Oil Spills And Its Effects On Marine Life

Crude oil is one of the major energy sources used for transportation but yet can cause a major ecological disaster among marine species. “One of the biggest oil spills that was into the Gulf of Mexico, The Deepwater Horizon (DWH). The Deepwater Horizon oil rig which exploded in April of 2010. About 800 million liters of oil was exposed into the Gulf of Mexico. Toxicological effects have been documented in benthic and pelagic fish communities, estuarine communities, mammals, birds and turtles, deep-water corals, plankton, foraminifera, and microbial communities”.

Oil spill events can affect all different organisms despite their locations or body structures. Oil spills mostly occupy the surface of the water, which can allow for a possible easy clean up. “Crude oils like petroleum oil that is used to fuel up vehicles and the ones filling up the ocean waters with its contaminations. Oil is a complex mixture of hydrocarbons and other organic compounds, including some organometallic constituents. It contain hundreds or thousands of aliphatic, branched and aromatic hydrocarbons, most of which are toxic to living organisms (ATSDR, 1995)”. So in layman’s terms crude oil contain dead plants and animals that have been dead over the years and have decomposed and hydrocarbons are another main components of petroleum. These types of oils that causes these ecological issues come from tankers and ships used for transporting crude oils or fuel oils to different locations across the world. So, an event happens during the transportation of the oil tanks that cause these spills, like leaks or natural disasters. Some people even dump the oil in the oceans because they don’t want to spend the money of disposing the oil contents. Oil spills can also become in to play from oil bearing rocks when they erode and also from submarine seeps. As said before oil spills generally are caused during the transportation across the sea waters. The transportation of crude oils is vast and convoluted so transportation needs to be taking care of properly for the process to go correctly and smoothly. “However, because of their high viscosity at reservoir conditions compared to conventional light crude oils, conventional pipelining is not adequate for transporting heavy crude oil and bitumen to refineries without reducing their viscosity”.

The higher the viscosity, the thicker the oil. For instance, in motor vehicles, when the engine oil gets in contact with higher temperatures the oil will break down and thinning out could cause metal to rub up against metal of engine parts of motor vehicles. That contact can cause the vehicle to break down. In colder temperatures the oil will thicken and will also cause friction as well. So transportation of the oil requires the viscosity to be reduced by heating of the oil itself, so this can be achieved by heating the pipelines that the oil will be transported in. They also reduce the viscosity by diluting the oils with hydrocarbons or a solvent. “The widely used diluents include condensate from natural gas production, naphtha, kerosene, lighter crude oils, etc. ” Adding diluent helps with the transportation of those heavy oils. There are also other ways like emulsification which is the breakdown of fats and oils. The emulsification for most crude oils is a formation of oil in water enhancing the flow of the oil through the pipes. Pour point reduction is also another known way to help with the flow of oil through the pipes. The pour point is the lower temperature at which oil can pour, the reduction of the pour point can be accomplished by pour point depressants (PPD) containing oil-soluble long-chain alkyl groups. Pipelines are the most common use for transporting oil. The transferring of the oil is from the pipes to the refineries or tanker loading facilities. Tankers are the containers that hold the oil and get them to where they need to go, especially overseas. Pipelines is the cheaper and easier way to operate rather than trucks or trains, having a lower carbon footprint. “On average 10,000-15,000 metric tons of petroleum enter the marine environment each day”. “There are four main types of accidents: refueling, collisions, groundings and hull damage, and these accident types account for 2. 4% to 21. 4% of the total. Since 79. 5% of occurrences involved less than 7 t, this shows that the oil spill accidents are mainly small; collision and handling oil spillages occurred in the 7–700 t range”. Most oil spills are remotely small despite what you see and hear about. Most of the oil spills you hear about those that cause major damage.

