Nutrients on Earth are essential for life on Earth. But they aren't evenly distributed. How do they end up in different places, and how does that affect life on Earth? How does life even work?!
In this episode of the Reversing Climate Change podcast, Nori Cofounder Ross Kenyon is joined by Dr. Joe Roman, a conservation biologist and author of Eat, Poop, Die: How Animals Make Our World.
An established view of how ecosystems emerge and change is through bottom-up processes, e.g. through chemistry or microorganisms. In this view, animals are often seen more as visitors passing through rather than as transformative agents themselves. Joe challenges this concept, arguing that much research has shown just how much mammals can change ecosystems, as well as carbon and nitrogen cycles! This has impacts for carbon removal, from ecosystem restoration to iron fertilization of the Southern Ocean.
The conversation also explores the complex relationship humans have with predators and rewilding, and our desire to simplify our environments, often to our peril. This legibility and safety, however, can often mean ecological sterility. Ross shares his experience raising urban chickens in an environment filled with raccoons.
Joe also talks about his ongoing research project on whales and the Great Whale Conveyor Belt, and his interest in studying invasive species as a source of food for humans.
This is one of those episodes that touches so much about our shared world!
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Eat, Poop, Die: How Animals Make Our World
Full Transcript
Ross Kenyon: You’re listening to the Reversing Climate Change podcast by the team at Nori, the carbon removal marketplace. This is a show about the innovators and entrepreneurs developing solutions to climate change. Hello and welcome to the Reversing Climate Change podcast with Nori. I’m Ross Kenyon and I’m the Director of Creative and Marketing at Nori, which is a carbon removal marketplace based in Seattle, WA. Today I have with me Joe Roman. Joe is a conservation biologist, marine ecologist, and author of his latest book, which is called Eat, Poop, Die: How Animals Make Our World. Thanks for being here, Joe.
Joe Roman: Hi, Ross. Thanks for having me on.
Ross Kenyon: I’m really happy to have you on. It’s been a long time coming. There are infinite books in any person. Why nutrient pumps? What got you so excited enough to spend presumably years of your life gallivanting around the world trying to figure out how nutrient cycling works in different cases?
Joe Roman: Yeah, for me, because I’m a scientist, it actually started in the field in the Bay of Fundy way back in the 1990s. So it’s not just a couple of years of writing this book, but also a couple of decades of working on this. I was studying the North Atlantic right whale. It’s a critically endangered species off of New England here, and one of the first whales I saw was a large male. It came up in front of our boat, and just before it dove, it lifted its flukes above the surface, and just as it sank below, there was this enormous fecal plume, really almost as big as the boat. And little did I know then that that was going to set the course for a lot of my research for decades.
Ross Kenyon: But also, how does that get your attention? That’s a disgusting phrase. It’s never been uttered on this podcast. I was hoping it would never come up. Like, as a scientist, how do you say that’s what I want to spend my time doing?
Joe Roman: I didn’t know that at the time, that I was going to spend much of my life dedicated to it. But here’s what you get out of this fecal plume. So at that time we collected it — the stench is pretty awful. But you can find out, most obviously, what they’ve been eating. And then you can also look at the hormones. So you don’t have to bother the whale. You can look at stress hormones. You can look at whether they’re pregnant. You can get an idea whether they’re sexually reproductive. And years later I realized you could also get at the nutrients, so you can get an idea of how they’re impacting ocean ecosystems.
Ross Kenyon: This is a very long-running fight. I asked one of the scientists on our team what he thought about the bottom-up versus top-down approach here, and whether or not your somewhat revisionist take on this argument is true or maps with his experience. But I think he had more sympathy for the classical bottom-up approach of how Earth is shaped by microbes. And your book is an attempt to challenge the story, or at least nuance the story somewhat. Is that a correct reading of what you’re trying to do?
Joe Roman: For sure. And there has certainly been some pushback from biological oceanographers and others in the field. I would say, shockingly, someone had asked me when I first proposed this book, like, doesn’t everyone know that whales and elephants have a big impact either in the oceans or on land? And the answer is actually not. Most of the research that’s occurred over the past 100 years has been these bottom-up ideas. And what do we mean by that? We mean phytoplankton — microscopic phytoplankton absorbing nutrients, and then maybe some small zooplankton eating that, and that’s driving much of the ocean systems. That’s true. I am not dismissing the role of phytoplankton or bacteria or tiny zooplankton. What I am arguing, and what we’ve seen in case after case, is that large animals also have a big impact as well.
There’s a reason, I think, one among many, why people don’t think that these large animals play much of a role. And that’s because in the past hundred years we’ve wiped out most of the large animals. Whale populations are depleted, seal populations have declined, fish populations have declined. So of course we’re used to seeing an ocean that’s largely small microscopic organisms. If we were to go back to an ocean 100, 200, 300 years ago, I think things would be quite different. And then we would see how whales can influence something like the Gulf of Maine, where we’ve done our research.
How does this work? So you have that bottom-up cycle, right? You have photosynthesis occurring at the surface, and then those nutrients are being depleted as those plants grow. What the whales are doing is feeding deep in the ocean, about 100 meters, 200 meters beneath the surface, coming up to the surface and releasing these big fecal plumes, basically fertilizing their own gardens. In the present state, I mentioned North Atlantic right whales — there are about 350 of them on the planet. Do they have any big impact? No. Let’s be honest, 350 animals, no matter how big they are, are relatively small. But if you look back to when there were 10,000 whales in some of these systems, that’s when you see an influence that’s more than all the rivers going into these systems combined, more than human inputs now.
