Deepwater Horizon Oil Spill Effect On The Gulf Ecosystem Biology Essay

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There have been several oil spill disasters since offshore oil drilling began in the late 1800's. However, the world had never seen a marine oil spill like the Deepwater Horizon spill. The Deepwater Horizon rig was a semi-submersible mobile offshore drilling unit capable of operating at depths of 8,000 feet and could drill up to 30,000 feet. Its construction was completed in 2001 and BP had rights to it until 2013. On April 20, 2010 an explosion on the rig started a fire and the crew of 126 aboard the rig had to be evacuated. There were 11 reported casualties. After burning for 2 days, the rig sank to the ocean floor. The cause of the explosion is being investigated. 20 hours before the explosion the pipe was actually capped with cement in order to temporarily abandon the well, but the integrity of the cap had not been assessed.  After interviewing workers, a theory of what caused the explosion was formed. The theory was that due to a failure in the cement and/or casing, a bubble of methane gas shot up the drill column and exploded. Due to this explosion and the rig sinking, the pipe connecting the platform and well started releasing crude oil into the gulf at a very high rate. The regulation device for the pipe, the blowout preventer, could not be activated, forcing engineers to come up with a way to manually cap the leak. The leak was finally capped 86 days later on July 14, 2010. The estimated oil released into the Gulf of Mexico was around 4.2 million barrels. The largest spill prior to this was only 3.3 million barrels. This spill has had catastrophic effects on the ecosystem of the Gulf of Mexico and this tragedy will continue to effect ecosystems in the gulf for many years to come.

The biome that has been affected the most is the ocean biome. The oil has affected every aspect of the biome. This includes ecosystems, food chains, and marine plants and animals. The oil has affected organisms in the ocean by getting on the organisms or being ingested by them. It has also affected sea birds and animals living around the gulf as well.

There are many ecosystems that have been affected by the oil spill. The spill occurred at a depth of 5000 feet, which is in the bathypelagic region of the ocean. This ecosystem is very dark and temperatures are only about 5⁰C. It is mostly inhabited by bioluminescent sea creatures. Animals in this region rely on what is called "marine snow" for their diet. Marine snow is pieces of dead animals from the regions above that sink down to the lower regions of the ocean. Because the oil is floating up to the surface, the marine animals in the mesopelagic and epipelagic zones ingest the oil, ingest contaminated animals, or swim in the oil. Thus, when pieces of these contaminated animals fall, animals that rely on marine snow will ingest them and become sick themselves.

As stated previously, the oil will rise to the surface and affect all of the ecosystem zones above the spill. From depths of 1000 meters to about 200 meters is the mesopelagic zone. This zone contains some light and temperatures from 5⁰C-20⁰C. There is some plankton present but not as much as the epipelagic zone. These plankton are a food source for many of the animals in this zone, and animals in this zone also rely on marine snow from the epipelagic. The plankton in this zone can easily be contaminated by the rising oil and harm themselves and organisms that ingest them.

The epipelagic zone is the top zone of the ocean, where plankton is in abundance and the biomass is the highest. Any animal that inhabits this zone can be affected by rising oil or oil slicks on the surface. Marine mammals that come to the surface to breathe can accidently inhale oil on the surface. Plankton in this zone can be contaminated by the oil affecting the organisms that ingest them. This region is where marine plants can be found in abundance, and when these get covered with oil they will most likely die due to O2 and CO2 exchange being hindered. Sea birds fish by diving into the epipelagic zone and will get covered in the oil and possibly die from it.

