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Tristin McHugh

[00:00:00] Michael Hawk: When I think of the ocean, it’s almost like a book. The cover of the book or the surface of the ocean prevents you from seeing inside.

[00:00:06] There’s a title, the ocean, which gives us a hint about what it is. And we probably have some preconceived ideas. When you’re looking at a book, you can see the graphics or the author, and maybe derive a little bit of knowledge, but we can’t really see inside to truly understand the stories that it wants to tell. And one of those stories is about a forest.

[00:00:25] Yes. There’s an underwater forest that serves multiple critical purposes for life on earth. And I’m talking about kelp forest. They generate oxygen, store carbon, balance chemical cycles, critical for life, and they support amazingly biodiverse habitats. But kelp are in trouble. In fact, 96% of the kelp forests in today’s guest region have disappeared in just a few years and the reasons are multiple and the solutions unfortunately are unclear. And that guest I mentioned is Tristin Anoush McHugh and she’s the kelp project director for the nature Conservancy in California. I knew I had to meet Tristin after seeing a wonderful short film called Forests Above and Forests Below. It was written and narrated by Tristin and it’s a powerful six minute film. Check the show notes for a link it’s on YouTube. And Tristin didn’t disappoint. Today.

[00:01:16] She helps us understand what kelp are and why they’re in trouble. We discussed the complex relationships they have with other amazing creatures, like sea otters purple urchins, and sunflower sea stars. And speaking of sea stars, we also discussed the dramatic impacts of sea star wasting disease. As well as how warming oceans might be disrupting kelps ability to reproduce.

[00:01:38] I found this conversation to be incredibly enlightening and extremely important. Oceans are disproportionately important. In fact, for our climate and life in general. Yeah, we all too often keep that proverbial book that I mentioned closed up and sitting on the shelf. So let’s open it up today and without further delay, Tristin Anoush McHugh tristin, thank you so much for carving out some time for me today. I’m really looking forward to learning a bit about Kelp.

[00:02:03] Tristin McHugh: . I’m so excited to be here. Thanks for having me.

[00:02:06] Michael Hawk: the reason I reached out and we’ve been talking about this already, so you know this, but for the audience. I attended this fun, short film festival that was put on by the Peninsula Open Space Trust here in the Bay Area. And one of the films was called Forests Above and Forests Below. And I was so inspired by it that I knew I had to do an episode on Kelp, and I wanted to find the people who made this film specifically.

[00:02:31] And I looked at the credits and I found you. So here we are today.

[00:02:36] Tristin McHugh: That’s such a cool finding story. I haven’t had that one yet, so that’s a good one. I like it.

[00:02:40] Michael Hawk: And I’m going to share that link to you, by the way, in the show notes, so people can see it’s six and a half minutes or six minutes or so. It’s definitely worth a watch. So let’s just jump straight in. What is Kelp?

[00:02:52] Tristin McHugh: Yeah, that is a great starting question. Kelp is an organism and a habitat. Kelp in itself is a photosynthesizing organism, like a tree, but it’s underwater, so it creates this beautiful dimensional structure that many organisms use for food, habitat, and shelter.

[00:03:12] Michael Hawk: when we’re thinking taxonomy and the tree of life, Where is kelp in that picture?

[00:03:20] Tristin McHugh: Yeah. When we think about the tree of life, kelp and seaweeds, algae are some of the most early on. Organisms that ever inhabited this planet, right? They are truly the foundational species to which all life depends on, frankly.

[00:03:33] And they’re very diverse as well.

[00:03:35] Michael Hawk: so it’s a type of algae.

[00:03:38] Tristin McHugh: Yes kelp is actually a subset of algae, right? So we have, I would say in layman’s terms, like microalgae. And you can think of those as your little tiny phytoplankton, like other small photosynthesizing organisms, and then you have macroalgae, which we think of as the ones that you can generally see with your eyes.

[00:03:56] And within that macroalgae category, there are actually these three kind of functional groups within that. There’s the brown algae, which are kelps, like the true kelps. There’s red algae, and then there’s green algae. And so each of those have their own, thing going on in terms of what they do, how they reproduce, and all of that.

[00:04:14] But really, when we say seaweed, we’re encompassing all of that. When we say kelp, we’re only really talking about brown algae.

[00:04:21] Michael Hawk: And I’m just going to assume I’ve learned a bit from past guests. So when we talk about common names like brown algae or red algae, that they aren’t always going to be brown. They aren’t always going to be

[00:04:31] Tristin McHugh: That’s right. Yeah that is, it actually comes down to most of their pigmentation too. Each of these types of algae have their own types of pigmentation to them, which further classify them into those genres, among other things, of course. But to the eye, no, most red algae actually looks pretty, pretty brown.

[00:04:49] And then brown algae often looks pretty, brown, but also green and red. It’s pretty mixed. But really what it comes down to is When you’re looking at these organisms, you can tell functionally And morphologically, they look quite, in their category.

