Nickel eating may be responsible for world's worst die-off.

[fuelair]

Re: http://today.msnbc.msn.com/id/50088...lamed-worlds-worst-extinction/?lite=obnetwork

Evidence/process supporting the idea that nickel using bacteria in Earth's oceans caused the death of much of the life in them in the latter part of the Permian -possibly from nickel-rich volcano output in Siberia. Recently presented. And not spotted on here - reported in last day or so........

 

[Dinwar]

My initial reaction is that I'm always dubious about any claim to have found The One True Cause of the Permo-Triassic Mass Extinction--I mean, for one thing there were actually two mass extinctions at the time (or pulses, depending on who you talk to).

The fact that they used genetic data also makes me twitchy. Not that the genetics is bad--it's just that if they're right we should see the types of things we see during the Late Cretaceous Ocean Anoxic Events. They should have present stratigraphic as well as genetic and igneous stratigraphic arguments.

I don't doubt that these bacteria contributed to some degree, but I've always been of the opinion that any single cause is inherently wrong when it comes to that event. There was too much going on, none of it good, and it all contributed to the worst time in Life's history.

 

[Skeptic Ginger]

My initial reaction is that I'm always dubious about any claim to have found The One True Cause...

Of course the article starts with:

may have worsened

Clearly not the straw you are arguing against.

 

[Dinwar]

Clearly not the straw you are arguing against.

Okay, I don't know what it is about me that upsets you so much, but it's getting a tad out of hand at this point.

Did you bother to read the rest of my post? I raised a specific flaw in their argument (well, a necessary component that they missed, anyway). Their argument is that these organisms removed most of the oxygen from the ocean, or at least a significant part of it. Okay, fair enough. Where are the rocks? We know what this type of thing looks like (I named the most famous example, but there are others). Do we see those formations in the appropriate areas at the appropriate time?

At this point, it's a mildly interesting hypothesis, nothing more. We know two things: there was nickle-rich volcanism at the end of the Permian, and nickle-eating bacteria evolved around that time. That's a pretty thin thread to hang even such a tentative conclusion as they drew on. In my opinion they're overstating how much of a role this mechanism played.

You want to counter my argument? Cool. I honestly hope you do. The place to start looking is marine sediment straddling the Permo-Triassic boundary. Look for black shales with paleofaunas dominated by a one or maybe two species, species of genera known to be resistant to oxygen deprivation. When you find those, I'll admit that I'm wrong. Until then, I'm sorry, but all it is is an interesting hypothesis. Plausible, but unsubstantiated. After all, it's entirely plausible that while the bacteria EVOLVED at that time, they didn't DIVERSIFY until well after it. They certainly wouldn't be the first species to do so, or even the only species to do so in conjunction with that event. And as I've said before, it's not enough to show that an idea is plausible--you have to show it actually happened.

 

[Skeptic Ginger]

Dinwar, your post starts off going on about about "one cause" when the article starts off saying "contributed". Then you say, no doubt contributed. So what is your point? They didn't demure enough? It's not that people are not reading your posts. Maybe you should take a look at how needlessly confrontational your posts are.

 

[Dinwar]

So what is your point?

I had a few. It's an occupational hazard.

First:

I raised a specific flaw in their argument (well, a necessary component that they missed, anyway). Their argument is that these organisms removed most of the oxygen from the ocean, or at least a significant part of it. Okay, fair enough. Where are the rocks?

This is a rather important point, in that without this data they can't prove their hypothesis.

Second:

That's a pretty thin thread to hang even such a tentative conclusion as they drew on.

This is my evaluation of their conclusion. It's plausible, but not well-supported.

Third, related to the second:

In my opinion they're overstating how much of a role this mechanism played.

I'm willing to accept that it happened. I'm actually fairly liberal in that regard. But when they're lacking such a major bit of data, this stuff is fairly low on the "What killed the Pelicasaurs?" list.

Finally, I did what every good scientist should do: I stated what data would prove me wrong. Specifically:

The place to start looking is marine sediment straddling the Permo-Triassic boundary. Look for black shales with paleofaunas dominated by a one or maybe two species, species of genera known to be resistant to oxygen deprivation. When you find those, I'll admit that I'm wrong.

