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Hank talks with MacArthur Fellow Dr. Victoria Orphan of CalTech about organisms of the deep sea and the impact it has on our environment.

MacArthur Foundation:

Dr. Victoria Orphan
Geobiologist, CalTech

MacArthur Fellows Bio:

Hosted by: Hank Green
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 (00:00) to (02:00)


H: Before we get into this SciShow Talk Show with Victoria Orphan, one of this year's MacArthur Genius fellows, we wanted to thank the MacArthur foundation for introducing us to Victoria and helping set up this conversation.  You can learn more about the MacArthur Foundation in the description below, they do a bunch of really cool stuff, you can check 'em out.

Hello, welcome to the SciShow Talk Show, where we talk to interesting people about interesting things.  Today we're talking to Victoria Orphan, geobiologist at CalTech and microbial biologist.  So geobiology, I assume, is the study of living rocks.

V: Well, so geobiology can be more broadly defined than that.  So geobiology is really trying to understand how organisms have been shaped by and shape the chemical and physical environment, both today and also throughout Earth's history, so I mean, partly what we do is detective work to try to piece together how things have changed over time and a lot of the work that I do is looking at environments, active environments today and pull together clues from these environments and how specifically how microorganisms affect chemistry and physical processes in a way that that can be translated to interpretation of signatures that exist in all materials.

H: Okay, so you're looking at like, current processes and seeing how, like, things that happened a long time ago might have been caused by those processes that we don't understand very well?

V: That's correct, yeah. 

H: So the thing that fascinates me about your work and the Earth is that I have this sort of idea of what Earth looks like, of what like, what life on Earth looks like and for me, it's like a forest with some trees and there's a bunch of stuff in the leaf litter and there's plants and there's bugs and there's fungus and there's microorganisms, but of course, land, even having that be land, is a huge like, you know, is the minority of the space on Earth and then you have all of the ocean which unlike land where you can live just on it, the ocean you can live at any point on the like, inside of it, and then you have the bottom of the ocean where, and I was watching a video of some of the work that you're doing, I was just like, ohh, look at all that life down there.

 (02:00) to (04:00)

All those little--that I never think about, that is just covering the entire ocean floor and so obviously, it makes sense that they would have a tremendous impact on the sort of composition of our planet, like, so what is that impact that they're having and how do you figure that out, how do you study it and what does it mean for us?

V: Yeah, I mean, it's an amazing question.  So if you go for--

H: Sorry, I asked too many questions at once, I do that all the time.  I should focus.

V: Yeah, yeah.  So if you look from space at Earth, right, it's--it doesn't escape peoples' attention that most of the Earth is ocean, right?  Far greater than 70% but really what you don't see is this amazing topography.  You're only seeing the surface of the ocean and it's really one of the last greatest unexplored frontiers on our planet and scientists have maybe studied far less than 5% of the sea floor and there is tremendous life not only, you know, in terms of diversity, of weird organisms that have adapted to the extreme pressures and cold temperatures of the deep sea but also, as you mentioned, they're playing important roles in the chemistry of our planet and in ways that we're just now beginning to try to unpack and understand, and so, for me, you know, part of my job as a scientist is trying to understand how these organisms influence the chemistry of the deep ocean but also I get to play explorer a little bit too in going to the deep sea and seeing these things firsthand.

 (04:00) to (06:00)

H: Yeah, so you, have you been down there in the deep sea?

V: I have, yes.  

H: You know, there's so much research to be done in the world and it makes a lot of sense that we've explored so little of the ocean floor, because if I wanna study some dirt, I just go out and study some dirt, but if I wanna study the bottom of the ocean, I gotta get a submarine.  Those things ain't cheap, I don't imagine.  

V: They're not cheap and we have a few of these manned submersibles so that actually bring humans to the deep sea firsthand, but there's also tremendous advancements in technology where you can have robots basically that are tethered to the ship and everybody can sit in a giant control room that looks a lot like Star Trek and you can watch on a big screen high-definition TV the deep sea unfold in front of you and so those kind of oceanographic experiences allows a lot of people to provide input into what they're seeing on the sea floor and so it's much more collaborative type of science experience using these remotely operated vehicles.

