Oil spills received considerable attention because of the immediate and very visible harm they cause to the surrounding ecosystem. Media attention usually subsides following the initial clean-up phase. However, the affected communities face a longer term ecological problem.
In the United States, the Exxon Valdez oil spill and the more recent Gulf of Mexico oil spill remained headline news for months. Today, reports of their long term environmental impacts receive occasional attention.
On March 16, 1978, the oil tanker Amoco Cadiz got caught in a storm off the coast of Brittany, France, at the southern end of the English Channel. It ran aground and began spilling oil. The site of the spill, along with inclement weather, complicated early clean-up efforts. In a week's time, the tanker split in two, insuring that its entire cargo of 1,619,048 barrels of oil (220,000 tons) would spill into the sea.
Approximately one-third of the spilled oil evaporated, one-third washed up along the coast and one-third was either recovered or sank to the bottom of the sea.
Research about the Amoco Cadiz oil highlights short and long term ecological problems associated with large scale oil spills. Large oils spills can cause considerable damage, depending on the time of the spill and the area affected. An article in BirdLife suggested that bird mortality was in the 20,000 range, ranking it among the highest rates recorded along European coast. In context, the numbers are relatively small compared to the estimated 375,000 and 435,000 birds killed by the Exxon Valdez oil spill.
High mortality levels among inter-tidal animals such as limpets, sea urchins and clams were also reported.
Along with the harm caused by the oil, clean-up activity affected the salt marsh areas of the Brittany coast, with recovery time estimated to be in the five year range.
Benthic organisms in the spill area were reported affected some ten years after the spill.
Research about the Prestige oil spill also contributes to our understanding of short and long term ecological problems associated with large scale oil spills.
On November 13, 2002, the oil tanker tanker Prestige sunk off the coast of Northwest Spain, spilling 64,000 tons of oil that affected French and Spanish coastal regions.
The World Wildlife Fund (WWF) published a study on the spill's short term ecological consequences, noting a decrease in the population of inter-tidal animals and fishery production for the region. Additional research showed high concentrations of heavy metals in the affected coastal wetlands.
High seabird mortality rates are associated with major oil spills, with both oil ingestion and oil covered feathers and skin cited as contributing factors.
Approximately 20,000 birds died as a result of the spill, and pathological studies conducted after the fact showed dehydration and exhaustion as the primary mortality factors. Oil on the birds' feathers and skin, weighed down their bodies and lowered their body temperatures to a point where they lacked strength to move from the oil spill area. Dehydration was probably aggravated by diarrhea caused by oil ingestion.
Birdlife International had this to say in a press release,
"The Spanish population of Guillemot has been hardest hit by the Prestige oil spill ", said Alejandro Sanchez, Director of the Spanish Ornithological Society (SEO/BirdLife). "We predict the Guillemot is now very likely to become extinct as a breeding bird in Spain. If this happens the Prestige oil spill will be remembered as a tragedy for Spain's wildlife as well as its people".
© 2001-2014. Patricia A. Michaels. All rights reserved.