Photo by Jim G.
Summary
How are human activities changing our oceans, and why do these changes all seem to support a new age of jellyfish? What are these ancient, diverse beings: harbingers of doom, or simply the most well-adapted form of life in the sea? In this episode we go jellyfishing for answers with preeminent jellyfish researchers Dr. Lisa-ann Gershwin and Dr. Lucas Brotz.
If you’d like to dive into more detail about a number of fascinating jellyfish species, we have a series of mini-episodes featuring Dr. Lisa-ann Gershwin – released first to our Patreon supporters at www.patreon.com/futureecologies
Shownotes
This episode features Dr. Lisa-ann Gershwin, co-creator of the Jellyfish App and author of Stung! On Jellyfish Blooms and the Future of the Ocean and Jellyfish: A Natural History; and Dr. Lucas Brotz, cnidarian scientist at UBC’s Institute for the Oceans and Fisheries.
Special thanks to Karen Barnaby, Kirsty Johnstone Munroe Cameron, Judy Homburger, Ilana Fonariov, and Diane.
Music for this episode was produced by Spesh Pep, Radioactive Bishop, Turku - Nomads of the Silk Road, and Sunfish Moonlight.
A lot of research goes into each episode of Future Ecologies, including great journalism from a variety of media outlets, and we like to cite our sources:
Brotz, L., Cheung, W. W., Kleisner, K., Pakhomov, E., & Pauly, D. (2012). Increasing jellyfish populations: Trends in Large Marine Ecosystems. Hydrobiologia, 690(1), 3-20. doi:10.1007/s10750-012-1039-7
Brotz, Lucas & Pauly, Daniel. (2017). Studying jellyfish fisheries: toward accurate national catch reports and appropriate methods for stock assessments. 313-329.
Gershwin, L. (2016). Jellyfish: A natural history. Lewes: Ivy Press.
Gershwin, L. (2014). Stung! On jellyfish blooms and the future of the ocean. University of Chicago Press.
Gibbons, M. J., Boero, F., & Brotz, L. (2015). We should not assume that fishing jellyfish will solve our jellyfish problem. ICES Journal of Marine Science: Journal Du Conseil, 73(4), 1012-1018. doi:10.1093/icesjms/fsv255
Graham, W. M., Gelcich, S., Robinson, K. L., Duarte, C. M., Brotz, L., Purcell, J. E., . . . Condon, R. H. (2014). Linking human well-being and jellyfish: Ecosystem services, impacts, and societal responses. Frontiers in Ecology and the Environment, 12(9), 515-523. doi:10.1890/130298
This episode includes soundscape audio recorded by Andrzej Kozlowski. It also includes audio recorded by Tobiasz 'unfa' Karoń, InspectorJ(Bubbling, Large, A.wav), scratchikken, murraysortz, tec_studio, and klanklbeeld, protected by Creative Commons attribution licenses, and accessed through the Freesound Project. A heartfelt thanks to klankbeeld, whose underwater sounds pack made this episode a pleasure to mix.
You can subscribe to and download Future Ecologies wherever you find podcasts - please share, rate, and review us. Our website is futureecologies.net. We’re also on Facebook, Instagram, iNaturalist, Soundcloud and Youtube. We’re an independent production, and you can support us on Patreon - our supporters have access to cool supporter-only mini-episodes and other perks.
Future Ecologies is recorded on the unceded territories of the Musqueam (xwməθkwəy̓əm) Squamish (Skwxwú7mesh), and Tsleil-Waututh (Səl̓ílwətaʔ/Selilwitulh) Nations - otherwise known as Vancouver, British Columbia.
This season of Future Ecologies is supported in part by the Vancouver Foundation. Learn more at https://vancouverfoundationsmallarts.ca/.
Transcription
Mendel Skulski 00:00
Hey everyone, we're back – obviously – from our midseason intermission. We spent October setting up our next moves for Season Two. And there are some really exciting announcements heading your way soon. We've also been listening to your responses on the little survey that we put on our website. And we're grateful for all of your feedback. I just wanted to highlight one response in particular, we asked how you felt about the amount of science we have on the show, and one listener wrote in: "I like learning about ecology, and how natural systems function / interrelationships that connect me more to plants, etc. I actually think 'science' is a product of the Western, capitalistic, atomistic civilization that's murdering the planet, and helps perpetuate a worldview of domination over and control of nature. So I'm pretty critical of that word. But facts about how things work even from an imperfect perspective, are interesting and make me love wild nature even more." So, I just wanted to say thank you for putting that so well. Our goal in making this show is to offer you a variety of perspectives, which may change how you move through this world, because this world is changing and we'll need to change with it.
Adam Huggins 01:17
And on that note, about two weeks ago, halfway through our midseason hiatus, the IPCC, the International Panel on Climate Change, dropped a 500 plus page report called "Global Warming of 1.5 degrees Celsius". If you missed it, that's fair. There's been a lot going on in the world. But, this is important, and it hit us here at Future Ecologies like a ton of bricks. The report reads as, sort of a roadmap of the possible futures that we could have depending on what we do from the present and it's written primarily for policymakers and international leaders in mind. But we're going to take it also as a bit of a roadmap to guide our work here at Future Ecologies and you'll be hearing more about that a little farther on down that road. For now though, we hope you enjoy the second half of our first season and continue to tell your friends about it. We really appreciate it.
[Bubbly-tech electronic music fades in]
Lisa-ann Gershwin 02:33
Okay, so this is the poem that I wrote just days before the book went to the printer. And it was about a dream that I had. And the title of the poem is: "She Dreamed She Danced With Jellyfish".
