@antdgar

TIMESTAMPS:
0:06 - Introduction: The challenge of searching for extraterrestrial life and the importance of understanding Earth's diverse life.
1:37 - Focus shift: Introducing the idea that much of Earth's life remains poorly understood.
1:51 - Guest introduction: Karen Lloyd, a microbial biogeochemist studying the deep subsurface.
2:10 - Defining "Intraterrestrials": Life existing deep beneath the Earth's surface (land or sea).
2:31 - Discovery: Life (microbes) found kilometers deep, wherever we can dig.
4:47 - Scale of Discovery: Not just a few species, but potentially billions, including entirely new phyla.
6:16 - Environment Deep Down: Exploring the conditions (depth, stability, lack of oxygen/light).
7:12 - Sampling Methods: How scientists access deep life (drilling, using natural conduits like hot springs).
10:50 - Deep Environments: Examples like ancient aquifers (billion-year-old water) and tectonic collision zones.
11:54 - Key Chemical Process: Serpentinization as a potential energy source for deep life (rock + water = fuel).
14:09 - Exploration Status: The deep subsurface is a vast, largely uncharted territory.
17:21 - Abundance of Life: Estimated 10^29 microbial cells in the subsurface.
18:41 - Drilling Technique: Description of using drilling ships and piston coring for sample collection.
21:10 - Relation to Surface Life: Initially seemed alien, now recognized via DNA; discovery of novel organisms.
23:07 - Asgard Archaea: Discovery of a unique group potentially linking Archaea and Eukaryotes.
24:43 - Eukaryote vs. Prokaryote Refresher: Explaining the cellular differences.
26:07 - Significance of Asgard Archaea: Possess eukaryote-like features, potentially pre-mitochondria ancestors.
29:39 - Deep Ecosystem Lifestyle: Extremely slow metabolism, living off buried organic matter or chemicals.
31:45 - Slow Reproduction: Cell division takes weeks in culture, likely much longer naturally (thousands of years?).
36:45 - Evidence of Activity: Amino acid chirality shows cells are actively maintaining themselves over long periods, not just dormant or dead.
39:52 - Longest-Lived Organisms?: Deep microbes may be the oldest living things on Earth.
40:29 - Alternative Energy: Microbes living off radiolysis (radiation splitting water).
41:50 - Electron Eaters: Organisms using tiny biological "wires" to directly consume/transfer electrons.
45:48 - Life and Thermodynamics: Life as an efficient entropy-producing system, harnessing slow-release energy.
50:57 - Origin of Life?: Argument for the deep subsurface as a plausible, protected "nursery" for early life.
56:54 - Astrobiological Implications: Subsurface life on Earth suggests potential for similar life on Mars, Europa, etc.
58:00 - Methane on Mars: Discussing transient methane plumes as a potential, ambiguous sign of subsurface activity.
1:00:10 - Shadow Biosphere: Possibility of entirely separate life origins on Earth (not yet found, methods might miss it).
1:02:08 - Surface-Subsurface Interaction: Deep life depends on surface inputs but also shapes Earth's crust and atmosphere.
1:03:38 - Potential Application: Carbon sequestration underground, requires understanding microbial responses.
1:05:38 - Future Research Needs: More controlled, targeted drilling is essential for progress.
1:08:00 - Pathogen Risk?: Archaea (a major deep life domain) have no known pathogens.

@CryofthePlanet

"Man, I hope Dr. Carroll has a good Mindscape episode to start my week."

Nice.

@brlopwn

What an enthralling episode. Dr. Lloyd conveys such depth (!) of knowledge and enthusiasm. Thank you for sharing this discussion!

@DudokX

Love this episode, she is really good at explaining her work. She is enthusiastic but also humble about what we actually know

@BBeu-i6t

Thank you Professor Lloyd!

@TheK3vin

Loved this so much!

@scignosis

Great episode. More biologist would be awesom 😊

@danielcook1271

Love this! Soooo interesting! Thanks both!

@Ava31415

.....and where they go to have fun! So good...preposterous even. thanks so much for that pearl.  Congrats to you both.

@redneckhippy2020

Fantastically important stuff, especially as the permafrost recedes and these organisms return to soil that's not been 'cultivated' in hundreds of thousands of years.  This will of course greatly effect/affect the 'climate/atmosphere', perhaps ultimately returning to high oxygen concentrations once again.

@Mythago314

Interestingly, PBS Spacetime channel just released a new episode, discussing the Fermi paradox (why there doesn't seem to be aliens / other advanced life forms around). They named eukaryotic cells as a likely bottleneck, requiring the incorporation of an aerobic bacteria into another cell. Which is exactly what's discussed in this Mindscape episode.

@jamieoglethorpe

Microbes were discovered at the bottom of the deepest mines in the World, the South African gold mines. Fascinating stuff. Here is my Gemini 2.5 Pro prompt: "Microbes discovered at the bottom of the deepest gold mines in South Africa". People go that deep. I recall the discovery coming as a huge surprise. Nobody expected that.

@chrismalloy3494

Best bits: Chirality death clock and radioactivity as a source of energy for microbes.

@symmetrie_bruch

very interesting

@sullyguy395

I’m not accusing you of this but it always sort of bugs me that people hold up extremophiles as reasons we might discover live in extreme environment. They overlook the fact that extreme environments where we find extremophiles on Earth are within colonization reach of one of the least extreme environments we know of. 

Yes, bacteria that evolved in warm, wet resource rich places can adapt to life in extremely hot, cold, dry, resource poor, high radiation places. That doesn’t means that such places are remotely likely to have life emerging in them without contact from such an ideal habitats. A surprising number of people seem to not be aware of that when discussing extremophiles in the context of extraterrestrial life.

@Alex-js5lg

Looking in a volcano and finding life there sounds like the biology equivalent of pointing the Hubble at "nothing" and finding 10,000 galaxies.

@inyoureyes9197

Sooo interesting

@DeclanMBrennan

5:10 - That's a very bland mnemonic. Racier versions are available.

@BBeu-i6t

Thanks Professor Carrol

@wadehines9971

I have to take issue with the commentary around 48 minute mark about entropy. Life isn't creating more entropy with methane than an explosion would. What it does is very efficiently create more work as it exhausts entropy. That work is often chemical work, such as synthesizing polymers or moving things within cells, or translational movement of the cell.