The lecture was conducted by Dr. Richard Lee.
Dr. Lee explains that, on average, there is a major oil spill every 10 years. Additionally, there are many very minor ones throughout the course of the year. The area of concern is how we must fix the destruction to the ecosystem.
Dispersants are widely used in order to mediate the effects of oil spills. They are aerially added to the water and it is very easy to add too much dispersant, causing almost equal damage to the wildlife and namely, the zooplankton in the contaminated water.
Further, more damage is typically done in the "clean up" process than what the oil spill does because nature, in running its course, cleans and disperses oil to a similar degree. The natural breaking down of oil can sometimes lead to better results than the processes used in the oil spill clean up process. In the process, animals either die, change, or become predators to the dead animals.
In the case of the Amico Cadiz 20 years ago, waves of oil crashed into the shoreline. In the Exxon Valdez incident, more damage was done when the clean up crews added warm water to the naturally very cold ecosystem, thus changing not only the temperature balance but chemical balance to an already compromised environment. Oil is, however of the main concern because light is blocked from the water and interferes with the natural circulation of oxygen through photogenesis (we learned this in chapter 10!)
Where do the dispersants come into play, then? Dispersants end up not changing the composition of oil but rather puts it into small droplets that are incorporated into the water molecules rather than sitting atop the water. However, for the dispersants to have any effect on the oil spill, they must be added no more than 48 hours after the spill or else they will be null. The widely-used dispersant is called "Corexit 9500" and 1.6 million gallons of it was used, maybe more, in the 2010 Gulf Oil Spill. The amount of Corexit 9500 used remains controversial because of its impact on the natural cleaning processes.
Zooplankton eat the dispersant which is worrisome because the oil particles after the breakdown from the dispersant are approximately the same size as the zooplankton resulting in the contamination of their food, fecal matter, and the break down process of the fecal matter. The oil particles, additionally, often become part of the zooplankton's food.
The shorelines that are most affected are those with silt and clay marshes like those off the coast of Georgia.
I really learned a lot from this lecture because I have little biology experience but still seek a career in the EPA. Dr. Richard Lee was an engaging speaker who furthered my interest in oil spills, pollution, and environmental justice!
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| Map of location and size of the 2010 Gulf Oil Spill |