Some oil compounds can be more toxic than others depending on the composition. Oil spills can cause serious damage just depends on how it spreads throughout the sea waters. “When oil is released on the sea surface, it spread horizontally in an elongated pattern oriented in the direction of the wind and the surface water currents”. “Fat soluble components may accumulate in the organs of animals and may be enriched in the food chain, even up to humans (Mackay and Fraser, 2000). Prolonged exposure and high oil concentration may cause the development of liver or kidney disease, possible damage to the bone marrow and an increased risk of cancer. To animals, even a slight staining by oil can be fatal. Oil stains can decrease the insulation of a bird's feathers causing the bird to freeze to death”. Oil spills can cause damage just by going through the different food sources. According to Onwurah, I. N. E, et al, oil spills also cause short term toxicity in birds caused by the oil spill exposure including diseases like lymphocytosis, epidermal hyperplasia, and hemorrhagic septicemia. The damage can vary from animal to animal depending on their habitat and the food they consume. “In 1986 a major oil spill in Panama polluted and killed extensive areas of coral reefs. Five years afterwards, reef areas are chronically threatened by oil and large amounts of sediments containing toxic hydrocarbons trapped in mangroves”. Some of the corals that were injured within the colonies had decreased in colony size, reduced size in egg production and their survival rate dropped. Like coral reefs don’t have a hard enough time surviving in the environment. All marine mammals spend most of their time at the surface of the water, breathing, swimming, and feeding, thereby enhancing the possibility of contact with the surface oil slick. “Fur-bearing marine mammals such as fur seals, polar bears, and sea otters may ingest oil during grooming. The limited data available indicate that oil is not particularly toxic at least to pinnipeds when taken in by this route”. Pinnipeds are another word for carnivore marine mammals like seals or walruses. According to Synthesis of Effects of Oil on Marine Mammals on page 30, benthic amphipods are quite sensitive to spilled oil; they are among the first marine animals killed and the slowest ones to recover. They also mention fish, in heavily oil-contaminated environments, do not accumulate and retain high concentrations of petroleum hydrocarbons, and so are not likely to transfer them to predators. Fish have metabolites are reactive so unlikely they would be released in a toxic during the digestion process that they would not pose as much of a threat. So thankfully fish tend to be more resilient upon the oil exposure when it seems to affect other species, the same goes as well for cetaceans the marine mammals. Shockingly oil spills even effect none know marine species too like the iguanas. “The oil may have had a direct toxic effect either on the iguanas themselves or on the algae they consume; the animals may have declined to eat because their food had been fouled; or their vital hindgut micro symbionts may have been poisoned so that the iguanas could no longer digest their food” (Wikelski, Martin, et al. ). They weren’t too sure how the oil spill affected the iguanas, they just know that it involved with the oil contamination.

Most iguanas are herbivores, which means they eat plants which is mostly leaves off of trees. The hindgut is part of the digestive system mainly responsible for the enzymes that breakdown the food. These deaths didn’t occur instantly after the exposure to the oil spill but few weeks afterwards. Geraci and Aubin also mention that marine mammals, except the manatee, are carnivores that rely on invertebrates or fish for sustenance. Their feeding strategies could lead to ingestion of oil-contaminated food, because most of the prey organisms can accumulate petroleum hydrocarbons in their tissues. So as you see it’s possible for the iguanas to die from oil contamination from the food they consume. They also can get contaminated by inhaling the oil causing inflammation. Wikelski also mentioned that there are a lot of factors to consider when cleaning up an oil spill that are occupying different parts of the ocean or areas of the water. For instance the location of the oil, whether it’s near the coastline or if it’s in the open ocean. If the oil is close to the coastline the purpose is to prevent it from spreading even closer to the coastline. Or even if the spill is in spread out in various shapes and the purpose is to collect the oil and get as much as you can as possible. The workers to be observant enough to be able to be sure that the spill is caught in time. “By removing spilled oil from the sea surface, dispersants obviously reduce the risk of contact. The oil remaining would be less sticky, and therefore less likely to adhere to fur, skin, baleen plates, or other body surfaces”. Oil dispersants is a mixture of solvents and emulsifiers allowing the oil to breakdown into smaller droplets. A solvent is added to lower the freezing point and reduce viscosity, which is easy for applying. Using the hydrocarbon dispersants is most effective on heavy viscous oils, like petroleum oil. Dispersants can be applied on the shore loosening the oil, making it easy for removal. The oil dispersants also on the other hand could most likely remove the natural oils of the marine mammals and decreasing the insulating properties in that fur. The insulating in the fur helps keep them warm and even protects them from small amount of oil contamination. The oil dispersant can be applied by hand or by boat or aircraft with the right equipment. The amount being applied from one liter for each 10 liters of spilled oil to a ratio of one to one, depending on the conditions of the sea water and how it is being applied. “Several bacteria are even known to feed exclusively on hydrocarbons (Yakimov et al. , 2007). For these (facultative) hydrocarbon degraders the occasional supertanker oil spill forms an occasional carbon banquet”. Overtime evolution has created bacteria that feed on only on those hydrocarbons that are in the crude oil. “Bacteria (and fungi) that grow in the oil fields produce peroxides, pitch acids and in some cases H2S that decrease the thermos ability and volatility of the fuel. Although many different species are involved, a notorious group of bacteria in this regard are the sulfate‐reducing bacteria”. These bacteria are common in low-oxygen environment which is seen in the results from hydrogen sulfide (H2S). The bacteria are able to produce the H2S from the sulfate in the oil. H2S is highly toxic and can cause frostbite, eye irritations, even death. Another method to cleaning up an oil spill is called in situ burning which according to Mullin, Joseph V, and Michael A Champ, it is a technique or tool that involves controlling the ignition and burning of the oil at or near the spill site on the surface of the water or in a marsh. In situ burning is effective, fast and inexpensive which works well for both the ecosystem and the cleanup crew if done correctly. However, it doesn’t get rid of all the oil.

