Could thermodynamic fluctuations have led to the origins of life?

Aug 16, 2010 by Lisa Zyga feature
(Left) Self-catalysis vs. (right) replication with inheritance in terms of kinetics: In the case of self-catalysis, all the initial states eventually lead to the same stationary state. In the case of replication with inheritance, the initial states lead to different stationary states on the stationary-state curve. The blue arrows show that the motion along the stationary-state curve is a drift pointing toward the increase of the most active replicase, R2. Image copyright: Doriano Brogioli. ©2010 The American Physical Society.

In the field of abiogenesis, scientists are currently investigating several ways in which life could have arisen from non-living matter. Generally, any theory of abiogenesis should account for two important aspects of life: replication (the ability to transmit mutations to offspring) and metabolism (the chemical reactions required for vital activities such as breaking down food). Although these two characteristics help to provide a working definition of life, more recently scientists have emphasized the importance of another key feature required for Darwinian evolution: selection, or the replication of mutations that provide an evolutionary advantage.

"The basic problem of abiogenesis is finding the first living entity that generated from non-living matter," Doriano Brogioli, a physicist from the University of Milan-Bicocca, told PhysOrg.com. “But what is the definition of life: is it replication, or , or simply self-catalysis? I think that it is not simply a matter of definition: what is necessary is 'evolution,' even if the entity that undergoes (or performs) evolution is not a classical living entity. After evolution starts, it can reach whatever complex structures: from a cell, evolution creates trees, whales, birds, ants, and all the prodigious current living world."

Purely chemical systems may possess the ability to replicate and metabolize, but scientists have found that chemical systems by themselves do not undergo selection; more active molecules are not replicated more than others, and useful individual mutations are not inherited by the offspring. Therefore, researchers have suggested that some kind of physical process is likely required to introduce competition among chemical systems and generate the selective pressure required for evolution.

"Three features are needed for evolution: inheritance, mutation and selection," Brogioli said. "Single molecules can replicate other molecules, including other copies of themselves, and can undergo mutations. But in a solution with replicases, each replicase replicates whatever it finds, including non-active molecules or less active replicases. Selection is not active. The reason is that (traditional) chemistry favors selfish molecules: the molecule that is more able to be replicated increases its concentration. In order for selection to take place, there must be a physical process. Confination due to membranes is the current way used by living organisms. But it is hard to believe that a complex structure like a cell can form spontaneously, since the replicating polymers must form together with the membranes themselves. This problem is found in all the theories of abiogenesis, including the RNA-world and the metabolism-first theories."

Brogioli has taken a unique approach to satisfying the requirement for selection by proposing that the answer may lie in thermodynamic fluctuations. These fluctuations, which are changes in the number of molecules in a given volume due to thermal motions, may allow selection to become effective, leading to the increase in molecules having an evolutionary advantage. By investigating some chemical systems that possess a feature that he calls "chemical marginal stability," Brogioli has shown that thermodynamic fluctuations induce not only a random walk, but a drift directed toward increasing replication efficiency.

Brogioli suggests that this drift represents an early form of evolution that took place before membranes began to enclose chemical systems; after this time, the membranes would have assumed responsibility for defining entities in competition with one another, allowing selection to take place. If thermodynamic fluctuations did play the role of selection in early life, it would overcome the problem of requiring replicating chemicals and the membranes that enclose them to emerge simultaneously.

In his paper, Brogioli looks at replication from a kinetics perspective, in which the kinetic counterpart of the inheritance of mutations is the presence of multiple stationary states, i.e., different lines of mutations can be present simultaneously, and their offspring inherit mutations. He shows that chemical systems that can pass mutations on to offspring can be thought of as systems with multiple stationary states, thus having the property of chemical marginal stability. These systems differ from a simple "self-catalytic" system (e.g., a purely chemical system) that merely produces offspring without transmitting mutations; the kinetic counterpart would be initial states that all lead to only one stationary state.

As an analogy of a marginally stable system, Brogioli considers the mechanical example of a marble on a flat surface, where any point on the surface is a stationary point. If the marble is disturbed, it reaches a different stationary point rather than returning to its original position, since there is no restoring force. Likewise, spontaneous concentration fluctuations can enable a chemical system to inherit a variety of mutations from its parent system, and any of these mutations can be considered stable.