I'm willing to accept that these bacteria contributed to the extinction--I see no real reason to reject the idea, at least, and as I said, it's plausible. But I have serious doubts about their methodology, in that they ignored a glaringly obvious test of this hypothesis, and I doubt it was a major factor (1% is still contributing, after all, and as I said, a LOT was going wrong at that point).

Paleoecology is complex stuff, and if you want me to boil my posts down to a single soundbite you'll be sorely disappointed. I'm going to continue to treat this type of thing as I always have. It's rather an obligation. So you get to put up with me actually processing this stuff and thinking about it more deeply than a one-line "point" can possibly allow. And we're not just talking paleoecology here--we're also talking about the role of genetics in paleontological research, which is an extremely complex field that honestly I'm still not sure where I stand on. So yeah, you're going to have to put up with seeing a bit of the process I'm going through working on this issue. Don't like it? Too bad. That's why I joined the forum, and that's how science is done. My advice is to ignore my posts if they offend you--I've got far too many reasons to actually give this type of thing serious thought to abandon it to satisfy some random person on the internet, and that's being generous when it comes to you and me.

ETA: Oh, and the rant about the "One True Cause" was more or less a general statement. Again, it's an occupational hazard. We all have our pet peeves, and the whole paradigm of finding even the main cause of the Permo-Triassic Mass Extinction is one of mine. I don't honestly CARE what was the most important--the emphasis on the relative importance of each mechanism is actually detrimental to the research, in that it draws attention away from the REAL question, which is the impacts on the biosphere, both during and after the mass extinction. The research in the OP is on the right track, but it's still too much in the paradigm of "We need to find The Cause!" for my taste. You may read it differently, and that's fine, but my experience with the mass extinction literature is that these types of research are still focused on the causes in isolation. If your experiences are different, cool. We should compare notes sometime. That's mine.

 

[fuelair]

Might I assume that some of the reason for causes in isolation might be that the scientists involved are each more interested in their specialty so consider it more likely that a cause based in their field is better for their field so they underlook at anything else and may overlook other factors/support for other factors.......

By the by, for me the article left plenty of indications there was no certainty on this, just they considered it a strong possibility and I recall they did say it needed more work!!(especially the Siberian volcanoes and gettingnickel from there to the oceans in quantity...

 

[Dinwar]

Might I assume that some of the reason for causes in isolation might be that the scientists involved are each more interested in their specialty so consider it more likely that a cause based in their field is better for their field so they underlook at anything else and may overlook other factors/support for other factors.......

The bane of my field....

 

[Wolfman]

Dinwar,

While Ginger may have been unnecessarily aggressive in her criticism, I do see her point. Here is your initial comment in response to the article:

My initial reaction is that I'm always dubious about any claim to have found The One True Cause of the Permo-Triassic Mass Extinction--I mean, for one thing there were actually two mass extinctions at the time (or pulses, depending on who you talk to).

The thing is, despite the title (which was obviously made by an editor, not the scientists in question), it was very clearly not even attempting to claim that they'd found "The One True Cause". These quotes more than adequately demonstrate this:

Nickel-eating bacteria may have worsened the world's worst mass die-off by producing huge amounts of methane

The study proposes that a series of steps caused the mass extinction, but that bacteria played a key role.

But while the findings are intriguing, many of the steps in this process are speculative

Your criticisms/questions about the study itself may be valid; but you launched your 'attack' with a statement that is a blatant straw man.

And just as faulty/poor methods may legitimately cause others to question a particular scientific theory, so too faulty/poor methods of argumentation on your part, in analyzing this article, may legitimately cause others to question your analysis.

 

[Skeptic Ginger]

Thank you Wolfman for your outside observation. I don't think frank = aggressive but I do realize frank quite often does = annoying. I'll try to be nicer.

 

[Dinwar]

Your criticisms/questions about the study itself may be valid; but you launched your 'attack' with a statement that is a blatant straw man.

Actually, it's not.

