GryphonCAST Episode 7 Transcript
Speakers: Michael Lim, Amanda Reside and René Shahmohamadloo
Michael Lim
Found in the Baltic Sea to the Great Lakes, people worldwide have heard of blue-green algae and their blooms in the summer. The green scum that floats on the surface of all kinds of water bodies doesn't look great and can close beaches and waterways. Despite its name, blue-green algae is in fact, a type of bacteria called cyanobacteria and can do a lot worse than ruin your summer holiday plans. Open your ears and mind and let's chat about that. Welcome the GryphonCAST, a podcast where we casually chat about science coming out of College of Biological Science at the University of Guelph and how the work can affect lives around the world. I'm your host, Michael Lim, with me today is co-host Amanda Reside and a special guest and postdoc, Dr. René Shahmohamadloo. We'll be chatting about Dr. Shahmohamadloo's recently published a study looking at how the group of toxins known as microcystins affect rainbow trout and how this differs depending on whether the toxin is inside or outside the cyanobacteria cell. We'll also discuss the severity of the hazards caused by cyanobacteria blooms. So as a quick break for our audience, and for with Amanda myself, how would you describe your research and I guess both the work done in the Fryxell labs and also in the lab that you're also part of in Washington, if that's correct?
René Shahmohamadloo
Yep, and Washington State University. Thank you so much for an opportunity to talk about all this work. So by training, I'm an ecotoxicologist and my research aims to advance our broad understanding of human induced environmental change on ecological and evolutionary processes and wildlife. So specifically, what I'm interested in and it's a new emerging field of research, is this idea of pollution driven adaptation. And it's been coined now as evolutionary ecotoxicology. So, it's combining evolutionary ecology and toxicology together, and what it does is it seeks to understand the role of adaptation of organisms. And what enables these populations of organisms to thrive in these anthropogenically stressed ecosystems. So, with my postdoc advisors, John Fryxell at the University of Guelph, and Seth Rudman at Washington State University, we've been testing the predictability and determining the ecological consequences of rapid evolution, both cyanobacterial species of like Microcystis, which we'll talk about today, but also the aquatic keystone grazer species called Daphnia magna, which is an important food source for fish. And I've been doing that combining benchtop growth trials, mathematical modeling and large scale mesocosm experiments to understand what is the rate, the genomic basis, and also the phenotypic consequences of Daphnia magna evolution and response to toxic Microcystis.
Amanda Reside
Wow, that's fascinating. So, why did you decide to get into this largely interdisciplinary research did you expect to be doing this work?
René Shahmohamadloo
You know, it's actually a funny story, because my PhD supervisor Paul Sibley, who's in the School of Environmental Sciences. But ever since my undergrad, I've been a big fan of aquatic toxicology and I knew that he was a leader of this work in North America. So, I always needed a point - somehow at one point in the year to meet up with him and chat about it and then see if there's opportunities to work with him. I went on one of these UofG job banks and then I get this really shady email. From a technician that wrote come tomorrow at this time, and bring your CV. And I showed up the next day and the guy was looking at me very seriously. And then he took a hard look at me and said, "Okay, I trust you and I'm going to assign you to volunteer with this PhD student" who happened to be supervised by Paul. And then while I was volunteering, Paul got this massive NSERC Create grant to investigate multiple stressors in the Great Lakes system. And then in the blink of an eye I finally got to research what I was so passionate about from the beginning. I'm glad in the end it worked out but it required some patience.
Michael Lim
So, you say that you've always wanted to work in aquatic toxicology. But was there like a key moment? I don't know. Maybe you're fishing as a small kid? No, I love, I love this research. And so you decided this kind of research on microcystins and toxicology in the Great Lakes.
René Shahmohamadloo
Yeah, I think my fascination for wildlife as nerdy as it is to say this it was fostered by Pokemon, I was always like [crosstalk] I think your generations can relate to that. And I definitely. I had such a fascination with the concept of going into the grass or the seas and discovering wildlife and I grew up in like Toronto and that I didn't get much exposure to wildlife in person. So it was through video games, but it wasn't so much a particular moment per se. It was more just my inspiration. I think it to devote my career and life to this stemmed a lot from my parents actually. They instilled in me this sense of duty to be of service to humanity in the world. And personally, I've always had this deep fascination with this notion that human beings are organic with the world and that our lives mold the environment, and it's itself also deeply affected by it, and that the one acts upon the other and every abiding change in the life of humans is the result of these mutual reactions. And then once I started at the University of Guelph, my studies and then learned more about aquatic ecosystems and how we can directly and indirectly impact it. It just kind of all coalesced to go about "Wow", this, my parents were instilling in me then, although it wasn't directly about aquatic ecosystems, it makes a lot of sense now.
