This article throws light upon the sixteen case studies on marine pollution.
Marine Pollution: Case Study # 1.
Sea food is a part of the human diet and harvesting of marine species provides a source of income to millions. Products from marine species are used as food additives, animal feed, fertilizer, clothing, jewellery, and cosmetics.
But development, over fishing, pollution and introduction of exotic species in marine habitats has jeopardized marine eco-systems as well as biodiversity. Construction activities, sewage and pollution from industries in the field large cities threaten coastal eco-systems.
Oil spills and release of waste from tankers at major ports also threaten marine life. About 24% of the world’s coasts are now at high potential risk of degradation. More than half of the world’s coral reefs, found in the Indian ocean and in the pacific, are endangered by pollution. Surface run off and discharge of effluents and waste from industries account for almost half of marine pollution.
Marine Pollution: Case Study # 2.
According to the United Nations Food and Agriculture Organization, about 70 million tonnes of fish and other marine life are thrown back, either dead or dying, into the sea each year by fishing fleets that do not want every-thing that come up on their nets or in their lines.
That tonnage is equal to about one quarter of the entire global fish catch in recent years. Fish are sometimes unwanted because they are inedible or too small to market. In some cases, they are discarded merely because they are not what the fisherman wanted to catch.
Besides, millions of other creatures such as sea birds, endangered sea turtles, dolphins, sea lions, whales and other marine animals, fall victims to the brutally inefficient methods now used by most large scale commercial fishing operations. In the southern hemisphere, e.g., it has been estimated that tens of thousands of wandering albatrosses are killed each year, hooked and drowned in the long lines of tuna fisher folk.
Marine Pollution: Case Study # 3.
A large crude carrier and an oil tanker collided, causing an oil spill of about 3000-4000 tonnes in the Singapore Strait on October 15, 1997. The 75,428 tonne Cyprus-registered oil tankers Evoikos was carrying about 123,000 tonnes of marine fuel oil when it collided with the Thai-registered Orapin global just outside Singapore port’s limits. Cleaning operations were in progress.
Marine Pollution: Case Study # 4.
A large oil slick is threatening marine life and birds along the United Arab Emirates (UAE) coastline. The slick was caused by stricken barge that spilled about 4000 tonnes of crude oil into the sea. Authorities have temporally shut down a water desalination plant to ensure that the oil slick would not be drain into the plant through its water intake pipes.
Marine Pollution: Case Study # 5.
Thousands of fish in North Carolina and the Chesapeake Bay in the US have been killed by Pfiesteria, a dinoflagellate, unicellular, pigmented, aquatic organisms. This is due to an increase in the amount of nitrogen, phosphorus and other nutrients that wash off the land from fertilizers and animal wastes, sewage and effluent pollution in oceans, dam construction and increase in water traffic.
Pfiesteria, is only one of the numerous toxic phytoplankton that plague the world’s water. Ocean blooms, resulting from pigments that are released during photosynthesis, are the most dramatic evidence of photoplankton activity. Cynobacteria, commonly known as blue-green algae, is not always blue-green. It derives its name from the variety that inhibits the Red Sea, causing frequent blooms.
If consumed, these produce brevetoxins, neurotoxic chemicals that harm a protein channel in the nerve cells of muscles, leading to paralysis. Chrysophytes (golden-brown algae) do not produce neurotoxin, but do cause brown tides that shade marine plant life and drastically affect the marine food chain.
Marine Pollution: Case Study # 6.
The United Arab Emirates is facing drinking water crisis because of oil spills in the world’s busiest shipping lane. Oil pollution has become a major concern in the oil rich gulf state where in the last two years (1996 and 1997), desalination plants have been shut down following accidents in the gulf involving oil laiden tankers and barges.
Nearly 60% of the UAE’s drinking water requirements are meeting from the sea. The desalination plants are crucial for meeting the country’s alarming water needs. In the past, several cases of oil spillage have forced authorities to close desalination plants. On January, 7, 1998, nearly 4000 tonnes of oil spilled from a barge near Ummal Qaiwain, forcing the closer of the Ajman desalination plant.
Marine Pollution: Case Study # 7.
The marine beach in Chennai may become out of bounds for pleasure seekers if the discharge of pollutants by the Adyar and Cooum rivers into the sea goes on unchecked. According to a study conducted by Institute of Ocean Management (IOM) in the Anna University, Tamil Nadu, the pollutants may not only lead to unbearable odour in the environment, but also cause several skin problems.
If the same trend continues, the beach may soon lose its character of supporting marine and coastal organisms. The Marine beach is the second largest beach in the world. Industries around the area are releasing effluents into the sea.
The study has shown a high prevalence of suspended sediments and heavy metals that may promote the growth of algae and deplete oxygen in water. Dumping of sludge, sewage, domestic wastes and human activity has reduced the quantum of water conveyed in the area.
Marine Pollution: Case Study # 8.