[Bubbly-tech music softens with chord]
Lisa-ann Gershwin 02:49
[Voice-tuned beneath the sea, dreamlike, reading] Amidst the swirling currents ride, strange jelly beans floating by, in reds and blues and brownish hues, far too many to classify. Long, stingy, stringy thingies, an eyeball on a tassel, with delicate pink tentacles, belying its dreaded stinging, hassle. Bald men o' war armadas, use nothing but the breeze, like sentinels from other worlds: an Odyssey o'er the seas. Wine-hued giant sea nettles and silvery ones with purple stripes, and ghostly moons so splendid, a zillion different types. Twirling spheres and clapping lobes, whose bodies catch the light, rows of flashing rainbows gleam, gifting new wild delight... And Irukandji thimbles, wicked tentacles long and fine, and as I reached to touch, the world shifted from brine to mine.
[Bubbly-tech music continues]
Lisa-ann Gershwin 03:59
It was most amazing dream, all of these jellyfish that I love, that are part of my life, were all around me. And they were all like this parade of jellies. And I really did reach out to touch . . . and boom, that's when I woke up.
[Music is more discordant and stops]
Lisa-ann Gershwin 04:22
You can't imagine it. You-you can't imagine. What stupid, filmy, brainless, spineless, nothingness of jellyfish could possibly be doing that could affect us. You just can't imagine.
[Deep, resonant tones fade into a hum, initially disappearing. The tones begin to gently reappear in the scene like shafts of sunlight breaking through water]
Adam Huggins 04:40
If you've been tuning into the first half of our first season of future ecologies then you'll probably recognize this poet laureate of jellyfish as Dr. Lisa-Ann Gershwin.
Lisa-ann Gershwin 04:49
I'm Dr. Lisa-Ann Gershwin and I work with jellyfish, and it's kind of a funny way of introducing myself because up until not very many years ago, whenever I would say I work with jellyfish, the commonest response I got was, "why?". And now, you say you work with jellyfish and people have questions: oh, um, you know, "have you heard of this one?" Or "ooo what about those stingy ones?" Or "ooo is it true that they really get that big?" or you know: there's more recognition about jellyfish now.
Mendel Skulski 05:19
And Lisa's work has been one of the primary catalysts for what you might recognize as a real cultural zeitgeist of jellyfish. Over the course of her career, she's identified and described over 200 new species.
Lisa-ann Gershwin 05:31
Yeah, I'm at 217 at the moment, so yeah. [laughs] And counting, you know, like, it blows my mind.
Adam Huggins 05:40
And if you're one of our Patreon supporters, then you'll have already been introduced to some of the many jellyfish Lisa has discovered and studied over the years. But today, instead of focusing on the individual species, we're going to zoom way out.
[Deep, resonant tones end in an abrupt fade]
Mendel Skulski 05:57
We haven't strayed yet from dry land for most of this first season,
Adam Huggins 06:00
– it's cause I get seasick
Mendel Skulski 06:01
– but as you all know, oceans make up the majority of this planet and the oceans, well, let's just say they've seen better days.
[Fast heartbeat electronic music begins]
Lucas Brotz 06:12
If you were to ask me, you know, "What do you worry about the most, what frightens you?". For me, it's ocean acidification.
Media Clip 06:19
[Unspecified Speaker] Yeah, there is a garbage truck of plastic entering the ocean, every minute, of every hour, of every day... [News Anchor] boaters and beach goers are reporting an invasion of stinging critters up and down our coast. [Unspecified Speaker, with coastal sounds in the background] If you continue this way, in less than 40 years, we won't have any fish left. [Unspecified Speaker] They not only pose a potential threat to the local food chain, but they're driving fishermen mad.
[Fast heartbeat electronic music drops beat and returns]
Lisa-ann Gershwin 06:45
It is a dark picture and I'm not a really pessimistic person. You know, I tend actually, [laugh] most people who know me would say that I'm pathologically optimistic, you know, like, annoyingly optimistic. Which is maybe why it came as a real shock to me that it's as bad as it is. And, if we sat down, and like if we white boarded by committee, alright guys, how do we screw up the oceans? Come on, give me some ideas here. You know, let's-let's whiteboard this, how do we screw up the oceans? The things we would whiteboard, are exactly the same things we're doing now, you know if we wanted to make life perfect for jellyfish, if we wanted to destroy fish, the things we would whiteboard, are the things we're doing exactly as we're doing.
Adam Huggins 07:33
And what we're doing, collectively, in many parts of the ocean, is creating ideal habitats for jellyfish.
Lisa-ann Gershwin 07:41
And they're having a Renaissance. You know, one of my colleagues described it as the "Golden Age of Gelata". And I love that, I just think that is such a perfect way of looking at the world . . .
[Music steps down for emphasis]
Lisa-ann Gershwin 07:56
. . . from the jellyfishes' point of view, this is their time. The biggest problem jellies have ever had was, you know those bony upstarts- fish. [laughs]
[Music emphasizes again]
Lisa-ann Gershwin 08:09
And so as long as fish have been around, you know, jellies have just not had the high quality life. So, you know, I think now that fish are faltering, jellyfish are like, "Oh yeah, we're back". Ya know? [laughs]
Mendel Skulski 08:23
So, in this episode of Future Ecologies, we're going to ask two questions: first, are jellyfish populations expanding, globally? And, if so, why? And what does it mean?
[Music resolves]
Mendel Skulski 08:38
Wait, that's three questions.
[Music fades out beneath Introduction Voiceover]
Introduction Voiceover 08:44
Broadcasting from Vancouver, British Columbia, on the unceded territories of the Musqueam, Squamish and Tsleil-Waututh peoples: this is Future Ecologies.
Lisa-ann Gershwin 08:57
You know, you got to kind of admire something that's been around for 500 million years-half a billion years-jellyfish have been around, and they haven't really changed. And, you know, in that time, other things have, you know, evolved and gone extinct and, you know, some things have evolved and then, you know, sprouted feathers and wings and feet and legs and learned to breathe and jellyfish have just stayed the same this whole time while everything else has been going through all this change around them. And jellyfish survived all these mass extinctions that have wiped out almost all life on Earth. And yet jellyfish haven't changed because they haven't had to, because what they do, works.
