Life, a powerful geological force ("Life as geological force.") This is the title of a work by a Dutch paleontologist Peter Westbroek, a specialist in biomineralization and studied in the Cantabrian Mountains. After this statement, seemingly innocuous, it hides something else: a reflection of a new unified vision of Earth Sciences and Life Sciences, the Gaian approach.
Gaia is a theory (rather than a theory, one could understand as a new way of conceiving the natural sciences), which suggests that the outer surface of the Earth and all living organisms in it, form a self-regulating system and homeostasis, this is a system in dynamic equilibrium, so any disturbance that results in a modification of this system to absorb the effects of the disruption and to maintain appropriate conditions for life. According to this, over time, life, interacting with the environment inert surface, would have maintained the right conditions for their existence. This will provide a framework in which to frame all the knowledge and research, both bio and geosciences.
Gaia theory was proposed by a British chemist, James Lovelock, in the '70s. His inspiration came when, working for NASA on the Viking mission, raised the question of in what way we could find out if a planet had life. The search-based analysis of complex biomolecules such as amino acids or sugars did not satisfy him, for the analysis, depending on location, even in parts of the Earth give negative results. He realized that the most accessible part of a planet is its atmosphere, and to compare the atmospheres of Earth and other rocky planets in the solar system fell account the uniqueness of Earth's atmosphere, the Earth has an atmosphere in a chemical imbalance. Planets like Mars and Venus have an atmosphere whose chemical composition is in equilibrium with the chemical composition of the outer cortex (the part of a planet surface): large amounts of carbon dioxide, with small proportions of other gases. Have an atmosphere "inert" gas it does not react with each other or react with surface rocks. In contrast, the Earth has an atmosphere of balance: its composition is dominated by the nirógeno and oxygen (in that order), very toxic reagents, which tend to react with surface rocks. And another of its peculiarities is its mixture of combustible gases like methane and oxygen, which react vigorously with each other. On the other hand, if these gases react together, the final composition of our atmosphere would be similar to Mars or Venus, incompatible with life, at least on a large scale. The fact that life exists on Earth since at least 3500 million years, indicates that the Earth's atmosphere takes a long time away from the deadly hold the remaining balance of planets.
This apparent contradiction can be resolved only to Lovelock, considering life as a superorganism, capable of tilling the earth according to their interests. Life acting as a powerful machine pumping gas, capable of compensating the losses, which are produced by chemical reaction of atmospheric gases among themselves and with the rocks. Any other consideration of biogeochemical cycles (cycles that abstractly represent the transit of chemicals from the rocks to life and this life again) not take into account the active role of life fail .
Subsequently, the theory was developed by Lovelock himself, in collaboration with biologist Lynn Margulis, and other authors. Laid the groundwork for what Lovelock considers himself a new discipline he calls "geophysiology" which tries to explain the operation of this superorganism.
Gaia has siblings: different versions of Gaia
One of the criticisms to which it was originally submitted Gaia theory was that it was a teleological theory, runner, so that the whole of life the Earth behaves as a single entity and self-regulated, it was necessary that agencies, in some way aware of what they had and that their actions were seeking an end (to maintain appropriate conditions for their existence). Something like the wolf conference "The book of the jungle. "
To address these criticisms, Lovelock proposed a simple mathematical model which he called "the world of Daisies" was a simulation of a planet similar to Earth, which lived only 3 species: daisies, black, gray and white. And that simulation subjected to a steady increase in solar radiation over time (as happens on Earth: As the Sun is consumed will increase the intensity of radiation). The result was parallel to the increase of radiation, the planet went from being dominated at first by black daisies (which absorb sunlight) to daisy gray, and finally when radiation solar was big, white daisies (their greater ability to produce albedo would make part of the reflected solar radiation, keeping the average temperature near the baseline). After a solar RADIATION threshold, the conditions would be impossible for life. With this simple model, showed that one could conceive of an ecosystem to maintain constant environmental conditions (despite external shocks, in this case, increased solar radiation) and suitable for their existence, without conscience or any purpose.
view of the widely circulated popular theory was reached in 1988 organized the American Geophysical Union a conference to discuss the details of the theory. Here, a geophysicist at the University of Berkeley, James Kirchner raised an important clarification: Gaia can be thought of as a collection of theories, where different researchers have proposed different versions of the superorganism. So distinguished between:
- Gaia Theory "strong" teleological theories, which imply an awareness of Gaia herself. As mentioned, this version is far from the original idea of \u200b\u200bLovelock, and are, obviously, unscientific theories. These theories include theories arising Gaia in the light of the movement of "New Era, and establish relationship issues such as Gaia and Atlantis and crop circles. They do not deserve further mention.