And that’s when you would really begin to see these differences. In areas where whales are still abundant — Hawaii, off the coast of Alaska — then you can also see these systems at work. But I understand this argument. I, you know, I live in that system. And I started out thinking about this when I first heard about the biological pump, which is largely driven by gravity and these microscopic organisms. And I realized that the whales are doing a pump of their own, so we call it the whale pump, to contrast with the idea that things are mostly gravity driven. But some species, like whales, seabirds, seals, no matter where they feed, they have to come up to the surface to breathe, unlike fish, right? So they’re always going to be moving nutrients either towards the surface or towards the shore, for those animals like seabirds and seals that are breeding on land.
Ross Kenyon: A similar process happened here with buffalo, where I think people thought that the plains would remain exactly the same even after a species was nearly exterminated, and that is not the case. In fact, they had basically created a fertile ecosystem of deep-rooted perennial plants that in many cases is just no longer as rich or as vibrant as it once was, or it’s much more fragmented through the animals not being there to create the environment. I think people think that animals just pass through environments rather than changing them, or they take the environment for granted. You’re nodding. So am I on to something with that?
Joe Roman: Absolutely. Maybe in one way we think of it as that people often think of animals as sort of passengers, right? You know, they’re following the food, and they’re just moving along that way. What we’ve shown is in many cases — bison are a great example. On land. We were talking about whales, but on land they can be drivers of these changes. They can enhance the sequestration of carbon because of the species of the grasses that they’re feeding on, and through nutrient cycling. Bison paddies, just like whale fecal plumes, have a big impact. They increase diversity because they’re creating wallows, right? So the bison are changing the habitat.
And, you know, I spoke to Matt Kauffman, who’s based out of Wyoming, for the book, and he had mentioned the first time they watched the way bison moved along the landscape. They’re supposed to be surfing what’s called the green wave. So they’re moving uphill or to northern areas to follow the fresh grasses, right? And a lot of the deer will just follow it along. But the bison stopped, and they’re like, they’re doing it wrong. Why aren’t they following the green wave? And then they realized that they’re actually choreographing it. They’re changing those ecosystems, those grasslands where they’re feeding. And by feeding on that, they’re keeping those grasses young, to have more nutrition. That’s good for the bison, but it’s also good for a lot of the other animals there.
So, looking at bison or looking at whales, those are two large-bodied animals that historically people might not have thought were very influential. But the more we see — and, you know, here’s the bad news and the good news. The bad news is we did an experiment already on this, in that we took out most of the whales, we took out most of the bison, and we got a hint of what would happen if we remove species. The good news is, for whales and bison, many species of whale populations are coming up. And now the new experiment is, well, what happens when these animals return? We’re getting all kinds of surprises.
Ross Kenyon: It’s an interesting way of understanding how humans process information — that they essentially broke a system and killed off one of the major processes that changed the environment, and then say, well, I don’t see any change happening now. But it’s because they intervened so early in the scientific development process that they just weren’t able to observe it, and then took it for granted. It’s more of a theory of sociology than of science or something, or nature. Is that...?
Joe Roman: Yeah, I think so. I mean, there may be some bias in this system as well. But certainly I think part of it is that when we look at ecosystems, a lot of the ecosystems that we study are manipulated with small animals because it’s easy and they’re relatively common, and rarely with those large animals, for the opposite reason, because they’re relatively rare. You have to do long-term studies, so you don’t see those impacts over time. I don’t know what the future holds for us. My life is dedicated to rewilding, to restoring these animals, to see more experiments of this kind. When we see bison, when we see whales — we could talk about sea otters — what happens when these animals come back? There are some expected changes, and then there are all the surprises that come along with them.
Ross Kenyon: Is there any way to know what we might see, or will it generally just all be surprises?
Joe Roman: There are models that we create, so we have an idea. So we know, for example, the impact of 1,000 whales in a particular area. What would it be like when there were historic numbers, two, three, four times that? So we can build models that way. But then, what we don’t know — for example, when humpback whales off the coast of Australia came back, and now they might be at numbers that they were historically. Amazing. They were down to like 600, they’re back up to like 25,000, after 25, 50 years of dedicated conservation. Killer whales started coming back and attacking the calves. And not only humans didn’t know what was going to happen — the whale moms had no idea. They had never been attacked by killer whales, so they were surprised and didn’t know what to do either.
So one of the changes was, it got us thinking about the nutrient subsidies of having these calves dying in this area, but also the behaviors of the moms and the calves themselves. What some of the moms started doing is moving towards the coral reefs in order to protect them, because from a killer whale’s point of view, you can live without a meal, right? So you’re not going to risk dying on top of a reef for a food source, but the mom might be able to save that calf, right? So the moms started changing behavior. And then there was also some indication of altruism. You started seeing some of the humpback males, even if they weren’t related, attacking the killer whales when there were calves around, and then also when there were other species of marine mammals.
No one really predicted this. And I could go on and on about all the surprises we’ve had here in New England. Gray seals, after the Marine Mammal Protection Act, came back. Few people thought, maybe sharks are going to come back too. And now great white sharks are fairly common in an area of Cape Cod where they were never seen in anyone’s lifetime — you know, anyone that’s living now. There’s a short-term change. Not everyone — some people like this. Surfers, maybe not so much. You know, on the West Coast, people have been living with white sharks for a long time. But on the East Coast, at least in the Northeast, that’s unusual. There are two surprises. We could go on and on with other examples of it.
Ross Kenyon: You talk about conflict as well, because most people want to think of conflict over reintroduction of species. I think that Yellowstone wolves is the first thing they think of. But you also talked about fur-bearing mammals in Alaska, where they’re changing the ecosystem, they’re no longer having these urchin barrens. And then fishermen are concerned that, hey, what’s happening to the shellfish that we depend on here? And maybe we need to actually restore the hunting balance that once existed, that makes sure that, hey, we’re able to maintain all of these systems in balance, and actually humans are a part of this. This isn’t something that’s outside of us. Maybe it’s something that we actually need to be involved in as well.