Adam Huggins 09:51
Before we tackle the big questions, let's talk a little bit about exactly what it is that jellyfish do.
[Mellow electronic music enters]
Adam Huggins 09:59
The first thing to know about jellyfish, is that nobody can agree on exactly what jellyfish are. It's a polyphyletic group, which means that there are a number of different unrelated groupings of organisms that are commonly referred to as jellyfish.
Mendel Skulski 10:14
As opposed to finfish, which most of you will recognize as fish. Some of these groups resemble the common jellyfish that we all know and, uh, love. But others are colonial organisms. That means they're actually made up of a bunch of little tiny individual organisms living together as one being-as one super colony. And still others are miniature vertebrates, that are actually more closely related to humans, than to other jellyfish.
Lucas Brotz 10:41
There's a huge diversity of jellyfish out there. There's probably about 3000 species-so far-of things that have been named and loosely fall under that category of jellyfish. And there's probably tens of thousands of more of these organisms that have yet to be identified and labeled according to science. So, there's an equally wide diversity of reproductive strategies. You know, some jellyfish spend their whole lives in the water column. Some jellyfish are hermaphrodites.
Mendel Skulski 11:14
That's Dr. Lucas Brotz. He's also going to join us on this exploration of jellyfish.
Lucas Brotz 11:19
Sometimes they call me Dr. Jellyfish instead of Dr. Pepper. And I'm a Cnidaria scientist with quantitative aquatics based at UBC's Institute for the Oceans and Fisheries.
Adam Huggins 11:31
There is a stunning amount of diversity and variability within the jellyfish groups, which makes it nearly impossible to generalize. So we'll make one last plug for those of you who haven't tuned into our Patreon feed. That's where you can learn more about these different groups. For our purposes here, though, just to get a sense for what a somewhat typical jellyfish lifestyle is, we're going to take a brief tour to the Scyphozoan lifecycle.
[Mellow electronic beats fade out]
Lisa-ann Gershwin 12:00
The basic jellyfish lifecycle is, it's very simple in a way, but it's like nothing we can relate to.
Lucas Brotz 12:08
There's sort of one lifecycle that is used by many of the jellyfish that people are familiar with, the sort of more conspicuous, pulsing Medusa bell . . .
[Pulsing tonal beats begin]
Lucas Brotz 12:18
. . . that everyone knows about from from going to the beach. They have a really fascinating life cycle. And so those adult pulsing jellyfish-we call those the Medusae-they are usually around sort of summer to fall in temperate environments, and they're sexually dioecious. So there's boys and girls, and they have eggs and sperm and they release those into the water column, when it's when it's reproductive time.
[Egg and sperm beaming into the water column background effect]
Lucas Brotz 12:50
And so those eggs and sperm will fertilize in the water column. Some species sort of brood their larvae, but for the most part, the fertilized eggs developed very quickly into a little larva that we call a planula.
[Underwater planula background effect begins]
Lucas Brotz 13:03
And that planula under a microscope just kind of looks like uh, I've heard it described as sort of a hairy Tic Tac.
Lisa-ann Gershwin 13:11
They're funny little things. They're tiny, tiny, little things that look like little miniature ciliated cigars. And so they're just these short, little, funny, little cigar looking things. And they move around in these weird little spirals. And they just like, doo-do-doo-do-do-do, in these little spirals, and sometimes they'll just stay in place, and they'll just spiral around in place. And other times, they'll actually swim in a corkscrew, they're just funny little things, and they're just trying to find a place to settle. And then once they settle, they kind of . . . burrow their tail in, and, well actually, well they burrow their head in so the head of the planula is actually the tail of the planula, they're weird. [laughs] So, so, they burrow their little head in like face first, but then that's actually the tail of the animal. So and then they settle in and they kind of cement themselves down with little sticky bits, and then the tail end now, becomes the head end.
Mendel Skulski 14:05
I can't make heads or tails of this.
[Deep, funky bass tones underscore the polyp transformation]
Lucas Brotz 14:08
It'll attach itself to that hard substrate and then slowly transform into a polyp. And these polyps, these jellyfish polyps, are really quite small.
[Small, laser-like tones join the underwater planula background effect]
Lucas Brotz 14:21
You can see them with the naked eye, but they're, they're really, really tiny. But when you look at them closely, or you magnify them, they look like kind of a tiny coral polyp, without the skeleton of course, or a miniature sea anemone.
Lisa-ann Gershwin 14:33
And they just sit there as polyps having their little tentacles out, grabbing little plankton and things, eating, and growing, and cloning, and cloning, and cloning, and cloning, and I mean they just clone lots of replicates of themselves.
[Miniature synth horn adds to the laser-like tones and underwater noises]
Lucas Brotz 14:47
And polyps, these jellyfish polyps, can exist on the ocean floor for years, we don't actually have a good idea of how long, it might even be decades.
Adam Huggins 14:57
So these colonies are really long-lived. And super resilient. Lisa has determined that they can clone themselves in 13 different ways.
[Bright jellyfish life-cycle music builds, previous themed are recalled when certain life-cycle stages are mentioned again]
Lisa-ann Gershwin 15:07
13 different ways. Come on, jellyfish are cool! [laughs] You've gotta admire something they can clone in 13 different ways. When they start cloning a colony, so you get one larva that settles right, starts cloning a colony, and there's like a leading edge. So only the ones around the outside of the colony are actually cloning more replicates. The inside, they're just fattening up, waiting to make baby jellyfish.
Lucas Brotz 15:37
When an environmental trigger causes them to start reproducing again, typically this happens in the spring in temperate environments, they'll go through this fascinating process where they start asexually cloning themselves and dividing to make little, tiny baby jellyfish.
Lisa-ann Gershwin 15:55
So when the conditions are right, these polyps that have fattened up undergo this process called strobilation. Each polyp . . .
