Marissa Baskett
Description: Marissa Baskett is a Professor of Environmental Science and Policy at UC Davis. She uses mathematical modeling to understand how ecological and evolutionary systems respond to environmental change across space and time. In this episode, we explore her work on kelp forest restoration in Northern California, where she explains how marine heatwaves, sea star disease, and unchecked sea urchin populations led to a 95% collapse of coastal kelp ecosystems. We also dive into how her models guide real-world interventions—from sea urchin removal to the potential reintroduction of sunflower sea stars—and how community involvement, adaptive management, and clear communication with stakeholders are essential to building long-term resilience in the face of climate change.
Website:
Publications:
Resources:
Show Notes:
[0:03] Introduction to Environmental Science
[3:01] The Role of Mathematics in Biology
[4:20] Building Effective Models
[7:33] Engaging Stakeholders in Management
[10:24] Challenges in Real-World Applications
[13:08] Climate Resilience Mechanisms
[16:51] Innovative Approaches to Adaptation
[18:36] The Importance of Social Factors
[21:09] Decision-Making and Governance
[26:47] Kelp Forest Restoration Efforts
[34:53] Understanding Kelp Dynamics
[41:06] The Concept of Partial Restoration
[44:32] The Future of Kelp Recovery
[51:44] Bridging Science and Policy
[55:49] Advice for Aspiring Ecologists
[58:57] Engaging the Public in Conservation
Unedited AI Generated Transcript:
Brent:
[0:00] Welcome, Professor Marissa Baskett. Thank you for coming on today.
Marissa:
[0:04] Absolutely. Thank you for having me.
Keller:
[0:05] We'd love to start off by hearing a little bit more about what got you interested in environmental science and conservation and how you ended up at UC Davis.
Marissa:
[0:13] So I grew up in California, always going to the coast and always loving going to the coast, right? And you talk to an ecologist, and that's often what you'll hear, that they grew up feeling connected to nature, and that has inspired them.
Marissa:
[0:31] And then when I was an undergrad, and I also got very interested in mathematics, and started to learn how you could combine those worlds. And I was actually starting to get into some more evolutionary biology and basic science at that nexus and had some really great undergrad mentors and getting engaged in research in that. But then I spent a quarter at the Hopkins Marine Station, which is Stanford's version of the Bodega Marine Lab, and had a quarter where I got to get immersed back in that ocean environment and realized that was my love, right? That was my home. And so as I went to graduate school, I wanted to combine all of those threads, giving back to the world by doing science that informs conservation management, being connected to ocean systems, but also combining that math and biology and manage to, through the guidance of another amazing mentor, my PhD mentor, Simon Levin, find a thesis that had the nexus of all of those pieces. Because the cool questions are often at the intersections. So when you find you're being pulled in different directions, getting that opportunity to look at, well, how do I actually bring those threads together, right? It can lead to some really cool questions. And so I happened to go to graduate school when marine reserves were really growing as a management tool in ocean conservation.
Marissa:
[1:54] For years, people hesitated in doing marine reserves in part because the thought is, you know, ocean organisms move a lot. And so how would setting aside a piece of place matter was a big question, right? Could that even affect change in ocean systems? And so it was a time of finding that some data, that there were effective reserves out there, some interest on the policy side and establishing them, including the California Marine Life Protection Act, and all of that leading to a demand for theory to understand and build models of, okay, how do we effectively design them to achieve, And so there was just a real opportunity there to jump in and bring in the math, bring in the ocean science, bring in the conservation, kind of right place at the right time.
Brent:
[2:44] Yeah. And it sounds like you kind of discovered your passion for math separately from a lot of the ecology stuff. Do you think a lot of the people now are starting to understand how useful math is within the biological sciences and are kind of pushing students a little
Brent:
[2:58] bit more now to understand both aspects? Absolutely.
Marissa:
[3:02] Yeah. I mean, especially with the way that data and model integration is often the way forward and super powerful. Before it used to be you kind of had your mathematicians and theoreticians working off in their corner, your people getting doing experiments or doing fieldwork in their corner and sometimes coming together and knowing that there's a power in crosstalk. Now I see more and more people doing both and learning both, whether it's, so there's a distinction between what we call statistical modeling and dynamical modeling, right? Statistics, static. You're taking the data you have and trying to understand what it means and build a model around it versus dynamical, you're trying to build a model that follows population change in time. And so those worlds used to be more separate and now they're starting to blend as you do model fitting to data and just all of these new tools developing, meaning that the lines are blurred. And so there is a power in learning all the pieces. And there are a lot of job opportunities in this world of data science that we have at the nexus with environmental science and with ecology, as well as in theoretical ecology, the more mathematical side that I typically do.
Brent:
[4:20] Yeah.
Keller:
[4:20] In your work, could you describe how you go about building a model? Obviously, different for different questions, but kind of at a high level, how you go about building these models to really tap into real life applicable scenarios?
Marissa:
[4:31] Yeah, so it always starts with the question. What's the question you're asking? Any scientific endeavor starts with the question. Because I work in models applied to conservation management, I start with questions about what are the alternate approaches to managing a system? What's the goal that people, managers, community members, what are they trying to achieve? What are the approaches they're looking at to achieve that? Because to be useful, you need to have those conversations and need to understand how that decision making process works. And then a model, by definition, is a simplified view of reality, right? So you're trying to distill the reality to, okay, so if we're trying to achieve those goals, and here are the tools we have them, what's the simplest possible way to say, what are the rules that get us to how this system works and connects to all of those and builds in the most essential elements of the system? And of those management levers.