Joe Roman: Yeah, I mean, that’s a fascinating story. Another sad one initially, in that the sea otters were incredibly valuable for their fur. They have about a million hairs per square inch, so...
Ross Kenyon: I couldn’t even make sense of that when you wrote that. It’s hard to imagine.
Joe Roman: Yeah, it, you know, the first time I touched one of these furs, I can still remember it. The lushness — I can see why people love them. It is so soft and so thick, and you can see why people wanted to wear it, whether either for warmth or because it was a status symbol. Unfortunately, it was so valuable that hunters ended up wiping out almost the entire population from Japan down to California. So it existed across the North Pacific and remained in the mid-20th century only in a few isolated pockets, one in Monterey Bay and also on Amchitka Island in the Aleutians.
Why does Amchitka matter? Because that was an area where the Defense Department wanted to test nuclear weapons. This was in the late 60s, early 70s. Greenpeace was founded as a protest against nuclear weapons. And one of the fur-bearer biologists in Alaska went to the Atomic Energy Commission and said, you guys are going to have a problem when you detonate this underground explosive. You’re likely to have hundreds, maybe thousands of otters washing up with clear impacts of pressure, and it’s not going to look good for you. We have a solution. We can trap them, keep them alive, and move them to areas where they used to be found. And now I forget the exact numbers, but I think at least two-thirds of the sea otters on the planet are descendants of these otters that were moved out, shipped from Amchitka to places like British Columbia, Alaska and the Pacific Northwest.
Now, they got buy-in from fur-bearing biologists at that point, because in the late 60s, early 70s, the otters weren’t protected. So even the governors wanted it, because this is going to be money, we can just start trapping again. The thing that changed was the Marine Mammal Protection Act came through in the next couple of years, which meant you couldn’t hunt them. So populations, they lagged for a while and then they boomed, right? So there are now tens of thousands of otters in areas where they hadn’t been seen for decades, and the only group that can hunt them are Native Alaskans. So they have a traditional right to hunt them, and they’ve been hunting them and they’ve been processing the fur and even selling some of them. But if you’re not Native, you can’t hunt them, and populations have expanded.
The good news is what this has done — and this is a phenomenal effect of rewilding — is kelp. There used to be what you described as urchin barrens, so there were lots of urchins in the absence of sea otter predators, and very few kelp forests. When the otters came back, they love urchins, sea urchins. Sea urchin populations declined, and now lots of kelp forests have been restored in areas where they hadn’t been seen in many decades, in some cases perhaps for more than a century. Kelp forests — lots of fish and other species depend on these forests.
On the downside, sea otters have a really high metabolism. They have to eat a lot. They eat, I think, like a quarter of their body weight a day. So they are just consuming all the time, much more than — they’re about the size of a Lab, which eats maybe a couple of percent of its body weight a day. Because it’s cold and they have to keep warm and they don’t have blubber — they have that fur — so they’ll eat a lot of things on the bottom, including geoduck clams, including Dungeness crabs, including a lot of other benthic species that fishers really like and are used to having in abundance, because there weren’t these large predators in that area. That’s created a conflict in some areas. Some people love having the otters back, and some people hate them and really would like to reduce the numbers.
Ross Kenyon: Is it possible to determine the net commercial effect of having otters rewild? Does it lead to enough tourism to compensate commercial fisheries? Or how do you even start wrapping your head around the potential trade-offs here?
Joe Roman: That’s the right way to frame it. There’s trade-offs in this, right there, and not everyone’s a winner or a loser. Interesting: when I went out on some tourist boats in Sitka, Alaska, they were fishers, you know, the people. They were making money taking tourists out to see the otters and see the whales, and they were also fishing. For those people that have adapted, I think that trade-off is — I can’t answer for them, but I’m guessing it’s probably worth it. For those that have maintained traditional fishing practices, most of them would really like to see sea otter populations decline.
I spoke to Mike Miller in Sitka. He’s a member of the Sitka Tribe, the Indigenous tribe there, and he proposes their work is to reincorporate humans into the system. Right? Because humans used to hunt otters — Indigenous groups — in order to reduce them in some areas where they were harvesting invertebrates, and in other areas that were set aside where there were plentiful otters and kelp. So that’s one vision that Mike had proposed. He doesn’t want to eradicate them all, but he also doesn’t think — you know, not being able to touch these otters is not acceptable. And I can say, I’ve been to Sitka a few times, I’ve seen behavior since hunting has changed, and I feel — and this is anecdotal only — that now you see some of the otters are much more wary around boats than they used to be, because they’re now being hunted in ways they hadn’t been before.
Ross Kenyon: When Native hunters take otters, are they able to sell them to non-Native groups?
Joe Roman: Yes, it has to be a handicraft. So you can’t just sell the hide, you have to make something out of it, and there are rules about what that is. So they have to tan the hide and then create either an artwork or something to wear or something like that. And then you can sell it outside of the group. But you can’t sell the hide alone. The unprocessed hide, it’s illegal to sell.
Ross Kenyon: Right. You can imagine that being set up in a gameable way where, you know, they would just take all of the ones that they could and sell them to some huge manufacturing interest, right?
Joe Roman: That’s right. And to date it’s locally owned and Indigenously owned, and that has not occurred, and I hope that that would not be an outcome for the future, that it would be sold to some external company.
