20 sep 2011

GFAJ-1 : life at the limits of the biosphere (2010)

Submitted by Anonyme (non vérifié)

As the NASA called for a conference, explaining that it would deal with an astrobiology finding that « will impact the search for evidence of extraterrestrial life », one the most common reaction was to expect the discovery of a humanoid life, or at least something going in that direction.

Some others reaction were to think that a bacterium had been found on another planet. Anyway, nothing could concern our own planet.

Those both reactions are, of course, wrong, because they are totally anthropocentric.

Human beings are a part of the biosphere, and so they don’t exist apart of it. There is no reason – if we put aside religion or the bourgeois cult of the human « citoyen » – to expect that extra terrestrial life should or must be « human », in a way or another.

In the same way, our own planet is of course a topic of astrobiology, which deals about the biology existing on a planet. It is indeed bourgeois thinking to think that our planet is a « controlled » big rock, and that we have not much to learn about it.

Of course, the discovery of the NASA scientists is another hit against such way of thinking. It shows again the validity of the dialectical materialist thesis that matter is in movement, and that life is produced by this movement. But let’s see first what this discovery is.

Till today, life as it is defined by scientists need the following elements : carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.

Here, phosphorus interests us particularly. The reason for that is phosphorus is absolutely needed to produce DNA and RNA. The storage and transfer of energy in the cells also need phosphorus (as adenosine triphosphate, or ATP).

And here phosporus plays here a key element in the biosphere equilibrium, because of its amount : phosphorus is scarce. On Earth, phosphorus is 12th in rank in abundance. But common forms are the following minerals : apatite, wavellite, vivianite. Life can’t use those forms. And we can notice also that those minerals are present mostly in some areas (Marocco for the 1/3, China for the ¼).

So, life’s development has a limit, life’s abundance has a frontier : the amount of available phosphorus. Here, we can see one important aspect of the biosphere : birds played historically a great role in the initial distribution of phosphorus, spreading it everywhere on the planet throungh their droppings.

We can also see how human beings are perturbing the biosphere, in using phosphorus for fertilizers in an incorrect way. In France, for example, in 2001 775.000 tons of phosphorus were used in agriculture ; the part that is « lost » in the environment brings a lot of disequilibrium, wit the collapses of population deprived of oxygen.

All of this stresses the importance of phosphorus. Nevertheless, this is true in the biosphere -in our biosphere. In a way here, we must see that the discovery of the NASA doesn’t come from the biosphere of the Earth, but from its extreme : the Mono Lake.

The Mono Lake covers about 65 square miles and is in California, in the USA. It is the habitat for millions of migratory and nesting birds, because of brine shrimps and of alkali flies feed on microscopic algae. Of course, this habitat had to be protected from ecocide, in a battle won in the 1970′s.

The water of this lake is characterized by hypersalinity, high alkalinity and a high concentration of arsenic.

Arsenic is toxic to life in the biosphere. But it sits just below phosphorus on the periodic table of elements; it is so really near from phosphorus, so at least react the living organisms when they are confronted to it… For this reason, Arsenic is famous as an effective poison.

But the conditions in the Mono Lake are very different from thoses in the biosphere. Some may even speak of a « shadow biosphere » – an anti-biosphere, like there is an anti-matter to matter.

And under those harsh conditions of this (other) biosphere, a bacterium exists, called « GFAJ-1 » by scientists, which is able to use arsenic instead of phosphorus….

GFAJ-1 is not an obligate arsenophile and it grew considerably better when provided with phosphorus. But in the laboratory of the NASA, this bacterium was able to live without phosphorus ; it did incorporate arsenic into its DNA, it did build cellular components with arsenic present in them.

Arsenic, a poison for life as we know it, is here used by life as we did not know it.

The consequence is here clear : in others biospheres, life might in use arsenic instead of phosphorus. Or life might use maybe something else, but so not necessary phosphorus. Life would appear in a totally different way, totally different as we would expect.

This is logic. What we called « life » is the moving matter on our planet, in a special area : the biosphere. A biosphere producted by the movement of matter, by the equilibrium of the chemical elements. In another biosphere than ours, there may be another equilibrium ; moving matter may then have different chemical compounds.

Let us here remember us here Vernadsky’s conception:

« The radiations that pour the Earth cause the biosphere to take on properties unknown to lifeless planetary surfaces, and thus transform the face of the Earth.

Activated by radiation, the matter of the biosphere collects and redistributes solar energy, and converts it ultimately into free energy capable of doing work on Earth.

The outer layer of Earth must, therefore, not be considered as a region of matter alone, but also as a region of energy and a source of transformation of the planet. To a great extent, exogenous cosmic forces shape the face of the Earth, and as a result, the biosphere differs historically from other parts of the planet. The biosphere plays an extraordinary planetary role.

The biosphere is at least as much a creation of the sun as a result of terrestrial process. Ancient religious intitutions that considered terrestrial creatures, especially man, to be children of the sun, were far nearer the truth than is thought by those who see earthly beings simply as ephemeral creations arising from blind and accidental interplayof matter and forces.

Creatures on Earth on Earth are the fruit of extended, complex processes, and are an essential part of a harmonious cosmic mechanism, in which it is known that fixed laws apply and chance does not exist. » (The Biosphere)

The discovery of the NASA makes us progress in the understanding of the biosphere : the existence of GFAJ-1 at the limits of the biosphere is a proof of the unity of life in the biosphere.

Inside the biosphere, nothing, no life, can exist in an isolated way. All life come from the dialectical organisation of matter, through the connection of the chemical elements – in the conditions of the biosphere.