Marissa:
[5:33] And making sure that there's something in the model that you can adjust to connect to the different management levers you're looking at. So from there, you kind of build your conceptual model. You write out your boxed and arrow diagram of what drives up and where does it go. And then you just turn that into math. If you have a boxed diagram, you've got a model, right? And you turn that into math, try to parameterize it, you run it, but you're always making simplifying assumptions. There are always parameters you don't know. So one of the most important elements is to then do a sensitivity analysis. Kind of push the edges of, oh, what am I not sure about? How do I test different parameter values? Maybe there's a different functional form that works here. And recognizing that you have simplified reality. There probably is, there definitely is something missing. What could be missing? What's important? And from there, loop back to, okay, what's the answer to the question? What does it depend on? And so what do we need for our next step of knowledge to better resolve this question?
Brent:
[6:28] Yeah. And then if you don't know what's missing, how do you go about finding it?
Marissa:
[6:32] Yes. So, right? That gets to your classic known knowns, known unknowns, unknown unknowns, right? You know that often when you present a model to a group, the most common questions you get are, but did you consider this? Right. And so I'm talking to lots of people, especially people who have a deep knowledge of the system in the field is one of the best places to get that pushback of, oh, but you didn't include this thing. And that's actually I see that as important in what I'm looking at. And getting some of those outside perspectives can be incredibly important, which is also what the peer review process is about, right? So doing that early with conversations, but later as you send it out to review, you'll get reviewer pushback of, oh, but they didn't include this and I think it's important. So then you got to go back and retest it. And, you know, you're never going to get all of them.
Marissa:
[7:34] That's part of the nature of it. And, you know, that's where some of the interesting statistical modeling comes in, including some of the more recent AI tools, but also tools like cross-correlation mapping that are just telling you the story from the beginning. Um saying well before cross-correlation mapping is like well before we pass from point a to c to, a to b to c and the next thing we got is d so let's use that relationship to predict out rather than use our mechanistic understanding that we build in a mathematical model and you actually often get better predictions from those statistical models more precise predictions than a mechanistic model but you can't adjust that statistical model with a management lever the way you can a mechanistic model, right? So they're serving different purposes. Are you trying to predict precisely? Are you trying to understand conceptually? But that can tell you, oh, if that's doing better than my mechanistic model, I might be missing something big. There's an unknown unknown in there. And so I got to start hunting for it.
Brent:
[8:37] Yeah, that makes sense.
Keller:
[8:38] And with that, is there a difference between the two models when you're working with management after you've written the paper and you have your predictions in terms of how you're conveying that data to the actual stakeholders?
Marissa:
[8:50] Oh, yeah. So you want to be anytime talking about a model, right? We always have to be careful. Models say what can happen. Data says what does happen, right? These are possibilities. These are not, and especially in ecology, we are pretty far from precise forecasting.
Brent:
[9:07] Right?
Marissa:
[9:07] We're not like weather forecasting. We're not saying this exact amount at this exact time. It's more generally, this tends to be more robust than this. This tends to be the outcome more than that. This tends to be more effective than that. So that relative prediction, a relative sense of what's going on, especially if you start to see it in lots of different people doing different models, gives the confidence. So you've got to clearly convey what you do know well, but also where the key uncertainties are. We don't want to. And identifying those key uncertainties is really important also for the management process, because if they can recognize, oh, OK, so here's what we expect, but here's what we don't know. How do we set up a monitoring data to help resolve that as we go? And that's the adaptive management process, right? You have an expectation that you've laid out from your modeling, whether it's conceptual or mathematical or statistical. And then you go out and get your data and say, do we get what we expected? And if not, why not? And that's what updates your learning to have a better decision the next time. So just understanding that the management process isn't itself a learning process, but we can use our models to plan for that learning and set up,
Marissa:
[10:21] okay, where do we focus that learning to be able to improve that management?
Brent:
[10:25] Yeah. And then starting to look at some of your actual work that you've done, what are some of the biggest challenges that you've had, like taking models and applying it to the real world? And do you have any good examples of that process?
Marissa:
[10:39] Yeah. So one of the challenges is capacity. And that often there's a need to make a decision now with incomplete data. And modeling takes time. Right? And takes people. And takes money to do it. And money is short. And if you're going to spend those dollars on funding a grad student or a postdoc to run a model versus actually going out and doing more restoration, planting more things, right? There is a prioritization that happens there. And so getting that, you know, having the capacity to include it in the decision-making process itself can be a challenge. And then there's the, you know, effective communication.
Marissa:
[11:29] Do people believe it? And you're not, and you don't want to believe the model, but to understand its utility, right? A model is always wrong. It's based on simplifying assumptions, but it can still be useful in thinking clearly through processes and navigating those decisions. And so communicating that clearly, communicating those knowns and unknowns is another challenge to the whole process. But, you know, there have definitely been, you know, an example right now of models being very embedded in the process is in the Great Barrier Reef restoration process happening right now. I am on a risk review science advisory board for that. So I'm not actually involved in the modeling, but I am on a science advisory board and talking to the people doing it. And that group, in understanding when and where and how will these potential interventions to support future persistence of corals under climate change actually move the needle, they're doing a lot of modeling to understand, well, what's the baseline if we do nothing? They call it the counterfactual, right? The no action baseline.
Marissa:
[12:47] And to say, OK, and then how much does that shift if you put in some of these possible interventions to understand their potential role in achieving that goal? And that is directly feeding into some of the decision making process around that. That's a major part of their initiative and a unique case where they have invested
Marissa:
[13:05] in the modeling from the get go in order to look at those questions.