[00:05:05] Michael Hawk: Got it. And for people like me who haven’t had the opportunity to go diving and really observing. from beneath the surface of the ocean, what kelp look like and a kelp forest looks like. Can you help paint a picture of, we can focus on your area. You’re in Northern California, correct?

[00:05:24] Tristin McHugh: Yeah, that’s right. I’m based in the Mendocote area. Mendocino Coast.

[00:05:28] Michael Hawk: So what does it look like? How, when you experience a kelp forest, can you just help us understand what it is that you’re seeing?

[00:05:35] Tristin McHugh: Taking a step back like when we’re talking about where a kelp forest is, we’re talking about these cold temperate reef areas, right? California in itself, As opposed to a coral reef system, we have a temperate reef system. So at its foundation, we have rock, and then building upon that rock is everything else that attaches to it, like kelp, right?

[00:05:55] Michael Hawk: Interrupting for a second. I just wanted to explain what a reef is because it took me a while to really understand the full scope. We often hear of coral reefs, but there are other types of reefs. So it definition that I found basically says a reef is a system of ridges that rise near the surface of the ocean.

[00:06:14] So very often there’ll be near a coastline and these ridges could be rocks. They could be sand, they could be coral or a number of other things.

[00:06:24] Tristin McHugh: And so there’s no root structure, but what you get is this organism with a holdfast that almost looks like a root system, but it’s not. physically anchoring itself to the seafloor. And then from that holdfast, you have a stipe, which is like a trunk. Think of a tree trunk that extends upward to, and when I’m talking about kelp canopies a canopy forming species like bull kelp or giant kelp, we’re talking about them extending all the way from the seafloor to the surface of the ocean, and then from there, they create these very rich, beautiful canopy structures.

[00:06:57] That trestle down, sunlight’s coming through them, and they’re gorgeous, right? We’re talking about these beautiful underwater trees. And then, that’s just the canopy, right? When you go back down to the seafloor, then that’s when you get those smaller sometimes also smaller kelps, but then also your red algae, your green algae, you have your corallines, Then you have your anemones attached to the seafloor and sea stars cruising around and some urchin, right?

[00:07:22] It’s like you have this full ecosystem right before you in a way that does parallel terrestrial forests. You can think about that understory I just told you about like ferns, right? Ferns or bushes or grasses and flowers. Like we have that same sort of general structure underwater.

[00:07:39] Michael Hawk: Presumably then there are various species living in this system that specialize in that understory or maybe in the mid story or the canopy.

[00:07:49] Tristin McHugh: That’s exactly right. So based on, the organisms itself, if you were just to take a snapshot. And look out, you would see diving birds pelagic birds just diving in the ocean. You’re going to see little fish. You’re going to see those benthic creatures like the sea stars, like the urchin cruising on the seafloor, and then harbor seals, and I’ve heard whales before.

[00:08:10] It’s just a beautiful environment.

[00:08:13] Michael Hawk: I wish I could experience it. And I might ask you either as part of this interview or after the fact for some resources, some pointers, videos, and things like that. In addition to the film that I mentioned before that that I could share so people could, really experience it as best they can, through the computer screen anyway.

[00:08:30] Tristin McHugh: Yeah that’s fair. I think, with those visuals, it’s really hard to describe, but really I do implore people to just, right now I’m looking outside my backyard and I see trees and I see the bushes, like I can almost replace them with some of the things that I see underwater and I conceptualize it in that way as well.

[00:08:47] So I just do implore you to think about like a terrestrial forest and those same functional groups you could almost replace Put water in it and that’s generally what you get.

[00:08:58] Michael Hawk: Yeah. And then you have that kind of magical. swaying of everything as the water is moving as the tides and the surface waves and everything else are affecting

[00:09:10] the life.

[00:09:11] Tristin McHugh: And yourself, right? You’re a visitor, in that system and everything knows it, you know it. And when you pause for a second, I’ve been underwater before, and just, you’re not supposed to hold your breath when you’re scuba diving, but when you just take a quick pause and listen, you can actually hear the cracking of shrimp and other organisms living in that system, It’s very dynamic. It’s very rich. And it’s also, depending on the time of day that you’re diving to the sunlight also alters the way that organisms. Behave with each other and among each other. So it’s quite beautiful to be under there and just experience it.

[00:09:47] Michael Hawk: So now that we have just a tiny taste of kelp, I want to step back and learn a little bit about you and how you found your way to study in kelp. So let’s go way back, actually.

[00:10:02] Have you always been interested in nature?

[00:10:05] Tristin McHugh: yes, for sure. My brother and I would just spend so much time outside and fortunately my parents really encouraged that. And I think I was always fascinated by water specifically, anything that creeks, rivers, lakes, ocean, , there was something about. Being in that medium that was just serene, tranquil, spiritual that I just fell in love with water itself.

[00:10:30] Michael Hawk: Did you grow up around water?