The issue is that this article wasn't published in a vacuum. It's part of a broader literature on the P/T mass extinction, and on mass extinctions in general. It's therefore perfectly justifiable to mention those trends, particularly when the article makes some egregious errors that exacerbate them. Failing to identify rocks deposited in anoxic environments is a serious failure, and the fact that they feel that they can argue that something contributed to the P/T mass extinction to any degree without bothering to check to see if it actually happened is an indication of just how fast and loose people play with the rules of evidence when it comes to mass extinction research. Furthermore, they failed utterly to provide any serious discussion for how much this contributed, which can easily lead to the impression that this is a vastly strongly causal mechanism than it actually is. I've seen analyses of how much one forcing mechanism contributes--they're extremely tedious and boring, but they're also extremely necessary to avoid falling into the very trap I've been criticized for mentioning.

This article is a baby-step away from the problem of finding The One True Cause, but it's still not a sufficient--or even GOOD--analysis of the relative importance of a particular forcing mechanism. The fact that the authors apparently felt it sufficient to say it's one of several factors simply isn't good enough, and the fact that people interested in science feel that it is is an indication of just how pervasive the problem I'm discussing is. No one would ever accept such a vague statement in, say, physics or economics or chemistry or biology, but in mass extinction research? Sure, that's good enough. One of several, right! Unfortunately, no, that's not enough. This is SCIENCE, not an opinion poll. We need to substantiate claims. Step one is proving that this forcing mechanism is actually real--which they've failed to do, but which I'm willing to accept as plausible. Step two is determining to what degree it occurred, and vague hand-waving simply is not good enough.

And just as faulty/poor methods may legitimately cause others to question a particular scientific theory, so too faulty/poor methods of argumentation on your part, in analyzing this article, may legitimately cause others to question your analysis.

Fair enough. If someone is ignorant of the mass extinction literature and wants to find an excuse to dismiss my arguments, I've handed them a reason on a silver platter. I'll go even further: What you're getting is one paleontologist's opinion. There are certainly others, and I've given those who hold other opinions even MORE reason to dismiss my arguments. That said, it's a pretty sad reason to dismiss them, and if someone's going to stoop to a fallacy in order to ignore what I have to say I seriously doubt anything I do will prevent them from finding an excuse. I'm also not going to ignore the broader context of the issue just to make Skeptic Ginger happy.

 

[Wolfman]

Actually, it's not.

The issue is that this article wasn't published in a vacuum. It's part of a broader literature on the P/T mass extinction, and on mass extinctions in general.

Yet you referred to no other articles, and ignored the fact that no where did this article claim that there was 'one true cause'. That's no more valid than if I, to argue with you, were to launch accusations based on things that other people had said, and attribute their claims to you. Essentially, your argument now seems to be, "Other people in other places have claimed that there is 'One True Cause', and despite the fact that this article makes no such claim, and without referring to any of those other claims, I will nevertheless begin my analysis by stating that I'm skeptical because of something that the scientists that did this study never said."

It's therefore perfectly justifiable to mention those trends, particularly when the article makes some egregious errors that exacerbate them

Yes, it is perfectly justifiable to mention those trends...except that you never did so. Not until you were called on your initial statement, and you then claimed that you weren't talking about the article in question, but rather referring to a 'larger body of work' that is never even alluded to in the initial post. Any rational reader would read your initial comment as referring directly to the article linked to in the OP.

This article is a baby-step away from the problem of finding The One True Cause

Wow...perhaps we're reading entirely different articles? Again, the statements in the article are full of tons of qualifiers that stress that this is only one part of many different processes. In fact, it explicitly states that there were a series of causes, and that they are simply proposing that this was one of those steps. How one can make the leap from "this may be one of many possible steps" to "they're virtually claiming to have found The One True Cause" is honestly beyond me.

Again, you raise valid points about the actual science behind this...which are worthy of discussion and consideration. It would have been much easier -- and much less distracting -- to simply say, "You are correct, the scientists in this study never made such a claim, and my statement to that effect was erroneous." But your arguments right now are seeking to justify a position that, I think to any reasonable reader, are nonsensical and logically inconsistent.

