[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: Vida en Marte: nuevos experimentos.
At 09:02 PM 11/24/96 +0100, you wrote:
>> De: Javier <ssta en lix.intercom.es>
>> GONZALO: TE AGRADECERE QUE ME
>
> Uy, perdon, ... no es exactamente asi, dije una cosa que no era. El
>oxigeno no proviene del que esta contenido en la materia organica, es otra
>cosa. (El origen de la confusion es muy tonto: al leer eso de 'surges' lo
>traduje por bombeo; esto es debido a que suelo ver la palabra asociada a un
>tipo de inestabilidad que se da en los compresores, pero que en espanyol se
>llama bombeo, aunque lo normal es que se use la palabra inglesa. (He mirado
>el diccionario y ya he visto que una cosa no es traducion literal de la
>otra)). Y claro, al entender eso del bombeo de oxigeno a la atmosfera, y
>mas adelante lo del almacenamiento de carbono organico... Pido disculpas
>por la metedura de pata. Si no me equivoco, lo que DesMarais dice que
>ocurre es que, al estar la materia organica enterrada, el equilibrio que el
>dice respiracion-fotosintesis se rompio, porque la materia organica es
>consumida por las bacterias en la respiracion para producir CO2, de manera
>que la 'cantidad' de respiracion no fue capaz de consumir todo el oxigeno
>para mantener la concentracion inicial, y esta aumento. Pongo la nota de
>prensa, y asi nos ahorramos complicaciones de errores de interpretacion. De
>todas maneras, advierto que yo no tengo nada que ver con DesMarais, y no
>pienso defender ni rebatir su hipotesis, porque no es mi campo y entiendo
>mas bien poco tirando a nada de estas cosas, asi que me fio del, digamos,
>'debate cientifico habitual'. Solo lo cuento porque me parece interesante:
>
>RELEASE: 96-219
>
>RESEARCH SUGGESTS MOST OF EARTH'S OXYGEN
>SUPPLY WAS PRODUCED BY GEOLOGIC EVENTS
>
> Refined calculations and new evidence support a
>revolutionary suggestion that global-scale geologic events
>produced the bulk of Earth's oxygen supply, a NASA scientist
>reported today.
>
> Scientists have long believed that oxygen collected in
>Earth's early atmosphere as a by-product of plant life from a
>process called photosynthesis, in which plants take carbon
>dioxide and water to produce organic matter and oxygen. Dr.
>David DesMarais, of NASA's Ames Research Center, Mountain
>View, CA, first suggested in 1992 a relationship between
>oxygen and the collision of continents, the resultant
>colossal mountain ranges and increased erosion burying huge
>amounts of organic matter in ocean beds.
>
> "Although photosynthesis did provide an oxygen source
>strong enough to sustain the amount of existing oxygen, the
>creation and assembly of large modern-sized continents was
>responsible for early dramatic increases in oxygen,"
>DesMarais said.
>
> (...)
> DesMarais' research correlates oxygen "surges" in the
>atmosphere 2.2 to 2.0 billion years ago with changes in the
>amount of carbon stored in Earth's crust at that time.
>During that time, several of Earth's "micro" continents
>crashed together forming new, stable modern-sized continents.
>As the continental fragments collided, towering mountain
>ranges formed. Their steep slopes produced rapid erosion and
>sedimentation, key to DesMarais' theory.
>
> Organic matter is normally consumed by bacteria and
>animals, a process that utilizes oxygen (respiration),
>producing energy and carbon dioxide and water as by-products.
>According to DesMarais, when huge amounts of organic matter
>were buried during cataclysmic collisions, oxygen was freed
>to accumulate in Earth's early atmosphere.
>
> "The cycle of photosynthesis (which produces oxygen)
>and respiration (where oxygen is consumed) is an almost
>break-even process," DesMarais said. Only when large amounts
>of organic material are buried in ocean sediments during
>tectonic upheavals can the amount of oxygen in the atmosphere
>increase substantially, he added.
>
> An independent recent study concludes that
>approximately three large continental masses were assembled
>between 2.5 and 1.9 billion years ago by the collision of
>smaller land masses. Two of these were assembled between 2.2
>and 1.9 billion years ago. These collisions formed
>Himalayan-class mountains with high rates of sedimentation in
>the ocean, burying organic matter.
>(...)
>
>
> Saludos
> Gonzalo J. Perez
> gonj en ctv.es
>
Gonzalo,
no me extranna que te confundieras. El articulo no esta bien escrito, e
invita a la confusion. El oxigeno se libera "por falta de consumo", al
reducirse el numero de organismos que lo fijan, y se rompio el "regimen
permanente" de que habla el autor, pero no por otra razon. Pero hay que
leerlo dos y hasta tres veces para darse cuenta.
Saludos
Javier
ssta en lix.intercom.es