H: That's pretty cool.

V: And even more cool are these autonomous underwater vehicles, which look like giant torpedos basically that are outfitted with all different kinds of physical and chemical sensors that they're sending off to map large swaths of the seafloor, so we're--we're at a point now where we're learning a lot more about the ocean and it's a very exciting time and it's a very important time for science in terms of looking at the links between how the ocean is influencing the rest of our planet.

 (06:00) to (08:00)

H: So the ocean being the majority of our planet, what are the effects that you're studying?  Like, what are the microorganisms doing that down there is, like, sort of important for me, living my daily life?  

V: So the process that we've been really fascinated by for over a decade is our organisms that consume methane in the deep sea, and the ocean's connection to methane is one that I think the general public doesn't typically think about, but there is a tremendous amount of methane that's stored in deep ocean sediments and like, in ice form, so these things called methane hydrates--

H: Where is that coming from?  Is that, like, old, like, fossil fuel kind of methane or is that being recently produced by microorganisms?

V: We don't actually have a good understanding of all of the sources that are contributing to these hydrates.  It's likely old but the chemistry of those hydrates suggests that some of it is biological and we don't quite understand the time scale of production versus consumption.

H: Okay.

V: So, um, they're giant basically ice layers that are stabilized because of the cold temperatures in the deep sea and also the high pressures, so just like an ice would form from water when you increase the temperature, these methane ices also form under these cold temperatures. 

H: So there's stuff down there eating that methane, because as we know, methane contains energy, you can oxidize it and burn it and cook your noodles.  

 (08:00) to (10:00)

Is--so there are organisms that can sort of do that same thing and provide energy for themselves?  

V: That's correct, yeah, and you know, it's easy to turn on the stove, right, and light a flame and it's really the oxygen in the air that allows the combustion to happen and there are microorganisms that can eat methane with oxygen and gain that same kind of energy.  However, the organisms that I study are even more remarkable in their sort of ability to gain energy not from eating methane with oxygen but actually, they're using some of the salt in seawater, so sulfate that's found in seawater, as a way of gaining that energy, and it's kind of a very Spartan living, so you don't get a lot of energy out of that process, but these organisms have evolved ways to do this through symbiosis with other microorganisms so it's this sort of collaborative effort that allows them to consume methane quite effectively in the deep sea.

H: What is the--what's the byproduct of that reaction?  What comes out?  Is it just carbon dioxide, like if normal oxidation happened or are we getting something weird?

V: So we get carbon dioxide, but we also have this other amazing process that converts that sulfate in sea water to hydrogen sulfide so that same stuff that makes eggs, rotten eggs stink, and then hydrogen sulfide in itself is this very life-sustaining chemical for organisms in the deep sea, so lots of people have seen hydrothermal vent systems and these amazing deep sea worms and other organisms that life off of the chemistry in the deep sea and a lot of that is this hydrogen sulfide.  These organisms have bacteria that use that hydrogen sulfide basically in a symbiosis, so we see the same thing happen in places where methane is being consumed through sulfate reduction, so you have these oases on the sea floor that are fueled through this process, so...

 (10:00) to (12:00)

H: And it's an entirely methane-fueled process.  So, theoretically, possibly, the methane originally came from some, you know, surface of the Earth, some photosynthetic system, you know, that sort of energy in the methane but then, but the system that you're talking about right now is entirely based on methane, so we could take that system off of the Earth into a place where there is no light, no energy except for the chemical energy in the methane and the system, not just the methane consumption but the methane consumption and the hydrogen sulfide consumption, as long as there was still methane, this biological system would continue to exist.

V: You'd have to have the methane plus an oxidant, so there still have to be sulfate or some other thing, so we more recently have discovered that these methane consuming organisms also can use iron oxides, too, so they can potentially grow with a solid mineral in addition to things that are dissolved in sea water, so it's a pretty remarkable buffet of things that they can eat combined with methane in the deep sea.

