Pacific Trash Vortex: differenze tra le versioni

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Il '''Pacific Trash Vortex''' e' un'[[isola]] di [[spazzatura]], soprattutto [[plastica]], formatasi nell'[[Oceano Pacifico]] a partire dagli [[anni cinquanta]], raggiungendo un [[diametro]] di circa 2500 [[chilometri]], una [[profondità]] di 30 [[metri]] e un peso di 3.500.000 [[tonnellate]], grazie all'azione della [[North Pacific Subtropical Gyre]], una [[corrente oceanica]] dotata di un particolare movimento [[spiraloide]] in [[senso orario]], che permette appunto ai [[rifiuti]] galleggianti di aggregarsi fra di loro.

== La North Pacific Gyre ==

La '''North Pacific Gyre''', o '''Vortice del Nord Pacifico''' ( conosciuto anche come '''Vortice Subtropicale del Nord Pacifico''') è una corrente oceanica a forma di vortice circolare localizzato tra l'[[equatore]] il 50° di [[latitudine]] nord. Occupa approssimativamente un'area di 34 milioni di km², si muove in senso orario ed è formato prevalentemente da quattro [[corrente oceanica|correnti oceaniche]] : la [[Corrente del Nord Pacifico]] a nord, la [[Corrente della California]] ad est, la [[Corrente nord equatoriale]] a sud e la [[Corrente Kuroshio]] a ovest.

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== WasteRifiuti ==

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Il centro di tale vortice è una regione relativamente stazionaria dell'[[Oceano Pacifico]] ( ci si riferisce spesso a quest'area come la [[latitudine dei cavalli] ) al cui centro si accumulano notevoli quantità di rifiuti, sopprattutto plastica, ed altri detriti a formare una enorme "nube" di spazzatura che ha assunto il informale definizione di '''Isola orientale di Immondizia''' o '''Vortice di Pattumiera del Pacifico'''.

The centre of the North Pacific Gyre is relatively stationary region of the Pacific Ocean (the area it occupies is often referred to as the [[horse latitudes]]) and the circular rotation around it draws waste material in. This has led to the accumulation of [[flotsam]] and other debris in huge floating 'clouds' of [[waste]] which have taken on informal names, the '''Great Pacific Garbage Patch''', the '''Eastern Garbage Patch''' or the '''Pacific Trash Vortex'''. While historically this debris has [[biodegradation|biodegraded]], the gyre is now accumulating vast quantities of [[plastic]] and [[marine debris]]. Rather than biodegrading, plastic [[photodegradation|photodegrades]], disintegrating in the ocean into smaller and smaller pieces. These pieces, still [[polymer]]s, eventually become individual molecules, which are still not easily digested.[http://www.mindfully.org/Plastic/Ocean/Pacific-Garbage-Patch27oct02.htm] The photodegraded plastic can produce [[pollutant]]s such as [[Polychlorinated biphenyl|PCBs]]. The floating particles also resemble [[zooplankton]], which can lead to them being consumed by [[jellyfish]], thus entering the ocean [[food chain]]. In samples taken from the gyre in 2001, the mass of plastic exceeded that of zooplankton (the dominant animalian life in the area) by a factor of six.

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The centre of the North Pacific Gyre is relatively stationary region of the Pacific Ocean (the area it occupies is often referred to as the [[horse latitudes]]) and the circular rotation around it draws waste material in. This has led to the accumulation of [[flotsam]] and other debris in huge floating 'clouds' of [[waste]] which have taken on informal names, the '''Great Pacific Garbage Patch''', the '''Eastern Garbage Patch''' or the '''Pacific Trash Vortex'''. While historically this debris has [[biodegradation|biodegraded]], the gyre is now accumulating vast quantities of [[plastic]] and [[marine debris]]. Rather than biodegrading, plastic [[photodegradation|photodegrades]], disintegrating in the ocean into smaller and smaller pieces. These pieces, still [[polymer]]s, eventually become individual molecules, which are still not easily digested.[http://www.mindfully.org/Plastic/Ocean/Pacific-Garbage-Patch27oct02.htm] The photodegraded plastic can produce [[pollutant]]s such as [[Polychlorinated biphenyl|PCBs]]. The floating particles also resemble [[zooplankton]], which can lead to them being consumed by [[jellyfish]], thus entering the ocean [[food chain]]. In samples taken from the gyre in 2001, the mass of plastic exceeded that of zooplankton (the dominant animalian life in the area) by a factor of six.

Occasionally, shifts in the ocean currents release [[flotsam]] lost from [[cargo ship]]s into the currents around the North Pacific Gyre, leading to predictable patterns of garbage washing up on the shores around the outskirts of the gyre. The most famous was the loss of approximately 80,000 [[Nike, Inc.|Nike]] sneakers and boots from the ship ''[[Hansa Carrier]]'' in [[1990]]: the currents of the gyre distributed the shoes around the shores of [[British Columbia]], [[Washington]], [[Oregon]], and [[Hawaii]] over the following three years. Similar cargo spills have involved tens of thousands of [[Friendly Floatees|bathtub toys]] in [[1992]] and hockey equipment in [[1994]]. These events have become a major source of data on global-scale ocean currents. Various institutions have asked the public to report the landfall locations of the objects (trainers, rubber ducks, etc.) that wash up as a method of tracking surface waters' response to the deeper ocean currents. [http://www.timesonline.co.uk/tol/news/uk/article1996553.ece]