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Topic: New paper: archaea, nickel, and the Permian-Triassic extinction (Read 306 times) previous topic - next topic

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  • osmanthus
  • Administrator
  • Fingerer of piglets
New paper: archaea, nickel, and the Permian-Triassic extinction
Pop-sci: Death metal: how nickel played a role in the world's worst mass extinction

Quote
Scientists previously thought that nickel released into the atmosphere could explain the glut of marine nickel 250 million years ago. But how could nickel get into the air? This is where our work comes in.

Volcanoes and champagne

Let's take a step back: how do nickel ore deposits form from molten rock (or magma)? Magma rich in nickel needs to come all the way to shallow depths beneath volcanoes, where it becomes enriched with sulfur, and forms liquid sulfide droplets.

The volcanic plumbing system then acts as a smelter. The sulfide liquid droplets scrub the nickel out of the magma. Ore deposits form when the sulphide droplets finally sink and accumulate at the bottom of the magma under the volcanoes. The nickel never reaches the surface - making it hard to explain how so much nickel got into the atmosphere.

A previous paper by our group showed that when liquid sulfide droplets and gas bubbles form together in the same magma they have a strong tendency to stick together. So, if there is a gas present, sulfide droplets can rise to the top of the magma chambers, taking the metals with them.
Actual article has links to other stuff, including the paper itself (not open access):

Role of degassing of the Noril'sk nickel deposits in the Permian-Triassic mass extinction event

Quote from: Abstract
The largest mass extinction event in Earth's history marks the boundary between the Permian and Triassic Periods at circa 252 Ma and has been linked with the eruption of the basaltic Siberian Traps large igneous province (SLIP).

One of the kill mechanisms that has been suggested is a biogenic methane burst triggered by the release of vast amounts of nickel into the atmosphere. A proposed Ni source lies within the huge Noril'sk nickel ore deposits, which formed in magmatic conduits widely believed to have fed the eruption of the SLIP basalts.

However, nickel is a nonvolatile element, assumed to be largely sequestered at depth in dense sulfide liquids that formed the orebodies, preventing its release into the atmosphere and oceans. Flotation of sulfide liquid droplets by surface attachment to gas bubbles has been suggested as a mechanism to overcome this problem and allow introduction of Ni into the atmosphere during eruption of the SLIP lavas.

Here we use 2D and 3D X-ray imagery on Noril'sk nickel sulfide, combined with simple thermodynamic models, to show that the Noril'sk ores were degassing while they were forming. Consequent "bubble riding" by sulfide droplets, followed by degassing of the shallow, sulfide-saturated, and exceptionally volatile and Cl-rich SLIP lavas, permitted a massive release of nickel-rich volcanic gas and subsequent global dispersal of nickel released from this gas as aerosol particles.
Truth is out of style

Re: New paper: archaea, nickel, and the Permian-Triassic extinction
Reply #1
Pop-sci: Death metal: how nickel played a role in the world's worst mass extinction

Quote
Scientists previously thought that nickel released into the atmosphere could explain the glut of marine nickel 250 million years ago. But how could nickel get into the air? This is where our work comes in.

Volcanoes and champagne

Let's take a step back: how do nickel ore deposits form from molten rock (or magma)? Magma rich in nickel needs to come all the way to shallow depths beneath volcanoes, where it becomes enriched with sulfur, and forms liquid sulfide droplets.

The volcanic plumbing system then acts as a smelter. The sulfide liquid droplets scrub the nickel out of the magma. Ore deposits form when the sulphide droplets finally sink and accumulate at the bottom of the magma under the volcanoes. The nickel never reaches the surface - making it hard to explain how so much nickel got into the atmosphere.

A previous paper by our group showed that when liquid sulfide droplets and gas bubbles form together in the same magma they have a strong tendency to stick together. So, if there is a gas present, sulfide droplets can rise to the top of the magma chambers, taking the metals with them.
Actual article has links to other stuff, including the paper itself (not open access):

Role of degassing of the Noril'sk nickel deposits in the Permian-Triassic mass extinction event

Quote from: Abstract
The largest mass extinction event in Earth's history marks the boundary between the Permian and Triassic Periods at circa 252 Ma and has been linked with the eruption of the basaltic Siberian Traps large igneous province (SLIP).

