Proliferation of hydrocarbon-degrading microbes at the bottom of Mariana Trench | Hacker News Reader

Proliferation of hydrocarbon-degrading microbes at the bottom of Mariana Trench

microbiomejournal.biomedcentral.com

91 pointsokket33 comments

Are there practical uses for "hydrocarbon-degrading" microbes? Like cleaning up oil spills? Or eating the plastic that the oceans are filling up with?

Oil is constantly spilling into the ocean at small rates, and has been for eons. Without these bacteria it would build up forever, fortunately as long as the rate of introduction is not excessively high it gets metabolized.

Could you inject these microbes directly into oil wells, perhaps in drilling fluid, to prevent extraction of said oil?

The microbes are one step ahead of you. Apparently, "Accumulations of biodegraded oils are abundant and have been a problem for petroleum production since the beginning of commercial oil production." [0]

[0]http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517...

The challenge is now how to ramp this up if we’re not willing to leave oil in the ground voluntarily.

According to this[1] paper, the bacteria are already essentially everywhere and the process is limited by the presence of water.

[1] https://www.sciencedirect.com/science/article/pii/S187167841...

> Or eating the plastic that the oceans are filling up with?

Not yes, so far as anyone knows. But they, without a doubt, eventually will. Plastic has lots of energy in it, and is made of the exact same atoms life is made from.

> According to a group of biologists in Japan, the newfound species — named Ideonella sakaiensis 201-F6 — breaks down the plastic by using two enzymes to hydrolyze poly[ethylene terephthalate], or PET.

http://www.sci-news.com/biology/ideonella-sakaiensis-bacteri...

Also, see list of citing articles to this old review:

https://www.sciencedirect.com/science/article/pii/S073497500...

I suspect that plastic degrading microbes would result in more CO2 being released into the atmosphere. Unless there is some sort of carbon sink in the process, I believe carbon in plastic form is less damaging than CO2.

Fish and most humans are full of microplastics. We still don't know which health effects this will have on us, probably not good ones.

CO2 on the other hand isn't, if the concentration isn't too high is non-toxic. However the climate impact could be problematic.

"...three Alcanivorax species that were isolated from 10,400 m water supplemented with hexadecane were able to efficiently degrade n-alkanes under conditions simulating the deep sea, as did a reference Oleibacter strain cultured at atmospheric pressure."

Interestingly the "Hadal zone" being referenced in the article is based on the greek myth "Hades":

https://en.wikipedia.org/wiki/Hadal_zone

> The cumulative area occupied by the 46 individual hadal habitats worldwide is less than 0.25 percent of the world's seafloor

Would bacteria from that region tolerate normal atmospheric pressures?

I would speculate that they could. Pressure should be a lot less significant at the bacterial scale. Sperm whales can survive at the surface and deep ocean, and are fairly closely evolutionary related to us so the pressure resistance is probably coming from large scale morphological changes and not structural differences at the cellular level.

Is pressure relevant to a molecular membrane? I mean: it is not a sheet of metal ee are talking about but a layer of proteins...

Pressure does affect chemical equilibria, the canonical example is that above a certain pressure calcium carbonate actually becomes soluble. That's why you don't find hard-shelled organisms at the bottom of the ocean. Kinetics are affected, too, because the energy of transition states varies with the pressure. That said, they grew the bacteria from their samples at ambient pressure without problems.

Mmh, thanks for the info.

A layer of lipid, really, although there are certainly proteins in the membrane.

I've no idea about pressure adaptation, but a quick google gives this (open) paper that looks useful:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487899/

From the abstract:

>Maintenance of the functionality of the membrane during changing environmental conditions relies on the cell’s potential to rapidly adjust the lipid composition of its membrane

So in other words, bacteria at depth seem to use a particular mix of lipids in their membrane.

Since things have to cross the membrane it makes sense to me that it has to be stiffer or less so at different pressures.

Thanks!

The internal part is at the same pressure, so they probably cancel. I'm more worried about the level of oxygen disolved in the water, but IANAB.

