[HN Gopher] Even the worst mass extinction had its oases
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Even the worst mass extinction had its oases
Author : Hooke
Score : 78 points
Date : 2025-03-19 05:21 UTC (2 days ago)
(HTM) web link (arstechnica.com)
(TXT) w3m dump (arstechnica.com)
| ZunarJ5 wrote:
| The technical term, as mentioned in the article, is refugium:
| https://en.wikipedia.org/wiki/Refugium_(population_biology).
| Using the term oases is mildly irking, haha.
|
| Though I have extreme reservations about the current state of
| conservation science (on questions of nature and it's own
| agency), this is precisely why conservation is extremely
| important. We must protect what we have left to let nature adjust
| to what we become and want to be:
| https://eos.org/features/critical-zone-science-comes-of-age
|
| Source: I work in palaeoecology.
| jordanb wrote:
| A while back I read a book called _Extinction_ by Douglas H.
| Erwin. It was a history of the end-Permian event.
|
| There were a few interesting takeaways:
|
| 1) When people started realizing that these dieoffs happened
| there was a belief that there was probably a common cause like
| impactors, but end-Permian almost certainly wasn't an impactor
| like K-T was. There are several things that can kick-off an
| extinction
|
| 2) One thing that is true is that the extinctions seem to follow
| the same script. Lots of things can kick them off, but once they
| start going it's a rock rolling down a hill very quicky. End-
| Permian seems tied to the Siberian Traps basaltic eruption, but
| that eruption had been going for thousands of years before the
| dieoff started.
|
| K-T definitely happened within years following the impact, but
| end-Permian seemed to be a "first gradually, then suddenly" as
| pollution from the traps put more and more stress on the
| biosphere until suddenly...
|
| 3) He posed the question: are we currently in an great
| extinction. He wrote that we are not because they look at the
| fossil record of really fundamental creatures (stuff like krill
| in the ocean) upon which the whole biosphere relies, and we're
| not yet seeing them collapse. But once such a collapse begins, it
| will be something that is unstoppable.
|
| 4) He thought that there is a big gap in our knowledge of
| survival and recovery. Why have none of these massive events just
| turned the planet into a dead world? How does life come back?
| Historically the early-Triassic was seen as a really boring thing
| to study because there's not much evidence of life in it, but
| understanding how life soldiers on through these "wasteland
| Earth" episodes is potentially a fertile ground for research.
| ashoeafoot wrote:
| Some total niche bacteria doing millenias of groundwork.
| mapt wrote:
| * End-Permian is associated with the Siberian Traps, but those
| in turn are associated with the Wilkes Land Crater impactor,
| which is antipodal to that event and may have seen antipodal
| seismic focusing.
|
| * "Going on for thousands of years" - Dating the End-Permian
| has confidence intervals on the order of 30,000 years.
|
| * Small size and diverse ecology almost guarantees survival of
| life. There is life basically everywhere we look, down to
| extremophiles living very slow lives in a random cubic meter of
| "solid rock" two kilometers deep. We have even evolved several
| chemical alternatives to photosynthesis as a primary energy
| source. Mammals and small birds deep in a cave somewhere appear
| to have been some of the only land vertebrates to survive K-T,
| and radiated out from there. Evolution does the rest.
| jordanb wrote:
| > associated with the Wilkes Land Crater impactor
|
| Erwin discusses that theory but doesn't agree with it.
|
| In any case, 1) there are other mass dyings that are
| definately not impactors like the oxygen crisis. 2) there are
| other basaltic eruptions on the scale of the siberian traps
| (like CAMP) where the cause is known and not an impactor.
| blueflow wrote:
| P-T is likely not due to the Wilkes Land crater, which would
| be 2.5x the size of the K-Pg impact and would have left an
| comparable amount (or more) of iridium in the boundary
| sediments. There are elevated iridium levels in the P-T
| boundaries, but only sporadically.
| jujube3 wrote:
| > End-Permian seems tied to the Siberian Traps basaltic
| eruption, > but that eruption had been going for
| thousands of years before > the dieoff started.
|
| The eruptions probably hadn't been "going for thousands of
| years." We can't "see" time periods as small as a few thousands
| years from a vantage point of 250 million years later.
|
| Biologists like to proclaim that things are gradual when
| they're really more likely sudden. This often reflects
| mathematical ignorance. For example, if the last specimin of a
| certain rare fossil is found in a stratum slightly older than
| the K-T stratum, does that mean it went extinct earlier than
| the K-T event? Probably not; it just means the fossil is rare
| so your sampling error is larger.