Ross Kenyon: As far as you know, even if it’s anecdotally, that system seems to be able to make sure that predators interacting with prey animals — you have to have that chase. And that’s one of the things that people who practice regenerative grazing are always trying to imitate. It’s one of the reasons why Yellowstone was transformed, because if the elk don’t know that wolves are watching them, they’ll just camp out and eat until they destroy their environment, essentially. So having that predator pressure, even if it’s human-generated, where humans are the predators, that’s important for prey animals to know that they can’t just camp out and not worry about anything, right? Like, that is a disruption, to not have that.
Joe Roman: Yeah, I mean, I think that’s a large question, but, you know, having the hunters in that system, with sea otters in particular, has apparently changed their behavior. It certainly lowered their numbers, and it appears to have an impact on the ecosystem as well. How much that is behaviorally generated, I don’t know. Maybe there’s some biologists have been testing that question, whether, even if we’ve observed some changes in behavior for the otters, whether that’s changed their feeding pattern. Perhaps wouldn’t be surprising. But at the moment, I think most people assume, or at least the folks that I spoke to, that it’s probably more of a numbers game: that when you’re reducing the number of otters, you’re changing the prey, or, you know, especially the benthic invertebrates in that area.
Ross Kenyon: I wonder if I’ve over-applied that insight, especially from terrestrial ecology, especially with regard to the examples I gave with wolves and elk, or even just how people choose to graze cattle. And also, like, what is gained if a humpback whale has to move into closer littoral seas where there’s coral and the orcas can’t get to them? Does that have some ecosystem effect that’s important to replicate even in the absence of the orca? Does that actually add something to this rewilding effort?
Joe Roman: Well, so the short answer is I don’t know, as far as moving it towards the coral system. Certainly sharks feed in that area, so they’re benefiting. And interestingly, in some of the historical breeding grounds off of Brazil, for example, the shark nurseries overlap with the whale breeding grounds. And possibly because the whales, which are feeding in high latitudes and breeding in low latitudes, they may be bringing all those nutrients in. That is, you know, a speculation, but a reasonable hypothesis for that area, that there’s some overlap. So some species are absolutely going to benefit from that.
What’s really been some of the fascinating work has been done in the deep sea. And in that case, we know that there are more than 100 species that rely on whale carcasses, that are only found on whale carcasses. Some of them including Osedax, which means a bone eater, a type of polychaete worm. It settles on the bone, mostly on the vertebrae of whales, and it doesn’t have a mouth, it doesn’t have a gut, it doesn’t have an anus. It’s not like any of the other animals I’m studying in the book. What it does, it has a root system — it’s almost operating like a plant, which is providing nutrients to the internal symbiotic bacteria that are providing the food for these worms. That’s just one of many fascinating species that are dependent on these whale carcasses.
In the deep sea, that may be true as well. In the shallow waters, we just haven’t — it hasn’t been as well studied, though. That’s exactly the paper that I’m working on these days, is looking at this nutrient transport across ocean basins, basically.
Ross Kenyon: One of the parts of the book that I respected your writerly abilities on is an elegy for the lost worms that would decompose whale falls. We don’t even know how many were lost just when whale populations collapsed during the hunting period, that we’ll never even know about. Why did you make me feel sad about that? It’s a weird thing to feel sad about.
Joe Roman: I’m sad about it, but you know, that was work with Craig Smith, who is at the University of Hawaii, really thought of this first, and then we worked together on a paper on it. But probably the first extinctions in the ocean were these worms and other deep-sea creatures, because we removed their only habitat, were these whales. They were whale falls. They were like islands in the deep sea. And once those whale falls started to disappear, then these animals — which, by the way, as adults they can’t move. So they land on that whale fall as larvae and they stay there forever, and then they will release more larvae towards the end of their lives. If those larvae don’t have any habitat, then they can blink out.
For me, I care about whales, I care about sea otters, but I care about all the animals in the ocean and on land as well. And I don’t have a bias. I mean, I love my North Atlantic right whales that I studied, but I also love the deep-sea animals that I’ve never seen alive, you know. But they also have a value to me, and I hope to others. And I’m glad that you responded the way you did. Then that means I’m doing my job in some small way.
Ross Kenyon: I think that’s right. Yeah. Let’s talk about the whale pump, because there’s a blog that got circulated several years ago. I work in carbon removal and carbon sequestration, and there was this idea of, is there some way to have carbon credits for whales? Is this a mockable idea? Does this actually make sense? I think people didn’t really understand how important this could be, or just going between the ocean column and, like, going up and down through various zones, and how this might actually sequester carbon in a believable way. And then there’s a whole secondary part of how to quantify this and track it over time. But can you explain just the basics of what a whale pump would even look like?
Joe Roman: Yeah. So we first proposed this idea working in the Gulf of Maine. And just like in your garden, different nutrients run out over time, right? You know, you might have to add nitrogen or potassium or phosphorus or whatever to your garden, or iron. Same thing happens in the oceans. When you have a lot of productivity, eventually the nutrients that the phytoplankton or the algae depend on run out, right? And in the Gulf of Maine, every year it’s nitrogen that runs out near the surface. You lose nitrogen, and then the productivity peaks — so growth is really strong, it’s called a spring bloom — and then in the summer it declines, because the water is stratified and all the nutrients are locked in the cold, deep waters.
Why do whales matter? Because they’re going across that barrier to feed all the time, multiple times a day. They’re actually helping to break down that thermocline, it’s called — so the difference in temperature. Not only are they going up and down through the thermocline and helping to break that down, and lots of animals do that, but they’re also coming to the surface to breathe. And in the deep sea, they’re not digesting. They’re basically shutting down most of their internal organs in order to save energy. And when they come to the surface, they rest, and that’s where they digest. And it’s also where they defecate. And we assume pee. We’ve seen some — it’s not as easy to see whale pee as it is whale poop.