[00:10:32] Tristin McHugh: Yes and no I grew up like East Bay area if you know where Mount Diablo is

[00:10:37] or, you know, yeah at the foothills of Mount Diablo. I grew up there and spent a lot of time visiting the ocean.

[00:10:45] Michael Hawk: So you had some affinity for water and you were near the ocean, not on the ocean. What was the next step then to get you into oceanic research and kelp specifically? ,

[00:10:57] Tristin McHugh: that’s a good question. So I think I knew at a young age, I was just like so in love with water. But then around high school, I took a marine biology course at my high school. And I just knew that there was something like, I just couldn’t put the books down. I couldn’t stop looking at it, couldn’t stop thinking about it.

[00:11:14] And it just consumed me, you know, I wanted to know everything about this place. And . It wasn’t even about kelp at the time. It was about, that big charismatic megafauna of the dolphins, the whales, the gateway animals, and yeah, I just never shook it. And I ended up applying to UC Santa Cruz for marine biology and I was accepted and started there the following fall.

[00:11:37] And it just, just went from there. It just never really stopped thinking about it, working on it. And just really immersed myself in the literature. And it wasn’t until towards the end of my college career that I started really scuba diving. And that was when I really tipped over into kelp because that is what we live right next to.

[00:11:57] And that’s where we were diving.

[00:11:59] Michael Hawk: mentioned. The gateway animals the mega fauna that started you on this pathway. Did you have any experiences that really hooked you? It seemed like the gravitational pull was taking you there. But I’m curious if there was one day where you’re like, yes, this is the system.

[00:12:16] These are the organisms that I’m going to spend the next X number of years with.

[00:12:22] Tristin McHugh: Yeah, it’s a great question. I think I was in college I would say I was like speed dating a lot of different types of marine biology, right? I was considering like deep sea, thinking about dolphins still, and just like the way that their physiology allows them to dive for long periods of time.

[00:12:37] That’s fascinating. I worked in the pinniped, which are like your seals and sea lions, pinniped cognition and sensory systems like that excited me. But when I, I went scuba diving in Monterey, that was the first time I got to be underwater in my backyard, that is like California. That is our underwater backyard and I got to do that and I looked around and was like, what is this?

[00:13:03] How did I not know this was here? It was just like mind blowing. And so the diving I think just being able to immerse myself in that system Silently, … You don’t have to like talk to other people about the experience You’re just like in your own experience in a lot of ways It was that moment that, I looked around and was like, wow, this is something, and it just hooked me from there,

[00:13:26] Michael Hawk: Yeah, I could almost imagine it being a little bit like, you hear about people that go in those sensory deprivation tanks, but in this case, you have a few senses that are deprived when you’re scuba diving, but then other ones then get excited and amplified.

[00:13:42] Tristin McHugh: Yeah, that’s right. I just remember like one specific moment. I remember going out for like my first dive in cold water and, I was nervous about all the things on my gear and just all the stuff I had to remember. And then it just came naturally, right?

[00:13:59] You’re like descending. And I remember looking up and seeing this like beautiful sunlight coming through the top of the, giant kelp canopy, and then seeing these young of the year rockfish, like these teeny tiny little fish like darting through the canopy, and that just it blew my mind. It was unlike anything I had seen before, so that, that was like one experience that just tipped me into that sphere that I’ve never left.

[00:14:23] Michael Hawk: Yeah. And I guess where I’m struggling at the moment and where we go in this conversation is there’s the big picture of the system and everything it does and how it’s all interconnected and interlinked. And then there are some of the specifics about it and maybe a way to. balance that as we get in deeper into kelp life cycle and everything else is I think a lot of people are familiar with with sea otters and the relationship that sea otters have with the kelp system.

[00:14:52] So maybe we can start there. Can you tell me a little bit about that relationship, about what sea otters and kelp do together?

[00:15:00] Tristin McHugh: Yeah, so sea otters and kelp, I think because we see sea otters on the surface of the ocean, and they’re really cute and adorable we kind of gravitate towards that relationship between that floating mammal on top of this kelp, but really the otter is an organism that interacts in a kelp forest, similar to the seals and sea lions, and their role is as an apex predator.

[00:15:24] And so they have this foundational role in kelp forest ecosystems, similar to that of sunflower sea stars in a way, where they have a disproportionately strong impact on a system. And so to further that point, what we know about otters is that they are really great hunters and they eat a lot of food, right?

[00:15:44] And by eating a lot of food, they serve their as a almost moderator in the, the type of food items they eat. And one that they eat in particular, sometimes, depending is a urchin, right? And so when I think of interest, especially now is the way that sea otter, urchin, and kelp forests interact with each other and how those those strings pull on each other.

[00:16:10] Michael Hawk: for those who have not experienced urchins, can you tell me a little bit? Because I think we’re going to talk more about urchins throughout the course of this discussion. But what, what does an urchin look like? And what’s their body plan and, what are they doing?