According to Geraci, and St Aubin wicking agents are used to lift the oil from the surface and allows for an effective burn. Not used well in open water, but better in deeper waters. If you do the opposite putting water on an oil based fire, it makes it expand and make it worse. Sinking agents do the opposite, “they are dense particles (2. 4 to 3. 0 g/cc) with hydrophobic surfaces, that when applied to a spill, adsorb the oil and cause it to sink”. These sinking agents include fly ash, sand, powdered cement, or other minerals coated with silicones, waxes, or stearates. The oil will sink rapidly to the bottom and remain. Weirdly enough theirs some people or scientist that believe it’s best to leave the oil to disperse and the oil will spread out by the waves or wind. There’s also a way to get rid of the oils by boomers and skimmers which is the most expensive oil cleaning technique. According to Choi, Hyung Min, and Rinn M. Cloud, the skimmer works on the surface of the water and surrounding the oil. This skimmer is a multi-robot system that helps surround the oil and prevent it from spreading any further causing more damage. “The skimmer has a coordinator determines the position and center of the oil spill first using a GPS receiver, then a barge carrying the robots move to the working place. According to the status of the oil spill (shape, area covered, one spill or many, direction and speed of wind, etc. ) the coordinator can dispatch a swarm of robots to surround and collect the oil spill, then the barge with an oil sucking equipment move it for another place to collect/dispose the oil in a safer way. Each robot works in two modes, viz. , autonomous mode and remote control mode”. The autonomous mode has a collision avoidance algorithm and ultrasonic sensor that helps the robots avoid collision with other robots and other objects like debris. According Wolcott, Douglas C. double hulls are a way to help prevent oil spills from occurring. A hull was a part of the tanker that’s used to hold and transport the oil, but the double hull is where they have space between layers so when penetrated without releasing the cargo. Double hull tanker itself doesn’t fully prevent oil spills but it can at least reduce the size of the oil spill if they happen to experience an accident. Double hulls are however tend to be on the expensive side. They also have a hard time fitting on the existing vessels and also might introduce technical problems. International shipping requires them to use the double hull tanker versus the single hull.

Oil spills are not of major concern thanks to technology improving, however we are not able to get to that time in this world where we are able to predict the next oil spill, but we are here to hopefully prevent it from happening or stopping less. The more we are able to learn about certain topics will make this world a better place and not have us being ignorant to the things surrounding us. We as humans, some of us have gotten used to being focusing only on the problems surrounding us but never looking at the bigger picture that could possible become that surrounding problem. We need to take better care of our planet, it is our home.

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