Brogioli discovered the drift motion by mathematically studying the thermodynamic fluctuations over time. He found that, if two replicases R1 and R2 are present, the most efficient replicase, say R2, begins increasing in number and becomes dominant. In volumes with a higher concentration of R2, more replications will occur, and a larger fraction of them will be R2. Afterward, an even more efficient replicase can arise due to random mutations, and its concentration will increase, and so on.

At the moment, the drift has been confirmed only by numerical calculations, and must be regarded as still theoretical. Brogioli notes that most chemical systems that have a replicase do not possess chemical marginal stability, and therefore are not affected by thermodynamic fluctuations. However, his study shows that the existence of a chemical system that is marginally stable and can undergo spontaneous evolution is possible. Investigating this theory further could have extremely important revelations. The demonstration of a marginally stable chemical system in the lab would not only be the first experiment in which a chemical system undergoes spontaneous evolution, but also the first in vitro model of a chemical reaction that leads to life.

"Currently, no replicase that can self-sustain its replication has been created, but replication of RNA polymers can be obtained by ligation of short oligonucleotides," Brogioli said. "This is a way [to find a chemical system could have marginal stability]. Another possibility is to create a more abstract system, in which replication is accomplished by an enzyme, and the activity of the enzyme is affected by the presence of one of the replicated polymers. Obviously, this is only a proof of principle of marginal stability and evolutionary drift, but not a realistic reproduction of the origin of life. The most interesting possibility is to consider the reactions proposed by the metabolism-first theories. In those theories, no replicating polymer was involved in abiogenesis, but only small constituting some kind of metabolic network. The target is to find a very simple reaction that can be marginally stable."

Explore further: New knowledge about host-virus coevolution unmasked from the genomic record

More information: Doriano Brogioli. "Marginally Stable Chemical Systems as Precursors of Life." Physical Review Letters 105, 058102 (2010). DOI: 10.1103/PhysRevLett105.058102

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TabulaMentis
Aug 16, 2010
This comment has been removed by a moderator.
Husky
not rated yet Aug 16, 2010
i would think the oceans black smokers are the selective agent on wich early live could synthesize. its thermodynamic gradient does not only select topologically chemical processes but there is a feedback loop from these chemical processes adding in the deposit or extract of substrates onto/from the black smoker itselve, altering its height, thickness, composition, effectively the black smoker evolves and its interacting/surrounding chemical processes with it
kevinrtrs
1 / 5 (7) Aug 17, 2010
@Husky,
So if these black smokers have been going for billions of years shouldn't they have evolved into some really substantial living entity by now?

However, his study shows that the existence of a chemical system that is marginally stable and can undergo spontaneous evolution is possible. Investigating this theory further could have extremely important revelations. The demonstration of a marginally stable chemical system in the lab would not only be the first experiment in which a chemical system undergoes spontaneous evolution, but also the first in vitro model of a chemical reaction that leads to life.

One does need to remember that this is a demonstration in the laboratory under carefully controlled conditions. One wonders what the probability is of finding such a spontaneous "chemically marginal stable" situation in real life. I guess it would be minute - as confessed by the researcher's comment.

Abiogenecists have a hard road ahead of them - total frustration!!
Skeptic_Heretic
3.6 / 5 (5) Aug 17, 2010
So if these black smokers have been going for billions of years shouldn't they have evolved into some really substantial living entity by now?
Moron. It's a volcano. The only group that holds that a volcano is alive are the Abrahamic theologists. After all, in certain context God appears to have been a volcano when Moses stumbled up the mountain to meet him.
Abiogenecists have a hard road ahead of them
But at least we don't fear what the journey will bring us.
Ethelred
3.7 / 5 (7) Aug 17, 2010
So if these black smokers have been going for billions of years shouldn't they have evolved into some really substantial living entity by now?
I take it you don't have a clue as to what a black smoker is? They aren't chemical reactions just the result of dissolved chemicals being deposited on the ocean bottom as the hot water meets cold water thus causing chemicals to drop out.
One does need to remember that this is a demonstration in the laboratory under carefully controlled conditions
I think we all understand that. It is kind of hard to learn about specifics if you don't control things.
Abiogenecists have a hard road ahead of them - total frustration!!
More like an interesting road. Are you projecting since you have NO evidence to support you and the entire Universe shows you wrong? I bet that really is frustrating. Otherwise why would you be posting so much nonsense here.