[00:16:22] Tristin McHugh: what are they doing? Yeah, urchin are probably one of the most impressive organisms in the world, I would say. There are hundreds of species all over the world, and in California we have I think up to four species, but two predominant species. One is, and they’re both native to these waters, One is the red sea urchin, which is a bit bigger, and the purple sea urchin, which is a bit smaller.

[00:16:47] But all urchin kind of follow the same body type generally. So think about an urchin as an organism that is Small, rounded, has a rounded top body and then lots of spine sticking off the back, almost like a pin cushion.

[00:17:02] If you want to think about a pin cushion, that’s basically an urchin. And they have their mouth at the bottom, and by bottom like they’re going to be cruising around the seafloor where rocks are. Their mouth is on the bottom there and they broadcast spawn, and so they need to be close enough to each other for them to spawn.

[00:17:20] They have a larval stage where their spawn goes out. into the open ocean, comes back to shore, feels turbulent, and then they settle. And so they’re an invertebrate and they’re highly effective. They’re, they’re a very efficient, very robust, very resilient organism that is known to be like a habitat or ecosystem indicator whether or not like their presence or abundance is shown.

[00:17:45] Michael Hawk: And beneath all those spines do they have a hard shell or, what’s going on there?

[00:17:50] Tristin McHugh: Yeah, beneath their spines they have this hard calcium carbonate shell, when you pick them up, they’re spiky. And then they also have these little tube feet that come off in little pincers as well. So they, if you looked at one you’d almost see like angel hair pasta coming off of them, like in between the spines, but this more I’m talking about a purple urchin, like this rosy purple color.

[00:18:10] I think they’re quite beautiful, frankly.

[00:18:13] Michael Hawk: Let’s now put some pieces together a little bit more fully I suppose.

[00:18:18] We’re talking a bit here about west coast. And as I understand it though, there are kelp all around the globe. you first of all, is that accurate? Are there really kelp everywhere? And then how are those systems similar, maybe different species, but similar in their function and how they look

[00:18:32] Tristin McHugh: Yeah. This is what blew my mind personally, was just thinking about like the renaissance that kelp is having right now in our global acknowledgement of where they operate, right? We know corals are in tropical places, right? Because typically those are the places people go to and they can get in the water somewhat comfortably and see them, right?

[00:18:54] We see that clear water and we can see corals. And they’re all over the world, ? Think about that same premise applying to cold water places. So when you go somewhere where it’s like Greenish water, turbid, and you’re questioning if you’re going to get in the water because of the temperature.

[00:19:09] Chances are, that is a place where , kelp and kelp ecosystems or algae systems can persist. And kelp is found all over the world, these ecosystems but they’re highly vulnerable in ways that we are just starting to understand, ? All over the world, we’re experiencing habitat loss for kelp.

[00:19:28] With corals, with mangroves, with these other systems, and that includes kelp forest ecosystems as well.

[00:19:33] I think, one thing that would help me as I seek to understand these systems a little bit more. You mentioned that, that kelp, they don’t have roots. They have these holdfasts. How it makes me wonder, like, how do they grow?

[00:19:47] Michael Hawk: What is their life cycle?

[00:19:48] Tristin McHugh: Yes, so kelp and algae, but specifically kelp and the canopy formers, are some of the fastest growing organisms in the world. So they can grow up to two feet per day, which is incredibly quick if you think about it in relation to bamboo or other fast growing species that we think about on land, but they can grow very fast and produce a vast amount of biomass, like a lot of it, right?

[00:20:14] And again, create this three dimensional structure that alters their surrounding physical environment. So as they’re growing super fast that typically happens in spring. And so I’m going to refer to kelp, maybe it’s kelp canopies for California and just. How we think about kelp is those canopy forming species and bull kelp, for example, which is what we have basically north of San Francisco that organism is an annual, right?

[00:20:38] And then generally south of San Francisco, we have Giant kelp dominated systems, right? And so that is a perennial species. Actually within the state of California, if you looked at it, we have an annual to the north and a perennial to the south, which kind of changes their life history characteristics and what you would generally see on a year to year basis.

[00:20:58] Let’s just focus in on bull kelp, for example, with this annual species. Typically what you would happen is, let’s go with the calendar year. We’re in spring right now, and so kelp is in its small little seed stage, and it’s now starting to take off. Light is becoming available, the day is getting longer upwelling, which means The strong winds are coming, moving that warm water off the top of the ocean creating that moment for the cool nutrient rich water from the deep to rise up and that’s creating like the most enabling beautiful conditions Hopefully for kelp to grow. So then what happens is springtime they’re growing. They’re growing. They’re like these little lollipop stage Towards the beginning of summer.

