
In Earth's hottest place, life has been found in strong acid - happy-go-lucky
http://www.bbc.com/future/story/20170803-in-earths-hottest-place-life-has-been-found-in-pure-acid
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knoepfle
"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](http://pubs.acs.org/doi/pdf/10.1021/ed083p1465)).

~~~
dekhn
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.

~~~
pdkl95
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/](http://jgi.doe.gov/news_2_2_04/)

[2]
[http://genome.jgi.doe.gov/?core=genome&query=acid%20mine&sea...](http://genome.jgi.doe.gov/?core=genome&query=acid%20mine&searchIn=Anything&searchType=Keyword&showAll=false&externallySequenced=true&sortBy=displayNameStr&showRestricted=true&showOnlyPublished=false&showSuperseded=true&sortOrder=asc&rawQuery=false&showFungalOnly=false&activateHighlights=false&programName=all&programYear=all&superkingdom=--any--&scientificProgram=--any--&productCategory=--any--&start=0&rows=50)

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

~~~
pdkl95
_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....](https://microbewiki.kenyon.edu/index.php/File:Ferroplasma_1.JPG)

[2]
[https://digital.wwnorton.com/ebooks/epub/microbio4/OEBPS/ima...](https://digital.wwnorton.com/ebooks/epub/microbio4/OEBPS/images/sfmb4e_1940.jpg)

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

------
narrator
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...](https://www.nasa.gov/centers/ames/news/releases/2003/03_87AR.html)

~~~
vbuwivbiu
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.

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SubiculumCode
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.

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

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

~~~
Mtinie
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?

~~~
jaggederest
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](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.

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

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slaveofallah93
"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".

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the_common_man
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/At-42-5C-mercury-
touches-last-years-highest-in-Chennai/articleshow/20269142.cms)
[http://timesofindia.indiatimes.com/city/chennai/Chennai-
swel...](http://timesofindia.indiatimes.com/city/chennai/Chennai-swelters-as-
real-feel-temperature-touches-45C/articleshow/34394474.cms)

~~~
dasil003
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.

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ridgeguy
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.

~~~
abakker
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.

~~~
ridgeguy
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.

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danso
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...](http://www.nytimes.com/2008/09/16/science/space/16obvacu.html)

------
Infernal
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](https://news.ycombinator.com/item?id=14951312)

~~~
SubiculumCode
same, and whoah.

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

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

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

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21
So is this 0.2 pH more corrosive/stronger than sulfuric acid or not?

~~~
zzazzdsa
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.

~~~
wfunction
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?

~~~
Pulcinella
[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.

~~~
yogipatel
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.

~~~
Pulcinella
Ah yes I had forgotten about activity. :)