H: Cool, and obviously methane is an important and like, large sources of potential methane are important because methane is a very potent greenhouse gas.  It's a huge thing of concern and so these organisms are basically helping that methane not escape to some extent, so understanding the system, how much of the methane escapes, especially I would assume, like are there processes that are increasing methane release in the sea floor right now?

 (12:00) to (14:00)

V: Certainly in places like the Arctic where you have permafrost and hydrates that are closer to the surface, there's been people who have gone up there to study.  I haven't been up to the Arctic but the reports are that there's increased methane vents being released and some of this may be due to the destabilization and the warming that's happening in the sea water up there and so again, we don't have a good way to predict what the trajectory is going to be with these processes, but people are noticing there's increased methane gas coming out in certain areas of the Arctic.  

H: So these microorganisms, they eat the methane when it's still in hydrate form or does it need to be gaseous for that?

V: I believe it has to be dissolved in the water.  However, people who have studied hydrates have found evidence of these microorganisms actually living in the hydrate matrix in some places and so it's likely there's some fraction of that that's dissolved and that's what they're feeding off of, rather than chewing on the solid substrate.

H: So you get a little bit, get a sample of the sea floor, you take that back to a lab, and then you figure out that there, like, how this micro-organism's, like, metabolism works?  I've never--I have a hard time understanding how we figured out how we determined how our own metabolism works, let alone something happening in a tiny single cell that is very difficult to observe and figuring out what the chemistry is going on in there, what--how are you doing this?

V: Yeah, it's pretty crazy, right?  So we're studying things that are like, the size of a, you know, 1/200th of the length of your hair.

 (14:00) to (16:00)

H: The width--

V: A micron [H: yeah] that lives, you know, over a mile deep in the ocean, right? So, there's a lot of technological challenges that go into even just collecting the sample. When we bring the sample back to the lab, it's mud, right? And in that mud, you have billions of microorganisms that are all interacting in various ways. In the case of our system, we're looking at organisms that are tied to methane consuption, so we can get information about these organisms through advances in molecular biology so we can look at the genomes and the DNA of the organisms that live in that mud without growing them in the lab. So, in classic microbiology, you remember people would streak a petri plate, ya know, and you would get colonies swarming and it turns out if you do this in a lot of natural environments, you only capture less than 1% of the total diversity of the microbes that are there. And so, being able to look through the lens of their genomes gives us a much more comprehensive overview of the total organisms that are there. And once you have that information, the question - the real challenge is what are all those organisms doing, and how are they interacting with one another? And so, this is where geobiology as a field really can offer some insights and that is by taking tools that have been used in geochemistry and in geology and coupling them directly with this sort of genomic understanding of microorganisms.  

 (16:00) to (18:00)

So we can look at who's there through their DNA and then we can measure the geochemistry of those organisms directly by using techniques that have been refined in the field of geology and geochemistry and so we, we look at chemical signatures in cells and these chemical signatures tell us something about what they've been eating and in some cases, we can follow, you know, the transfer of carbon from one organism to the next organism and put together a food web of what's going on in the deep sea.

H: Right.  So you can see that symbiosis in action, you can see--

V: Right.  

H: So you're basically looking at the products of reactions and then from the products, inferring what reactions are going on?  

V: That's correct, yeah, and so in some cases, we can actually add in a chemical that um, so we use these things called stable isotopes to do a lot of our work and basically it just has a different, it has one more neutron than the other, the common form of the isotope, and so we can add this into our sample and follow the organisms as they are consuming that.  So if you add a carbon-13 labeled methane into your sample, you can follow its oxidation into CO2, you can follow it into the biomass of cells, and so from using this sort of detective work, we're able to see who's eating what and where its end products are going in the system.

H: So, when I go to a swamp, it smells of eggs.  Is this same kind of respiration going on in land systems?

V: You do find methane consumption, and if there is sulfate in these freshwater systems, it tends to be less than what you see in the marine environment, but um, you also can find methane coupled to things like nitrate, these iron oxides that we talked about, and oxygen as well.  