[00:21:40] They’ll start hitting the surface of the ocean and then once it’s summertime towards the end like August, September ish, that’s when Bull Kelp will start creating its reproductive parts, which are sorus, right? Like sorai, which is similar to the way that if you want to think about spores, as relation to like fungi, for example, So they’ll create these like little spore packets that will adhere to the blades. So like the top of the bull kelp on those blades that you see, you’ll see these milky patches and that those are the spores. That’s what is going to create all the little babies. And so those, abscess, they release off of the kelp and then sink to the seafloor, typically, hopefully.

[00:22:23] And then they, males, females find each other, they spend a little time doing what they do, and then hopefully they’ll attach to the seafloor. By, late fall to begin that cycle again. And so it’s this one year cycle where you go through this basically go from seed to reproductive adult, die, senesce, and begin it again.

[00:22:42] And kelps are also known to create seed banks. So they can also have a delayed growth cycle on year to year variations or longer very complex, very interesting, but yeah each system and Organism is different as well.

[00:22:56] Michael Hawk: I’m just fascinated by the parallels to plant life on the surface. And when you say that, seed bank, for example, any idea how long those seed banks can persist?

[00:23:06] Tristin McHugh: Yeah. Get this small story, but we had that very question, right? So we had experienced kelp loss in the North Coast and what we saw was Basically these places that had kelp strongholds were not actually performing anymore. There was something in the water, temperature very likely, not urchin this time, but temperature that was inhibiting them from growing.

[00:23:30] It’s more like, is kelp, are seeds even here? And so we did this small study with University of Alabama and Ireland Galway, who were doing work like this. And we basically went out and collected rocks, brought them back to the lab, scrubbed them to see if there was even kelp on there on these.

[00:23:50] visibly bare rocks. And yes, there were actually two different species that we’re able to categorize. So we knew that there was a seed bank, but there is something inhibiting that organism to grow. So to your question about how long these seed banks can last depends on the species, but we do know from other places in the world, like it could be decades.

[00:24:09] It could be thousands of years where I think we’re still in nascent stages of really understanding the true abilities of these seed banks in marine environments.

[00:24:20] Michael Hawk: So we’ll get into some of the conservation challenges that exist more fully. I know that’s a good teaser. You say something,

[00:24:26] Tristin McHugh: Yeah, sorry, I jumped it.

[00:24:27] Michael Hawk: Oh, no. I want to get there. You also mentioned the cold water upwelling and the nutrient rich water. Help me understand, first of all why is that cold water that like deeper cold water, why is it so nutrient rich?

[00:24:40] Tristin McHugh: Yeah, so that deeper water is pretty nutrient rich. If you think about, if you’ve ever walked the beach and seen Like all the algae that washes up, like all that, I don’t want to say like dead stuff, but dead stuff that just washes up on the beach. That’s only a fraction of how much dead stuff actually happens in the ocean.

[00:25:00] So a lot of it sinks, And that’s, typically carbon and other Organic materials, right? And so those materials break down in the deep sea and they create nutrients, those nutrients in addition to other things like minerals, things like that those are really like the foundation of where that like nutrients comes from is the sloughing off of other like organic compounds.

[00:25:22] And then again, like when you have winds happen and the circulation of the ocean, the tilt of the earth, all these phenomenal processes that we don’t really see, up here necessarily, these processes are happening. And that warm water slough soften gives way to cool, rich water to rise up and create that The enabling conditions really that , underwater plants like kelp, need to grow because there are certain nutrients they need to also build their bodies, right?

[00:25:52] They need certain levels of carbon and nitrogen and these other things to grow.

[00:25:56] Michael Hawk: So it sounds like it’s analogous to nutrients cycling on the surface in a way where plants, animals that die, they fall to the soil, they break down, those nutrients become available to the next generation. And then you have all this complexity of the water system and how the upwelling works.

[00:26:14] The kelp are photosynthesizing as well.

[00:26:17] Tristin McHugh: Yeah, kelp seaweeds are photosynthesizing organisms. Really good at it. Really efficient at it. And they, their productivity parallels and actually exceeds. most all terrestrial systems just because of that boom and bust life cycle they have. And also just how the ocean is in itself as a photosynthesis, it’s basically a lung, right?

[00:26:37] Like the ocean is where a lot of our oxygen, most all of our oxygen comes from.

[00:26:43] Michael Hawk: And I’ve heard it said that kelp are really important Organisms for carbon sequestration as well.

[00:26:51] Tristin McHugh: Yeah. Ooh, this is like one of those in the kelp world, there, there are like a few different schools of thought on that, but For me personally, I think about them as temporary carbon storage or intermediate carbon storage, right? So they are, of course in the carbon cycle where they’re basically utilizing carbon from the seawater, the ocean’s a sink, right?

[00:27:11] And so when we have carbon dioxide, the ocean itself has the ability to take in some of those compounds and from there kelp and other seaweeds photosynthesizers can use those those materials in their processes and so they will do that, but then again, They don’t have a root system and so that carbon is locked in their bodies, and then when they senesce, or when they die that carbon is re released and so then it breaks down, and so I think that’s why, it can go sequester itself in the deep sea, some of it, and then some of it washes up on land.