 

[Dinwar]

It would have been much easier -- and much less distracting --

There's enough blame there to go around. It also would have been far easier and less distracting for you and Skeptic Ginger to say "Wait, that bit didn't make sense. Could you explain it?" Instead you both took a belligerent stance. I may make a few statements that appear to be non-sequiters, but I have reasons for what I say. It was your assumption--yours and Skeptic Ginger's--as well as my omission that caused this. And frankly, I honestly didn't think that I had to mention that there was a broad literature on what is likely the second or third largest event in the history of life on Earth. It's my fault; most of the people I discuss this type of thing with are familiar with that literature (all geologists seem to be at least passingly familiar with it) so I don't need to explain it. I will try to avoid that in the future.

Now that we've cleared the air a bit, is there anything left to discuss regarding the article?

 

[Skeptic Ginger]

Oh for pity's sake, Dinwar. Do you want to have a discussion or do you want to whine people aren't nice to you?

You launched a straw man argument,

I'm always dubious about any claim to have found The One True Cause of the Permo-Triassic Mass Extinction

Just admit it and move on. Or don't, and move on anyway.

 

[Roboramma]

The fact that they used genetic data also makes me twitchy. Not that the genetics is bad--it's just that if they're right we should see the types of things we see during the Late Cretaceous Ocean Anoxic Events. They should have present stratigraphic as well as genetic and igneous stratigraphic arguments.

Interesting idea, that sounds like a good follow on study to help test the original idea, no?

 

[Dinwar]

Oh for pity's sake, Dinwar. Do you want to have a discussion or do you want to whine people aren't nice to you?

I don't care if you're nice or not. I admitted I didn't explain myself adequately; I refuse to admit to a crime I didn't commit.

If I promise to be a good boy and make sure I explain myself, will you cut out the attempts at character assassination? And I'm not just talking here--you have a nasty habit of doing this every time we're in the same thread.

Interesting idea, that sounds like a good follow on study to help test the original idea, no?

Definitely. Thing is, we can say to a certain extent that this didn't happen. I know of some P/T marine deposits in the Mojave, and none of them exhibit that sort of lithology--they're grey, but not black, and if there ARE monocultures they occur after the extinction (ie, they occur as a result of the extinction, not as a cause). I know it's not conclusive, but it certainly indicates that if there was a massive drop in ocean oxygen levels it wasn't global. I'm honestly not sure about the area around the volcanic traps in question, to be honest--it's not an area I've seen in person or researched in any depth. While a massive die-off in one area of the ocean CAN potentially cause (or contribute to) an ecosystem shut-down, it'd have to be exactly the right one at exactly the right time and exactly the right species. Upwelling zones account for a significant portion of marine primary production (that's where the nutrients are, after all) and shutting one down probably wouldn't have anything more than a regional impact.

In fact, the nature of upwelling zones indicates that these nickle-eating bacteria probably didn't contribute at all to the mass extinction. The ocean already has ecosystems that experience large-scale blooms, and in the ocean ecosystems are far more mobile than we tend to think of them on land. Black smoker ecosystems are constantly moving, for example (though the individual critters may or may not), and whale carcasses create temporary ecosystems. It's likely that any large-scale bloom in the ocean would attract exactly the same types of critters as any upwelling zone would (or would provide a suitable habitat for such critters, since they do tend to stray due to numerous processes). What probably would actually happen is that there'd be a large initial bloom, but it would be quickly exploited by marine critters. And it doesn't make sense for there to be a local anoxic event, for two reasons: First, to have a noticeable impact on a mass extinction it'd have to be a really, really big event. And second, the ocean's surface and thermohaline circulation would constantly be adding more oxygen to the water. The reason we had ocean anoxic events in the late Cretaceous was that the world warmed to the point where thermohaline circulation shut down.

The more I think about it, the more I think that while such a bloom probably wouldn't help things too much, it probably can't be said to contribute to the mass extinction either. Of course, we can (and probably will) debate the semantics of that statement now...