Keller:
[13:09] And looking more into climate resilience itself, what are some of the main evolutionary mechanisms that we have that kind of allow systems to change to be more climate resilient?
Marissa:
[13:20] Yeah, so there's two levels to that. One is the protect the adaptive climate. And so you can allow natural adaptation to take place. And there's a whole school of thought around these ideas of these climate refugia, these areas of either high genetic diversity and adaptive capacity or slower climate change. So it's more likely the organisms can keep up. And that comes from a theory and some data from the last glacial interglacial cycle where the areas of recovery after the glaciers receded tended to be in these geological data sets tended to be these refugia, these pockets of areas that things managed to persist through and then grew out of. So that's led to this idea of, well, maybe focusing on protecting, restoring, even maybe these refugia could be a source, but how do you define the refugia? How do you identify what is a refugia then becomes a question, especially under anthropogenic human-driven climate change compared to that more natural glacial interglacial cycle.
Marissa:
[14:31] So protecting that kind of adaptive capacity, protecting hybrid zones and gradients, because that's an area of high genetic variation that could be a source of adaptive capacity. Looking for those places that might have already selected for high heat tolerance or whatever stress tolerance you're looking at. So there's take those places, reduce all the other stressors in those places, right? Because climate change is one of many ways in which humans are affecting the system. But first and foremost is habitat change, habitat loss, right? And the ocean that's on land, first and foremost in the ocean is harvest, right? So look, there's also invasive species, there's pollution. So look at some of those knock-on stressors and say, well, let's reduce those as much as we can in these places that.
Marissa:
[15:21] Could be our source of adaptation. The next level that gets a little more controversial and a little riskier is, well, what if we actually go in and try and promote that adaptive process? And so there are people considering questions of things like assisted gene flow, right? Find those places of high stress tolerance as source populations for restoration and outplanting, or do a screen for stress tolerance when you do restoration and outplanting.
Marissa:
[15:53] Assisted evolution. This is happening in the lab in corals, but they haven't actually been put out into the wild. Take the algal symbionts in the corals. There's a lab group, Madeline Van Oppen's group, that's been taking these symbionts and for years now have been selecting for higher and higher heat tolerance of those algal symbionts with the thought that at some point, there might be this demand to put those in the corals that they're using in restoration. So stress hardening, that's more of a physiological approach or pre-exposure. If you're going to be doing restoration, putting something out there, reintroducing something, maybe pre-expose them to some of those stressors you're going to expect them to have to harden them up in some ways, right? Because you can have some of these what we call plastic responses, right, of different growth forms that might.
Marissa:
[16:51] All the way up to, and this is getting much more pie in the sky and much riskier, gene editing, right? You know, what if you can identify those stress-tolerant genes and splice them in?
Marissa:
[17:05] Identifying them, understanding, you know, what are some of the knock-on effects on that, that's much more down the road, newer idea, not yet lab, fully lab tested, right? We know we can gene edit a coral, that's happened, but identifying the right genes and doing that, that's still not there yet. But all of these have trade-offs, right? What's the trade-off between stress tolerance and other traits? As you're moving things around, could you accidentally transport disease, right? There's all these possibilities for unintended consequences. So this is why risk analysis becomes such a big part of it. And understanding what the potential trade-offs are so the decision makers and the community members can account for that, right? are those risks we're willing to accept, right? That's not a, you know, what risk level a group has is not a scientific question. That's a question for that group of decision makers and community members, right?
Marissa:
[18:02] So understanding what the risks are and understanding approaches that might mitigate those risks. So once you get to some of these more, you know, intervention-based approaches rather than protection-based approaches and conservation-based approaches that can be done with smart decision-making, right? And not just putting the blinders on or plugging or saying, not worry about the risks, we're just going to forge ahead. We know that leads to disaster. There are so many accidental invasive species out there because people just
Marissa:
[18:32] willy-nilly put stuff out without stepping through that careful analysis.
Brent:
[18:36] Yeah. And I know one thing that I saw in some of your research was looking at social factors and how that influences resilience. Could you briefly touch on that?
Marissa:
[18:44] Yeah. So that's all through collaboration with wonderful social scientists in this department and members of our lab, because I am not a social scientist. I am an ecologist by training. And so getting into some of this multidisciplinary, what we call coupled human natural systems or coupled social ecological systems work takes collaboration between people with different experts. But what we're trying to do with kelp right now is trying to understand how we account for future climate change in restoration actions and what are the options there. And thinking about restoration, right, ecologists tend to think about ecologically, put stuff out, take out nuisance species, right, those types of things, put out more kelp, reintroduce other species and do mitigation on local stressors. But it's people doing that. And people doing that takes a whole human system and social system.
Brent:
[19:48] To do it.
Marissa:
[19:49] And so part of the ability to be nimble in response to future climate change is not just having the ecological tools, but also having the social structure to quickly pick those up, right? What's your capacity for R&D? What's your permitting process that enables that, right? Where are the barriers to achieving restoration goals? Is it a knowledge barrier? Is it a financial capacity barrier? Is it a governance barrier? So understanding that and understanding opportunities to reduce some of those barriers provides an opportunity for faster responses to extreme events like marine heat waves, right? And therefore, a more resilient system in that sense of a faster response. The same way that, you know, an ecological side of things, we can think of, okay, then what are those interventions that we might be implementing? Which ones of those might lead to a faster recovery of the ecosystem? Holistic viewpoint um of thinking of restoration as a whole coupled human natural
Marissa:
[21:02] systems process can then inform okay how do we have this greater overall resiliency to climate.