[Moody electronic music with water sounds in the background, different phases of strobilation are matched with various changes in tone and pitch]
Lisa-ann Gershwin 16:04
. . . goes through this metamorphosis where it elongates, and differentiates, into a stack of disks, like like a stack of coins, or like a stack of dinner plates, little tiny dinner plates. And each of these ephyrae, they're called-or baby jellyfish-becomes a little, flower looking creature, like a little daisy. And they have these eight little arms, and each arm has a little sense organ, and they have these four little lips on the inside, and they start pulsating, trying to break away and they eventually do, break away, and they look like these little flowers beating away in the water, and they're voraciously hungry and they eat everything they can get their lips around. So because they're small, they can only eat small stuff. But you know, they eat fish eggs and sometimes fish larvae and plankton that the larvae would eat. And they grow very, very fast. They can go from just a couple of millimeters, which is like a 10th of an inch to dinner plate size in just a couple months.
[Final growing baby jellyfish synth effect deepens pitch and cescendos before fading]
Lucas Brotz 17:10
And they can feed and grow very rapidly and grow into the Medusa that we started the story with. And so it's a really fascinating life cycle with many stages. Not necessarily one after the other, but they can kind of exist in different stages within a population at the same time. So after those polyps go through that process, they-the polyp-doesn't necessarily die, they can stick around. But it's fascinating to me that these species have both sexual and asexual reproduction within the same lifecycle. It's it's probably one of the secrets to their success.
Adam Huggins 17:48
And here we are, back again to the Medusa that we're all familiar with, that can put out either sperm or eggs and begin the cycle all over again.
[Underwater background effect ends]
Adam Huggins 17:57
But Lucas pointed out something key: all of these life stages can coexist in a population, in a given area. And it's actually the polyp stage, not the Medusa stage, that really maintains the population. The Medusa is actually more of a dispersal mechanism, really for the polyps, which can happily subsist out of sight tucked away somewhere for years and years, waiting for the right conditions to strobilate.
Mendel Skulski 18:22
I feel like I've been to a party like that.
Adam Huggins 18:23
And when those conditions arrive, boom, you've got a whole smack of jellyfish . . . smack being the actual official name for a big herd, so to speak, of jellyfish.
Mendel Skulski 18:33
The collective noun is "smack"?
Adam Huggins 18:35
The collective noun is smack. [laughing]
Mendel Skulski 18:36
Oh my god. woooooah. [laughing] How did I just learn that?
Adam Huggins 18:43
You learned something during the recording of Future Ecologies, Mendel.
Mendel Skulski 18:46
Wow. So, just as a sidebar, I think it's it's really neat that this jellyfish life cycle actually mirrors what happens in fungi – in mushrooms. Where, a mushroom is this ephemeral thing that just pops up when the fungus wants to reproduce itself in the same way that a polyp bed will produce Medusae in order to generate more polyps. What's really happening in mushrooms is that there's this mycelium that lives on for years and years-
Lisa-ann Gershwin 19:13
There is this part that nobody ever sees. It's small and inconspicuous and under things, and we just have no idea that it's there. It's completely off our radar.
Mendel Skulski 19:23
-and that's the true fungus and the mushroom is just this once in a while fruit. And I think it's kind of, it's kind of neat to reimagine jellyfish as just this vehicle for reproduction-
Lisa-ann Gershwin 19:32
-and then when the conditions are right, boof! You get all these mushrooms or all these jellyfish.
Adam Huggins 19:36
Also like fungi, jellyfish have huge but largely unnoticed effects on their ecosystem. We'll talk about those after the break.
[Deep, plusing baby jellyfish sound effect from earlier]
Adam Huggins 19:52
So some of you have been wondering why we have these breaks since we don't run advertisements and the answer is, because we feel like it. And also for public service announcements like this one. In Canada and the United States in the next two weeks, it's time to practice democracy.
Mendel Skulski 20:09
If you live in BC, we have a referendum coming up for proportional representation. Expect a ballot in the mail, fill it out, send it in-
Adam Huggins 20:17
-by November 30, preferably.
Mendel Skulski 20:19
And if you live in America, I think you know the drill.
Adam Huggins 20:22
November sixth, midterm elections, get out there and vote. All right, is that it? That's it. Back to the show.
[Same, deep, pulsing baby jellyfish sound effect]
[Faint, glimmering music enters]
Adam Huggins 20:35
So, many jellyfish have this unique lifecycle that hasn't changed in hundreds of millions of years, and has allowed them to survive multiple mass extinctions and the rise of much more complex organisms. They might not be the smartest or the fastest, but they may very well be the hardest to kill.
Mendel Skulski 20:52
And it's this cockroach-like quality that has been grabbing headlines over the past decade or so. As our ocean changes, the idea that jellyfish are ascendant has made its way into popular consciousness. But much like the widespread notion that you can slowly boil frogs to death without them noticing-
Adam Huggins 21:09
-which I've never actually seen anyone do. And I would probably try to stop them, if they tried.
Mendel Skulski 21:15
Don't boil frogs! That makes you a bad person. Anyway, we wanted to see if there's actually data that shows that jellyfish populations are expanding. Lucky for us, Lucas has been working on this very question.