Another negative effect of the oil on the ocean environment involves cleaning up the oil. A chemical called Corexit 9500 is being used as a chemical dispersant to speed up the breakdown of the oil. Chemical dispersants are not widely used due to their known negative effects on the environment. The dispersants cause the oil to break up into very small pellets that can be ingested by microorganisms and other creatures. Studies have shown these chemicals to be 10,000 more toxic to primary producers than the crude oil itself. The EPA has approved dispersants to be used in waters over 30 feet deep and oil that is 5 kilometers away from a shoreline. Because of the magnitude of this spill and that it was only 50 miles away from the shore, chemical dispersants have been used in great quantity."By June 16, 2010, 1.3 million gallons of dispersant have been deployed-902,000 on the surface and 423,000 subsea-by far the largest ever use of dispersant in a U.S. oil spill."(Cleveland). Although the effects of Corexit are well known, the rationale for using it involves keeping as much of the oil from reaching the shoreline as possible and affecting the plants and animals of the coastal ecosystem.

Despite efforts involving sand barriers, chemical dispersants, and controlled burns, currents and weather carried the oil to the shoreline causing negative effects on even more ecosystems, specifically the estuaries present along the gulf coast. Estuaries are the area of the ocean where salt water mixes with fresh water from rivers and the river water is prevented from going into the ocean by marshes or barrier islands. They are one of the most biologically productive ecosystems. The plants that are a part of estuaries provide food for many animals in the ecosystem. One of the most important is phytoplankton. The oil kills these plants by covering them and preventing oxygen and water exchange to occur, therefore effecting animals that rely on these plants for food. Estuaries also serve as a breeding ground for marine animals and birds. It is a safe area to breed and allow their young to be born without a large threat because many predators cannot survive in the low salinity. In May Jeff Manzer, who runs eco-tours out of the mobile bay estuary, commented on the effect oil hitting the estuaries of the gulf would have, "When you start taking this estuary and the Louisiana on, you're looking at almost 90 percent of the marine life of the north part of the Gulf of Mexico as being born there, and that's where the oil is coming to"(Barrentine).  If the waters of the estuaries are polluted with oil, then the toxins can kill or harm the offspring of many different animals. Animals that use estuaries as breeding grounds include fish, mollusks, and even birds. Estuaries are already being diminished due to land development and the oil will degrade this vital ecosystem even further.

Because of the magnitude of this oil spill there have been and will be many populations of animals affected by this catastrophe.  Populations of birds that live around the gulf have all been impacted. By Aug 16, 2010, 1,924 birds had been found oiled but alive and 1,886 had been found dead and oiled. The population of birds hit the hardest is the population of northern gannets. These sea birds dive into the water from heights of 40 meters in order to catch fish. The gannets are unable to tell the oil is on the surface because the oiled water appears to just be calm water. This illusion of calm water causes more birds to dive into the water because they prefer to dive in waters that are calm. When oil gets on the feathers of birds, they are weighed down and the water repelling chemicals on their feathers are removed, making it difficult to fly. The oil also makes it difficult for the birds to thermo regulate, often causing hypothermia.

Whale sharks are another population that the oil impacts. Although not native to the gulf, these giant sharks migrate through the gulf. Whale sharks are filter feeders and feed on plankton. Physical spotting and tagging have shown the whale sharks have not been avoiding the spill. This means they are ingesting contaminated plankton and crude oil. Because whale sharks are filter feeders they ingest large amounts of water and this water goes over their gills. If the water they ingest has oil in it, this oil will get caught on their gills causing respiration to be difficult and can kill the shark. Just like other sharks, whale sharks do no float when they die due to a lack of a swim bladder, so it is impossible to tell how many sharks are being killed by the spill.