I’d guess pressure due to ionic concentrations is more relevant

were able to efficiently degrade n-alkanes under conditions simulating the deep sea, as did a reference Oleibacter strain cultured at atmospheric pressure.

So yes, it seems at least some of them can.

If they don't have compressible gasses in them, I don't see why they shouldn't. There would be gas dissolved in the water inside them that would have to be dealt with I suppose. But the water itself is damn near in-compressible. The volume of water inside them down there would be the same up here.

Decompression explosions like the Byford Dolphin accident happen when compressible gasses are involved. Compressed gasses are like springs that store huge amounts of energy. This is why pneumatics have very energetic failure modes while hydraulics are relatively safe (injection wounds and oil fires notwithstanding)

Bi-layer membranes, such as cell membranes and walls of organelles, are squeezed together, so may be thinner and stiffer. It would not be surprising if some species could not adapt to lower pressure, just as we are ill-adapted to vacuum.

I'm not a biologist but I believe the pressures should be equalized inside and out.

The problem humans have with pressure is mostly related to humans being filled with gasses. Contrary to popular belief, humans don't explode when exposed to a vacuum. The fleshy bits hold together just fine, but trying to hold your breath would rupture your lungs, forcing you to exhale, which causes you to asphyxiate.

There have been a few cases where isolated body parts were depressurized, which caused painful swelling but no permanent damage. I think it's likely that swelling occurred because the rest of the body was still pressurized, in effect squeezing the body out into the unpressurized portion of the suit. This is similar to one of the failure modes of old style diving bell helmets where depressurization of the helmet could force a diver's body into the helmet.

NASA/USAF put (whole) dogs in a vacuum: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/196600...

The paper is pretty short read.

They reference another study that was conducted with primates, but I'm not able to find it at this moment.

Here's the part about primates: "After decompression to approximately 1 mm. Hg absolute, the squirrel monkeys appeared to lose consciousness sooner than the dogs. As with dogs, they had both tonic and clonic seizures shortly after unconsciousness and this progressed to flaccid paralysis. Subcutaneous emphysema and swelling occurred, but was not as marked. During and following recompression to ground level, the monkeys recovered similarly but seemed to exhibit staggering and disorientation for a longer period. Two monkeys died as a result of these low pressure exposures, while no dogs died from exposures that were less than 120 seconds. [...]"

It's under "Observations made on small primates" on page 7.

NASA once accidentally depressurized a man while testing space suits in a vacuum chamber. He lost consciousness in less than 15 seconds, but fully recovered after depressurization. He reported feeling his saliva boil which is... exciting.

https://www.youtube.com/watch?v=KO8L9tKR4CY

http://www.spacesafetymagazine.com/aerospace-engineering/spa...

During Project Excelsior, Joseph Kittinger's right hand was depressurized at 100,000 feet and swelled up, but he was ultimately unharmed.

https://en.wikipedia.org/wiki/Project_Excelsior#Test_jumps

It is meaningless to conclude anything from "equalized pressure" beyond that nothing is changing in size.

To conclude from animals recovering from pressure changes that the high or low pressure is harmless is equally absurd. Leave them at the given pressure and they die.

Humans under high pressure, exposed to nitrogen, or even a normal amount of oxygen, soon die. Not from gases exploding, but from different physical and chemical behavior of substances under high pressure. Under high enough pressure, at normal temperature, gases become liquid.

A cell membrane under pressure, after pressure has equalized, does experience the same pressure on both sides. But because cell membranes have two or more layers, the stuff in the middle gets squeezed. Is the pressure in the middle equal to that on either side? Of course, otherwise it would continue getting thinner. Does that have anything to do with the topic? Nothing whatsoever.

Eight orders of magnitude pressure difference, not likely in one generation.

8 orders is crazy!

Though to be honest I think unicellular organisms take pressure differences much more easily than multicellular orgs.

well it's 1000 times which in math speak is often described as three orders as in 10, 100, 1000

yep that is wrong.

mistook 1 *10^8 Pa as, times "pressure atmosphere".

it is only three orders of magnitude greater psi

Three orders of magnitude qualifies as "a hell of a lot" in any reasonable estimate.

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