So, you know, as I mentioned, the first time I saw it, I thought that’s pretty cool. But as a friend of mine, Dick Barber, said, you know, is it ecologically important, or is it a fart in a hurricane? It’s a big ocean, right? How much nitrogen are we talking about? Sure, there’s some nitrogen in those plumes. So we modeled, we counted up how much nitrogen would come in those plumes, and as I mentioned, even in their current depleted state, it’s as much as all the nitrogen that’s coming in from the rivers. So, a substantial amount. Importantly, whales are there in the summer, not in the winter. So when those nutrients are limited, that’s when the whales are bringing those nutrients up. In the Gulf of Maine, it’s nitrogen. In the Southern Hemisphere, the limit is iron, and whale fecal plumes are also iron rich. So there’s a whole Southern Hemisphere group that’s looking at this whale pump as well. So we’re finding it in different systems.
What we’re talking about in that pump is what you’d expect, going up and down, right? It’s bringing nutrients from the depth. And sometimes it’s not even that deep. They might just be recycling it, because whales are lazy, like any animal — if they can feed at the surface, they’re not going to dive. You know, why put all the extra energy in? So sometimes they’re just recycling those nutrients at the surface, and sometimes they’re bringing external nutrients in. And that matters in your question. You sort of framed this as carbon. Here’s where — as Daniel Schindler, who I was introduced to, who works on salmon, said, you know, ecology isn’t rocket science, it’s a lot harder.
And this is where things get challenging, because there’s a lot of organisms in the ocean, they’re moving around all the time, we barely know what a few of them are doing. And now we’re trying to say this is the effect of these whales on the carbon cycle. And it’s completely different what they’re doing. If they’re feeding at the surface, they’re mostly recycling that carbon and other nutrients, and that’s important, but it doesn’t have much drawdown of carbon, doesn’t have much impact on the carbon cycle. If they’re feeding at depth and coming to the surface, then they’re releasing those nutrients from an area where it’s been stored or not available — then that can have an impact on the carbon cycle. And there have been some estimates that have put it at as high as 7% change in areas where whales are found.
My colleague and I, Heidi Pearson, are very concerned about the economic valuations that have come out. I don’t think the science is there. That is way ahead of the science, the uncertainty that’s involved in this. If you put that there, you can say, sure, you know, a whale might be worth $2 million plus or minus $3 million, right? So now you’re saying, OK, well, maybe some whales actually are a carbon source. So we’ve been worried about those numbers. It’s a nice story, but to my knowledge it’s way ahead of the science, and it’s very speculative, and I wouldn’t put a dollar on it, that’s for sure. And I wish it were true, by the way. I want it to be true. But magical thinking isn’t gonna make it.
Ross Kenyon: So I think that was the general consensus too. I think it was most useful as a thought experiment of understanding what could actually happen here. What about something like iron fertilization of the ocean? You spend a lot of time talking about this. That’s been very controversial. I think most people still think of Russ George off of Haida Gwaii, just sort of renegade doing it. But there are also scientists who are very sincere who are trying to see, does this make sense? Does this actually add to the biological value of these ecosystems? Does it disturb it in some way? What’s the line in there? He says, if you give me a tanker full of iron, I can change the world. This is one of the scientists you talked to — 50 years ago said something like this.
Joe Roman: Yeah, yeah, probably. Victor Smetacek. So, yeah, I mean, I’ve worked with a panel on the National Academy of Sciences about carbon dioxide removal in the oceans, right. And one of them was this natural restoration, which is what I look at. What would ecological restoration mean? And it could be very high. It could be as much as a billion tons of CO2 a year, but the uncertainty is so broad that it could be a lot less than that too. So as a scientist, what’s the answer? More research, right? I mean, we just don’t know the answer. There’s just too much variability.
Unfortunately, we’ve put a lot of money so far into the research for iron fertilization, and I want to say this is not my area of expertise, but sitting on that panel there were scientists with excellent reputations, who really know their stuff, who completely disagreed on the effectiveness of iron fertilization. One of the people on the panel has spent a lot of time on that, and he, I think, is quite optimistic about that approach. And Victor Smetacek, who I spoke to, is, you know, a die-hard fan of that, and I respect both of them. But we also brought in scientists who said it’s just going to turn back up. So you’re going to fertilize it and most of that carbon is just going to be released back into the atmosphere. And the truth is, I think most people agree that most of the carbon is going to be released. But even if you could get a good fraction of that carbon to sink down to the deep sea, that can have a big impact on the global carbon. I don’t know the answer to that one. I wish I did.
Ross Kenyon: You know, I feel like in that case it’s another one where there have been some high-profile studies, but that’s another where I think it’s very much worth getting some more information. Because if it does work, it could — you know, as you know, I mean, on this podcast we’re facing one of the biggest challenges humanity ever has, and we have to answer that, and we’ve got to get to net zero.
Joe Roman: We all — well, all the science, and all of us climate scientists agree on that. But that’s not going to be enough. And that’s where these animals come in, the plants come in, or these other more physical approaches that are going to have some biological response. Adding iron — I think it’s worth pursuing. You know, from my view, I think what we’d want to do is, it’s worth spending money on the research, because if it is effective, then that could be a really important tool. So from my view, I wouldn’t dismiss it, but I also wouldn’t say, you know, put all your eggs in that basket either. I would say let’s — and I forget the number, we have it in the National Academy report, but it’s probably north of $100 million — invest that in research, and then we’ll get some better answers to how much of that carbon is likely to be sequestered.
And just to finish that thought, you know, that there will be trade-offs. You’d mentioned that earlier. And that in the deep sea, some of those areas are not used to having a lot of nutrients in there. So there will be an effect on the animals and plants that live in the oceans as well. So we just have to be mindful that it’s not free, or that just throwing a lot of iron out there, even if it’s effective, will have consequences.