One of the kill mechanisms that has been suggested is a biogenic methane burst triggered by the release of vast amounts of nickel into the atmosphere. A proposed Ni source lies within the huge Noril'sk nickel ore deposits, which formed in magmatic conduits widely believed to have fed the eruption of the SLIP basalts.

However, nickel is a nonvolatile element, assumed to be largely sequestered at depth in dense sulfide liquids that formed the orebodies, preventing its release into the atmosphere and oceans. Flotation of sulfide liquid droplets by surface attachment to gas bubbles has been suggested as a mechanism to overcome this problem and allow introduction of Ni into the atmosphere during eruption of the SLIP lavas.

Here we use 2D and 3D X-ray imagery on Noril'sk nickel sulfide, combined with simple thermodynamic models, to show that the Noril'sk ores were degassing while they were forming. Consequent "bubble riding" by sulfide droplets, followed by degassing of the shallow, sulfide-saturated, and exceptionally volatile and Cl-rich SLIP lavas, permitted a massive release of nickel-rich volcanic gas and subsequent global dispersal of nickel released from this gas as aerosol particles.

Old Nick is evul??
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Re: New paper: archaea, nickel, and the Permian-Triassic extinction
Reply #2
really not convinced by this study.

Re: New paper: archaea, nickel, and the Permian-Triassic extinction
Reply #3
really not convinced by this study.
Why not? (I don't know enough about the chemistry to have an opinion either way.

Also: in b4 'the fludde diddit!'

Re: New paper: archaea, nickel, and the Permian-Triassic extinction
Reply #4
because every few months we have a new "this chemical released in the siberian traps must have been responsible for the P-Tr extinction, obviously the earth was a toxic sludgepile" study and they're all dumb as nuts.

The P-Tr is probably less severe than previously thought based on new stratigraphic work, and has clear direct selectivity on organisms, both within communities and between communities. There's a ton of work that's come out on this and it really does seem that there are shifts in life history strategies both within and between communities across the P-Tr, which is consistent with the climatic hypothesis but not really consistent at all with a toxicity hypothesis. I'd also assume that toxicity would have direct effects on overall developmental health of organisms and we'd expect to see a higher rate of deformity in the P-Tr transitional beds, and we don't see that either. In fact, we see huge diversification of amphibians and bony fishes across the P-Tr boundary, which is inconsistent with the tox hypothesis because those are taxa that are consistently susceptible to toxicity in modern ecosystems due to a combination of high skin permeability and the nature of egg laying and embryogenesis in these organisms.

In other words, the issue is that all these environmental toxicity hypotheses might be perfectly fine chemistry but they don't actually explain the extinction they're claiming to explain. They are not at all consistent with the biological signal.

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: New paper: archaea, nickel, and the Permian-Triassic extinction
Reply #5
But it's not about environmental toxicity at all. Beats me where you got that idea.

It's about methanogenesis by archaea, who relied on a supply of nickel for their metabolism. IOW, it's more about nutrient supply, or at least catalyst supply, than it is about environmental toxicity. They're not suggesting every fucking critter on the planet came down with heavy metal poisoning. They're suggesting that foaming lava may be a mechanism by which large numbers of archaea ultimately got stuff they wanted to eat.
Truth is out of style

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: New paper: archaea, nickel, and the Permian-Triassic extinction
Reply #6
There's a ton of work that's come out on this and it really does seem that there are shifts in life history strategies both within and between communities across the P-Tr, which is consistent with the climatic hypothesis but not really consistent at all with a toxicity hypothesis.
Great. Then you'll be pleased to know that this paper is supporting the climactic hypothesis[1], and is not intended to provide any support whatsoever for a toxicity hypothesis.
Specifically, increased methanogenesis by archaea, leading to increased global temperature.
Truth is out of style