Keller:
[21:09] Change yeah and with interventions you mentioned the stakeholders earlier like when it comes to decision making who like who controls that are people like for the for the coral reefs for example and the great mentioned type or will it be more top down from a governance level.
Marissa:
[21:28] It's so varies place to place in the case of australia it's the great barrier reef marine park authority that's the decision making authority um but they are doing this in partnership with community members and they're doing a lot of interviewing and understanding people's goals people's priorities, and doing a lot of surveys. And also the traditional owners, the indigenous populations. The pilot programs that they are doing are winter, this summer, right? Just going to start up. One of the pilot programs is specifically piloting, how do we do this in a way that's an effective partnership with those traditional owners and making sure they also have full say in what's going on here. And so how to set that up well and effectively, that takes a lot of communication, a lot of time, but it's going to be really interesting to see what happens and their implementation of that. And I think if it's successful, it could be a real model of that kind of partnership.
Brent:
[22:39] And then kind of on the coral reefs too, is the symbiont diversity more important than the actual coral diversity? Because I know you said you can edit the genes of the corals, but I know that if the symbionts aren't attaching or actually working together with the coral, it doesn't matter, correct? Yeah.
Marissa:
[23:00] So bleaching, the actual outcome of bleaching is that the membranes, the thylakoid membranes, like the, you know, if you remember your plant sciences and those thylakoids, those are breaking down from heat.
Brent:
[23:17] Stress in the symbionts.
Marissa:
[23:18] So it's the symbionts that are breaking down. There's still question, are the corals expelling them? Are they leaving? But it turns white. The coral turns white. It bleaches because it no longer has that symbiotic algae doing the photo.
Marissa:
[23:35] But the thermal tolerance, you know, its ability at what temperature does that start to happen depends on the coral animal host, the symbiotic algae, and the microbiome all together. So it's actually a three-piece holobion driving that stress tolerance, right? Different coral morphologies affect this. It's a bleaching. The breakdown is a temperature and UV interaction. So if you have a mounding coral with shading structures, you can have some of those symbionts recede into the center of the coral and survive and regrow out versus a branching coral has a lot of exposure, right?
Marissa:
[24:12] So you have different coral morphologies in different coral species with different susceptibilities and certainly variation in the corals within a species. And then the symbionts clearly have variation in their thermal tolerance, right? What are their membrane structures, heat shock proteins, all these things that determine their thermal tolerance. And then the microbiome is playing its own role in all of this. And we don't fully understand that piece. And there are some elements of the microbiome that under stressful conditions go from symbiotic to basically virulent. Right uh and so the what the relative contribution of each piece is to temperature tolerance is still an ongoing major question in coral ecology and i think one of the most important questions we're facing in coral ecology and what the amount of adaptive variation in each of those pieces is and that's going to vary location to location um and how much you know we think about within versus Across species, diversity is playing a role. All of that is.
Brent:
[25:16] A huge question, right? Yeah, that makes sense.
Keller:
[25:19] In the Great Barrier Reef, is there currently an idea of which intervention style might be best or is that still not there in the research?
Marissa:
[25:28] So that's still... There's best has a lot of elements.
Keller:
[25:34] Right?
Marissa:
[25:35] Which one will most move the needle in thermal tolerance is one definition. Which one we can do now in a cost-effective way and scale up easily is another piece of it, right? Which one carries the lowest risk? So I think a lot depends on how you define best, right? And that's, again, something science can say which one is which, and then it's up to managers and community members to say, okay, which ones of those than do we prefer given all of those different elements um what grape barrier reef is piloting right now is a screening for uh stress tolerance in um uh in in the corals that they plant out with different methods for uh getting corals to plant out in their restoration process so that's a bit more that's more at the ready lower risk that it's carrying because you're not moving things around too much you're staying within coral provenances instead of moving things across coral provenances um so that's where that community has decided to start uh but um certainly different
Marissa:
[26:46] places might have different.
Brent:
[26:48] Priorities yeah yeah and then kind of switching a little bit to like California and the kelp forest restorations could you describe your work there.
Marissa:
[26:55] So yeah the um this starts with a series of events um around 2013 to 2015 first there was a disease outbreak and the sea star the big mini armed pycnopodia sunflower sea star that eats the urchins that eat the kelp. Immediately on the heels of that, there was a marine heat wave that might have made the disease worse. The disease outbreak preceded it, so there's a lot of question marks about that relationship. But also, heat stresses out kelp. Heat means low nutrient waters that make it hard for kelp to grow.
Marissa:
[27:38] And when you start to have less kelp And not many predators, the urchins go from sitting in their crevices, hiding from predators, being happy to eat off of whatever drift kelp that's broken off of the live kelp floats down to the bottom, to suddenly being hungry and starved and not afraid of predators, to going out and then mowing down kelp. So eating live kelp, mowing down the whole fast. And so over the course of a few years on the California North Coast, there was 95% of, 60-fold increase in visible urchins, purple urchins primarily, versus the red ones are the ones that are harvested. And then once the urchins have eaten all the kelp, they can go dormant and sit empty. And you break them up and there's nothing inside. And so they're useless to a fishery because there isn't the meat inside that we use for uni.
Brent:
[28:35] Right?
Marissa:
[28:37] And so 95% loss on the california north coast um 50 loss in the central coast very patchy south coast was barely hit um there are a lot of possible reasons for that uh one of them is that the sea the sunflower sea stars were the main predators left on the north coast central and south have sea otters um and south also has the rock lobsters and the um sheephead that eat earth urchins so we had more redundancy in predators. But also, we have a bull kelp on the North Coast that's an annual species versus the giant kelp on the Central and South Coast that's a perennial species. So all these reasons why the North Coast.