Lucas Brotz 21:27
Right. So it's a very interesting question. Um, you know, usually my response to the question, are jellyfish increasing globally is, what do you mean by a jellyfish? What do you mean by an increase? What do you mean by global? And over what timeframe? Because really, depending on how you define the terms of reference of the question, could lead you down the road of a different answer, whether it be a yes, no, or a maybe. But I've spent a big part of my career, sort of digging into that question, and we have put some parameters around those terms. And, we have come up with sort of a conclusion that it looks like, jellyfish are increasing in many places. It's definitely not all species, everywhere. But when we look around the planet, we only have a limited amount of data on jellyfish, because they have historically been under studied. But when we examine, say, over the last 50 or 60 years, where we have data, where we can look at jellyfish population changes, we find a couple of important conclusions. One is that it does appear that jellyfish are increasing in many more coastal ecosystems than they're decreasing. So that gives us a sign that yes, something global is going on here. As well, some of the places that we're really certain they've increased, where the data is really strong to indicate there's more jellyfish around now than there were in previous decades, these areas are scattered all around the globe. So they're not necessarily directly connected or right next to each other. So we're seeing increases in places like Asia, you know, off the coast of China and Japan. But then, you know, certain areas around North America and the East Coast, even remote places like Alaska, or Hawaii, or Antarctica. So we have these sort of disparate spots all around the world that tell us, you know what, if jellyfish are definitely increasing in all these different places, there could be some sort of global phenomena that's affecting them.
Mendel Skulski 21:28
So basically, from the data that we do have, it looks like jellyfish populations are indeed undergoing a global expansion, with regional variation, of course. With any generalization this large, there are always caveats. Like we've never paid that much attention to jellyfish. So the more we look, naturally, we'll see more, but there are good reasons to believe that this is happening.
Adam Huggins 24:00
And that's because we, humans, are the primary driver of change in the ocean. [laughs] It's like, it's because we-
Mendel Skulski 24:08
-we-
Adam Huggins 24:08
-in case you needed a reminder, humans-
Mendel Skulski 24:12
-we-fellow-humans-
Adam Huggins 24:12
[laughing] it's like I'm posing as a human.
Mendel Skulski 24:12
[laughs]
[Somber piano notes]
Adam Huggins 24:21
And that's because we [deep vocal edit "humans"] are the primary driver of change in the oceans. And we know from observation that oceans and seas that are highly impacted by people, are places where jellyfish populations can expand rapidly.
Lisa-ann Gershwin 24:36
There are certainly a range of things that humans are doing that are impacting the oceans negatively. And jellyfish react to these directly or indirectly. But in so many cases, things that we're doing are benefiting jellyfish. For example, when we overfish, jellyfish love this, because fish are their predators and competitors. Well, you take away anything's predators and competitors, and it's going to do really well. I mean, that's just basic ecology, Ecology 101. Take away the predators and competitors, woohoo! Field Day, right? A more direct effect is warming water. Jellyfish love warming water, warmer water. So any increase in temperature, as long as it's not too much. I mean, you could boil them and that's bad for them. But you know, just a little bit of an increase, a couple degrees kind of thing. You warm up the water a little bit, fish find it much harder to extract oxygen from the water, because warmer water holds less dissolved oxygen. It's like us trying to breathe on Mount Everest, it's harder, we have to work harder. So fish do really, really poorly in warmer water. But jellyfish, they hit their Renaissance in warmer water. It amps up their metabolism, they grow faster, they breed faster and more, they live longer; summertime lasts longer for them, they love warmer water.
[Glimmering music is recalled]
Lucas Brotz 26:02
We're seeing jellyfish increase their ranges and some increase their reproductive output. So we'll have certain species that, that sort of thrive more in warmer waters. Of course, warmer waters isn't good for all species of jellyfish, if you have a cold water species that say in the Arctic, that could be negatively affected by, by warmer waters. But we're certainly seeing these other more opportunistic species expand their ranges and, and even in Antarctica, one of the stories there has to do with global warming where there's a decline in sea ice, which has resulted in less habitat for for krill, which need the sea ice for a certain part of their lifecycle. And so that's increasing the amount of habitat for [selphs] which is a kind of jellyfish that we find in the Southern Ocean. So even even in a place as far away as Antarctica, we're seeing a real shift in jellyfish populations due to global warming.
Mendel Skulski 26:58
Overfishing obviously benefits jellyfish and warming water, receding sea ice, which is associated with global warming, is also going to boost most jellyfish populations. But what about that other major effect of global warming? Ocean acidification?
Lisa-ann Gershwin 27:14
Ocean acidification is another very interesting thing for jellyfish. So there is some recent research that demonstrates that they are affected negatively, a little bit. But by the time jellies are affected, everything else is much more affected.
Adam Huggins 27:29
And the same goes for various kinds of pollutants that we dump into the ocean.
Lisa-ann Gershwin 27:33
Pollution? You know what they don't care, it doesn't bug them. They don't care. They're the last man standing when everything around them is dying.
[Muted, siren-like sound fades in with background music]
Mendel Skulski 27:41
By the time ocean acidification or pollution gets bad enough to seriously affect jellyfish. Everything else will be toast.
Adam Huggins 27:48
-Toast with jelly.
Lisa-ann Gershwin 27:49
So there's a certain type of pollution that I've become very fascinated with, scientists call it eutrophication. It's just a fancy word for too much nutrients.
Lucas Brotz 27:59
We dump a lot of nutrients into the ocean, whether it's from excess fertilizer,
Lisa-ann Gershwin 28:04
runoff from farms, or
Lucas Brotz 28:06
– sewage or things like this, ultimately sort of fertilizes the ocean. So you get these algae blooms. There's-there's really dramatic algae blooms going on in Florida right now actually, I encourage the users to to google it and check it out where all species in the in the marine environment are being affected with dramatic fish kills and things like this. So you get these algae blooms, and eventually they'll-they'll die and as they start to decompose, this uses up a lot of oxygen as the bacteria are decomposing them. A lot of the oxygen will get used up . . .
Lisa-ann Gershwin 28:41
. . . and it creates what we call "dead zones" where every living thing dies, everything and you know, it either results in extremely low oxygen or actually zero oxygen, where it's low oxygen pretty much only the worms survive, where there's no oxygen even the worms die and it creates these moonscapes; it's just unbelievable. Jellyfish love this. That's their turf, man. They're good there. So what they do, is they hang out in the oxygenated water near the top, you know, right at the surface, and then they go down and they can slurp up the gunk that's in these dead zones. And they store oxygen in their jelly, their tissues, and then they come back up when they get low on oxygen, they need more oxygen, they come up and recharge. [laughs] They're like little rechargeable phones, you know. [laughs] And so, you know that they go down there and they just like slurp, slurp, slurp, slurp, you know, they they get all this, you know organic matter . . .
