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Effects of Oil Spills, Sewage, Pesticides & Dumping on Marine Life
Isidora Simovicon 14 October 2012
Transcript of Effects of Oil Spills, Sewage, Pesticides & Dumping on Marine Life
The immediate effects of toxic and smothering oil waste may be mass mortality and contamination of fish and other food species, but long-term ecological effects may be worse. Oil waste poisons the sensitive marine and coastal organic substrate, interrupting the food chain on which fish and sea creatures depend, and on which their reproductive success is based. Commercial fishing enterprises may be affected permanently. It becomes very hazardous for wildlife as there are toxic effects of exposure or ingestion, injuries such as smothering and deterioration of thermal insulation, damage to their reproductive systems and behaviour. Long-term ecological effects that contaminate or destroy the marine organic substrate and thereby interrupt the food chain are also harmful to the wildlife, so species populations may change or disappear. Oil Spills In 2000, several thousand penguins were affected by a fuel oil spill after the iron-ore carrier Treasure sank off South Africa Oil Spills In more detail, some of the harmful effects of oils spills on marine life include:
hypothermia in birds by reducing or destroying the insulation and waterproofing properties of their feathers;
Hypothermia in fur seal pups by reducing or destroying the insulation of their woolly fur (called lanugo). Adult fur seals have blubber and would not suffer from hypothermia if oiled. Dolphins and whales do not have fur, so oil will not easily stick to them;
birds become easy prey, as their feathers being matted by oil make them less able to fly away;
marine mammals such as fur seals become easy prey if oil sticks their flippers to their bodies, making it hard for them to escape predators;
birds sink or drown because oiled feathers weigh more and their sticky feathers cannot trap enough air between them to keep them buoyant;
fur seal pups drown if oil sticks their flippers to their bodies
birds lose body weight as their metabolism tries to combat low body temperature;
marine mammals lose body weight when they cannot feed due to contamination of their environment by oil;
birds become dehydrated and can starve as they give up or reduce drinking, diving and swimming to look for food;
inflammation or infection in dugongs and difficulty eating due to oil sticking to the sensory hairs around their mouths;
disguise of scent that seal pups and mothers rely on to identify each other, leading to rejection, abandonment and starvation of seal pups; and
Damage to the insides of animals and birds bodies, for example by causing ulcers or bleeding in their stomachs if they ingest the oil by accident. Oil Spills Isidora Simovic 10Z Sewage The sewage being released into our seas originates primarily from kitchen, bathroom and laundry sources. These include the chemicals that we use for washing and cleaning which is toxic for humans but we still flush it into our oceans. Sewage also contains waste from food preparation, dishw ashing, garbage-grinding, toilets, baths, showers, and sinks.
When it comes to sewage, some marine creature can withstand the harsh treatment and the wastes but many other animals and plants will be poisoned and will die. The discharge of sewage into the sea does contain some nutrients which when elevated slightly may increase algal and plat growth under certain background conditions. However, when it is presented in a high concentration of nutrients, it can be responsible for the formation of algal blooms which reduce light penetration through the water column, may produce toxins and can cause oxygen depletion when decomposition takes place. In the process of sewage decomposition, oxygen in the surrounding water is used the discharged concentration is too great and will cause the amount of oxygen available for fish and other marine will decrease significantly resulting in death. It is not as instantaneous as oil spills where fish can be seen floating in the water, the effects of sewage can be result in a long and painful death.
Sewage Death comes in a variety of ways. Some of these chemicals suppress the immune system allowing the onset of disease . Heavy metals, pesticides, persistent organochlorins, plastics, surfactants and aromatic hydrocarbons can disrupt the endocrine system interfering with sexual and bone development. There is evidence that these chemicals can also disrupt the complex hormonal processes as juvenile salmon acclimatize to the saltwater ocean environment. This is bad news for the billions of juvenile salmon that spend months in the shallow waters around Vancouver. Many juvenile salmon simply will not make it.
Many of the toxins found in sewage can also alter the behaviour of fish, interfering with normal swimming, schooling and migration in different ways that significantly reduce their chances of survival.
Pesticides Pesticides and other toxic chemicals that are used in gardens and around the home, on farms and industrial manufacturing that would run off into the water. The decomposition of pesticides is similar to sewage run off, where the surrounding water is used for its oxygen in the process of decomposition, leaving a lot less for the fish and other marine life. Though there are pesticides that are relatively non-toxic, but there are several others that are highly toxic. This is because some pesticides rapidly breakdown after application. Some bind tightly to soil particles suspended in the water column or to stream bottoms, thereby reducing their availability. Some are quickly diluted in water or rapidly volatilize into the air and are less available to aquatic life.
Pesticides, again similar to sewage run-off, do not often cause immediate death like oil spills. Small doses of some pesticides, also known as "sublethal" doses, can alter behaviour, weight loss, impaired reproduction, inability to avoid predators, and lowered tolerance to extreme temperatures. Repeated exposure to certain and many pesticides can result in reduced fish egg production and hatching, nest and brood abandonment, lower resistance to disease and hormonal change. The overall consequences of these sublethal doses of pesticides can result in a lowered population, affecting food chains and webs.
Pesticides Not only do pesticides kill marine life, they can reduce the availability of plants and insects that serve as habitat and food for fish and other aquatic animals. Spraying pesticides and even herbicides, can destroy the shallow, weedy nursery area for many fish species provide abundant food and shelter for young fish where they depend hugely on. With the destruction of these areas, their chance of survival is reduced and the population decreases.
Pesticides which kill these fish or marine life that are at the bottom of the food chain are then consumed by their predators which also then become contaminated. Until they reach the top of the food chain, being humans, where when we consume the food, we too become sick and contaminated by the pesticides that we used in the first place.
Dumping of Toxic Wastes The rise in human activities surrounding and in the water has adversely affected the marine life. The dumping of toxic wastes is a broad outline and includes everything said before such as oil spills, pesticides, sewage, pollution, herbicides, garbage and others. With bigger pieces of pollution like rubbish and garbage, larger marine life such as whales, dolphins and turtles who mistake it as food and then will die a painful death.
Plastic debris, debris from ships, discarded fishing nets and other similar items that are there purely because of human negligence act as severe agents of marine pollution and have an effect that cannot be imagined unless witnessed.
Industrial and factory run-off are full of toxic and poisonous chemicals which then contaminate the marine life. Leading them to have a long and painful death. Consequently, as said before, other larger marine creatures who then become contaminated themselves. So, it continues on up the food chain.