Amanda Reside
To get into the study that you published recently that we want to talk about today. For our listeners, it was called "Cyanotoxins within and Outside of Microcystis aeruginosa Cause Adverse Effects in Rainbow Trout (Oncorhynchus mykiss)". So to begin, I'm curious about your interests in microcystins. Harmful cyanobacteria blooms produce a myriad of different toxins. So, what attracted you to studying microcystins over other cyanotoxins like the neurotoxin anatoxin-A for example,
René Shahmohamadloo
Great bonus points for knowing anatoxin. It's microcystins. It's the most widely studied of the cyanobacteria family. When it was first detected and found to cause death in humans and wildlife. It had this name, coined "fast death factor". The neat thing or comparison between microcystins and another cyanotoxin like anatoxin. Anatoxin has a half-life of one to two hours whereas microcystins can live up to three weeks in water without degrading and its potential is of course it can reside for even longer periods. If it's within a cyanobacterial cell and not lysed and free running in water. The species that produce microcystins like Microcystis aeruginosa, or Microcystis (the whole family in general), they're cosmopolitan all around the world. So, it's been a big concern globally for freshwater ecosystems because they can impact our drinking water sources. etc. The other thing that's been really concerning for us is that climate change projections are saying that a harmful algal bloom event, maybe right now, it's a few days up to a week, week and a half. By 2090, it could reach up to 39 days. So, what's really concerning is that we know Microcystis that produces microsystems actually do particularly well in warmer environments, and they can outcompete other species of green algae. So, I don't want to be dystopian about this, but it's a little bit frightening to think that they could actually dominate healthier food sources of algae for wildlife as we move towards 2090 So we need to be thinking now about what are the implications in present day and how does it impact fish, like rainbow trout?
Michael Lim
So, based on its categorization, being a neurotoxin for anatoxin-a, obviously, there must be other toxic effects of microcystins. So for our audience, could you briefly describe what some of the toxic effects are, and what determines toxicity is it like, concentration, time, type?
René Shahmohamadloo
Yeah so, briefly, the mode of toxicity for microcystins is it's a liver toxin so it accumulates in fish, in humans, other mammals and wildlife and it attacks the liver organ. How it does that, is it inhibits protein phosphatases which are really important for cell regulation. It causes necrosis, apoptosis, and then eventually it will cause organ failure and death in the organism at a high enough concentration. But there have been studies that have looked at these impacts, but those are not commonly occurring. So usually, the kinds of effects you'll see they're different between humans and wildlife. So for humans, some symptoms from ingestion of these toxins could be, you might experience abdominal pain, or maybe vomiting and nausea, or even diarrhea or blistering around the mouth. With wildlife, there are of course, like phenotypic effects that we can see from microcystins ingestion. It could be reduction in growth or capability to reproduce or maybe you might see swimming behavior patterns or delay of hatching of fish embryos. But then the life stage of the organism in that respect is key here as the younger life stage you go, the impacts could be more pronounced in later life stages.
Amanda Reside
So, the study in question cyanotoxins within and outside of Microcystis. Can you explain briefly why you think, studying the differences in microcystin toxic dynamics between intracellular (so, inside the cell) versus extracellular (outside the cell) is important?
René Shahmohamadloo
Yeah, for sure. It's really important that we want to emulate all instances where a harmful algal bloom event is occurring. I found that the bulk of literature was only investigating microcystins when it was in its extracellular form. So, the way researchers have done this was either they forcefully ruptured the cells to release the toxins in the water, or they bought an analytical grade. And in several instances, studies were administering these microcystin toxins and fish by oral gavaging or intraperitoneal injection and these aren't realistic with what fish experience in the real world. So, aware of all of that, I thought we need to design an experiment that's novel and exposes fish in a way that they would naturally encounter blooms. So, I thought one natural way is by balneation, where they're just swimming in the water where the toxins reside. Now, one analogy that's helped me understand the relevance of this work is comparing it to when a human being has a life-threatening event like a heart attack. When I think about like, the deep literature search I did where everybody's looking at like extracellular microcystins, I liken that to when a human being has a heart attack. Meaning that it's already happened. It's too late. And the bloom has released the toxins in the water and the impact has happened. I wanted to capture that moment. But I also want to capture a moment before the heart attack happens. So, what are the underlying sublethal symptoms occurring in the background? Understand when fish are in danger, and the data I found shows that fish are in danger in all moments of a harmful algal bloom when they encounter one. So, that's why it was pretty ground breaking for me to see in all instances, we need to be paying attention to this problem.