Ross Kenyon: So much to think about with any sort of interaction with an open system like that. And even within the carbon removal community, there’s a big split between the closed-system purveyors — people are doing things like direct air capture, where it’s very easy to measure. Once it’s in a geological reservoir, it’s mostly, you just know it’s there. Open systems, though, have huge potential, and in many cases it could be cheaper. But they’re also interacting with complex ecologies like soil, like the ocean. How do you even conduct science when there’s so many variables? What does it even mean to conduct an almost non-replicable scientific study in the ocean? What does that even mean?
Joe Roman: Here’s someone who I’m very jealous of: Nick Graham, who I chatted with for the book. He has studied the impact of seabirds. What he has, and we don’t have with whales, is there are some islands — he looked at the Chagos Archipelago — that have rats, invasive rats, and other islands that don’t. And if you know what invasive rats do, they feed on the eggs of seabirds. So there are basically no seabirds on some of these islands and highly abundant ones where the rats aren’t found. So he has that system. It’s not in the open ocean, but it’s an oceanic system. And he’s looking not only at the nutrients that are coming in onto land by the seabirds, but also into the coral reefs and the waters around it.
And he found that the fish are bigger, and parrotfish are larger. There are a bunch of species in areas around seabirds, presumably because of the fertilizing effect of these fish. That’s a great study. It’s also in the wild. He didn’t have to kill anything, he didn’t have to manipulate, and he’s finding these differences. Why does this matter for climate change? In one exciting way, it’s the restoration of these large parrotfish. They feed mostly on dead corals. They poop sand. If you go to a tropical beach, in many areas 80% of the sand has gone through a fish, right? It is biogenic, as they say. So these fish, if they’re large enough and abundant enough, can actually, for these islands, keep up with climate change. They may increase the resilience of a lot of these island systems.
And that’s all in part, at least, thanks to the seabirds and the poop. You know, that one ounce of poop per day that they’re releasing in that area. And again, we’re just scratching the surface. No one’s surprised, really, that if there are seabirds, it changes the plants on that island, especially if there are no plants there. But that that is changing the coral reefs and the fish around the reefs, and the way the reefs and the islands are formed, is fascinating.
Ross Kenyon: Have you looked into other ocean-based carbon removal methodologies?
Joe Roman: So this again is not my area of expertise, but we were talking about sea otters, and there have been studies looking at the impact of sea otters and kelp restoration, which are substantial. So if you restore kelp systems, they can draw down quite a bit. You know, they’re very fast growing, so they draw down a lot of carbon. One of the open questions there is what’s the fate of that carbon. How much of that is, you know, are herbivores eating it and it’s just released, and how much was just washed into the deep sea?
And one of the numbers that we have — again, these are colleagues that I worked with for that National Academy of Sciences report — is if it sinks beneath 100 meters, then that’s going to be, that’s 300 feet, that’s going to be sequestered for a certain amount of time. But it’s really not till you get to 1,000 meters, a kilometer, or thousands of feet, that you can expect, at least in certain areas, that that could be sequestered for more than 100 years. And that’s the number we’re looking for when we’re talking about carbon removal.
You know, you’d mentioned that whale pump. Yeah, we know it can help enhance carbon storage or carbon fixation, but we don’t know how long that lasts. Is that a matter of days, weeks, months, years? But if we want to get to the 100-year gold standard, then that has to fall into the deep sea. And that’s the question with kelp. You know, and again, we could talk about two different scientists. Some have put out some really fascinating numbers for how much the sea otter can impact the carbon cycle. And others are like, wait a minute, what’s the ultimate fate of that carbon? And I think there’s a trade-off there.
As a scientist, this is an exciting time to be a scientist, when you don’t know the answer. But it’s also frustrating, because you talk to policymakers and they’re like, well, just give us an answer, you know. I mean, how are we working with so much uncertainty? And I agree. I have to say, before I started this book, I knew a lot more about animals and their impact on the world than I do at the end. Like, now I have more questions than I ever did, really. Because, like, oh my God, every one of these systems opens up the opportunity, opens up new questions and the opportunity for more studies. And I know that isn’t always satisfying, but that’s the way it is.
Ross Kenyon: It’s at least job security.
Joe Roman: It depends. The ultimate job security, right. Yeah.
Ross Kenyon: Keep scientists off the dole, basically. Number one goal right there. Are you feeling optimistic about the future of rewilding? Are you very concerned? How are you feeling right now?
Joe Roman: Today I’m feeling more optimistic. I mean, because we’ve chatted today about quite a few success stories, right? We’ve spoken about sea otters. Great whale populations in the 1970s were on the edge of extinction. It’s hard to imagine, if you go to places like Hawaii and Alaska now, if you’ve ever been on a whale watching boat, that that wouldn’t have happened 50 years ago. There was good policy under the Marine Mammal Protection Act, the Endangered Species Act, that restored these species. Ultimately, for something like sea otters, bison — they were also on the edge of extinction, they’re nowhere near back to the numbers they should be. But I believe that the numbers are going to increase. Native groups want to have them on their land. People want more of a natural migratory pattern. There’ll be obstacles to it, but I think the future for those animals as well is good.
Wolves are another great story, right? So you mentioned the wolves of Yellowstone, where really they had been hunted almost completely out of the lower 48, you know, until the 1990s. However, you know, on the other side — so there’s the cause for optimism: rewilding, when we put our minds to it, it can be effective. But there are, as we mentioned, those deep-sea worms that we never see. There are thousands of species that don’t get the attention of whales, sea otters and wolves, that we need to pay more attention to, and that often means more funding. In this case, it’s not really about research so much. It’s often just like, give some money to the conservationists.