Ethelred
peteone1
1 / 5 (3) Aug 22, 2010
Moron. It's a volcano. The only group that holds that a volcano is alive are the Abrahamic theologists. After all, in certain context God appears to have been a volcano when Moses stumbled up the mountain to meet him.

Not nice to call anyone a "moron", a person cannot be faulted for not being as scientifically literate as you or I. In any case, your statment about God being a "volcano" is absurd at its face, and I think that misapplied cynicism hardly makes your case. Just in case you were serious, everyone who has read the Bible knows that God is a spirit, and that He "inhabited" the Mountain. ;-)

But at least we don't fear what the journey will bring us.
What if the journey (which is still a loooooooong one for you who pruport that somehow nonliving chemicals can magically, by some yet unknown principle of physics or chemistry, make the immensely complex step from bits and pieces of organic chemical components to a living cell) points you all away from Darwin?
Skeptic_Heretic
not rated yet Aug 22, 2010
What if the journey (which is still a loooooooong one for you who pruport that somehow nonliving chemicals can magically, by some yet unknown principle of physics or chemistry, make the immensely complex step from bits and pieces of organic chemical components to a living cell) points you all away from Darwin?
Then that's what it does, and my ideology changes to suit the proved observation.

Does your mythology do the same?
In any case, your statment about God being a "volcano" is absurd at its face, and I think that misapplied cynicism hardly makes your case. Just in case you were serious, everyone who has read the Bible knows that God is a spirit, and that He "inhabited" the Mountain. ;-)

http://www.youtub...-lSvS028

The reality is this isn't a statement of a volcano but more probably the standards of the exiles. ie: roman style standards, like Caesar's Eagle. Interpretation is open, is it not?
Modernmystic
3.3 / 5 (3) Aug 23, 2010
Well it looks to be an improvement over the mica sheets idiocy...

The theory/article at least admits the significant problems still left with abiogenesis and attempts to address them in a COHERENT and REALISTIC manner. Kudos for that at least.

However as the article itself states...still no cigar...
ArcainOne
5 / 5 (3) Aug 23, 2010

Not nice to call anyone a "moron", a person cannot be faulted for not being as scientifically literate as you or I.


I learned what a blacks smoker was in elementary school... about 20 years ago.

Just in case you were serious, everyone who has read the Bible knows that God is a spirit, and that He "inhabited" the Mountain. ;-)


... moot point.


What if the journey (...) points you all away from Darwin?


and that is what we call... science. Many of Darwin's theories have already been "disproven" really more like "improved" or "evolved". That is why they are called Theories and not facts (and in scence even they are suspect). If science eventually leads to a different, simpler, or more complex then so be it. Thats what you do as a scientist, you test, test some more, and test again.
GaryB
3 / 5 (1) Aug 24, 2010
I'm equally interested by another "mystery": We have a big planet + 4 Billion years of time. Why don't we find many different systems of life than just those based on DNA or RNA? Why shouldn't life be generated again and again with different basis each time?

Possibly it is because once you have life, it out-competes anything else.
TheWalrus
1 / 5 (3) Aug 26, 2010
Could thermodynamic fluctuations have led to the origins of life? Silly question. Everyone knows evolution violates the 2nd law of thermodynamics. ;-)
TabulaMentis
not rated yet Aug 26, 2010
Could thermodynamic fluctuations have led to the origins of life? Silly question. Everyone knows evolution violates the 2nd law of thermodynamics. ;-)

Would you please elaborate on that a little bit more?
Skeptic_Heretic
3.5 / 5 (2) Aug 26, 2010
Could thermodynamic fluctuations have led to the origins of life? Silly question. Everyone knows evolution violates the 2nd law of thermodynamics. ;-)
Except there's no isolated system and therefore no violation.

Talking out your ass about things you don't understand won't get you very far in life.
However as the article itself states...still no cigar...
Because replicating over 3 billion years of chemical reactions isn't something easily done in a few hundred years.
Why don't we find many different systems of life than just those based on DNA or RNA? Why shouldn't life be generated again and again with different basis each time?