| jordanb wrote:
| I'm massively summarizing the book but he talks a lot about
| the history of the timeline for end-Permian.
|
| At the time of writing of the book it was "less than 60k
| years" which seems like a long time, but when the extinction
| was first discovered it was believed to be a very gradual
| change taking place over 10 million years, turns out that it
| was believed that end-Permian and end-Guadalupian were the
| same event.
|
| As isotope dating has gotten more and more accurate, the
| length of time for end-Permian has gotten shorter and
| shorter. There's also other evidence that it was a very
| sudden event, evidence of fungal explosions for instance
| during the event suggesting massive amounts of decomposition.
|
| In any case, as I said the P-T took "no more than 60k years"
| but the Siberian traps were erupting for at least 120k years
| before, so there's at least 60k years unaccounted for between
| the start of the eruptions and the start of the extinction.
| js8 wrote:
| > He thought that there is a big gap in our knowledge of
| survival and recovery.
|
| Well, you don't want to know how far you can safely bend over
| the cliff before falling down. I think attempts to gain such
| knowledge in a practical way should be explicitly banned.
| jordanb wrote:
| His point was people should be more interested in the early
| Triassic.
| Qem wrote:
| >but end-Permian seemed to be a "first gradually, then
| suddenly" as pollution from the traps put more and more stress
| on the biosphere until suddenly...
|
| AKA the Seneca effect. See
| https://terebess.hu/keletkultinfo/seneca.pdf
| pfdietz wrote:
| I wonder if the P-T extinction was due not just to CO2 release
| from the volcanism (and the other bad effects from the magma
| intruding into the largest/oldest sedimentary basin in the
| world), but also due to authigenic clay formation in the ocean.
|
| When clay forms in the ocean, it pulls calcium out of seawater.
| Calcium is normally balanced by two bicarbonate ions, so its
| removal causes the bicarbonate to shift back to carbonic
| acid/CO2. The ocean acidifies and CO2 is released. This has
| been called "anti-weathering", since it's the opposite of the
| normal process that draws down CO2 by weathering of silicates.
|
| Sufficient injection of silicic acid and aluminum into the
| ocean could accelerate this process.
| morkalork wrote:
| I love the retro cgi article image, it gives me fuzzy nostalgic
| feelings for the 90s era of Myst, Reboot and The Mind's Eye.
| mfro wrote:
| The artist appears to be committed to the bit:
|
| https://fineartamerica.com/profiles/corey-ford?tab=artwork
| yobert wrote:
| Yeah it reminds me of POV-Ray, in a fun way!
| david422 wrote:
| Ok I went looking through those paintings. That is an ... odd
| account. AI? Not AI? Looks like mostly just screenshots from
| some 90's computer games.
| PaulKeeble wrote:
| Life will survive what humans have done. When our numbers are
| dropped substantially by many C's of climate change a lot of
| wildlife will be able to repopulate and survive although much
| wont because it will be too hot for correls and many other
| species. We are taking many species with us every year at the
| moment, its a mass extinction event, but even if we fire all our
| nuclear weapons we wont wipe out all the land animals and fauna.
| Its not just humans being put in jeopardy by what we are doing
| but it ought to be enough to get off this maybe extinction path.
|
| 1.5C done, Onwards to 2C, should hit it before 2030.
| yieldcrv wrote:
| > Scientists have debated whether this event caused nearly as
| much terrestrial destruction.
|
| Is this the right phrasing? I thought the whole planet was
| terrestrial
|
| Not a distinction between sea and land life
| WaltPurvis wrote:
| Using "terrestrial" to refer only to land-based life is proper,
| i.e., it's a common and accepted definition of the word.
| adrian_b wrote:
| Latin "Terra" actually meant "dry", so it was the proper term
| for dry lands, as opposed to seas and oceans. For instance,
| "continent" is an abbreviation for "terra continens", i.e. dry
| land that is contiguous. Spanish "tierra" and the cognate words
| in the other Romance languages, which usually correspond to
| English "land", have remained closer to the original meaning of
| the word.
|
| The entire planet was very seldom, if ever, referred as
| "Terra". The correct Latin word for the entire planet was
| "Tellus" (whence the adjective "telluric"), whose likely
| meaning was "support" in the sense "the earth that supports us
| on it".
| didgetmaster wrote:
| I have heard that scientists estimate at something like 99.9% of
| all species that ever lived have ZERO evidence left in the fossil
| record.
