In Earth's hottest place, life has been found in strong acid | Hacker News Reader

In Earth's hottest place, life has been found in strong acid

bbc.com

146 pointshappy-go-lucky48 comments

"Pure acid" isn't quite right; it's an aqueous solution with a pH of zero. Zero isn't a special value. You can have negative pH (cf. http://pubs.acs.org/doi/pdf/10.1021/ed083p1465).

Yep. Iron Mountain Mine makes this place look pretty wimpy. pH -3.6, temps above 47C, boiling sulfur dioxide, etc, etc. Dunno if the pH -3.6 they sampled has anything living in it.

Well, based on this article it either was not tested for life or it didn't have it.

There are at least 5 extremophile species in the biofilms at Iron Mountain, according to the sequencing done at the JGI[0][1] in the early 2000s. They've continued[3] sequencing more samples form the mine ove3r the last decade, so I suspect the actual number of known species is far higher.

The effort to sequence their genomes was one of the first attempts to directly sequence an environmental sample without first culturing and separating the individual species (with environmental samples, the separation happens during assembly). This is important when there no known way to culture the bacteria/archaea under investigation.

[0] Disclosure: I provided software support for this project.

[1] http://jgi.doe.gov/news_2_2_04/

[2] http://genome.jgi.doe.gov/?core=genome&query=acid%20mine&sea...

This is one of those epic replies[1] that makes HN so neat. Wondering whether anything lives in Iron Mountain's hostile environment? No worries - the guy who provided software support for that project will elucidate the matter (with links to boot!).

[1] Perhaps the most epic of epic replies was Colin Percival's legendary snorter: https://news.ycombinator.com/item?id=35079

I don't think they actually found living microbes in the pH -3.4 wash, though.

Ferroplasma acidarmanus lives as a biofilm directly in the acid streams[1][2]. I'm not sure what the pH is in those specific areas, but it's very low (below 0). Compared to abiotic leeching of the iron pyrite in the mine, Ferroplasma greatly speeds up the reaction by using ferric iron as a catalyst:

    4Fe2+ + O2 + 4H+ → 4Fe3+ + 2H2O 
    FeS2 + 14Fe3+ + 8H2O → 15Fe2+ + 2SO42- + 16H+

The natural pyrite ore does not produce the extreme acid runoff. The problem starts when we mine out an area and oxygen is introduced, which is used to create Fe3+. This allows a much more efficient conversion of pyrite into a lot of acid.

This extremophile excretes pure sulfuric acid.

[1] https://microbewiki.kenyon.edu/index.php/File:Ferroplasma_1....

[2] https://digital.wwnorton.com/ebooks/epub/microbio4/OEBPS/ima...

Wow. Thanks, I wasn't aware of Ferroplasma acidarmanus or any other organism that excretes strong acids.

Thank you, we've updated the headline.

What would be the threshold for calling something "pure acid" (in the acid/base sense ;) )?

Well not in terms of pH, but there are several acids that can exist as a pure liquid, undiluted by water. Pure vinegar, undiluted by water, is called glacial acetic acid. It is something that can be bought from a chemical company. Because there is no water, there isn't really a pH. That doesn't mean it isn't incredibly hazardous, though.

>Because there is no water, there isn't really a pH.

Could you elaborate? Wikipedia doesn't seem to suggest water is necessary (it talks about moles per unit volume) but I may be misunderstanding something.

I'd say you have moles per unit volume of H3O+ ions. These form as the combination of H+ ions (readily present in copious amounts of acid) and crucially, H2O molecules.

The definition of pH is pretty much a measure of the proton concentration of things dissolved in water. You can look at similar measures in non aqueous solution but then it doesn't fit the definition properly.

On the other hand, pure oleic acid isn't especially toxic. It's a major component of Lorenzos oil.

Nuthin but protons?

There are more inhospitable places on earth for life than this and they are much less hot and acidic. For instance, in the Atacama desert, the driest parts of which have never recorded rain and look like a spitting image of Mars, NASA scientists looked for bacteria and found absolutely nothing[1]. The researchers even said: "The Atacama is the only place on Earth that I've taken soil samples to grow microorganisms back at the lab and nothing whatsoever grew."

1. https://www.nasa.gov/centers/ames/news/releases/2003/03_87AR...

Just because nothing could be cultured doesn't mean there was nothing there - some organisms can't be easily cultured. The real test would be to run the soil through a DNA sequencer.

What a pleasure it is to have this forum where people can zero in on loose language and logical fallacies. I do not mean this sarcastically in the least.

It seems to be getting worse as well. Not just here, but everywhere online.

If you fell into 100C hot and extremely acidic water it would be a big problem – Barbara Cavalazzi, University of Bologna

Food for thought.

Semi-serious question: In the unfortunate circumstance that you find yourself immersed in 100C water with a PH of 0, which condition would be the one that has the higher likelihood that it would kill you first?