An oil spill of Mikuni on the North-Western coast of Japan is threatening wildlife and nuclear reactors. The spill was caused by the Russian oil tanker Nakhdka, which was carrying 15,300 tonnes of heavy fuel oil. The tanker split in two and sank in the Sea of Japan on January 6, 1997.
The oil spill has hit the shore along a 100 km stretch, where 15 nuclear reactors are located. The oil might enter the cooling systems of these plants which depend on sea water to cool the steam from power generating turbines. Moreover, there are many fish farms, fishing ports and tourist resorts, along this coast.
Marine Pollution: Case Study # 9.
An oil spill in the English Channel is threatening marine life along a 225 km stretch of southeastern coast of England. According to British coast guards, no accident had been reported to account for the slick. They said that a ship could have taken advantages of fog and illegally discharged oil waste from its tanks into the sea.
Marine Pollution: Case Study # 10.
In the worst even oil spill disaster in Japan a huge oil tanker ran around near the port of Yokohama on July 2, 1997, creating a 66.5 sq. km oil slick in Tokyo Bay.
The tanker Diamond Grace, was carrying 300,000 kilolitres of crude oil when it hit a well-marked shoal about 6 km south east by the port and spilled out about 14,000 kilolitres of oil, raising adverse impact on the ecology of Tokyo city. The Bay is home to clams, lungworms, crabs and other marine creatures.
It is also a resting and feeding ground for thousands of wild birds, such as common cormorants, terns, and black tailed gulls. The entire ecosystem of Sanbanse will be affected if the oil spill damages diatoms (algae), sea strings and other sea weeds. They Bay is also a rich fishing ground for fisher folk who annually catch some 20,000 tonnes of fish including flounders, ark shells and sea urchins.
Marine Pollution: Case Study # 11.
Southern Spain is facing an ecological disaster following a toxic spill that has led to the flow of contaminated water and acidic mud towards the sea. Poisonous waste coming out of the spill is proving deadly for every-thing in its path as it moves down stream in rivers and man-made channels to the gulf of Cadiz.
The flow of the waste has been diverted away from the Donana National Park, one of the Europe most prized nature reserves. Environment minister has described the ecological and agricultural damage to the region as catastrophic. According to an estimate about 6000 hectares of farmland has been damaged.
The problem began when a giant holding pool at the Aznal collar mine, owned by a Canadian — Swedish company, burst its banks,. After that, about 5 million cubic metres of waste flooded out of the reservoir into the Guadiamar River, which flows into the Atlantic Ocean.
Marine Pollution: Case Study # 12.
Some 1500 tonnes of the territory’s farmed fish have been killed because of a red tide of toxic algae. Such environmental setbacks have also threatened Hong Kong’s image as a tourist destination. This is most serious red tide. With the harbour side, stench of dead fish and the closure of several popular beaches are underlining the severity of the problem.
The government officials say that the lethal bloom of algae is a natural phenomenon across the world’s oceans. Environmental groups, however, say that pollution and deteriorating environmental conditions are the main cause of disaster. Pollution contributes to the blooming of red tides, particularly large tides of long duration, like this one.
According to experts, algae thrive on nutrients provided by sewage and other effluents.
Marine Pollution: Case Study # 13.
Oil leakage from a cargo ship that sank near Oland Island is now threatening the eco-sensitive landmass off the southeast coast of Sweden. The incidence occurred in the first week of November 2006, when 8,500 tonnes vessel Finnbirch got caught in a sea storm and sank 20 kms off the island.
The vessel was on its way to Denmark’s Aarhus from Helsinki and was carrying about 250 tonnes of heavy oil and another 10 tonnes of machine oil. The oil slick has fouled an area 10 kms along and 400 m wide along the Swedish coastline.
Marine Pollution: Case Study # 14.
A recent major soil spill of Estonia’s north western coast has damaged the marine ecosystems in the Baltic Sea and its delicate bird population. The spill was located in the coastal areas of Laanne and Harju countries, some 100 kms southwest of the capital. Tallinn. It was caused by an unidentified ship, which might have deliberately leaked the oil.
The spill could kill as many as 35,000 birds — far more than previously feared. Many birds have already died. The oil has coated the feathers of many birds including swans and the rare long tailed duck, which spend the summer in Sweden and Norway and the winters in Extonian waters.
Marine Pollution: Case Study # 15.
India’s Western coast is now on the verge of one of the biggest environmental threats as a marooned 75,000 tonnes merchant vessel could spill nearly 650 tonnes of furnace oil into the sea. On the night of May 29 — 30, 2006, the cargo vessel had been wrecked on some rocks in the Arabian Sea off Karnataka’s Karwar coast due to rough weather.
Now, split into two, the ship is stranded in the sea with oil leaking from it. At-least 20 tonnes of oil has already spilled into the sea. The oil content in the sea water is now four times above the danger level and in the sand, it is also above the danger level.