Michael Lim
An interesting aspect of your study was that you chose to study the effects of microcystins, both at adult and juvenile levels and fish. So, you kind of touched upon this earlier where a younger life stage might be more sensitive to microcystins. So in that case, do they provide additional insight into what the effects of microcystin toxicology is on rainbow trout? So, using your previous analogy, kind of like not just looking at heart attack risk in adults, also looking at it say in teenagers or even children. And also considering the fact that you separated your age based on the size of the fish. So adults were about 300 grams and juveniles were about 50 grams. Do you think there's an effect of body size, age or some combination of both body size and age on the effects of microcystins?
René Shahmohamadloo
That's a great question. I definitely think it's a combination of both classic studies. We look at are how in children and teenagers exposure to toxin is a lot greater than an adult. And the younger life stage you are, your organs are still developing and are more prone to toxicity than an adult who has a fully developed mature organ that is better able, capable to manage, or withstand toxic insult. So, I suspected that juveniles exposed to microcystins - there’s probably going to be a more pronounced effect just based on my training and human toxicology. But also knowing that the size of the organism too does matter. So, they're a smaller organism that means there's less room to move for the toxin to move around, which means more potential for to bioaccumulate. And it was pretty cool seeing how there was kind of this in the graphs. You see this plateau. It's interesting too, how in the kidneys there was greater amount in the juveniles than the adults. And I thought that was really fascinating because, potentially, I mean, if I had to postulate, it could be that it reached a carrying capacity in the liver in the juveniles and then microcystins went to the next detoxifying organ, and like the kidneys. And then I think that's probably what was happening whereas the adults maybe were better capable to manage it and withstand it and there was an accumulation. There was some distribution elsewhere but there may have been other mechanisms that could allow it to get curated out.
Amanda Reside
So, your team also made a point to use concentrations of microcystins that I believe were substantially lower than what previous studies have used. So, can you explain for the people listening, why you chose these particular concentrations and why that matters when you're studying environmental toxicology?
René Shahmohamadloo
I'm really glad that you're asking this question because it's been a pivotal shift in my career as an ecotoxicologist. So, a lot of my training has been, you know, develop your lethal concentration curves at which 50% of organisms die. And I reached a point where I thought to myself, but we don't want aquatic systems where 50% of organisms are dying, like we should be thinking more 95-99% are alive. It's this new area of research. And it's kind of it's been illuminating for toxicologists to think about the role of sublethal effects. So, intentionally I chose a level that was much lower, but naturally occurs in freshwater systems. So, the reason I chose those values of 20 micrograms per liter and 100 micrograms were is because it's a range you would find in the environment. But it's also a range that is of relevance to organizations like the World Health Organization. So, they have recreational guideline value for microcystins to protect humans, which is at 20 micrograms per liter. Now fish are not going to stop swimming say, "Oh, it's a beach enclosure, [crosstalk] per liter, but I thought, like we set these values for ourselves based on studies but there are organisms too that live in the systems, I think, well, if humans need to get out of the water at these levels, what's happening to the fish?
Amanda Reside
So, based on the results that you found, do you think that microcystins pose more of a risk to wildlife inside or outside of the cell? I knowyou just talked about it a little bit, building from that, how would that affect human users of these bloom affected waters?
René Shahmohamadloo
Yeah, it's a great question. I definitely find that microcystins for - so I'm going to, I'll use rainbow trout and Daphnia as a comparison. In Daphnia when microcystins are within the cell, it matters more. Why? Because they consume the algae directly and it's a staple food source. In rainbow trout when it was free running in water, the microcystins (an extracellular form) it accumulated more rapidly and in higher amounts than the intracellular form. Now, that's not to say that both of them are not a risk to wildlife or humans. And that was what was an important takeaway from the study - was that even though it's accumulating in higher amounts, when we look at the proteomics level, we're seeing that there's activation regardless of stress related proteins. We see evidence of early stage evidence of formation of carcinogen - carcinogenesis or oxidative stress, etc, etc. So, for humans, thinking about this like thinking about the environmental implications a lot of our work with if you go to like Environment Canada, they track blooms on the US side with no other tracking blooms. Bloom tracking tends to happen in the later stages. And my work from this paper and moving forward advocates that we need to be tracking blooms as soon as the weather's warming around May or June, and thinking about what could be happening in waters. Because, the frightening thing about Microcystis and microcystins,are that it could be at levels that may be visibly you don't see it, but it could be there and accumulating at this background sublethal levels. And it could be stressing out organisms and I think about the recreational, and angler hunters, and fishers who are out there and they're not aware of the problem and what are early warning systems - rapid early warning systems - that we could develop to protect the general public, but also ultimately protect wildlife too.