|
| While I think that a great many things can be learned by studying
| the relative few fossils discovered; making broad assumptions
| about ecosystems based on limited evidence seems like a bit of a
| stretch.
| myflash13 wrote:
| This is why "evolution" is just another creation myth. Of the
| 0.01% evidence left in the fossil record, massive leaps of
| faith are needed to construct a definite story with any
| certainty. Darwin wrote about this as well.
| goatlover wrote:
| What is this anti-scientific comment doing on hacker news?
| Evolution is a fact. It happened and it's still happening.
| The exact way species evolved is theoretical based on
| existing facts.
| myflash13 wrote:
| Here comes the clergy defending the orthodoxy. Dare to
| challenge the dominant myth (logical arguments
| nothwithstanding) and you'll be labeled.
| tomrod wrote:
| Make reddit style claims, get reddit style responses [0]
| [1]
|
| [0] https://imgflip.com/i/voggo
|
| [1] https://tenor.com/view/watch-it-
| gif-3524753964604521397
| Loughla wrote:
| I feel like the basis of your argument requires you to
| very heavily misinterpret the word theory as being equal
| to the word belief.
|
| There's a reason those two things have different words
| for them. You know that, right?
| andrewflnr wrote:
| Don't feed the troll. Especially don't feed them with
| tricky semantic distinctions.
| itishappy wrote:
| That's 0.01% more evidence than competing theories, no?
| tomrod wrote:
| Nah, evolution is much more predictive than creation myths
| -- to the point we've been able to cause speciation in labs
| simulation conditions aligned to evolutionary theory.
| Evolution isn't based solely on fossil records, and truth
| be told Judeochristian creationism couldn't account for
| extinction which the fossil record indicated. The 0.01%
| evidence is just a biased sample, but even a biased sample
| can be useful in context.
|
| Remember -- a good theory fits the evidence, and a good
| metaphysical framework allows adaption and update of truth
| with new evidence.
| itishappy wrote:
| I think we agree. Regardless of the actual numbers, we
| clearly have more evidence for evolution than anything
| else.
| nurettin wrote:
| Genetic algorithms work, and you can observe evolution in
| bacteria simply by exposing them to an acidic environment for
| several generations, so what do you mean by creation myth?
| daedrdev wrote:
| We literally know how genes change which cause evolution can
| do it ourselves, can measure how genes have changed between
| different groups of people and compared to animals and
| regularly evolve ecoli in real time for medical research
| jordanb wrote:
| Scientists are aware and account for that.
|
| One way they do that is by focusing not on megafauna but on
| creatures that exist in immense numbers in a biosphere like
| insects or even smaller creatures. They also look at pollen and
| other biological matter that gets spread evenly.
|
| They can also look at the effects life has on the structure and
| chemistry of earth. For instance, they know when oxygenation
| happened because there are chemicals in older rocks that can
| not form in the presence of oxygen, while there are chemicals
| in younger rocks that can _only_ form in the presence of
| oxygen.
|
| A big evidence that the end-Permian effected land as much as
| the ocean is the behavior of rivers. When plants are present,
| rivers tend to meander because plant roots hold onto the river
| banks. When plants are not present, the river is able to take
| the shortest path to the ocean. Rivers banks laid down at the
| end of the Permian meander, river banks laid down at the start
| of the Triassic do not.
| tomrod wrote:
| > Rivers banks laid down at the end of the Permian meander,
| river banks laid down at the start of the Triassic do not.
|
| * subject to relative flatness
|
| But what an interesting thought, I'd never considered how
| river topography might indicate world conditions. So start of
| Triassic really was a blow to life!
| 1970-01-01 wrote:
| This is also why some hypothesize that Mars may not be a dead
| rock.
| Loughla wrote:
| It does stand to reason that if there was life on Mars there
| might still be life on Mars. Everywhere we look on Earth, life
| exists, even in extreme environments and independent of the
| sun's energy.
|
| I think the first alien we'll find will be an extremophile
| bacteria or other microorganism.
| andrewflnr wrote:
| Almost certainly microorganism, but not necessarily
| extremophile. It depends what you mean by "find". We might
| "find" oxygen in an exoplanet atmosphere and go, "yay, they
| have... algae?" :D
| tomrod wrote:
| That would be hugely important, actually.
|
| With N=1, we know that life exists but not how common
| different development might be. Algae on another planet
| would suggest panspermia of common development pathways.
| w0de0 wrote:
| It seems to me that "refugia" would be more apposite word for
| this phenomenon than "oases."
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