I would want to kill myself over not knowing if my underwear were clean should I survive and had to be medically treated.

It depends on which ion(s) in particular was in the solution.

If it was something relatively pleasant, like the referenced sulfuric, carbonic, and chloric acids, the heat would almost certainly be more of a problem in the short term. In the long term you'd be missing significant portions of your anatomy due to the dehydration of your skin by the sulfuric acid, but that could certainly wait.

On the other hand, if it were (for example) hydrofluoric acid, you'd have nerve transmission issues and your heart would stop well before you'd be cooked thoroughly.

Here's an interesting video by Nile Red showing that it's not the acid, per se, that is especially dangerous: https://www.youtube.com/watch?v=XeVZQoJ5FdE

Now, when you heat things, all the reactions speed up. So it'd certainly be only a few seconds before things would get very drastic.

And with hot fuming nitric acid, you'd go up in flames.

The temperature. It takes far less long to boil alive than to dissolve.

A man fell into the boiling lake on Dominica and was cooked to death in seconds so I'm going with that. But acid is made stronger by heat so it's not necessarily separable.

"Pure acid" is a pretty meaningless description. Water is a weak acid (and also a weak base) so in a sense ordinary water could be described as "pure acid".

Is 45C such a big deal? Chennai (India) routinely gets such temperatures and humidity is like 95%. Look no further for a place teeming with life ;)

http://timesofindia.indiatimes.com/city/chennai/At-42-5C-mer... http://timesofindia.indiatimes.com/city/chennai/Chennai-swel...

If by routine you mean once in the last 50 years. This place just happened to hit 10° hotter than that during the random interval researchers were there to measure it.

The article suggests a considerable degree of physical danger in walking around to collect hot pool water samples. This would be a good use case for drone-based collection, at least for surface samples.

I was thinking the same thing, but, I would worry that the drones might not work well in that atmosphere. Very hot air filled with toxic gasses would definitely require better than average "weather" sealing. Looks like the atmosphere is made up of Hydrogen Sulphide and Chlorine, and would require getting awfully close to 0ph boiling water.

I'd hate to see what happened if the drone failed and you dropped a mix of plastic, metal, and a high-density lithium battery into it. I suspect it isn't worth the environmental risk.

Really good point. I hadn't thought about what volcanic-sourced water vapor would do to just about everything a drone is made of. Not pretty, I'm sure.

Was expecting this to be another article about yet another environment in which tardigrades have been discovered to survive http://www.nytimes.com/2008/09/16/science/space/16obvacu.htm...

In case you, like me, doubted the use of the word "pure" in the headline:

> The team found life in a pool where the acidity was measured as zero pH.

Cool!

EDIT: Nevermind, someone with a better understanding of pH chimed in: https://news.ycombinator.com/item?id=14951312

same, and whoah.

How much in common do extremophiles have with even simple garden variety microbes? Do they share any proteins?

Isn't one of these lakes the same as the one that Periodic Videos talked about recently (https://www.youtube.com/watch?v=Uaj722cg9Gk)?

I've always wondered how the bacteria in these highly acid/high temperature pools ever got started.

So is this 0.2 pH more corrosive/stronger than sulfuric acid or not?

It is stronger

Well, pH refers to the concentration of protons in water solvent. Since pure sulfuric acid has no water (excluding that which is in equilibrium with sulfur trioxide), pH isn't really well defined for it. A better definition of acidity which does not have this problem is the Hammett acidity function. Sulfuric acid on this scale has an acidity of -12. (Note that this acidity score is not fully comparable to pH. However, with a difference so massive (a factor of one trillion times more acidic), this subtle difference ceases to be relevant.)

If you're asking about corrosivity, sulfuric acid gets its reputation because its also strongly dehydrating. Thus, it does wonderful things like rip the water out of your skin or char paper. I would hazard a guess that the water they've found in the paper does neither of those things.

I thought pH = -log[H+]? where [H+] is the molarity of the hydrogen ion? That doesn't involve water in the definition... what is the definition you're referring to?

Edit regarding your reply asserting water is necessary (I can't reply now due to throttling):

What about all the acid/base reactions that don't involve water? You can't ascribe any pH to either of them in that case?

[H+] is shorthand for [H3O+]. H3O+ (hydronium ion) requires water plus a hydrogen ion from the acid. There aren't actually free H+ ions floating around. They are all attached to water molecules.

That's the definition of p[H]. The definition of the "real" pH is the -log of H+ activity. H+ activity is the concentration of H+ * a coefficient. In practice, the coefficient is considered to be 1, however there are cases (such as extreme concentrations) when that approximation isn't valid.

Ah yes I had forgotten about activity. :)

From: https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/s/Sulfur...

* 98%, concentrated (pH about 0.1)

[This 98% is what you usually buy in a bottle to use in a chemistry laboratory.]

* 33.5%, battery acid (used in lead-acid batteries) (pH 0.5)

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