Michael Lim
Out of curiosity, I'm not sure if you know this, but how do people know the effects of microcystins on humans? Is it just kind of like an accidental exposure because they go swimming and they go, "oh, no, I'm exposed" ... and then we will document the effects ar just like, you can sign up. You drink a little bit of microcystin see what happens?
René Shahmohamadloo
No, unfortunately, there's no sign up. There are a few things that unfortunately happened. So, there was in Brazil, microcystins got into the drinking water or the water source that was used for dialysis of patients and there was close to 40 deaths I believe. Direct evidence - "okay, we know it can kill humans for sure". Along the way. There's just been monitoring of symptoms in children, teenagers, adults from accidental ingestion. If you're swimming in Lake Erie, and you think, "Hey, no, it's not that bad. I'll just swim in there. And see what happens". But then there are these symptoms developing. Usually they might report it if it's to Health Canada or the US equivalent, they might be reporting the symptoms. There's actually even new research that came out of Hans Paerl's lab, showing the aerosol effects. So, of course, microcystins, they don't end up in the air unnecessarily. But if you think about waves and splashing if you're living on the coast, there's potential that it's out in the air. And there's a pretty interesting paper that came out last year showing the impacts of microcystins that can accumulate in your nostrils, etc. So, it ends up in places we don't expect it to and even if you're trying to be careful about it. I'm not advocating we have to start wearing masks at the beach, but just being aware that there are different ways in which it can accidentally accumulate in humans as well.
Amanda Reside
Don't drive your motorboat through a bloom.
René Shahmohamadloo
Yeah, you know, one great piece of advice from Ingrid Chorus. She is a revered former World Health Organization scientist - now retired. She's critical to all the guidelines we follow. And she was saying that if you can't see your feet through the water, if there's a bloom you should be wary of being in that water. So, that's one qualifier for the toxicity of a bloom. My work on the other hand, is, you know, it's challenging that and thinking maybe you can see your feet you could see the fish in there, but we're seeing sublethal effects too.
Michael Lim
Also, you got me thinking like so if you're an angler, and you catch a fish swimming in a lake that has algal bloom, if you cook the fish, do you break down the toxin, or are you just ingesting the toxin when you eat the fish?
René Shahmohamadloo
Very, very important question. No, microcystins is not destroyed by heat or boiling. For all the listeners, on this podcast, you can Google the "Toledo 2014, Ohio Water Crisis", and you'll find news clips like from PBS where ... I mean it's not shocking to us because we've gone through a pandemic now but at the time, it was shocking there were some people running into grocery stores, supermarkets, getting bottled water because the state declared an emergency saying you do not drink, do not boil, this microcystins is in there and it won't degrade by boiling it. Do not shower in it. So, it was it was quite a crisis to find that. I forget the other part of your question, but it was really important.
Michael Lim
It was if you if you ate fish with toxic exposures like yeah,
René Shahmohamadloo
This was a critical, I guess I didn't mention this but part of my PhD work was in collaboration with the Ontario Ministry of Environment, Conservation, and Parks. So, I did all my work there. And I worked with some of the senior scientists who are responsible for fish consumption advisories in Ontario. And one very important take home - they always stress related to consumption of fish and we know they accumulate other contaminants like mercury, PCBs, etc. is that you want to separate out the organs from the fish before you cook. And, you know, I've challenged that idea. I've said that some scientists would tell me "Oh, but people know they fillet their fish before they cook" and I told him, "Wow, you know, I know some. It's not necessarily true. I know some cultures are, you know, where people cook it whole and then they divide up". The concern for that for microcystins in particular, is that if you're cooking the fish whole, and you know there's large amounts of it in the liver, there's potential that it could leach out and go into other places you don't want it to go. So, what the Ministry of the Environment encourages is before you cook, make sure you fillet the edible muscle tissue that we consume. It accumulates at levels that are not of concern for human consumption, take that into consideration.
Michael Lim
So, I think as a researcher, we all like to think that we have the perfectly designed experiment, but obviously not always things go according to plan or you end up finding something out that you completely did not expect. So, if you go back in time, and change one thing about how you did the study, what you studied how you did it, what would it be and why?
