Viaje a las profundidades del Océano (VIDEO) + Extrañas criaturas marinas (FOTOS)

  Pero, ¿qué es un Océano? U n océano es una enorme masa de agua salada que representa un importante ecosistema para el equilibrio ecológico de la Tierra y que constituye el  71% de la superficie terrestre , gracias a los 360,132,000 km² de su extensión. Y,  ¿cuántos océanos existen? Lo que cubre gran parte de la superficie de la Tierra, es en sí, un solo océano. Es decir, una sola masa de agua. Para un mejor estudio, el hombre dividió esta enorme masa en 5 partes de acuerdo a su ubicación geográfica. Por ello, la expresión “los océanos”, es correcta. Importancia de los océanos *Absorben entre un 25 y 30% del dióxido de carbono emitido a la atmósfera, por lo que Equilibran el clima de toda la Tierra. *Representan numerosos ecosistemas para diversas formas de vida animal, vegetal, bacteriana, protista y fúngica. *Son hogar para miles de especies, conocidas y aún desconocidas. Existen aproximadamente 250,000 especies conocidas, pero se cree que puedan haber 750,000 más. *Proveen fuentes

26-Mar-2011 - Radiation spike in sea by Japan nuke plant

Photograph provided by the company operating the Fukushima Daiichi Nuclear Power Station, TEPCO, showing workers wearing special overalls while working on restoring power lines in the reactors 3 and 4 of the plant, Okumamachi, in the prefecture Fukushima (Japan).
24/03/2011 | TEPCO / HANDOUT
English Article
Radiation levels have jumped 10-fold in days in seawater near Japan's tsunami-hit nuclear plant, officials said on Saturday, as workers battled to stabilise the crippled power station.

Drinking a half-litre (20-ounce) bottle of similarly contaminated fresh water would expose a person to their annual safe dose, said an official, who however ruled out an immediate threat to aquatic life and seafood safety.

The iodine-131 level in the Pacific Ocean waters
just off the Fukushima plant was 1250 times above the legal limit compared with readings of 126 times higher taken on Tuesday, and 145 higher on Thursday.

"This is a relatively high level," nuclear safety agency official Hidehiko Nishiyama said in a televised press conference on the test results from Friday released by plant operator Tokyo Electric Power Company (TEPCO).

Assessing the likely impact on aquatic life, Nishiyama added: "Generally speaking, radioactive material released into the sea will spread due to tides, so you need much more for seaweed and sea life to absorb it."

He added that because iodine-131 has a half-life - the time in which half of it decays - of eight days, "by the time people eat the sea products, its amount is likely to have diminished significantly".

However, TEPCO in a statement also said that levels of caesium-137, which has a half life of about 30 years, was 79.6 times the legal maximum.

The assurances did little to lift the gloom that has hung over Japan since a massive 9.0-magnitude earthquake struck on March 11 and sent a monster tsunami crashing into the northeast coast in the country's worst post-war disaster.

The wave easily overwhelmed the world's biggest sea defences and swallowed entire communities. The confirmed death toll rose to 10,151 on Saturday, with little hope seen for most of the 17,053 listed as missing.

Radioactive iodine, caesium and cobalt levels in water in the turbine buildings next to reactors one and three were 10,000 times the normal level, raising fears that the reactor vessels or their valves and pipes are leaking.

The worst-case scenario at reactor three would be that the fuel inside the reactor core - a volatile uranium-plutonium mix - has already started to burn its way through its steel pressure vessel.

Radioactive vapour from the plant has contaminated farm produce and dairy products in the region, leading to shipment halts in Japan as well as the United States, European Union, China and a host of other nations.

Higher than normal radiation has also been detected in tap water in and around Tokyo, about 250 kilometres from the plant, leading authorities at one stage to warn against using it for formula milk.

Japan widened the zone around the plant where it suggests people evacuate, to 30 kilometres - still below the 80 kilometres advised by the United States, and larger areas including Tokyo in other nations' alerts.

Environmental watchdog Greenpeace started its own monitoring near the plant, charging that "authorities have consistently appeared to underestimate both the risks and extent of radioactive contamination".

"We have come to Fukushima to bear witness to the impacts of this crisis and to provide some independent insight into the resulting radioactive contamination," said the group's radioactivity safety adviser, Jan van de Putte.
The campaign group said it would provide "an alternative to the often contradictory information released by nuclear regulators".


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