[00:27:43] I think that’s why we think about it as like a temporary carbon storage, but nonetheless, thanks for the oxygen kelp.

[00:27:51] Michael Hawk: Yeah. And I guess everything all carbon sequestration is temporary, depending on the timescale that you’re

[00:27:56] Tristin McHugh: Right, right.

[00:27:58] Michael Hawk: it’s interesting to think about that way. So then also then makes me wonder, we say you hear about. And again, apologies if it’s, it feels like I’m jumping all around, but the, my mind is just going a million miles per hour right now.

[00:28:12] You

[00:28:12] hear about ocean acidification and coral bleaching and things like that. Do kelp then in a way help to mediate the acidification?

[00:28:24] Tristin McHugh: Of course. That is, Basically where kelp interacts to is in that chemical cycle, right? And they of course have an impact on helping, carbon in a way and also just create a better environment. And when I say by better environment is.

[00:28:38] Yeah, so ocean acidification in itself, is part of that chemical cycle too. And so they all interact in a way, right? It’s like everything is tied to itself. And so whether you’re respiring in the system, like I think of humans or I think underwater, ?

[00:28:51] Your invertebrates. There are those that are. Inhaling and respiring. And then there are others that are doing like kind of the opposite, right? And so your kelps, your photosynthesizers are inadvertently helping buffer all those respirers in the ocean

[00:29:08] Michael Hawk: Yeah, I guess what I’m envisioning here, like I tend to think in, in graphs and I’m seeing these relationships in my head of if the kelp were to suddenly disappear you would have a lot of carbon released and you would have a more acidic environment as a result even if temporary and maybe actually that’s a transition now into some of the conservation aspects.

[00:29:31] You said that on the north coast, something else happened, not the urchins that caused the kelp to endure pretty dramatic losses. I’m going to flip this on its head for a minute. What do you mean by not the urchins? Because I think for, for my yeah, I’ll leave it at that. What do you mean by not the urchins?

[00:29:51] Tristin McHugh: great question.

[00:29:52] So kelp can be lost, The threats to kelp are many, Destabilized ecosystems is one, But in this circumstance, it could also be many, There could be many reasons why an ecosystem is not performing, or thriving, And so up here, what’s interesting is, As a diver, you know these things because you see it with your eyes, but from the surface, when you’re looking out and you see kelp, you’re like, okay that’s doing fine.

[00:30:21] When you look out and you don’t see kelp, a lot of folks would switch their brains and say, oh, there’s an urchin under there, like eating the kelp, keeping it, keeping it from persisting. But if you go diving in some places kelp is there and urchin are not there.

[00:30:38] And you can also go somewhere where kelp is not there and urchin are not there, which kind of leads you into this, what else is going on here? And so water temperatures. And so kelp in itself is very nutrient dependent, nutrient and temperature, because temperature and nutrients are linked, especially in ocean systems.

[00:30:56] And so when we saw the losses that we did it was not only due to a grazer, it was also due to uninhabitable ocean conditions. The water was frankly too warm and scorching kelp from being able to grow.

[00:31:09] Michael Hawk: Super interesting to me because the, the basic story that I had heard, and maybe this is true in some locations, maybe not. Please enlighten, but I’d heard a lot about how the system had gone askew in some way and it had led to a huge increase in urchins and as you said, they’re grazers and there’s been a lot of focus on on the urchins. preventing the kelp from flourishing. So I, is the takeaway here that’s rarely the case? Sometimes the case is never the case.

[00:31:44] Tristin McHugh: It’s sometimes the case. Yeah. I think, again we try to focus in, we, we find the villain, that, that villain that’s, keeping the system down or, interacting with it in a negative way. And that is true, but also, urchin are native species. And so I’m going to focus in on like purple urchin because that’s the species of the outbreak that we’ve been seeing.

[00:32:06] And so purple urchin, for example, they’re native species. And they are responding when they go into overpopulation and this is characteristic of urchin all over the world that we’ve seen when something happens, like a change in their available food source, like kelp. They eat kelp, And so when you have warming waters that inhibit kelp from growing, it creates this negative feedback loop where urchin change their behavior from basically passive grazers, Which means like usually they’re hanging out in cracks and crevices in the seafloor, just waiting for drift algae to come to them. When that drift algae. Is no longer coming to them. They’re like, Hey, where’s my food? And then tie in this, right? Around 2014, we also experienced the loss of a final apex predator in the North Coast specifically, which is the sunflower sea star.

[00:32:55] So without food, without an apex predator, and we don’t have otters up here either. They were extirpated in the mid 1800s along with the fur trade. And they have not yet recolonized this area. When you have the loss of apex predators and then you have warm waters, that is creating a condition where urchin are like, hey, I’m going unchecked, I don’t know where my food is, I’m going to go find it, and they did and so they were responding to what was happening in the ocean.

