AskDefine | Define jetsam

Dictionary Definition

jetsam

Noun

1 the part of a ship's equipment or cargo that is thrown overboard to lighten the load in a storm
2 the floating wreckage of a ship [syn: flotsam]

User Contributed Dictionary

English

Etymology

From jetteson (see jettison).

Noun

  1. articles thrown overboard from a ship or boat in order to lighten the load of a ship in distress
  2. In the context of "by extension": discarded odds and ends

Translations

See also

Extensive Definition

Marine debris, also known as marine litter, is human-created waste that has found itself floating in a lake, sea, ocean or waterway. Oceanic debris tends to accumulate at the centre of gyres and on coastlines, frequently washing aground where it is known as beach litter.
Some forms of marine debris, such as harmless driftwood, occur naturally, and human activities have been adding similar material into the oceans for thousands of years. Only recently, however, with the advent of plastic, has our influence become an issue—plastic marine debris does not biodegrade.
Waterborne plastic is both unsightly and dangerous; posing a serious threat to fish, seabirds, marine reptiles, and marine mammals, as well as our boats and coastal habitations. Ocean dumping, accidental container spillages, and wind-blown landfill waste are all contributing to this growing problem.

Types of debris

A wide variety of anthropogenic artefacts can become marine debris; items such as plastic bags, syringes and other medical waste, buoys, rope, glass bottles and plastic bottles, cigarette lighters, beverage cans, styrofoam, lost fishing line and nets, and various wastes from cruise ships and oil rigs. Plastic comprises over 80% of all debris, a component that has been rapidly accumulating since the end of World War II, as it does not biodegrade.

Nurdles

A nurdle is a plastic pellet typically under 5mm in diameter. They may be released directly into the environment (as a spilt industrial raw material or a cosmetic exfoliant), or through the physical weathering of large plastic debris. Nurdles are a major contributor to marine debris and can cause starvation to any marine wildlife that ingests them, as well as potentially releasing toxins. They are also known as mermaids' tears, a pre-production plastic pellets or plastic resin pellets.

Source of debris

It has been estimated that container ships lose over 10,000 containers at sea each year (usually during a storm). One famous spillage occurred in the Pacific Ocean in 1992, when thousands of rubber ducks and other toys went overboard during a storm. The toys have since been found all over the world; Curtis Ebbesmeyer and other scientists have used the incident to gain a better understanding of ocean currents. Similar incidents have happened, with the same potential to track currents, such as when Hansa Carrier dropped 21 containers (with one notably containing buoyant Nike shoes). In 2006, thousands of bags of Doritos chips washed up on the beach at Frisco, North Carolina. In 2007, MSC Napoli was beached in the English Channel, and dropped hundreds of containers, most of which washed up on the Devon coastline.
Though it was originally assumed that most oceanic marine waste stemmed directly from ocean dumping, it is now thought that around four fifths of the oceanic debris is from rubbish blown seaward from landfills, and washed seaward by storm drains.

Law of the United States

In the United States, the Beaches Environmental Assessment and Coastal Health Act of 2000 was enacted to help reduce the risk of diseases for users of water from the American coastline and Great Lakes. The act authorizes the EPA to award program development and implementation grants to eligible states, territories, tribes, and local governments to support microbiological testing and monitoring of coastal recreational waters that are adjacent to beaches or similar points of access used by the public. Currently, the California Legislature is considering a host of bills designed to reduce the sources of marine debris, following the recommendations of the California Ocean Protection Council.

Ownership of debris

Lost, mislaid, and abandoned property can be of consequence within property law, admiralty law, and the law of the sea. Salvage law has as a basis that a salvor should be rewarded for risking his life and property to rescue the property of another from peril. On land the distinction between deliberate and accidental loss led to the concept of a 'treasure trove'. In the United Kingdom, shipwrecked goods should be reported to a Receiver of Wreck, and if identifiable, they should be returned to their rightful owner.

The Great Pacific Garbage Patch

Once waterbourne, debris is far from immobile. Flotsam can be blown by the wind, and follows the flow of ocean currents, often ending up in the middle of oceanic gyres where currents are weakest. The Great Pacific Garbage Patch is one such example of this, comprising of a vast region of the North Pacific Ocean rich with anthropogenic wastes. Conservative estimates of its size compare it to Texas, whereas some reckon it closer to the size of Africa. The mass of plastic in our oceans may be as high as one hundred million tonnes. and Hawaii. Clean-up teams around the world patrol beaches to clean up this environmental threat.

Environmental impact

Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey. Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection. Tiny floating particles also resemble zooplankton, which can lead filter feeders to consume them and cause them to enter the ocean food chain. In samples taken from the North Pacific Gyre in 1999 by the Algalita Marine Research Foundation, the mass of plastic exceeded that of zooplankton by a factor of six.
Many toxins can be found in plastic materials (where they are used as plasticizers, etc), one of the most harmful being polychlorinated biphenyls, which can leach into the surrounding waters. While safety standards are increasing (PCBs were banned in the 1970s), all the plastics produced in the years prior are still circulating in the world's oceans. It has also been suggested that persistent organic pollutants may be collecting and magnifying on the surface of plastic debris, adsorbing permanently to its surface and making oceanic plastic debris far more deadly that it would be on land.
Ghost nets are fishing nets that have been left or lost in the ocean by fishermen. They can entangle and kill fish, dolphins, sea turtles, sharks, dugongs, crocodiles, penguins and other seabirds, crabs, and other creatures, including the occasional human diver.
However, not all anthropogenic artefacts in the oceans do harm. Iron and concrete do little damage to the environment as they are generally immobile; in fact, they can even be used as scaffolding for the creation of artificial reefs, increasing the biodiversity of a coastal region. Entire ships have been deliberately sunk in various attempts to do just that.

See also

References

External links

jetsam in Japanese: 漂流・漂着ごみ

Synonyms, Antonyms and Related Words

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