Possibly it is because once you have life, it out-competes anything else.
We know of two distinct forms of DNA in nature and have constructed a third in the lab. There are certainly more forms of life possible than we can imagine. I'd say you hit the nail on the head with your conclusion.
TabulaMentis
not rated yet Aug 27, 2010
Could thermodynamic fluctuations have led to the origins of life? Silly question. Everyone knows evolution violates the 2nd law of thermodynamics. ;-)

Could you type up a law for the "Thermodynamic Law of Evolution?"
Modernmystic
not rated yet Aug 27, 2010
However as the article itself states...still no cigar...
Because replicating over 3 billion years of chemical reactions isn't something easily done in a few hundred years.


Interesting I thought that life started far earlier on Earth than 3 billion years after it the Earth cooled and it had any chance to form.

Some people put it at about a tenth that figure.

Moreover if we had an honestly good theory I'm pretty sure we could devise lab conditions which could satisfy those early circumstances and create our own life pretty easily, according to this it doesn't sound all that hard a thing to do.

After all isn't it the contention here that if life can arise it will? Seems it should be a fairly simple process then really shouldn't it...not something THAT far beyond current biochemical technology to replicate whole cloth.

You can't have it both ways. Either it's a common, simple, and inevitable process...or it's something a lot different.
Ethelred
4 / 5 (4) Aug 27, 2010
You can't have it both ways. Either it's a common, simple, and inevitable process...or it's something a lot different


Common - perhaps but we only have one example. Life did get started pretty fast. I notice that SH said OVER 3 billion. The evidence for the earliest life is based on stromatolites which are pretty clearly of biological origin but there are no actual fossilized cells.

Anyone claiming one tenth isn't going on evidence. 300 millions years ago is LONG after life was pretty much everywhere with LOTS of fossils.

The Earth is a big place. A lab is a very small place. What is inevitable with millions of years and many cubic miles of active chemistry can be still be VERY low odds in any feasible lab experiment.

That ISN'T both ways. It is the way of probabilities. A false dichotomy like that is a sign that you don't want to think realistically.

Ethelred
Ethelred
1 / 5 (1) Aug 27, 2010
We know of two distinct forms of DNA in nature and have constructed a third in the lab.


I know of one. How about a link. The first time you posted that I think there was a link that didn't really support that conclusion. Two slightly distorted DNA structures with the same chemicals is what I remember seeing.

Ethelred
Skeptic_Heretic
not rated yet Aug 27, 2010
We know of two distinct forms of DNA in nature and have constructed a third in the lab.


I know of one. How about a link. The first time you posted that I think there was a link that didn't really support that conclusion. Two slightly distorted DNA structures with the same chemicals is what I remember seeing.

Ethelred

And that's what they are two distinctly different arrangements of similar components. They are not "slightly distorted".
http://upload.wik...-DNA.png
Picture of the three constructs. Most likely a divergence from a single start, however, considering how often we see transcription and meta-exchange betyween simple life forms, what makes you think all the components of modern life arose together?
Skeptic_Heretic
not rated yet Aug 27, 2010
Re-read my last post and it's fairly dismissive and not quite logical.

Eth, think of it this way. If Szostak's hypothesis is correct, the multitude of polymer arrangements that would be self replicating must have been utterly enormous, meaning multiple "starts" to life. These would have shared material, self reorganized, and through natural selection the slowest or lesat fit would have perished. There cannot have been a single "life start" molecule. It is logically dubious to suggest as such.
peteone1
1 / 5 (2) Aug 27, 2010
What if the journey (which is still a loooooooong one for you who pruport that somehow nonliving chemicals can magically, by some yet unknown principle of physics or chemistry, make the immensely complex step from bits and pieces of organic chemical components to a living cell) points you all away from Darwin?
Then that's what it does, and my ideology changes to suit the proved observation.
Yes indeed. That's why I am no longer an intellectually vacuous agnostic ;-)
Does your mythology do the same?

Skeptic_Heretic
5 / 5 (1) Aug 27, 2010
Yes indeed. That's why I am no longer an intellectually vacuous agnostic ;-)
Then what are you now? An intellectually dishonest theist?
Modernmystic
5 / 5 (1) Aug 27, 2010
SH apologies if I misunderstood your post.

Were you saying it took 3 billion years for life to get started, or that life has been around for 3 billion years, because either myself or Eth is confused.

Please clarify if you would be so kind sir before I continue with my point because some of it hinges on these time frames.

