When the Permian Oceans Stopped Breathing

Ola: Welcome back to Fault Lines. Picture Pangaea—one continent, one ocean (Panthalassa), and tropical surface water pushing past thirty eight, maybe forty degrees Celsius. Amara: That's bathwater—that's soup. Ola: Soup with almost no oxygen left in it, two hundred and fifty two million years ago. Amara: Okay, so today we're doing something new—we've put Chicxulub on trial before. The asteroid, the dinosaurs. Ola: Right; today the descendants bigger—the Great Dying, ninety six per cent of marine species gone, seventy per cent of land animals. Amara: And Ola's already got his notebook out. Ola: Guilty—because a new study just walked in claiming they finally solved it. Amara: Solved, as in case closed? Ola: That's what we're going to test. Amara: There's a lineup of suspects, too-Siberian Traps, hydrogen sulfide, ocean acidification-and I don't think they all get equal blame. Ola: They don't; and here is what bugs me: how do you explain Seventy per cent of land deaths with an ocean argument? Amara: Plot twist! Maybe you can't. Ola: Which is why we're going to argue about it properly. Amara: Oh, we are absolutely arguing about it. Ola: And whether Nine Nine living species can really stand in for animals that died a quarter billion years ago. Amara: I have thoughts on that. Ola: I figured, Follow the incentives, not the rhetoric; same for extinct clams as it is for politicians. Amara: Somehow you always get pickleball logic into paleontology. Ola: It's about visibility and patience, same rules. Amara: Well, let's see if this case actually holds up. Ola set the scene properly—what did this ocean actually look like? Ola: Picture one continent, Pangaea, one ocean wrapped around it called Panthalassa. No ice at either pole. Amara: And the water at the equator eventually hits somewhere near thirty eight, maybe forty degrees Celsius. That's bath water, hot tub water, bath water that's also losing its oxygen, layer by layer, all the way to the seafloor. Ola: Right, and here's the detail that got me. Sperling's team says the ocean didn't start this way; it started cool, well-oxygenated. Speaker 3: Wait, so this wasn't a slow bake? No! Okay, so get this: according to ScienceDaily's piece today, something dumped a massive pulse of carbon dioxide into that system, and the ocean just flipped. Amara: We've argued Chicxulub on this show, the asteroid, the iridium, all of it. We've never put the Great Dying on trial. Speaker 3: Because it's messier. No crater, no smoking gun you can hold in your hand. Amara: Just numbers, two hundred fifty-two million years ago, and the numbers are brutal—ninety-six percent of marine species gone, seventy percent on land. Speaker 3: But not evenly; that's the part that should bother you. Go on, get this: Brachiopods, think clam shaped filter feeders, nearly wiped out completely. Crinoids, too, those feathery sea floor animals. And clams and snails, roughly half of them made it through. Half same ocean, same event, wildly different outcomes-and get this-this dot org's coverage of the study points out Brachiopods and Crinoids had run the seafloor for something like two hundred eighty million years before this, the dominant group, since animals first showed up. And they never got that seafloor back. Never? Never! Clams and snails just took over-permanently. So why do the shell shaped losers lose and the shell shaped survivors survive? That's what the new study claims to answer. Whether it actually does, That's what we should argue about. Cold, oxygen rich ocean, one carbon pulse and a kill list that makes no obvious sense on paper. Paper! So what actually happened inside those animals' bodies when the heat hit? Ola: Okay, so get this: because this new paper doesn't just describe the die off, it actually tests the bodies of the animals involved. Amara: Wait, tested how? Like actual living animals? Living relatives, yeah. The PNAS paper came out July sixth; Marquez, Sperling, and the team, and they ran respirometry on thirty eight species, nine Paleozoic-type, twenty nine modern. Ola: Paleozoic-type meaning brachiopods, that kind of body plan still alive today somewhere? Amara: Exactly-some collected right off San Juan Island in Washington-they put them in closed chambers and watched oxygen