[00:33:23] So it’s really hard to villainize them because they’re just, they’re native species, they’re responding to these like large climactic warming events that were occurring and then also a disease that took out their top predator.

[00:33:35] Michael Hawk: It sounds a lot like some of the stories you hear about trophic cascades and, the famous Yellowstone wolf stories and in the absence of wolves the elk and some of the browsers really flourished and that had a negative impact then on, on maybe the willow trees or, some of the vegetation that they eat.

[00:33:54] So I want to get back to some of the conservation challenges, but maybe talk about restoration because I’m sitting here thinking like, how do you recover a system like this that, that goes askew so dramatically?

[00:34:08] Tristin McHugh: Yeah. That’s the question, right? And I think that’s both an ecological and social question of what do we do to mitigate any more loss? If it’s helpful, the backstory here is I was diving at the time, and I remember seeing this with my eyes in 2013, we started to see sea stars wasting.

[00:34:25] We didn’t know at the time what was going on or the extent of it, but we saw specifically the sunflower sea star, which is this huge, beautiful organism with 10 plus arms that cruises the seafloor super fast and is a great predator,

[00:34:39] Oh, think about like a hula hoop sometimes or like a hug if you want to give someone a hug, like that’s how big these animals can get.

[00:34:48] Very impressive. Super fast at cruising the seafloor and highly effective at eating and they actually emit like a Pheromone almost that like emits this fear response, right? So there are videos of this and I’ve seen it like a sunflower star on the seafloor Just like cruising pretty quick and Everything just moves out of the way like just gets out of the way because it’s just that effective and that fearful so Around that time, sea stars, including sunflower stars, died.

[00:35:19] We saw over 5 billion, an estimated 5 billion animals die from about like 20 13 to 2016 time timeframe, roughly. So this massive loss, and it was not only in California. This was like the whole Eastern Pacific throughout their range. So colleagues in Alaska British Columbia, Washington, Oregon, California, Mexico, like all of it.

[00:35:43] So that was happening about a year later, we got this warm blob event. So this. It was this like marine heat wave, right? So it was this very deep, very big amorphous body of water that moved onto the eastern Pacific coast, right? So the west coast of the U. S. and Canada and Mexico, and just stuck there for two years.

[00:36:05] At that the 2015 2016, we also had an El Nino, right? So when we were talking about upwelling, what happens in El Nino is basically the trade winds stop, You get these like warm water events as well. And so all of these things were happening in concert with each other. And we talked about warm water, kelp stops growing, And then you have these big storm events, right? There’s so much going on that kelp was struggling to survive and struggling to grow. Urchin, again, just were like, no predator, no food, I’m coming out. And they moved in, in these like large batches. So multiple stressors, we’re still trying to understand it’s You know, they’re all connected in a way, but when we talk about what we can do to potentially mitigate any more loss, we’re, we’ve lost 96 percent of kelp canopy in under a decade, That is like unusual and unprecedented, in California and specifically Northern California, Sonoma, Mendocino counties. And the question now is like, what, if anything, can we do to mitigate? Any more loss and protect and defend that 4 percent that we have left. And so that’s really where myself and, this big, there, there’s a large group of folks here in California working to address what we can do.

[00:37:21] Michael Hawk: you stated it earlier, that there’s a sea star disease that’s also at play here.

[00:37:27] Tristin McHugh: Yeah, so there is something called sea star wasting disease that was triggered in 2013. And. Researchers have suggested that it’s reduced the global population of sunflower sea stars specifically by an estimated 94%. And so that triggered it eventually actually triggered the IUCN, the International Union for the Conservation of Nature to classify the species as critically endangered.

[00:37:52] So the sunflower star is now listed as critically endangered, which is This definitely helps support also the recovery efforts that are going on right now as well to reestablish that predator.

[00:38:02] Michael Hawk: Is it understood what the causes of the wasting disease are?

[00:38:07] Tristin McHugh: That’s where we’re at right now. There have been there, there’s been a lot of interest and insight to figure out what that is. And the Nature Conservancy has supported the captive breeding program to first, I think when this was all happening. Basically, make sure that this species doesn’t go extinct.

[00:38:23] So Friday Harbor Labs, Jason Hodin, up in Washington pioneered the first captive breeding program , just to keep those species going. And then from those programs, there’ve also been a deep dive into what is the causative agent of disease? And we’re not quite there yet, but some were thinking a densovirus that we’re not sure anymore.

[00:38:41] So it’s we do very much, when we say disease, we very much do need to understand still the epidemiology of what caused this and what’s continuing to cause it. Cause it’s not over yet. We still see stars out in the wild wasting, but we also see healthy ones.

[00:38:55] Michael Hawk: Is there any indication that maybe those healthy ones are like genetically predisposed to be able to fight off whatever the, Whatever this is. I guess this is a loaded question because if the epidemiology is still unclear, it’s probably hard to draw those conclusions.