And as we know, it’s not about managing the animals, it’s about managing the people, right? It’s about managing what people are doing. You know, typically it’s not like that. Sometimes you can just drop an animal somewhere and it’s going to do well. But often it’s also about managing expectations. Some people call it slow conservation, prepping, right? Don’t just release the wolves in Yellowstone and hope for the best, but also have meetings and, you know, have the expectations in groups. So what’s the impact of a sea otter or a wolf in this area? So setting those expectations. I’ve met with people here in New England — we haven’t had a wild puma or mountain lion here, except for ones that have passed through, a breeding population, well over 100 years. There’s a possibility that it’s going to have to be, if in the short term, we’re going to have to release them. But there’s a possibility right now that they can be restored to this area.
So there’s the good news, but we also need to think about the plants, we need to think about the habitat. And one of the numbers that I came up with in the book that fascinated me and is quite worrisome is the amount of biomass on the planet. Mammalian biomass: 60% are cows, pigs, sheep and other domestic animals, 36% are humans, and only 4% of all the mammals on the planet are wild. That includes whales, deer, all the mammals, wolves, all the ones we’ve been chatting about. Until that number goes up, it’s hard to really be optimistic that we’re going to get anywhere. Now, we have to save that 4%. But we also need to think of a way — and there are many different directions, and it’s not going to be easy, no matter what path you take — where we could increase that sliver of pie so that wild animals also could have a place on the planet. By the way, these numbers are similarly concerning for birds, though not as severe.
Ross Kenyon: I can understand intuitively why humans like simplifying their environment in this way. Releasing mountain lions, even if it has some potentially only abstract effect — I suspect it will be much more than that — but, you know, for every mountain lion you release there will be X number of maulings that will happen. Same with in Southern California too, where a hiker gets mauled and such and such. You say, is it worth the ecosystem value of this thing? I keep chickens, and I am constantly battling raccoons and trying to make sure they do not steal my chickens. And part of me just thinks I would love to just kill these raccoons. I suspect they have an ecosystem benefit even in an urban environment to keeping them here. Maybe they do, maybe they don’t. I don’t actually know. But in my heart I want to simplify the environment and kill the predators and deal with that.
That being said, a little owlet fell inside of a predator net that I had, and I had to spend an hour beautifully cutting it out. It was so patient and so loving, and I don’t know, I probably anthropomorphize this thing too much, but it was elegant and delightful. But I know that I paid this price. For every chicken I protect with this net, I may have some sort of beautiful baby owl that falls into it, some of which they may get caught around their neck and die. And how many animals am I willing to trade off for my chickens? How many owls is it worth? And wouldn’t it be better if I could just get rid of the predators that even create this problem in the first place, specifically raccoons?
That’s sort of the calculus that I don’t think people who do not interact with animals in a non-pet-oriented way even understand. I think I’ve only understood this since keeping animals that are closer to farm animals than to pets. But even me — I’m sympathetic, I read your book, I liked it, I want to do a podcast about it — and even I have these simplification desires inside of my soul. What do I make of that?
Joe Roman: Yeah. No. And I think that is a long history, human history, is that we’ve done that on purpose. You know, we’ve had bounties on mountain lions, and it worked, and on wolves. And so we’ve gone out and they’re considered vermin and you can hunt them. So that is a natural response, I think, to a system. And that comes with some benefits, right? You don’t have to worry about predators. But it also comes with costs too. And they’re ecological costs, and they can be economic costs too. When you simplify the system, diseases rise often. So you have abundant cows or whatever, any species, or humans — when you have large numbers moving around the world, as we’ve seen with COVID, but lots of other diseases, those disease patterns can move fast through a system, and there’s less resilience, whether it’s for your domestic animals or for humans or the remaining wild animals that are there.
Biodiversity — there’s been several studies — can reduce the movement of infectious diseases, because of several different patterns. One is predators can feed on sick animals, so the predators can have an impact, as well as what’s called a dilution effect. So if you have a bunch of different species in the system, that disease doesn’t run through the system as fast. And Lyme disease is an example of this here on the East Coast. But there are several other studies, schistosomiasis as well. So it’s mostly zoonotic diseases, diseases that animals get. When you reduce that to just a few animals, it may seem simpler, but you know, then you’re gonna have — and we’ve seen this time and time again with domestic animals — large disease events where people end up killing their entire herd or their entire group because of those diseases, or you’re relying on antibiotics and others. That’s one of the trade-offs when you’re removing, you know, whatever ecosystem benefits and costs in those systems.
And you’ve mentioned, I think, regenerative agriculture or agroecology, where there are attempts for people to share the landscape with wild animals, right, and to include those ecological processes. I lean in that direction, though I’ve chatted with someone for the book who says that’s not enough, that that comes with trade-offs too. But I personally want the wildlife there. I’m not a farmer. I, you know, I can look across the way and there are farms here in Vermont, and you know, we have pets. So they’re at risk from the coyotes and other species that are out there. But personally, I think they have a space, as deserving a space as we do, to this planet, to the area around me — understanding maybe you don’t want them in your backyard, you know, you don’t want the raccoons in your backyard, and there’s some trade-off there. From my view, having those wild animals is worth it.
And I think a lot of that’s true for a lot of farmers around here. Now, do they want the pumas back? I wouldn’t go so far. You know, I don’t know if they want the mountain lions back or not, but I think a lot of people value the owls and the other wild animals that are out there, which can provide some benefits as well as some costs.