René Shahmohamadloo
Great question. And the answer is the length of the study. Like yeah, blooms occur for 96 hours. They can occur for shorter or longer. Now saying "Yeah, it's true and I tried". I tried to, you know, pinpoint the median between one to seven days - let's do four days. I took care of it by the follow up study that I spoke about that in Chemosphere where we did one week of uptake and one week of depuration. So, it was a two week long study but in that moment, I was thinking I would have been really nice if it was a bit longer or we followed it with a period where those rainbow trout that were exposed would then be put in water only so that we could see how much or they could be decorated out. In the end I did that with a follow up study. I could have averted using more resources like more fish to answer that question. But yeah, that definitely, I think 96 hours. It was a good amount of time, but it could have been a bit longer.
Michael Lim
So, I think that's enough questions for me and Amanda, we provided you enough. It's time to take some from social media. So Amanda, if you will have our first question.
Amanda Reside
Yes. All right. So this first question says, "When I think of algal blooms, I think of pollution coming from farms or cities. Is there anything at the level of the individual that I can do to reduce how often this pollution runoff occurs?"
René Shahmohamadloo
Oh, that's a great question. I think the biggest thing as a starting point we can do is we need to raise awareness about nutrient management. I think one thing that we can do to raise awareness is just understanding that there are tools created by OMAFRA. For example, for knowing the correct amount of nutrients to apply on the land and there are these resources available. You don't need to necessarily over apply nutrients. I find like this is a large level problem that needs to be tackled by industry and government, but at the level of community and individual. We need to raise more awareness about these new tools and approaches. And also, I think just raising awareness that harmful algal blooms are happening and they are linked to nutrients. I think sometimes we just don't like pretend it's not happening. And yet every year when NOAA releases their satellite imagery we're seeing in the Maumee River, it happens all the time. That's where it begins. And then depending on weather patterns, it can make its way up to the Canadian side of Lake Erie. Like, the more the public understands and raises awareness about the connection between land and water. And, you know, along the way, highlighting studies like these that show sublethal effects. I think that would be motivation.
Amanda Reside
My next question, "Do algal blooms provide any benefits even if they're short term?" I remember being told that algae and oceans produce a lot of the oxygen.
René Shahmohamadloo
Yes, great question. Oh, this is a difficult one to navigate. There are blooms of cyanobacteria, they're blooms of diatoms, blooms of algae. So it depends what bloom we're talking about. I will only speak to cyanobacteria. And why it is a point of contention, is there are species of cyanobacteria that are used as health supplements. There have been some preliminary studies though that have come out showing how this is a widely unregulated market. And you need to be really careful. So, there was a study I don't know if it's necessarily Spirulina, but a variety of algae tablets, supplements and they wanted to quantify the cyanobacterial toxins. And what was shocking, was the variety, even within, you know, among all these supplements. So there were some that had none, some that had very high amounts, and then what it speaks to is, there are some, you know, purported benefits but there are also risks that come with that too.
Michael Lim
Before we end, do you have any final comments you'd like to make about your work? And if our listeners only take away one thing from our chat today, what do you hope it is?
René Shahmohamadloo
I think it's really important for the listeners to know like our goal is of a blooms researchers isn't to erase them. Like they're the reason we breathe. They also coexist with us in manifestation, like you know, the proliferation of these species is a manifestation of an imbalance and imbalance relationship between humans and the environment. I want to end this podcast on a note of excitement. I think there's been such advancements in Omics tools that by the year 2050, I can totally envision you know, a child can take a little sample and then immediately get a lot of information out of that which today it would be very expensive and time consuming to acquire.
Michael Lim
That bring it full circle back to the whole Pokemon thing as you go adventuring? [crosstalk] Yes, there you go.
René Shahmohamadloo
Yeah, and even Pokemon is accounting for genetic variation. You're seeing differences within species.
Amanda Reside
And that brings us to the end of today's podcast. A big thanks again to our guests Dr. René Shahmohamadloo for joining us today, GryphonCAST is brought to you by your hosts Michael Lim and me Amanda Reside with editing assistance from Ian Smith. If you're hungry to learn more about more science topics, check out SCRIBE research highlights, that's S-C-R-I-B-E research highlights on the University of Guelph website at uoguelph.ca. Or you can follow us on social media @UofGCBS. Find us on Instagram, Twitter, and Facebook. Music in the podcast comes from uppbeat.io details in the show notes. Until next time, stay curious.