Brent:
[29:21] Was probably younger.
Marissa:
[29:23] Central Coast has mostly recovered. North Coast still just has these patches of kelp. And there was a blip a few years ago where it looked like it was starting to recover because we had some really good cold nutrient rich years and then that.
Brent:
[29:38] Didn't that kind of fizzled yeah.
Marissa:
[29:40] So it's still those communities are still very hard hit.
Brent:
[29:43] On the north.
Marissa:
[29:44] Coast and so what our group is trying to do is understand ecologically you know what are the sources of kelp surviving through this and recovering from it in the places where we've seen it um why do we get that and then how do we leverage that for that kind of ecological optimization of restoration, what life stages are most effective to plant out is what my student May, who's over there, is working on some models of, or how do we think about different combinations of urchin removal and kelp-out planting is what Jorge Arroyo Esquivo, who's a student in this group, worked on, right? So thinking about those ecological interventions, but also getting the data with collaborators on why do we see the resisting kelp where we see it. And then trying to understand the human part of the community. What are people's goals? How are they shifting with climate change and the increase of these extreme events like these marine heat waves? And how are people connected to kelp in different ways and what does that mean for restoration goals?
Marissa:
[30:56] Putting all of that together into understanding, so colleague here Mike Springborn and his student Kim and Kim are working on bioeconomic model, then what's the optimal approach to restoration? But then Tyler Scott and his student Gabby Yang and our postdoc Mary Fisher looking at this question of, okay, they're doing a survey right now to understand the kind of decision-making network that's happening with all of this and where are the barriers to.
Brent:
[31:25] Achieving what's optimal?
Marissa:
[31:25] So getting to those, how do you reduce those barriers for that more nimble response in the future? So it's multi-institutional. We got Santa Cruz and Cal Poly Humboldt involved in this as well. They're the ones doing the data side, our Davis team doing the modeling side, right? Multiple institutions, multiple collaborators across disciplines from governance and political science to economics to ecology to oceanography, right? All coming together to look at these questions of how do we account for climate change and kelp restoration.
Brent:
[31:58] Yeah. I think Keller and I are definitely more familiar with like giant kelp being from Southern California. So with bull kelp, what does it mean to be seasonal? Does it completely like detach from the rocks in like the winter or whatever? Yeah.
Marissa:
[32:11] So when the winter squirms come through, most of them get scoured out. They can't, a few of them will live a second year but most of them live only one year and then a few to a second year and then i don't know that we've seen anything past that and so and they have a very different dispersal right so you think of your giant kelp um so you guys have probably seen it if you've ever been swimming around southern california swimming around especially catalina right it's a beautiful place to go swimming in the kelp or if you've gone to the monterey bay aquarium and you see the giant the kelp tank that's giant kelp right you see that leafy structure all the way up yeah bull kelp has the long thin stipe and then all the leafy structure.
Brent:
[32:52] At the top okay yeah.
Marissa:
[32:53] And then they have these these sore eye bags essentially these these that uh that have all of their seeds what kelp call you know what are seeds for kelp that drop down okay um and so but then some of them detach and float so you get this kind of uh different dispersal pattern for them um but yeah so they they you know the the storms on the north coast, And so they mostly just get ripped out by those storms every fall to winter and regrow. And a big question that is still under investigation is, you know, how much of that is last year's sorai that dropped down and regrew versus is there a kelp version of a seed bank? Right we know in desert plants think of hundred year blooms in desert plants there are lots of seeds that persist for years if not decades waiting for those perfect conditions to go bloom um could a similar thing happen in kelp how long can that germ bank as we call it for kelp last that's all a big question and so one thing uh we're looking at are different you know we don't have the data for that but we're saying okay given different assumptions about that how might.
Brent:
[34:10] That affect the restoration decision making and then how long do the purple uh sea urchins like stay dormant or.
Marissa:
[34:17] Can i mean we know in the lab it can be a long time for years in the wild big question mark there too you know when they're sitting dormant they're they're empty they they don't they're not getting any nutrition they're pretty weak and so in these urchin barrens as we call where you have lots of dormant urchins, slightest bit of plant arrives and they consume it and they go back to dormant, right? But they're pretty weak and nutritionally depoperate.
Marissa:
[34:48] And so they're pretty susceptible to disease outbreaks in that stage. And so that's, you know, there's a natural, like all of this shifting is natural. It's natural for kelp to be ephemeral, to get ripped out by winter storms and come back to have a patchiness to it of sometimes this is the place and that the place what's unnatural is how many years it's gone without um and so you know it's part of the natural cycle right for urchins to maybe form a baron be dormant but then maybe have a disease outbreak or otherwise die of starvation but it takes them a while for those types of.
Brent:
[35:27] Do they look different on the outside?
Marissa:
[35:30] No, they look the same. You got to crack them open to find out. But you'll know, you know, if you look, if, if you look down and it's just all urchins, it's carpeted with urchins. Those are, unless there was kelp there very recently, those are likely to be your dormant empty urchins versus if it's, um, All, you know, if you see urchins in crevices and there's lots of kelp there, they're going to be feeding. So you know more by the environment.
Brent:
[35:59] Okay. That makes sense.
Keller:
[36:01] And in the broader research, there's a lot of different areas to go into. But with the kelp specifically, with the areas that have recovered, what are some of the traits of those kelp areas that have allowed them to recover?