drain out while temperature climbed, direct measurement, not just fossils and guesswork. Ola: Okay, so get this: the mechanism is warming speeds up how fast an animal burns oxygen, but warm water physically holds less of it. Amara: Right, it's a supply and demand squeeze. Modern fauna-clams, snails, urchins-have these fast muscular metabolisms that could still scrape by. The old Paleozoic crowd: slower engines, no cushion. Ola: Okay, but here's my method question: if slow metabolism Tubalism is bad news in a crisis; why weren't brachiopods extinct already? They'd been fine for hundreds of millions of years! Amara: Wait for it-that's what ScienceAlert flagged in their writeup: "At rest, the Paleozoic fauna handled low oxygen better than the moderns. Ola: Wait, better? So resting brachiopods outperform a resting clam? Amara: Yes, but the second they had to be active-feeding, moving, anything-that advantage just vanished completely. Ola: Get this, it's not that they were universally weak. Weak, they lost their one edge exactly when the ocean demanded activity. Amara: And activity was the new normal: warmer water, higher metabolic demand, no rest. Ola: That's a genuinely strange trade off to build a body plan around. Amara: There's a line from Sperling I keep coming back to. He told reporters, quote: Ola: Shifting off the larboard bench, the def- Fans still gets witnesses; first one up, the Siberian Traps. Amara: Oh, I love this guy, volcanic super villain of the whole Permian. Ola: Okay, so get this: pretty much millions of cubic kilometers of lava plus magma sills baking straight through Siberian coal beds on the ground. Amara: That's heat plus coal gas cooking before it even hits daylight. Ola: Right; and the volcanic winter piece surprises people; sulfate aerosols hit first; a cold snap centuries before the heat shows up. Amara: Wait-cooling before the Great Dying gets hot? Ola: Exactly; cold first, then the carbon backlog catches up, and the greenhouse spike runs for tens of thousands of years. Amara: Whistle-killer changes weapons mid crime. Ola: Witness two, hydrogen sulphide, the Euxenia case. Amara: Toxic water, no oxygen, full of sulphur bacteria. Ola: Green sulphur bacteria biomarkers specifically, they only live in water with zero oxygen and hydrogen sulphide. Lee Kumps upwelling model has that gas rising onto the shelves and killing everything it touches. And there's a land version: malformed pollen; that's the ozone argument. Deformed spores as evidence the gas reached the stratosphere and- You then tore a hole in it. Amara: So this crosses on to land, too! Ola: It tries to; witness three is already sitting in the room, honestly-acidification. The PNAS paper behind the Stanford study says the ocean warmed, lost oxygen, and got more acidic. Amara: Three symptoms. Ola: The team tested two: heat and oxygen-acids right there in their own abstract, untouched. Amara: So they didn't rule it out, they just Just didn't run the test. Ola: Correct; and then the one that bothers me most, the land problem-that extinction number from earlier-on land there's no sea water up there to Speaker 3: Why? Ola: deoxygenate. Amara: No hypoxia model for a tortoise. Ola: Right, no gills to suffocate. Whatever killed things on land it wasn't dissolved oxygen dropping in the ocean. Amara: Which means the heat hypoxia case, even if it's dead right for brachiopods Speaker 4: - Amara: Here, Pods, Ola: still isn't the whole file—one strong witness in a room with three others still talking. Amara: So what's the verdict here? Ola: Split: volcanism likely started the clock, heat and low oxygen did the killing in the water, and ozone acid still on the stand. Amara: And that ocean back then, warming, losing oxygen, turning acidic, reads a little too close to this week's headlines. Ola: Hmm; four witnesses, one heat and oxygen headline; next up we cross examine it. Amara: I already know whose witness stand you're storming. Ola: Building on that, I keep circling back to the proxy problem. Amara: Which proxy problem? Ola: Okay, so get this-nine living species standing in for animals that died two hundred and fifty two million years ago-modern brachiopods speaking for brachiopods that don't exist any more. Amara: Mm-hmm. Ola: Does that actually hold? Amara: It holds because the