[00:39:09] Tristin McHugh: Yeah. That’s the question. I think in a similar way that we, when we lost 96 percent of kelp, 4 percent remaining, we’re like, what’s up with you? 4%. Like what? Why did you survive? What was your enabling condition? Is it you or was it the place, so I think there’s a lot of like question around that and I think that’s especially true for sunflower stars too, but they, again, they must have some resistance to that disease that prevented them from wasting or they were isolated enough that it never made it to them.

[00:39:37] And there were some, pockets of sunflower star populations found during the disease time. The deep fjords of BC and other places. So it does make you wonder that very question.

[00:39:48] Michael Hawk: And are the captive breeding programs, are they successful so far?

[00:39:52] Tristin McHugh: Yes, when I think about like recovery actions, I think of them in two ways is one is through, reestablishment of natural predators, right? Because the ecosystem itself cannot persist in this imbalanced state, It’s. It needs to have some level of top tropic predator for it to, function in a way that is sustainably healthy.

[00:40:13] Humans can’t do that. We can’t emit fear as much as we want to. We can’t emit fear the way a sunflower star does, so nothing replaces that. But in that same vein, there are some other human mitigated tactics that we can do and start exploring to get in the water and again, prevent any more loss from happening.

[00:40:31] Michael Hawk: What are some of those tactics?

[00:40:32] Tristin McHugh: Yeah, so that is where I focus a lot of time. But globally, apex Predators, working hard to make sure that they’re enabled to get back in the wild. That’s one. But then in terms of human activities, I think of it as like grazer suppression.

[00:40:47] If you have a grazer over abundance of grazers, like we do purple urchin, and then there’s also kelp enhancement, which is really focused on catalyzing vegetative recovery. Think of it as like seeding the sea floor. So for example, in Northern California, we’ve done restoration You basically have to go underwater, look at the system, and prescribe a treatment.

[00:41:10] You don’t know what kind of restoration that needs to be done until you physically touch the earth, in a way, and try to understand. And I think another important caveat here, too, is we’re very much in the learning stages. I think right now, everything that we’re doing is experimental with the keen eye that we do not want to hurt the system.

[00:41:28] We want to help the system. And when we go and when I’m talking about restoration right now, I’m really talking about these experiments that we’re doing at these scales that’ll tell us whether we should proceed or whether we should halt the breaks. And so that’s like an ecological answer, but then also a social one because, some of what we do needs that social uptake.

[00:41:46] Would you like me to dig into like the specifics of what kind of restoration?

[00:41:50] Michael Hawk: would love, I’d love to hear like some, What are some of the experiments that you’re working on right now and how do you contain them so that they don’t, since it is, as you said, an experiment, how do you contain it so that it doesn’t cause too much harm, but it’s still large enough scale to, to be indicative of something that might work.

[00:42:08] Tristin McHugh: in the first year, we started, I would say, organized restoration that I became involved in 2020. And so at this time, Mind you, when we talked about, we’ve been focused on the ecology here. We haven’t really talked about the human dimension much, but with the loss of kelp we also lost a abalone fishery, right?

[00:42:30] We had the last recreational abalone fishery in California was up here in Northern California. With the loss of kelp, abalone were pushed into the shallow environment, out competed and died. And so you know the folks who were participating in that recreational fishery, we’re not feeling great.

[00:42:47] And there also with Abalone, there’s deep cultural and spiritual connection by many to Abalone as well. Just acknowledging that is like the back base here of community. the What we’re doing here and why we’re doing it. In addition, red urchin were outcompeted similar to abalone. So the red urchin industry that we have up here was also negatively impacted.

[00:43:07] That fleet actually filed for federal fishery disaster, this was happening 2014 to 19. And by 2020, we knew that this was not going to fix itself, quote unquote. I think there was a lot of, at the time, there was a lot of conversation on do we intervene or let the system do what it does.

[00:43:23] But looking globally, we know that urchin can persist in a barren state. So urchin can create these barrens that can persist for decades and decades like 70 plus years. We’ve seen them do this in Japan and same thing in the Aleutian Archipelago, so we know that they can persist. The question then was, if we know that now, what can we do to protect that 4%?

[00:43:46] We mobilized a commercial diver fleet, we got state support, the state of California was like, this is not going away, let’s start understanding what we can do to mitigate. We received funds from the Ocean Protection Council to get in and test this very first soft toss question, which was, can commercial urchin divers be systematically remove purple urchin harvests to them.

[00:44:07] And if so, what happens? What, what are the consequences of that? Do we get kelp recovery? What does it look like logistically, cost wise, all of that? None of that had been done in a bull kelp system in California. So that’s what we set out to do. And we found that they can reduce that density on the sea floor.

[00:44:25] And we do see some kelp recovery, but we did not see a sustained big kelp forest. And so that tipped our line to our next set of questioning is how can we catalyze vegetative recovery? And so that spun up our kelp enhancement work as well.

[00:44:38] Michael Hawk: Yeah, it makes sense. And then I keep thinking in the back of my head about this