 (18:00) to (20:00)

H: Yeah, yeah, and I guess that it's sort of like, in a swamp system, it would be required, because oxygen is so good at doing its job of oxidizing, it would be required that you have some system where all of the oxygen has been consumed for these alternate metabolites, I guess, to be produced.  Well, that is neat.  What are--so you just got this Genius grant.  Congratulations, you're a genius now.  What do you do with your money?

V: That's a very good question, one that we've been asked quite a bit, and one that we're still--so I--there's another MacArthur winner at CalTech who's a good friend of mine and so she and I have been talking quite a bit about how to maybe sort of pool our collection of resources in some way to do something even more substantial.

H: Cool.

V: But I think both of us really strongly believe in education and trying to give back to the community, like, anybody in our position, if you ask, probably has been, you know, tremendously influenced by mentors and teachers in our past that have helped us along our careers and so we wanna be able to provide those same kinds of opportunities for kids as well and try to promote STEM sciences to young students and get them excited about this wonderful world of science and the environment around us.

H: Well, that is very cool.  Congratulations.   How does it feel?

V: It feels, of course, it's a wonderful thing.

 (20:00) to (22:00)

It's um, it's humbling to be selected, you know, there's so many deserving people out there and, you know, I feel incredibly fortunate to have this recognition and I'm--I love sharing the limelight with my fellow MacArthur class and it's just been a really fun time to get to know all of these people.

H: Yeah, that's another side benefit is that now you're in this group and you get to hang out with others who have, you know, all done something really cool and interesting and useful for the world.  Is there any immediate practical like, I can be less worried about the environment now that I know that there's methane eaters covering the ocean floor?

V:  I wish.  I wish we could say that.  I think it's--the thing that I'm most hopeful about is the technology has come a long way in terms of our ability to understand natural ecosystems and so from that standpoint, I think, you know, projecting out ten years, we might be at a point where we can start to do these forecasting models and understand what's going on and how these organisms are influencing our planet under different environmental conditions and changing climate.

H: And is it safe to say that like, right now, like, seafloor methane is a big giant question mark in climate science?  Like, we know that it's bad.  We know that it's a potentially huge positive feedback loop, like, if methane stars to warm, like, if the effect of methane starts to be significant on the warming, the effect of that seafloor released methane, then it's just gonna cause more seafloor release methane, like, then we're just in, we're just in a giant cycle, so like, there's that concern that it could be much worse than we think and we just don't have a good way of studying it yet.  

 (22:00) to (24:00)

V: Yeah.  I mean, the thing that gives me pause is there's, of course, always interest in discussion about how do you harvest these hydrates as a fuel source, and it's this--we don't understand enough about the deep sea, we, you know, it's--I think of it as equivalent to you know, just starting clear-cutting in the rainforest and then after the fact realizing that there's all of this tremendous, you know, potential for medicine and all these things, you know, we just have not invested enough in understanding the deep sea and that baseline needs to be established before we start thinking about using it as a potential--

H: Well, it's hard enough on land to capture methane in a way that doesn't release a huge amount of it into the atmosphere, like, that happens when we harvest methane on land.  I can't imagine not losing, you know, the majority at least of the methane if you're disturbing the seafloor.  Then you're intentionally releasing--not intentionally, but like, you are being the cause of the release of that methane into the atmosphere.

V: Yeah, yeah.  We know there were periods in Earth history where there have been, you know, predicted large methane responses and we can see this sort of recorded in old sediment records and things and so, so certainly, it's not unprecedented to have these massive releases of this greenhouse gas and, but yes, I agree, it would be better not to--

H: Start poking more holes.

V: Start poking around.  A better understanding of the system, yeah.  

H: Well, thank you for helping us get a better understanding of the system here for the people watching on SciShow, but also for all of the Earthlings.  

 (24:00) to (24:34)

We need a better understanding of the systems, so thanks for doing the great work and keep it up.  This is Victoria Orphan, it's a pleasure to have you on.

V: Thank you, Hank, it was nice talking to you.  Thanks.

H: Thank you to Victoria Orphan for sharing all your smarts with us.   Thank you to the MacArthur Foundation for helping set this up, and thank you for watching.  It's great to have you here, and we'll see you next time.