Ross Kenyon: There have been successful ways to manage, because obviously wild predators versus ranchers, farmers — this is a long-running fight. But there have been compensatory programs that have said, hey, if you have animals killed by a predator, we’ll just pay you. And in fact that payment has reduced a lot of conflict, in my understanding. So there are ways to manage this too. It doesn’t just have to be a zero-sum game, we get predators or we get farm animals. There’s also ways to say, like, we need both, and we’re willing to pay for the difference.
Joe Roman: I agree totally. I mean, so, you know, from one view, why does one group have to pay more for conservation than others? And I agree that’s not fair. We need to figure out a way to make it fair for the farmers, Indigenous groups. So the local groups there need to have buy-in and a say in our conservation decisions. Absolutely. And one way is towards compensation. Other ways are — well, I mean, there could be many different ways, but that would probably be one of the first ones — is the money, is education, or, as we’ve seen in lots of areas even around Yellowstone, where you get these booming ecotourism and values around the wild animals themselves.
Ross Kenyon: Yeah. What’s next for you, Joe? Is there another book coming?
Joe Roman: Well, yeah, I mean, one of the other things I do work on — it’s another eating story, but it’s called Eat the Invaders, and the idea is using human appetites to reduce invasives. Because we’ve been chatting today, and most of my life I dedicated to trying to reduce human impact on wild systems. But there’s one way we actually want people to go out and reduce wildlife — non-native wildlife — and that is invasive species. They’re often delicious. They’re easy to find. I’m sure if you went in your backyard right now you could find a weed or two. That would be true for any of the listeners as well, as for me.
But if you live near the ocean, there are lots of non-native species, and it’s an easy to harvest, delicious meal. Often people eat them in their native habitat. They come somewhere new and people are like, well, why would I eat this periwinkle snail or this green crab or [unclear] or something. But a lot of times these things were brought here intentionally. So it’s a bit more tongue-in-cheek approach, but I think it’s one that can help people learn about the ecology of the area, have a really good meal, get to know some of the chefs in the area. Foraging has really taken off in the past couple of years. So that’s another one of the projects that I work on, is trying to think of a new approach to conservation that gets people out and thinking about the animals and plants that surround them.
Ross Kenyon: Yeah, I’ve — I’m looking at this list here. I’ve been involved in the hunting of wild pigs before, where they just destroy the land in Texas and landowners are like, please, please, they take over, and that’s all that can live in these places. I’ve had lionfish before. In many places you’ll go where there’s no fishing or no hunting, if you have the right kind of sling, lionfish are just always on the menu, and it’s good too. It’s a lionfish to eat — don’t get poked by them. But also there’s things like Asian carp taking over the inland waterways of the United States, which is also, if you can eat as many of those — I don’t think you could probably eat enough of those to make a dent in them. But if you’re going to eat anything, it seems like those are probably good places to start.
Joe Roman: I think so. Lionfish I consider like the gateway species, because it’s a white firm meat, you know, and it’s — but, like, who doesn’t like — you like fish? You will like the taste of lionfish. And, as you noted, be careful with the spines. But that’s a great example. And what’s changed since I first proposed this idea is, we’re not going to eradicate — almost in no case are we going to have species disappear because of this. Invasivorism is one term. But there could be something like functional eradication: that is, if you reduce the numbers enough, then that’s going to have an impact on ecosystems. And we’ve started to see that for lionfish, in areas where the populations declined, native biomass of fishes has increased in those areas.
So that’s what we’re looking at, because practically speaking we’re not going to eradicate lionfish through spearfishing. They’re too deep, it’s inconvenient. And so we shouldn’t set a false expectation. However, we should also note that that is the goal. We’re not talking about sustainability here. And often when you talk about it, it’s like, wait, what? You don’t want it to be sustainable? Like, no, we want to actually reduce the numbers where it’s not worth going out and looking for them. So, you know, we need to be clear about what our goals are here.
Ross Kenyon: Well, I’ll put a link to Eat the Invaders in the show notes here. That’s what you’re going to be working on next. You’re going to be diving deeper into that.
Joe Roman: It’s one of the projects. The other one that I’m particularly working on this afternoon is a scientific paper on what we’ve been discussing earlier, which is called the Great Whale Conveyor Belt, and the movement of nutrient subsidies across thousands of kilometers, thousands of miles every year, by species like humpback whales or fin whales or blue whales. They feed in high latitudes. They breed in low latitudes. They don’t feed in those low latitudes. They basically go six months without eating. But they’re peeing, they’re metabolizing, they’re releasing lots of nitrogen and phosphorus. And if you’ve ever been to a place like Hawaii, the reason the waters are so clear is because they’re nutrient poor.
So this is one way that whales can provide these subsidies across vast distances, in their pee, also in the placentas that they release, and calves — just like any other mammal, infant or calf mortality is pretty high. So we were chatting about this earlier: sharks and other fish species can feed on it. They even feed on the skin of these animals, because they’re constantly sloughing. So we’re kind of like, what we do with the whale pump, you know, how important is this? So that’s our question now: how much nitrogen are we talking about? What’s the impact on those local — the local ecosystem? Stay tuned. Should be out, I hope, in the next month or so.
Ross Kenyon: Thanks for being here, Joe. I learned a lot. I appreciate your effort to be a science communicator and to share this with the wider world. I think it’s important. It’s also just a really fun book. I like the focus on so many of these case studies. I think it’s very accessible to a layperson. So thank you for what you do, and thanks for being here.
Joe Roman: Yeah, thanks for inviting me, Ross. It was great chatting with you.
Ross Kenyon: Thank you so much for listening. If you could please subscribe and give us a great rating and review on Apple Podcasts, or a rating on Spotify, that’d be much appreciated. It helps us get our content out to more people. You can sign up for our newsletter at nori.com, follow us on social media, and we will catch you next time.