Marissa:
[36:12] So one of the things that a few groups, well, our colleagues at Bodega Bay and Cal Poly Humboldt and Santa Cruz have found, but also other groups like the Sonoma State group of finding, is that river mouths are areas of persistence. And um a an idea there is that the fresh water deters urchin grazing at the river mouths and so both some students at sonoma state and some members of our team at kalpali humble are doing some experiments understanding what levels of fresh water input might lead uh to uh to um that level of deterrence of urchin grazing. We have a student, Rina Storia, up at Cal Poly Humboldt doing these experiments. And, you know, she's finding it's, you know, kind of these medium levels of freshwater input. Urchins start to try and get out of their tanks and at high levels, they actually do die from that. And so that's one possible source. And so one of the large-scale restoration sites that Sonoma State and the Greater Farallones National Marine Sanctuary and a bunch of groups are involved in. It's at the Big River area in Mendocino because you've got that freshwater imp.
Keller:
[37:37] And then another kind of quick question on the initial wiping out of the kelp in Northern California. There's 95%. Had there been in the past another large percentage loss since we've been studying it? Or have we seen a recovery? Or is that the first time we've seen just a massive? 95%?
Marissa:
[37:56] I would have to look at Meredith McPherson's paper to know for sure because she's got a nice long-term data set. We also don't have as good long-term data for the California North Coast like we do for the Central and South. Because a lot of the long-term data is satellite data using chloroflual concentrations and the fogginess of the North Coast make it difficult to get the satellite data for that region. But folks have been working on that. There are definitely some people working on how do we get some of these historical time series. I mean, obviously, every winter they rip out, right? And so that level of loss every winter is normal. But again, this multiple year and just talking to somebody who a member of our team of Frankie up at Cal Poly Humboldt, who, in addition to being doing research in this area, he grew up diving in that region. And he said what jumped out to him is just the complete lack of new kelp coming in after the die-off, right? The die-off wasn't the shock. It was the lack of new kelp coming in and that persistence of that die-off that made people realize, oh, there's something different happening here.
Brent:
[39:07] Yeah. And then when looking at the kelp, I'm sure there's a million metrics you could be tracking.
Marissa:
[39:13] Yeah.
Brent:
[39:14] Which metrics are standing out as the more significant ones that you guys are going to hopefully use to apply to conservation efforts?
Marissa:
[39:22] Yeah. So that, I think, is a question to ask again in six months. So another role that I'm playing and a number of us are playing is on a science advisory committee to the kelp restoration and management plan that the California Department of Fish and Wildlife and the California Ocean Protection Council in California Sea Grant are putting together. And so they're doing this with a science advisory board and they also have a community working group for community input into that plan as well. And we are right now working on the prioritization of monitoring metrics. That is, we've got our laundry list of a ridiculously long number of metrics, and our next step is how do we winnow that down into what's.
Marissa:
[40:11] And then what are our various monitoring thresholds into that? So that is in the process of being figured out as we speak. But certainly overall kelp cover and taking into account its ephemeral nature. So thinking about the natural variability of that and when have we gone outside that natural variability. Because it starts with kelp cover, right? And kelp biomass. But it's not just about kelp. Kelp are what we call the foundational species. They form the forest, the underwater forest that everything else lives in. But it doesn't end there. And so how do you think beyond kelp to the other members and what are key other members of that kelp forest community and ecosystem? And following those, I think, is still something that's a question.
Marissa:
[41:04] What's the role of understory kelp? Our giant kelp and bull kelp are the ones that form the forest and the structure, but there are lots of other owl species in there, too. All these different pieces.
Keller:
[41:16] In your work, we saw that part of the kelp forest recovery was around partial restoration. Could you explain that concept and how that ties into the Field of Dreams hypothesis?
Marissa:
[41:27] Yeah, so this goes back to the old, that Kevin Costner movie, Field of Dreams, if you build it, they will come. That there's a longstanding idea in restoration ecology, that this question of you don't necessarily need to restore the ecosystem entirely, you need to restore just enough such that natural processes.
Brent:
[41:50] Can kick in and take over.
Marissa:
[41:51] From there. And that's, if you can find out where some of those levels are, that's more efficient, right? You're spending... Spread those dollars out more if you can restore just enough, and also more natural, right? Now if you keep going when natural processes can take over, you might start to interfere and impede that versus just letting nature take its course. So the question we looked at, and this was one of Jorge's papers, was, okay, what do we mean by how far? We can think of how many years in a row, how big of an area, but also how far ecologically. Do you just remove the nuisance species and let it take off? Do you also start to replant your foundation species like your kelp and let the rest of the system go? And so that paper was looking at which ones of those decisions really matters the most. And what we found was in a model, again, model saying what can happen, data says what does happen, that really that scaling up ecologically, having multiple of those interventions.
Marissa:
[43:08] Having both the nuisance species removal and the foundational species addition, right, that's where the investment tends to pay off the most. Um basically if you have one of those you're going to have to do a lot more of one of those, uh you know each and if you do a combination you can get to those thresholds much more easily um versus and then it starts to spread from there and so if you can get past that threshold and stay past that threshold you don't have to keep going right you can let nature take its course.
Marissa:
[43:47] But, you know, that's the theory. What the data says, and I think, you know, a lot of the current restoration actions right now are then, what is this looking like? You know, did the data match up to that? And what's really exciting about this big river restoration project going on is it's actually going to be a really interesting test of those expectations because they're starting to do these different combinations of different levels of.
Brent:
[44:18] Mm-hmm. Would you say that the goal is to find the minimum effective dose of each one in relationship to one another and then to let the natural processes continue from there?
Marissa:
[44:30] Exactly.
Brent:
[44:30] Yeah. Yeah, that makes sense.
Keller:
[44:32] And if you could focus, like, I know there's obviously many ways you could, but if you could focus on one aspect of that partial restoration, do we have an idea now what that could be for kelp?