There are many groups of people that have a responsibility to respond to disasters such as the Deepwater Horizon spill. The first group would be the government. Because the government controls regulation of the oil rigs, steps need to be taken to prevent other spills. After such an incident on an oil rig, the government should mandate that all of the oil rigs in U.S waters should be thoroughly inspected. Although there are regulations and routine inspections in place, a phenomenon called the iron triangle can occur. This is a relationship between congress, bureaucracy charged with oversight, and interest groups such as oil companies. With each doing favors for each other the regulation can be overlooked, until a disaster such as the Deepwater Horizon spill occurs. Favors could include electoral support, friendly legislation, and lobbying support. In 2004, the Minerals Management Service's (MMS) issued an exclusion from the National Environmental Policy Act (NEPA) to certain gas and oil companies in the gulf, including the Deepwater Horizon site. A document called the Draft Environmental Impact Statement (DEIS) went over the environmental impact of 11 sites in the gulf and possible effects of spills if they were to occur. However, the hypothetical spills in this document were never over 4,600 barrels so the effects of a spill were severely understated. "Early in 2009, BP sought approval of the exploration plan for this well, whose flaws might have been detected by a full blown review under NEPA.  That did not occur due to the categorical exclusion…" (Cleveland). This lack of regulation and exclusion rule is evidence that a lack of strict oversight contributed to the most devastating oil spill in history. Congress has been very involved in investigations since this spill but this involvement will not do much to prevent the oil from harming the environment. The government needs to keep the spill from happening instead of just figuring out who to blame after the spill.

Communities also have a responsibility in these disasters. The first responsibility is to keep pressure on the government to keep regulations from slipping even years after the incident. If the MMS tried to pass this exclusion right after the Exxon Valdez accident, there is no way the public would allow it. But because people stopped paying attention due to the time lapse, the MMS was able to get away with letting these oil rigs go unregulated. Another responsibility involves protecting ecosystems affected by the oil. Some of the ecosystems affected by the oil, such as estuaries, are already destroyed by land development. Communities of these ecosystems have a responsibility to further protect the ecosystems because as fragile as they are, they cannot handle the effects of the oil and land development devastation.

Individuals must act as a part of the community and participate. It is up to the individual to not be apathetic towards these kinds of disasters. If everyone puts the responsibility on others, nothing will get done. Individuals need to put pressure on congress to keep strict regulations and help protect ecosystems affected by the spill as a community. Individuals can also do their part in the cleanup effort. Like what is currently going on in the gulf. Fishermen that have been put out of work by the oil are helping by using their boats to skim the oil from the surface of the ocean.

The effects of the oil will undoubtedly last for years to come.  Based on previous oil spills, the effects of the Deepwater Horizon spill can be predicted. Oil from the Ixton spill in 1979 has been found as recently as 2002 by a snorkeling biologist. The effect on marshes has also been documented. "Beaches get scrubbed by waves and storms, but marshes can develop tar mats lasting decades" (Achenbach). This is just one example of lasting effects of oil on an ecosystem. Previous spills being used to assess the long term effects of the Deepwater Horizon spill are not near the magnitude of the Deepwater Horizon spill, so it is difficult to predict accurately what the effects of this spill will be in the future. Between the immense amount of fragile ecosystems such as estuaries and large biomass areas of the epipelagic marine zone, recovery of the Gulf of Mexico will take a long time. Populations hit hard by the spill, such as northern gannets, will struggle for years to recover in number.

 There are some positives that will come out of this tragedy. Regulations on these oil rigs will hopefully be increased and be enforced for decades to come. Awareness of ecosystems along the gulf will be raised and groups advocating to protect them can gain support from this. Florida has been trying to raise awareness about its estuaries for quite a while and this tragedy will open people's eyes to how important they are to their lives.

The Deepwater Horizon spill has affected many of the ecosystems involving the ocean in ways that can be devastating and long lasting. Animals that inhabit areas of water 5000 feet and above have been and will continue to be at risk for getting ill and dying from the oil. Invaluable ecosystems such as estuaries could be greatly affected, causing a rippling effect to any animal that interacts with them. A lack of regulation and an iron triangle relationship is part of the reason this spill was able to occur. Everyone has a part to play in the cleanup effort and preventing catastrophes like this oil spill from happening again. The government, communities, and individuals must all do their part to protect the Earth's ocean biomes. The long term effects of oil spills are well documented, but none of the magnitude of the Deepwater Horizon spill. It is known that the oil can potentially last quite some time, and marshes and plant life can be affected for years. It will be a long time before this spill is over with, but hopefully there are plenty of lessons to be learned to prevent future occurrences. It is sad that something like this spill has to happen for people to start paying attention to the environment, but hopefully some greater good comes of it.