Thanks! :)
Skeptic_Heretic
not rated yet Aug 27, 2010
MM, current hypotheses postulate that life had a very early start on our planet and that the creation of cellular life began taking place sometime during the first billion and a half years of the planet's existence. I think my statement of 3 billion may have been a bit large, allow me to recant and insert, 3 million years worth of chemical interactions.
Modernmystic
5 / 5 (1) Aug 27, 2010
Eth, think of it this way. If Szostak's hypothesis is correct, the multitude of polymer arrangements that would be self replicating must have been utterly enormous, meaning multiple "starts" to life. These would have shared material, self reorganized, and through natural selection the slowest or lesat fit would have perished. There cannot have been a single "life start" molecule. It is logically dubious to suggest as such.


Wow, OK this has me thinking...thinking a lot. In fact I'm going to have to process this for a little bit because it just might have changed my mind on this whole issue.

I'm not prepared to continue my previous argument at this time as I think it may be irrelevant.

Suffice to say it had occurred to me that life may have "started" and failed multiple times by natural means, but something I hadn't considered is that subsequent "starts" might have benefited from previous "starts" in some way and thus incorporated otherwise "useless" material...
Modernmystic
not rated yet Aug 27, 2010
So then if true this solves a lot of my problems with she sheer amount of information and systems needed for a single operating cell to come into existence in a LINEAR manner.

If the process can be shown to be a PARALLEL system, well, at least for me that casts a WHOLE new light on the subject.
TabulaMentis
1 / 5 (1) Aug 28, 2010
@Modernmystic

So then if true this solves a lot of my problems with she sheer amount of information and systems needed for a single operating cell to come into existence in a LINEAR manner.

If the process can be shown to be a PARALLEL system, well, at least for me that casts a WHOLE new light on the subject.

I estimate that one (1) superstring (open or closed) contains one (1) byte of information.
Skeptic_Heretic
5 / 5 (2) Aug 29, 2010
So then if true this solves a lot of my problems with she sheer amount of information and systems needed for a single operating cell to come into existence in a LINEAR manner.

If the process can be shown to be a PARALLEL system, well, at least for me that casts a WHOLE new light on the subject.

Well that's almost a given. The first protocells very well could have been developed linearly, however due to how random the environment was when it came to energy, resources, etc it's a given that you'd wind up with a chemical soup of cells, cellular material, maybe even something as exotic as proto enzymes. Again, this is all speculation, but it is quite feasible seeing as natural affinity runs the show.
I estimate that one (1) superstring (open or closed) contains one (1) byte of information.
I estimate that you don't know what a byte is.
TabulaMentis
1 / 5 (1) Aug 29, 2010
@Skeptic Heretic

From the last I can remember, a byte contains 8 bits of information.

In an article by Scientific American called "Information in the Holographic Universe" a bit of information would be "One Planck Area" that is measured in units of entrophy.

Please see the following link:

http://www.scient...-2003-08

So, according to string theory, how many bits or bytes of information would one single cell contain?
Skeptic_Heretic
not rated yet Aug 29, 2010
In an article by Scientific American called "Information in the Holographic Universe" a bit of information would be "One Planck Area" that is measured in units of entrophy.

And how big is a superstring?
TabulaMentis
not rated yet Aug 29, 2010
In an article by Scientific American called "Information in the Holographic Universe" a bit of information would be "One Planck Area" that is measured in units of entrophy.

And how big is a superstring?

A superstring (string) is one Planck length, correct?
Skeptic_Heretic
not rated yet Aug 30, 2010
A superstring (string) is one Planck length, correct?
As far as the theory goes, yes. So how would a single, indivisible item, that carries no additional information occupy a datastream that consists of multiple divisible parts?
TabulaMentis
1 / 5 (2) Aug 30, 2010
A superstring (string) is one Planck length, correct?
As far as the theory goes, yes. So how would a single, indivisible item, that carries no additional information occupy a datastream that consists of multiple divisible parts?


I had to read the article again to make sure I was on the correct track.
My question should have been directed towards chemicals, not cells.
So the question should be stated this way: Based on string theory, how many bits or bytes of information does one chemical contain?
There should be research material on that question and was hoping somebody had the answer.