 

[JeanFromBNA]

Eh, I read between the lines of Dinwar's post when he wrote "one true cause." Seems like a "theory of the moment" is posited at predictable intervals that purports to explain a mass extinction, and there are a lot of them: http://www.cosmosmagazine.com/news/3164/mass-extinctions

If you qualify a theory (or demure, as Wolfman says) to death, what is the point in it?

As an amateur rock and fossil hound, I would rather hear Dinwar's feedback than an argument about language. But, I suppose Skeptic Ginger has a point in requiring Dinwar to be more precise in his language. He's more than capable of it, as his posts demonstrate.

 

[Skeptic Ginger]

... As an amateur rock and fossil hound, ...

I love rocks and fossils.

I have a lot of cool things. I found dinosaur fossils at a garage sale, verified by the university museum (Burke museum) to be hadrosaur bones, jaw and toe bones.

My son and I collected fossils at the town of Fossil in Oregon and in NE WA at the fossil site in Republic. We hunted meteorites near John Day, OR, that ended up being a very interesting trip. No meteorites, but a flat tire on a very long logging road venture and a dig on the property of a woman we met in the Chamber of Commerce made it all worthwhile.

I do own a number of meteorites I bought, all kinds of fossils, crystals, and a huge collection of different kinds of lava from Pele's tears to everything Mt St Helens threw at us, most of which I collected myself.

Then there are all my seashells.....

 

[jhunter1163]

Do let's try not to personalize our arguments, and to remain civil and polite.

Replying to this modbox in thread will be off topic  Posted By: jhunter1163

 

[Dinwar]

The more I think about this concept, the less I like it.

Mass extinctions are global in nature, crossing multiple bioms and impacting the very nature of the biosphere. (I prefer bioms to ecosystems, because the term ecosystem carries with it the implication that the system is relatively isolated, which simply isn't the case anywhere on Earth.) Something like the Chixilub Impact can do it, because it impacted pretty much (but not quite) all bioms on Earth. More subtle issues, like the shutdown of the Equatorial Current, can as well, because while those subtle forcing mechanisms impact other aspects of the ecosystem, such as storm paths and temperature gradients.

The issue is, I don't see this adaptation having a global impact. It certainly would have a local impact--but even there, I'm not sure it would be as profound as the authors speculate. The organisms that adapted to eating nickle obviously were already in the system, so there were already predators, and it's unlikely that this muation would make then inedible to those predators. And ecossytems aren't linear, meaning that we can't assume that just because a new resource was exploited the phytoplankton will therefore necessarily grow out of control. More likely the ecosystem already had feedback loops to prevent such a thing. An ecosystem can be top-down controlled (after a certain threshold, obviously), meaning that an increase in primary producers will be temporary, as the primary consumers and secondary consumers ballance it out. The thing with marine ecosystems is that unlike terrestrial systems the primary producers are reproducing widly fast as it is--that's why there's so much less primary producer mass per consumer mass unit in the oceans (very, very high turn-over). So the odds are that any exploitation of new resources would likely alter the local biom, but not substantially. (The difference between these nickle-eaters and, say, the Gulf of Mexico is that we're dumping a LOT of bioavailable nutrients into the Gulf, as well as over-fishing and doing other things. There's a difference between figuring out how to exploite one nutrient and having nutrients everyone can exploit injected into the system. For one thing, EVERYTHING is growing fast in the Gulf [some, admitedly, faster than others], while the idea discussed here is that just one thing would grow fast.)

This adaptation may have had a regional impact, meaning it impacted its biom, but it's misleading to say it contributed to the mass extinction--and this is where the authors committed an error common to the "Find the One True Cause" mentality. Not everything happening at that time contributed to the mass extinction. To say something contributed to the mass extinction is to say it contributed to those global forcing mechanisms. The world still continues during mass extinctions, and normal events such as originations and extinctions still occur. A regional event that doesn't extend beyond that biom can only be said to contribute to the mass extinction if we're willing to say that everything going on at the time contributed--an obvious fallacy. And since they haven't even proven the adaptation in question had significant regional impacts (they didn't discuss stratigraphy at all), it's extremely premature to discuss global impacts (another error common to the search for The One True Cause).