- Gaia Theory "weak", among which one could distinguish different approaches: coevolucionaria, the influential ... In general, one can say that these theories suggest that life has substantial influence on the physical environmental conditions. Here, for the purposes of the article, I distinguish between weak Gaia theory in the strict sense (here and encompasses the original, Lovelock) have proposed that as a result of the interaction between agencies and between them and the environment which are based, the physical characteristics Land remains appropriate for the existence of life. And the weak Gaian theories at large (or superdébiles) have proposed that abiotic characteristics of ecosystems are modified in different ways by (Note the nuance between for and for).
Gaia, "accepted theory?
The idea that organisms interact and modify environmental features one would question it.
More discussion, however, is the idea that life has kept these physical characteristics of land suitable for preservation.
IMHO, I think the right point is between what I call "weak Gaia ss" and "Gaia superdébil." Clearly
ideas as "extreme" as those of Don Anderson, a geophysicist who was a life responsible for the existence of plate tectonics seem to "fuck" by the hair.
However, today known facts of the history of the Earth, and processes (such as the so-called climate feedback loops, with the participation of living in many of them), in which shows that life has played a major role in terrestrial conditions at megascopic. I will cite two examples:
- Today, it seems clear that the vast diverisificación achieved by cyanobacteria, (some photosynthetic bacteria) was responsible for the existence of oxygen in our atmosphere. It seems clear that 2500 million years ago, oxygen levels began to rise sharply as a result of the activity of these organisms. On the other hand, seems well established that the actual content of oxygen in the air (21%) is held constant because the contributions made by plants are equal to the losses. Another interesting issue is that in our atmosphere coexisting oxygen and methane, two gases are very reactive with each other and on the other hand, their numbers remain more or less constant over time (industrial activity has led to an artificial source of methane that can break this "equilibrium"). This seems to be due to the contributions made by agencies are needed to offset losses.
- today known processes by which life can intervene in the global climate. An example is that of phytoplankton. Marine phytoplankton, for some reason not yet understood, proliferates in glacial epochs. When the bodies of the agencies "phytoplankton" decompose, emit a chemical, dimethyl sulfide (DMS) in the atmosphere is oxidized to give rise to sulfur acid. But this oxidation is slow and DMS have time to diffuse into the stratosphere. Once there, is where it is oxidized and sulfur acids act as cloud condensation nuclei. These clouds do indeed screen for sunlight and reflect it, so that the Earth's temperature drops (this is what is called albedo). This involves increased proliferation of phytoplankton, and consequently, higher productivity of DMS, and thus lower temperatures. That is, the process feeds itself. But this does not continue forever, there comes a time when water temperatures are below the optimum of phytoplankton, which stops their growth, reducing the contribution of DMS (reduced to This albedo due to stratospheric clouds) and there will be a trend in this area as temperatures increase again. On the other hand, the low temperatures mean a higher amount of bare soil, allowing plant ecosystems are installed, reducing the albedo and somewhat offset the effect due to phyto-plankton.
This last example illustrates how complex the relationships between organisms and their physical environment, and as within the biosphere-geosphere can identify small systems that act as genuine thermostats capable of maintaining the values \u200b\u200bof physical parameters (either temperature, or composition of air, or sea salt) in an optimal point suitable for all agencies. And this without any plot or conniving or awareness on the part of Gaia.
In conclusion, one could say that Lovelock's original idea was bold, but in view of numerous observations, every time you can see that in a sense, the idea that organisms are active in the dynamic external Earth was true. You may be confused with the excessive importance granted because we know that the biosphere is affected by external shocks, about which little or nothing can make your ability to self-regulation. As an example, the fall of a meteorite. It is also true that living beings have not been limited has played the role of secondary character, entirely passive, which are traditionally assumed in the theatrical climate. Today we know that organisms have some ability to control the environment in which they settle, and sometimes this control may have implications worldwide.
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