Everything Everywhere Daily: History, Science, Geography & More - The Deep Biosphere

Episode Date: March 3, 2021

Imagine taking all of the trees, grass, animals, insects, fish, coral, and bacteria on the surface of the Earth and in the sea. Basically, every living thing on the planet. If you were to add it all up, all of the biomass, it would be quite a bit. Yet according to some scientists, that might not even account for most of the life on Earth. Learn more about the Deep Biosphere on this episode of Everything Everywhere Daily. Learn more about your ad choices. Visit megaphone.fm/adchoices

Imagine taking all of the trees, grass, animals, insects, fish, coral, and bacteria on the surface of the earth and in the sea. Basically, everything on the planet. If you were to add it all up, all of the biomass, it would be quite a bit. Yet according to some scientists, that might not even account for most of the life on Earth. Learn more about the deep biosphere on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? throughline is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night.

And how it shaped the world now. Time travel with us every week on the Throughline podcast from NPR. I want to tell everyone about the upcoming intelligence speech conference. This year's conference will, not surprisingly, be taking place online. It will have 40 of the Internet's top educational content creators giving presentations on a wide variety of topics including culture and history. This year's conference will be taking place on Saturday, April 24th, starting at 10 a.m. Eastern Time.

And I'll be speaking there as well. I'll be doing a presentation on how travel and history are two great things that go great together, sort of like a peanut buttercup. You can register for the conference by going to Intelligent Speechconference.com and if you use code every at checkout, E-V-E-E-E-E-R-Y, you can get 10% off your registration. Go to Intelligent Speechconference.com.

To start this discussion, when I'm talking about the deep biosphere, I'm not talking about the soil, the layer where all the worms and the roots are. For the purposes of this discussion, I'm going to call that the surface. What I am talking about is everything below that, starting at about two meters down all the way to five kilometers down on land, and everything below the bottom of the seafloor down to about 10 kilometers in the ocean. You might be thinking, how is this possible? If you go down that far, you encounter a solid rock. There's no light, there's no oxygen, there's too much heat and pressure. How is it possible that anything could live, yet alone, have so much life that might rival everything on the surface?

Well, to explain that, we have to back up a bit. If you think that life can't possibly exist that far down, you aren't alone. No one ever really considered it. The idea defies everything we know about what makes life possible. Moreover, it's extremely difficult to explore deep beneath the earth. The only way to do it is via drilling or very deep mining, and our ability to go really deep is a rather recent development. In the 1920s, researchers began to note that some oil wells were bringing up hydrogen sulfide and bicarbonates. These things are normally the product of bacteria, but the wells were deep enough that there shouldn't have been any life. Nonetheless, they took samples of the water from the well, and they were able to grow bacteria. In the 1930s, scientists were able to grow bacteria

that came from coal. Not only did they find bacteria, but when they heated the coal to 160 degrees Celsius, well above the boiling point of water, the bacteria started to rapidly grow. As ocean drilling became a thing, whenever samples were taken from the ocean sediment or below, they always found bacteria. However, most of the seven-examination, was dismissed. The consensus view was that life was impossible for all the reasons I gave before. They assumed that any bacteria found in such depths or under such conditions must have been contaminated from the surface. Nonetheless, the same results kept coming in. In the 1980s, the United States' deep-sea drilling project began taking core samples from below the surface

of the ocean, and they found more microbes, lots of microbial life, in fact. The thing which began to change everyone's perception was a paper written in 1992 by Thomas Gold from Cornell University. Gold wasn't a biologist or even a geologist. He was an astronomer. His paper titled The Deep Hot Biosphere resulted in a fundamental shift in how we view microbial life below the surface of the earth. He began his paper as follows. Quote, new forms of microbial life are being discovered in such abundance deep inside the earth that some scientists are beginning to suspect that the planet has a hidden biosphere extending miles down,

whose total mass may rival or exceed that of all surface life. If a deep biosphere does exist, scientists say, its discovery will rewrite textbooks while shedding new light on the mystery of life's origins. Even skeptics say this thesis is intriguing enough to

warrant new studies on the subterranean realm, unquote. In the 30 years since the paper was written, the evidence has only gotten stronger to support Gold's hypothesis. They have found all three domains of life deep in the earth. These aren't plants, animals and fungi, which are kingdoms, but one step up from that, the various single cell forms of life, archaea, bacteria, and eukaria. They found nematodes, which are tiny animals, living at the bottom

of the deepest mine in the world in South Africa. They found evidence of life in mud volcanoes at the bottom of the Mariana Trench, the deepest place in the ocean. This mud is being brought up from hundreds or thousands of meters below that. The reason why there might be more microbial life below the surface of the earth than there is on the surface is that there's just so much of it and it goes down so far. If you think about it, most life on the surface of the earth is only about one or two meters up or down from the surface. Microbes, however, keep going for miles and miles.

So how do they do it? How can life live down there when it's mostly rock? For starters, solid rock really isn't solid. There are very small pores in the rock, about the size of a micron, just big enough for microbes to fit. Some rocks, which are sedimentary, might be much more porous, enough for water to flow right through them. What do they live on? The microbes that far down have found novel ways to get energy, including using things like hydrogen, sulfur, and iron for food. Almost all of them are anaerobic, which means that they don't use oxygen.

Moreover, they have extremely slow metabolisms. They can lie dormant for a very long time. And by very long, I do mean very long. In 2020, Japanese researchers found bacteria taken from coring samples under the seafloor, which they believed to have been dormant for a hundred million years. Moreover, they were able to get them to reproduce once they were taken back into the lab. There is an incredible diversity of life that goes down that far. There are estimates that there might be more than one trillion species of microbes on and in the earth,

and we have only discovered a fraction of 1% of them. So what are the implications of this? If there are all these microbes below us, why does that matter? The biggest implication is that if life can exist so far below the surface, even in a dormant state, then it might be possible elsewhere. perhaps somewhere like Mars. Just looking on the surface might not be sufficient if we're looking for signs of life. Even if life is no longer on the surface of Mars, it still might be somewhere below the surface.

Another implication is that microbes in the Earth may have it a role in the evolution of life on the planet. It might not be that life started on the surface and went down. It might be that it started below and came up. So the next time you're walking around with the grass below your feet, realize that most of the life below you isn't the grass. It's the tons and tons of microbes and bacteria, which are filling up the miles of pores in the rock. The associate producer of Everything Everywhere Daily is Thor Thompson.

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