model didn't just describe the past. At last it predicted it. Ola: Meaning? Amara: Stanford's team ran the metabolic tolerances from living relatives and asked who should have died at the class level. The answer matched the actual Permian casualty list. That's a test, not a curve fit. Ola: A test built on nine data points. Amara: Nine data points that reproduce a two hundred fifty two million year old die off pattern nobody fed into the model beforehand. And that's not nothing. Ola: Fine; I'll give you that it's clever. Amara: And it's not built from scratch; it leans on the twenty eighteen Science paper, Penn, Deutsch, Payne, and Sperling, the metabolic index work. Ola: The same Sperling? Amara: Same research line, yeah. Ola: Okay, here's my actual problem: volcanism versus heat and hypoxia. Confirming the murder weapon doesn't tell you who pulled the trigger. Pull the trigger. Amara: No, it doesn't. The Siberian Traps stay the trigger. Heat and low oxygen are how that trigger killed things in the water; two different claims. Ola: So when ScienceDaily's headline says "Solved," what got solved? Amara: The selection mechanism: why clams lived and brachiopods didn't, not the ignition source. Ola: Half a mystery, then. Amara: Half a well tested mystery. Ola: I want to know what would break this. What result flips your verdict? Amara: If a low tolerance group had survived at high rates, or a high tolerance group went extinct anyway, either one kills the model. Ola: And nobody's found that yet. Amara: Not that I've seen. Ola: Because final nail in the coffin gets you the headline, partial confirmation of one selection mechanism doesn't. Amara: That's a press release problem, not a data problem. Ola: Sure; but that's the incentive. Nobody gets cited for saying we narrowed it down. Amara: The oxygen heat mechanism earned its headline; the land animals and the trigger question didn't get one. Ola: So we've got a strong half and a shaky half. Amara: A verdict split right down the middle. Ola: Quick pivot back to that beach question from earlier. Amara: THE CLAM SHELL QUESTION. Ola: Right, Okay, so get this: ScienceDaily's framing: Today's beaches are covered in clam and snail shells because of who won two hundred and fifty two million years ago. Amara: Okay, so get this: Clams, snails, urchins, fish-they inherited the sea floor. Their bodies handled the heat and the low oxygen; brachiopods and crinoids mostly didn't. Ola: That selection story holds up; the trigger still Siberian Traps, still unresolved on timing. Amara: And get this: Sperling, the study's lead voice, told ScienceAlert something that really stuck with me. Ola: Go on. Amara: He said, "Worst case warming projections ... Put us on track for Permian-Triassic levels. Speaker 5: Wow! Ola: that's a heavy sentence! Amara: He also said there's still time to change course. Ola: Still time!--doing a lot of work, that phrase. Amara: It is. Ola: So, what moves me off the fence? Give me a hypoxia mechanism for land animals, and I'll drop the objection. Amara: For me, it's the trigger. Pin down how fast the Siberian Traps pushed carbon dioxide, and the timeline gets sharper. Ola: Until when, strong on who survived, thin on why it started. Amara: Fair; but the ocean you're swimming in right now, that's the record of it. Ola: Clamp! M's and snails every beach on Earth. Amara: Every single one. Ola: So where does that leave us-half solved, half still open, I think. Amara: Oh, well, you just can't let the verdict sit clean, can you? Ola: The part that got me was the beach thing-ScienceDaily's team traced today's clams and snails straight back to those Permian survivors. Amara: Right; the ones with the tougher metabolisms; every shell you pick up is basically a 252-Million-Year-Old winner. Ola: And ScienceAlert's piece on Sperling's warning stuck with me: "Worst-case warming this century could edge towards those same Permian-Triassic numbers. Amara: Which is exactly why this one felt urgent, not just old. Ola: Exactly; ancient ocean current lesson. Amara: Okay, if this episode cracked something open for you, subscribe, leave us a review. Ola: And e mail us: hello@haymato.com Tell us which epoch we should argue about next. Amara: Thanks for hanging out in Panthalassa with us. Ola: Until next time, stay curious.