Mendel Skulski 29:41
Acidification, pollution, eutrophication. These are chemical changes to marine ecosystems. But there are also physical modifications, like for example, trawling, which is where a fishing boat will pull a giant, weighted net that drags along the ocean floor to catch fish.
[Thalassophobic gyrating tones underscore trawling]
Lisa-ann Gershwin 29:58
Trawling is one of the best things that can ever happen to jellyfish. So when you trawl, you're actually dragging these heavy nets with, you know, chains and all this stuff this heavy, heavy stuff, you're dragging along and you flatten the three dimensional habitat. So all of the, you know, the corals that are sticking up, and the sea pens that are sticking up, the macro algae that are sticking up-wham!-they're all razed to the ground. But what happens then, is when that rock gets turned over, okay, that's now new fresh habitat for jellyfish larvae to settle and start growing more polyp colonies. And, of course, with anything that's space limited: first on site gets the space. Well, jellyfish tend to be first on site.
Lucas Brotz 30:48
That's actually a link to sort of one of the last major factors, which is coastal development, and we think this is basically providing more habitat for those jellyfish, polyps. Some species seem to prefer to be up underneath structures, probably to avoid too much sedimentation. But you can imagine the natural environment: there aren't a lot of overhanging structures, maybe some rocks or the underside of some of those bivalve shells. But when humans develop a coastline of course, there's a huge amount of shaded habitat. We have marinas, breakwaters, oil rigs, aquaculture operations, net pens, all these things, potentially creating more habitat for for jellyfish polyps. And often when we go down with scuba equipment and just sort of inspect and look at what is growing on these structures, and in many cases, it's jellyfish polyps.
[Pensive tone builds, then fades out]
Adam Huggins 31:44
I've got to say so far, this exploration of jellyfish is making me feel really evolutionarily inferior.
Mendel Skulski 31:50
I don't know how to say anything nice [laughs] in response to that.
Adam Huggins 31:55
I was not jelly-fishing for compliments there. [laughs]
Lisa-ann Gershwin 31:58
But we are incredibly delicate compared to them. You know, they can survive anything. Okay, maybe not a frying pan. So [laughs] now look, there are some things they can't survive, but-but even when the jellyfish itself dies: like a frying pan, right you know you run over it with your car okay? splat no more jellyfish, you know, stranded up on the beach high and dry, [zip noise] no more jellyfish, but no, man that's not it because they got those polyps! Don't forget the polyps, right? There's always more jellyfish because they got those polyps and we haven't worked out any way to get rid of the polyps.
Mendel Skulski 31:58
Woaaahhh . . . Oh my god.
Adam Huggins 32:39
So to sum it up, while an individual jellyfish Medusa might appear delicate, jellyfish as a whole organism are virtually indestructible. And basically everything that people do to marine ecosystems, benefits jellyfish, usually at the expense of fish, and other more complex organisms.
Mendel Skulski 32:57
We're starting to see these effects all over the world. After the break, we'll take a closer look at what a jellyfish apocalypse might look like, using a real world example. And we'll ask, what can we do? And what does it all mean? All, after the break.
[Deep, pulsing baby jellyfish sound effect from earlier]
Mendel Skulski 33:22
Up to this point, we've been talking about an abstract jellyfish lifecycle and the abstract human activities that are creating a very real increase in global jellyfish populations. But in the Black Sea, there is nothing abstract about any of this.
[Vibrant music immediately reminiscent of the Black Sea fades in]
Adam Huggins 33:45
A little geography here: the Black Sea is a huge inland sea, in the Mediterranean, separating Eastern Europe from the Middle East and Western Asia. It's bordered by Ukraine to the north, Romania and Bulgaria to the west, Turkey to the south, and Russia and Georgia to the east. About a third of Europe drains directly into the Black Sea. It holds significant biodiversity, and historically, it supported a very productive fishery for the countries that ring it.
[Black Sea drum solo underscores]
Mendel Skulski 34:17
Back in the 1970s, large amounts of freshwater was being diverted from rivers, like the Danube, that drain into the northern part of the Black Sea. This disrupted regional hydrological patterns and degraded formerly productive habitats. The water was used for irrigation and hydroelectricity, for the most part. All this increased irrigation, coupled with new industrial methods of farming, led to a boom in agriculture in the North. The result, excess nutrients pouring into the northern Black Sea and leading to eutrophication. Finally, fishing was taking place on new, industrial scales, leading to rapid declines in populations of previously abundant fish.
Adam Huggins 34:55
And by the early 1980s, all of these pressures had already led to large blooms of native jellyfish species, like Aurelia aurita, the Moon Jelly. But the other shoe was about to drop.
Lucas Brotz 35:07
As we transport all of our goods around the globe, sometimes creatures from the ocean come with it and in the form of ballast water and these big shipping tankers. And so, we've seen jellyfish from one part of the world pop up in another region where they certainly weren't native. And in some cases, they've exploded in population, probably because they haven't evolved with a natural predator there and they can really overtake an ecosystem. We saw this happen in the Black Sea, where jellyfish were eating a lot of the fish eggs and fish larvae, and they really just took over the entire ecosystem.
Mendel Skulski 35:42
A number of invasive species were introduced to the Black Sea at the time, but the most consequential, was a species called Mnemiopsis leidyi also known as the Sea Walnut. It's a ctenophore, which is a group of jellyfish more commonly referred to as "comb jellies". These jellies don't pulse through the water like the Medusae we're more familiar with. Instead, they use rows of cilia that run down their bodies; they glide deftly through the water. Mnemiopsis is hermaphroditic, it's self-fertile and voracious, which makes it a potent invasive species. It's originally native to the Atlantic Ocean, but it's been introduced to many places, including the Black Sea.