Marissa:
[44:42] And again, I'd say that depends on management priorities and community priorities. There are community members, especially part of the tribal communities, that are actually against urchin removal because urchins are a natural part of this system. Purple urchins are native to these ecosystems, and they're just responding how they always responded to these conditions, right? And so it's not like an invasive species that we've brought in from somewhere else. And so if a local community priority is really about not getting to that kind of interference, right, then it makes sense to say, okay, where's the threshold if we just do the kelp outplanting? Planting versus if, you know, if you have community members that, for example, the, again, the purple urchins don't traditionally have a fishery. The red urchins do. They kind of form the bearings together, but the purples are the dominant ones in Northern California. It depends a bit on where you are. And so you have a lot, there are still a lot of red urchins, but they're empty, so they're not of value to the fishery. Landings have been down by 80% in the red urchin fishery, and it's.
Marissa:
[46:03] Because of the loss of income to that community. And so there, there's a demand for employment of that community to be engaged in the purple urchin removal. And there's a real interest in those community members on the urchin removal side. And even this idea of, there's a company called Urchinomics that's about, well, instead of just removing them and killing them, they might be useful in fertilizer because of the calcium additive they bring, removing them, keeping them alive, putting them in tanks, feeding them algal pellets, then they start to grow their uni, and then you can sell them on the sushi market, right? And so maybe even potentially developing a use for them. So, you know, there's a lot of dependencies there on, okay, if you have that demand and that economic interest in the local community, maybe that approach makes more sense for that.
Brent:
[46:54] Yeah. Do you ever look at adding urchin predators back into the mix? Because you originally talked about the starfish dying off.
Marissa:
[47:02] So that's a big question of sunflower sea star reintroduction. And that's the grant we're writing right now of understanding the capacity for that. The big fear is that the disease outbreak, the sea star wasting.
Brent:
[47:16] Disease outbreak will just.
Marissa:
[47:17] Happen again. And that disease outbreak started with the sunflower stars and cascaded to a lot of other sea stars up into the inner tidal. Including the ones that, if you've ever gone poking around the intertidal, right, those five-fingered, brightly colored okra sea stars, right, that it really hit them too. And so there's a big, those have recovered while the sunflower sea.
Marissa:
[47:38] So there is a big question of, hey, you know, there's a danger here. There's potential under 10 consequences. Plus, there's a question of, you know, do you source from outside California? There are a few sunflower stars left. They've spotted a few. There are a few in aquariums that are of California origin. And so if you go only of california origin are you facing a big genetic bottleneck but if you source outside california are you bringing in maladapted individuals and just can you grow them and what stage do we introduce them yeah um there's a group called the sunflower star lab in monterey bay that's figuring out how we grow up sunflower stars they've got a lot of uh sunflower star babies at the moss landing marine lab and then there's uh jason hoden up at friday harbor marine labs was the real pioneer because this wasn't an organism we even were growing in captivity before yeah right so just how you grow in captivity to reintroduce is still a question um so he and when did they start eating urchins and all of that so he's been doing amazing work on that and will they eat urchins and barrens or do you have to give them urchins that are well fed turns out they'll eat barren urchins and they they're better at catching them because the barren Urchins are so tired and poor nutrition and all of that. So yeah, so there are a lot of questions to be answered in order to do it, figure out effective reintroduction, but there are a lot of people working on those questions.
Brent:
[49:07] That makes sense.
Keller:
[49:08] And looking out into the future for kelp forest resilience, what are some of the future research questions or strategies you think we need to really make large strides in this field?
Marissa:
[49:18] I think those questions of reintroduction, there's a reason why I'm working on a great proposal with others on that now.
Brent:
[49:24] Is that those are really important.
Marissa:
[49:26] Because another model that Jorge did suggests that, again, the model says what can happen, data says what does happen, that it is feasible to recover kelp forests with the tools we have in terms of kelp out planting, arching removal. But if you get that recovered forest, it's still going to be vulnerable to the next marine heat wave, have low resistance to that heat wave, unless those sea stars are some predator. So that future resiliency to climate change in some ways likely rests in the predator recovery as well.
Brent:
[50:05] And so, yeah, how do we get there.
Marissa:
[50:08] Especially with the sunflower sea stars for the California north coast is a major question.
Marissa:
[50:15] How to scale up some of these restoration interventions and that's that's what the Sonoma State and Greater Farallons group are working on in really creative ways of, doing kelp out planting is such an intensive process you're doing diving and trying to do it and the urchin removal too it's individual divers and so how to do this in a way that you can do more faster drop it from a boat that type of thing and they're working on some new structures that might enable that and that that's really cool um and yeah understanding you know i i think also so far it's really focused on some of those i made the distinction earlier between protect or restore what we have to let it be able to recover naturally versus those next level interventions, of, you know, do you do a heat screen for stress tolerance or a screen for heat tolerance? Or, you know, all those things that people are starting to do with corals. When do they start to happen? You know, what's the capacity to do that potentially with kelp? At what point is that of interest as part of the management toolkit for the managers and community members, right, all of that.
Marissa:
[51:42] Big questions there and people are starting to work.
Brent:
[51:44] On this as well and then how do how's your work like actually shaped different like strategies that the government's using like more looking at the policy side of things like how often are you working with policy members and like being able to implement the strategies you discover in the lab.
Marissa:
[52:00] Um so i tend to make a distinction between managers and policymakers right so policymakers are the you know folks in uh government writing laws that type of thing uh whether you're talking staffers or assembly members or things like that versus managers are people like government agencies are saying okay this is the law how do i actually implement it right here's the marine life management act how do we develop a help restoration and management plan, given the law of that act.