I consider strings (superstrings) to have one byte of information each.
Thermodynamic fluctuations have an evolutionary effect on strings.
I consider strings to be divisible into smaller parts in sub-Planck scales.
Strings grouped together can act like a computer.
In the future we may have string computers.
Skeptic_Heretic
5 / 5 (1) Aug 31, 2010
I consider strings to be divisible into smaller parts in sub-Planck scales.
Then you don't understand the theory. Not even a little bit. It is rather difficult to try to catch you up on it without knowing your background and in what manner to frame the explanation. PM if you'd like to be filled in.
dbrogioli
not rated yet Aug 31, 2010
I do not think that string theory matters when dealing with chemistry and evolution. Indeed, the calculations in my article can be done also with "symbols", so everything there is known. It comes out that there is evolution, and that evolution does not violate first and second principle of thermodynamics (it comes out that the external free energy source balances the increase of order, as described in the paper)

But I'm very interested in black smokers. As I know, the idea that a black smoker can "evolve" is only fantasy, and no details has been given up to now. But I can be wrong. If you know this theory, can you explain it in more detail? I mean: what exactly happens, what kind of chemicals are produced and so on?

References are welcome, but please make a summary of the theory for making a discussion!

Doriano Brogioli
Skeptic_Heretic
not rated yet Aug 31, 2010
As I know, the idea that a black smoker can "evolve" is only fantasy

It appears a great many people do not understand what a black smoker is. It is a volcano. It was the source for the energy and monomers, not the non-living item that "gave birth" to life.
References are welcome, but please make a summary of the theory for making a discussion!

Ok, yet again, the Szostak hypothesis for abiogenesis. Lipid vesicles, which are readily available just about everywhere in the world today and billions of years ago form the protocell membrane. They are permeable to monomers, which black smokers produce. Their eruptions are primarily hydrocarbons, evaporated clays, and anhydrites which when heated and cooled release charged monomers that will self polymerize under thermodynamic flux. The rest of the hypothesis is above in both text and video form. Enjoy.
Skeptic_Heretic
not rated yet Aug 31, 2010
Excuse my above post. Are you the Doriano Brogioli spopken of above or are you standing in as a lab assistant or otherwise? If you are the Doriano Brogioli, I'd really like to speak with you on this research. My apologies for the commentary above, I'm not used to seeing actual researchers on this site, typically it's more of the creationist ilk.
dbrogioli
5 / 5 (1) Aug 31, 2010
Yes, it's me... anyhow, I'm nobody, so please do not apologise.

So you follow Szostak idea. It's really interesting, I agree. In his theory, you need two things: some replicating molecule and the membranes. My research shows that membranes are not needed. Simply this. The same replicating molecules you need in Szostak theory are enough. Since it's simpler, it can be more fundamental (_can_ be, _may_ be: I do not state that _it_is).

Is a marginally stable chemical system likely on the earth? I do not know, and currently I have no evidence if such a system is "usual" or "unusual". Simply I do not know this. But I'm the first who speaks of marginal stability in chemistry, so no one else knows the answer. This question falls in the framework of "systems chemistry", but no one has still asked it.

I'm pleased to discuss with you in this forum; if you please, fill in the field "contact informations" with your e-mail in your profile!

DB
Skeptic_Heretic
not rated yet Aug 31, 2010
Is a marginally stable chemical system likely on the earth? I do not know, and currently I have no evidence if such a system is "usual" or "unusual".
Well an in lab simulation wouldn't be too difficult. The issue would be whether this is a quick chemical reaction or if it was over geologic timescales.

I'd assume the former would yield many reasonable chemical facsimilies, however, would any be self replicating on the short term. Quite worthy of a lab build in my opinion.
dbrogioli
not rated yet Aug 31, 2010
Not so simple. RNA replicases are only hypotetical molecules, and Szostak knows this. Joyce, and many others, tried to create replicases, with few, partial results, not enough for experiments. No general RNA replicase has been found up to now. Molecular replicating systems with DNA and proteins, like the ones found in living organisms, are working for sure, but they do not work alone, outside a living cell: no one is able to isolate the necessary molecules. I have some ideas for doing the work in laboratory, but I'm also looking for a totally different approach, like metabolism-first theories. I heard about black smokers described as metabolic entities, as themselves. If I can understand that, I can find a hint for some unusual reaction that is marginally stable. This is why I tried to stimulate the discussion about black smokers.
Any discussion on unusual theories is welcome!
DB

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