Adam Huggins 36:21
And once it arrived, it immediately took advantage of the declining fish populations and eutrophified conditions to explode in population, completely taking over in the course of just a few years. 1982 was the introduction, and 1989 was the peak in population.
[Other instruments rejoin drum]
Lisa-ann Gershwin 36:37
In its heyday, 95% of all the biomass in the Black Sea, every living thing, 95% was this one species of invasive jellyfish. That's how much it had taken over. Yeah, it's just like it blows my mind every time I try to think of what that . . . looks like.
[Vibrant Black Sea music is replaced by wet, disquieting jellyfish and ocean noises]
Lisa-ann Gershwin 36:59
I just I don't know if my mind starts to implode or something like, I just can't go there. And I mean, there was a perfect example of this sort of cascade of problems that ultimately led to complete flipping of the ecosystem.
Mendel Skulski 37:16
And in the Black Sea, nothing really ate these things. In the ocean, there are some species, like ocean sunfish and sea turtles, that do eat jellyfish. But in the Black Sea, Mnemiopsis was, in effect, the apex predator.
Adam Huggins 37:30
When we think about apex predators, we usually imagine lions, or bears, or ourselves, but in a jellified ecosystem, the lowly, brainless jellyfish can actually fill that role.
[Fast heartbeat electronic music is recalled]
Lisa-ann Gershwin 37:45
You know, I learned the typical food chain that we all learn, you know, phytoplankton are eaten by grazers like copepods, you know, these tiny little crustaceans and pretty much everything bigger than a copepod eats a copepod. And, you know, then small fish, eat them and then medium sized fish eat them, and then large fish, eat them and so on, you know, and, and then we eat the fish and, you know, that kind of thing. So the typical food chain that we all, you know, it's what we learn. And so this is now what's called the "high energy food chain", because there's a lot of energy that's transferred up the food chain. And ultimately, you know, we require a high energy food source to sustain our own bodies. So there's a lot of energy being transferred up and being consumed. The low energy food chain, that's where jellyfish roll the world. So the top predator, and we're talking the sharks, the humans, the whales, right, the top predator on the low energy food chain is jellyfish. It's not sharks, it's not humans, it's jellyfish. And so we don't really think of them as the top predator, but they are, in their world. So the low energy food chain has a different type of phytoplankton, things called flagellates, and microbes and things like that. And so that food chain-it's a shorter food chain-there's not as many steps, not as many, you know, this eats that eats that eats that kind of thing, right? And jellyfish are the top predator. The funny thing about jellyfish though is even though they're the top predator in the low energy food chain, they're not stuck there. They're also in many cases, the top predator in our food chain, the high energy food chain, because they sort of reach over with their tentacles-getting a little metaphorical here, right?-but they reach over with their tentacles, and they rob food from the high energy food chain, you know, they're not going to eat a shark, right? But jellyfish will eat the eggs and larvae of a fish and they'll also eat the plankton that the larvae would eat. So this double-whammy of predation and competition can absolutely wipe out, not only that fish population, but everything up food chain that relies on those fish.
Adam Huggins 40:15
This, to me, is the crux of the problem. That once an ecosystem has flipped to being dominated by jellyfish, it might be, for all intents and purposes, impossible to flip it back. Lisa has referred to rapid jellyfish population expansions as a death rattle for a marine ecosystem.
Lisa-ann Gershwin 40:34
Yeah, absolutely. So some of, well, most of the systems that we see that have flipped to being dominated by jellyfish, they're incredibly resilient. You know, we always talk about resilient ecosystems, right? Yeah, you want resilience. [laughs] Let it be dominated by jellyfish that is resilient. That's not budging. That is not changing. I don't spend quite so much time thinking about what we can do with jellyfish ecosystems, you know, once they flipped; I'm really more concerned with how to identify before something is flipped, and what can be done to keep it from flipping. So, to save somebody before the death rattle.
[Heartbeat music ends with a dramatic, bubbly water noise]
Adam Huggins 41:25
So, Mendel, you're a designer: what can we do about this?
[Gentle, wet jellyfish soundscape underscores dialogue]
Mendel Skulski 41:30
People have talked about kind of developing and growing . . . human applications for jellyfish and then those come in and a lot of pretty out there forms I mean, the obvious one is-is eating them, and creating this consumer demand for a new kind of food stream. There's things like mixing them into concrete so that the concrete flows better or are using them as filters for-for nanoparticles. I mean, industrial lubricants, that sort of thing.
Adam Huggins 42:03
Right? Which is kind of the like, that's the best way we can think of to use capitalism to help us solve the problem of too many jellyfish, right? Like, make a demand for them in some industrial capacity.
Mendel Skulski 42:14
Right! And, and is that misplaced? Like, if we start to create value for them, does that give us the right incentive to put our ecosystems back in the trajectory that we actually want them? Or does that just sort of excuse our current behavior? Jellyfish are eaten in several different cultures. And it's not hard to imagine, in the same way that sushi went from being, you know, disgusting raw fish in North America to being one of the most popular foods-
Adam Huggins 42:42
-It's still disgusting, raw fish.
Mendel Skulski 42:44
It's all perspective. And it seems very reasonable to imagine that in a decade, everybody could be eating jellyfish, but what happens when we start to really like it?
Lucas Brotz 42:56
And so I think if we adapt to fishing for jellyfish as sort of the new normal, then we might lose sight of what our ultimate goal is to potentially restore ecosystems, marine areas to what they potentially could be. And so, if we adapt too easily to that, I think that it could be a big reason that we would sort of stop doing the things that are potentially causing increases of jellyfish in the first place. You know, global warming, invasive species, overfishing; it might give us an excuse to continue to do those things which which obviously isn't good.