Brent:
[52:34] And so to date.
Marissa:
[52:36] Most of my work has been engaged more with the manager's side, right? So not necessarily saying, what's the law, but more, okay, given that framework, the policy framework that we're working in, how do we achieve these goals? And how do we effectively achieve these goals? And yeah, a lot of my projects involve direct collaboration with government agency scientists who work with managers or government agency managers and making sure that they're part of the conversation from the beginning of the project to make sure the questions they're facing are the types of things that are informing our scientific approaches. So for our kelp restoration project that's working with Cal Fish and Wildlife and Ocean Protection Council and both Greater Farallons and Monterey Bay National Marine Sanctuaries, as well as ReefCheck, a citizen science group that's engaged in a lot of these restoration activities and the monitoring of their efficacy as well. So, and, you know, for other work I've done, I've collaborated a lot with NOAA Fisheries scientists who then work with the managers and are able to do some of that translation. And that's a very important part of doing effective management research.
Keller:
[53:48] Is working with scientists from like government organizations or like, no, like, is that dynamic different than working with other academics or is it generally a very similar process?
Marissa:
[53:59] Well, it has some similarities and some differences. I mean, when you're working with a government agency scientist, they're still scientists. They still love the research questions, right? You very much engage on that.
Marissa:
[54:09] But it's, you know, it's working on a different timescale. They're looking at, we need an answer soon, and we need it very specifically for this system in this place, versus the academic scientist is thinking, I'm going to write a five-year grant, right? And I'm thinking decadally in terms of what this could affect change in, and I want to generalize beyond this. I want to leverage this specific system for this specific place to get to a broader understanding that others could use elsewhere. And so how to find the questions at the nexus of those things, right? In some levels, there's a complementarity, right? That if you're always focused on putting out fires, you never get to plan long term. So having these partnerships allows some striking a balance of thinking, okay, you're worried about this now, but here's some potential for it. And it's totally understandable, right? That's your purview.
Marissa:
[55:08] Um but what if we start to think longer term how do we integrate some of that in so there's some there's some win-win in pulling that together but there's also some balance to be had like how do you balance answering the broader question with also while also helping somebody with their specifics and very place-based this system this question right uh that takes some careful conversations and delicate look into, okay, how do we find something we're all interested in and all want to?
Brent:
[55:40] And then kind of wrapping up here, what advice would you give to students who
Brent:
[55:46] are interested in ecology, conservation? Are there certain skills that you see becoming more useful in the future that you would try to steer them towards? Those type of things that they should think about.
Marissa:
[55:58] It's hard to go wrong. There's so much need out there that anything you build is going to be useful in some way. I'd say, you know, there's always the follow your passion, but also, you know, have an awareness, right? A lot of science is there's careful planning, but there's also a serendipity to it. So you need a bit of that capitalizing on serendipity, recognizing an opportunity when it's there. I started out as a conservation ecologist. And these days, almost everything I do is restoration ecology. It's been a real shift. And, you know, all this kelp stuff up until the North Coast decline happened, all of my kelp work was on sustainable fisheries management and kelp systems and marine reserve design in that world and marine reserve monitoring. And so assuming there is a kelp system, what helps maintain it? And this has been a real shift of where do you grow it, you know, but having, you know, if it's gone, how do you recover it?
Marissa:
[57:03] But having the models that we built earlier made us ready for this unexpected thing that happened on the California North Coast. And so having, looking, understanding when those opportunities arise and being ready to pivot for them. And so as a student thinking a bit about, okay, where are my interests and where do they intersect with some of these demands, what the world needs, right? Looking for those intersections.
Marissa:
[57:32] Certainly um you know there's a lot of in students there's a lot of dread of statistics, hesitation on computer programming all that kind of stuff those are actually fun those are problem solving i think they get a bad rap there's a lot of statistics can be really creative how do i make sense of my data math modeling is testing your logical river rigor right i'm thinking this way does it really work out how I'm thinking? How do I formalize that? How do I communicate that in the universal language.
Marissa:
[58:07] Computer programming, right? Everybody is doing some kind of programming in ecology, whether you're programming your statistical analyses or programming models. And so, and it's, again, it's a fun problem-solving thing. How do I find the algorithm that does the thing I want to do? And so I think learning how to blend that with a love of natural history, right? Because our understanding of ecology comes from our understanding of these systems and being very deeply familiar with them. That's part of the balance that ecologists have to taste. And everybody's going to sit at a different point in the spectrum on that balance. But I think respecting all the points of the spectrum and knowing, okay, here's where my strengths are, and here's where I might have to work with somebody else to bring in that piece, right? So those collaborative skills and communication skills become.
Brent:
[58:55] Really important too. Certainly.
Keller:
[58:57] And for the general population that might not have a science background or be working to become a scientist, but really care about conservation, whether it be forest or it be the ocean, how can they better support the biodiversity efforts kind of as an outsider?
Marissa:
[59:13] So there's a lot of community science programs out there that are really exciting, right? BioBlitz Day, being a part of various iNaturalist programs. If you love marine systems, looking into reef check opportunities because they engage community members of all sorts in marine system monitoring through volunteer efforts. So there's a lot of really great opportunities out there. And anything as an individual that somebody can do on climate change makes a difference because it is the looming impact that we're facing.
Brent:
[59:48] In these systems. Definitely.
Keller:
[59:50] Well, thank you for your time today.
Marissa:
[59:52] Absolutely.
Brent:
[59:53] Thank you. Thank you guys.