisheries.” One of first things realized when the spill occurred was that it not only affects fishing and seafood industries, “but also others which directly depend on them, such as net makers, transport companies, shipyards, supply companies, wholesalers, etc., with knock-on effects on the remaining economic sectors.” The impact began with the fisheries being closed immediately after the spill occurred. The bands affected 913.5 km for fishing and 788 km for shellfish collecting along the coast of 1121 km. Bans along the Death Coast for certain species and methods of fishing persisted for the longest amount of time after the spill. For example with the mackerel fisheries, handline fishing was closed for a long period of time, yet the fishermen with otter trawlers could move further out to sea and keep mackerel on the market.The oil spill impacted the fish communities by preventing them from reaching their normal reproductive rates either by decreasing larvae survival, or hindering adult reproductive capacity and egg-laying viability. The decrease or absence of eggs and larvae affects both the future population of that fish, but also affects the food chain and the other organisms needing those eggs, larvae and fish for nourishment.Bioaccumulation also has to be monitored very carefully. The Prestige oil had low solubility, high viscosity and adherence, low dispersion capacity, and slow degradation, making it extremely persistent in ocean water and in bonding to surfaces. The oil would disperse throughout the water column and then marine organisms could absorb total polycyclic aromatic hydrocarbon (PAH) contaminants from bottom sediments, suspended particulate matter and food-sources. In a study monitoring PAH levels in mussels, research showed that the total PAH level will likely decrease in time due to degradation and volatilization of lighter compounds (aging). Yet, surprisingly, research shows that total PAH can increase again due to downwelling and turnover, causing settled oil to disperse in the water column and filter through mussels and other mollusks. The decrease and resurgence of total PAH levels in the Prestige-affected mussels prove the importance of long term monitoring for bioaccumulation and other oil impacts.Oil spills are a difficult study. Many different factors play into the behavior and impacts of oil, often making it difficult to compare incidences. In a review of past spills, environmentalists should focus mainly on the anthropological behavior; what clean up methods were effective and what did humans do right and wrong? From the nine spills in this review, booms and skimmers were used most often. It is now clear that booms are temperamental and are only effective when used in calm water. Skimmers can become clogged if too much seaweed is present and are only useful with stationary, properly contained slicks. If properly contained, it seems that burning oil can be surprisingly successful and is a smart way to eliminate the dispersal of oil. On land, studies have shown that in the past, humans have caused more problems than the oil itself. Trucks and heavy machinery, including pressure washing, are all dangerous. Humans have a way of overlooking just how delicate ecosystems can be and it is important to alter the cleaning methods to consider the fragility of the environment. Marshes and mangroves suffer the most, especially when humans attempt to aid in their recovery. More studies must be done to determine ways to keep oil from entering into these sensitive areas. If present, further research needs to explore how to more carefully remove the oil, such as with delicate flushing instead of pressure washing.Fisheries and fauna recovery throughout history prove more difficult to compare due to the wide range of environments where past oil spills have occurred. Although studies have proven that mollusks and other benthic organisms suffer the most from oil, other recoveries are more complicated. Factors such as topography, climate, currents, and history of the area play a very large role in fauna behavior and vary widely from location to location. Therefore, it is beneficial to study past incidences and the impacts that the fisheries and fishing communities experienced. More importantly, science should not forget the power of understanding the Gulf. More research needs to be focused on the Gulf fisheries both when affected and when free of oil. How are proper projections and decisions for the future of Gulf fisheries supposed to be made if scientists still do not have concrete, baseline facts regarding the oil and fish present in the Gulf of Mexico? If more research is conducted regarding the dead zone, fish communities, fish kills, and population conservation, then hopefully past studies will no longer need to be reviewed and, instead, the right choices regarding the Gulf of Mexico will become clear.Above Photo: NOAA Incident News, oiled shore line from Prestige incident

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