Adam Huggins 43:37
I kind of doubt that though. Because from what I understand, jellyfish is at best, a suitable flavor carrier for other flavors like-I-it doesn't seem like it has much flavor on its own. And it's only certain species of jellyfish that are edible. Right? Definitely not all species of jellyfish are edible and something we have talked about a whole lot in this episode, but something that Lisa spends a lot of time doing in her career, in Tasmania, where she works, is protecting people from jellyfish stings during bloom situations and trying to predict blooms because you know-newsflash!-jellyfish are really dangerous. Some species are really dangerous, and even the not-so-dangerous species, they can still harm you, they can still sting you. Was it? I mean, it might also have been Lisa, who was just talking about how some people are working on machines where the machine sails through the water and it has blades on it and it just chops up jellyfish.
Mendel Skulski 44:33
Oh man . . .
Adam Huggins 44:33
[laughs]
Mendel Skulski 44:36
Yeah . . . I don't know.
Mendel Skulski 44:39
I don't like that vibe.
Adam Huggins 44:44
Just the jellyfish Terminator.
Mendel Skulski 44:45
Yeah . . . That's not the kind of solution that I want to see.
Adam Huggins 44:49
Right? If ecological restoration means deploying jellyfish terminators into the water. That's pretty-that's pretty far from the version of ecological restoration that I work within. So is there any hope then? Will the Black Sea forever be a sad pool of jelly?
[Quiet, sad pool of jelly noises]
Mendel Skulski 45:09
Well, actually, the Black Sea has made a partial recovery. And in a roundabout way, it proves Lucas's point that, if we change the underlying patterns of human activity, then we can change the outcome. It's just that in the case of the Black Sea, we were forced to change the patterns.
[Deep, harrowing music begins, with bass tones, chimes, and synth]
Lisa-ann Gershwin 45:27
And the only reason that it kind of "flipped back"-and I'm putting that in air quotes-is because of a very, very, strange and unexpected, simultaneous happening of things that would never happen in a normal world like that. I mean, I think they could just never happen again. And so, because the fisheries collapsed, the fishermen stopped fishing. So strangely enough, this actually gave the fish a bit of a chance because the fishing pressure stopped; simultaneously “[Latin Binomial]” primary predator-also itself an introduced species-was introduced in ballast water, accidentally. And also, at that same time as the Soviet Union was breaking apart, and having all kinds of political problems there, the subsidies-the fertilizer subsidies-to the farmers stopped. And so, the runoff of the fertilizers stopped, because farmers were using less. And so the nutrients coming down into the water and creating this dead zone, that slowed as well. And so these three things that would never actually happen on purpose, all happened at the same time; the cost of doing those things on purpose . . . would never make them possible. I mean, putting farmers out of business, putting fishermen out of business, introducing a species that you don't know what's going to happen? It's still not enough. It still hasn't gone back to what it used to be. You know? And so, I don't think the typical person . . . is even aware that that kind of thing is happening, particularly in the ocean. Because you know, it's under the cloak of water.
Mendel Skulski 47:15
It's funny, people don't seem to do anything differently until it's totally dire.
Adam Huggins 47:19
Yeah. And like, like Lisa said, jellyfish is already the death rattle . . .
[Music fades out]
Adam Huggins 47:24
. . . there's no guarantee that an ecosystem can come back after that. And as somebody who practices ecological restoration and studies it, that's the most terrifying thing when, when your ecosystem undergoes a total threshold shift from a place where maybe you can bring it back to where it was, or, or-or bring it to a place that's acceptable. I think this is one of those cases in which we can't really provide the hopeful, forward-thinking ending that we would like; like no matter how much technical acuity that we bring to this problem, or, or-or how we shift our thinking-this is something that we're going to be dealing with. And it's just a question of how bad it gets. At the at the end of our interview, Lisa actually turned it around on me and she said so,
Lisa-ann Gershwin 48:13
Someone your age because I'm-ahem-a little bit older than you . . . okay? [laughs] Yeah, probably double, I'm guessing, but from your point of view, um . . . are you angry that we've let it get like this? Are you angry that we didn't do something earlier?
[Confident, repetitive drumstick hits begin under dialogue]
Adam Huggins 48:34
And I just told her I blame Baby Boomers for everything.
Mendel Skulski 48:40
[laughs]
[Nervous, electronic tones play from music]
Adam Huggins 48:40
-Baby Bloomers, can we call them Baby Bloomers now?
Adam Huggins 48:51
Thanks for listening. We'll be back in a couple of weeks. Please tell everybody that you know, subscribe, rate and review the show, wherever podcasts can be found; it really helps us get the word out.
Mendel Skulski 49:02
In this episode you heard Lisa-ann Gershwin and Lukas Brotz.
Adam Huggins 49:07
This has been an independent production of Future Ecologies. Our first season is supported, in part, by the Vancouver Foundation. If you'd like to help us make the show, you can support us on Patreon. We have a whole series of mini episodes profiling cool species of jellyfish with Dr. Gershwin. To get access to these, head to patreon.com/futureecologies.
Mendel Skulski 49:28
You can also follow us on Facebook, Instagram and iNaturalist. The handle is always Future Ecologies.
Adam Huggins 49:36
Special thanks to Karen Barnaby, Kirsty Johnston Munroe Cameron, Judy Homburger Ilana Fonariov, and Diane.
Mendel Skulski 49:42
Music in this episode was produced by Spesh Pep, Radioactive Bishop, Turku - Nomads of the Silk Road, and Sunfish Moonlight. You can find a full list of musical credits, show notes, and links on our website: futureecologies.net.
Adam Huggins 49:59
And this is a Sepsh Pep jam, enjoy:
[Funky, electronic jam plays, with a hardy drumstick baseline, and an airy, masculine vocal before an alien, computerised finale]
Transcribed by https://otter.ai and edited by Wren Hieu