Dr. Lorian Schweikert: Deep-Water Ocean Exploration and Bioluminescence

Full transcript of the Tom Rowland Podcast, Episode 430 — Dr. Lorian Schweikert — Deep Water Ocean Exploration, Bioluminescence, and the Search for the Giant Squid in the Gulf of Mexico.

Cold Open: Life Below the Photic Zone

Lorian Schweikert: The biggest thing was understanding how life operates below the photic zone. Below a thousand meters, there's no longer a trace of sunlight, but you still have this incredible biodiversity down there — all these fishes, invertebrate animals, and more. They have to communicate, find each other, find prey, and evade predators, and they mainly do that with bioluminescence, the biological production of light. So we were trying to understand the mystery of how life operates and the function of bioluminescence in those extremely dark, cold waters. We were also looking for new species and for adaptations that occur in the deep — producing, for example, some of the most extremely dark, or black, biological material on Earth. We were also looking at the abundance and health of animals, and how that may have been tied to the Deepwater Horizon spill. And lastly, we were looking at whether we could find the giant squid, which had never been recorded live or observed living in the Gulf of Mexico prior to this. I'm Lorian Schweikert, and this is the Tom Rowland Podcast.

Welcome Back

Tom Rowland: Hey, everybody. Welcome to the podcast today. One of our most popular guests ever was Dr. Lorian Schweikert. She told us about fish vision — she's done a tremendous amount of research on the way fish see. And as anglers, we can take that information, understand it a little better, and it can help us catch more fish, or understand why we're not catching as many fish as we think we should. I love that conversation. She knows so much about fish biology, so we have her back today, and I'm really excited about it because she just did this big research trip out in the Gulf of Mexico, in very deep water. She left out of Mississippi, out in front of Venice, Louisiana — an area I'm familiar with. It's a fish factory, and they started doing all kinds of studies in really deep water, like five, six, seven thousand feet deep. Really deep. And one of the things that was uncovered was the second giant squid sighting on video ever. We've got video of one off the coast of Japan, and this expedition has number two — and it's number one with an ROV, a remotely operated vehicle called the Medusa. She tells us all about the giant squid, what we know about it, and unfortunately there's way more that we don't know. Not many have ever been seen — only a couple, ever, in the deep part of the ocean. There's history throughout Moby Dick and all kinds of literature about the giant squid, but it's just a mystery — not a mystery like Bigfoot, where there are tons of sightings and legend but no conclusive evidence. We do have conclusive evidence for the giant squid. So we talk about that difference, what it means, and what the future of study for the giant squid might look like. It's a very interesting conversation that goes into all kinds of stuff they studied and learned on that ship. So I hope you enjoy this conversation with Dr. Lorian Schweikert, and here we go. Alright, Lorian, welcome back. How are you?

Lorian Schweikert: I'm doing well. I'm glad to be back.

Tom Rowland: Well, you've had some changes in your life. Congratulations on your new son.

Lorian Schweikert: Thank you. Yeah, my son was born, John, and I've got a new position — a professorship at the University of North Carolina Wilmington. So just a lot of change since the last time we spoke. A lot of good things.

Tom Rowland: Well, that's great. So you had a baby during COVID. What was that like? Did you — I assume you were in the hospital. Did your husband get to go with you?

Lorian Schweikert: Yes. So he was born in April, right when COVID was really peaking, and some hospitals across the country were only allowing birth mothers in, not partners. It was a really scary time, but luckily it worked out and my husband got to be there for the birth.

Tom Rowland: That's good. That's good.

Lorian Schweikert: And it has been fantastic. It has been life changing.

Tom Rowland: Yeah, well, those are three of the most important days of my life — being there for the birth of my children. That's awesome. I've got three, though mine are a little older than yours — a twenty-three, a twenty-one, and a seventeen-year-old. So we're a little ahead, but I remember those days very well.

Lorian Schweikert: Wish us luck — we're teething, we're cutting molars.

The Gulf of Mexico Research Expedition

Tom Rowland: So with that, you've still been able to do some scientific excursions. You were telling me about your recent Gulf of Mexico trip, and I'm super interested in this — first of all, I want to know what you were doing out there. Why don't you tell us about this latest excursion?

Lorian Schweikert: Yeah, so I got the incredible opportunity to go on a research expedition into the Gulf of Mexico. People study marine biology their whole lives and only get an opportunity to do this maybe once or twice, or maybe never — so I kind of won the golden ticket. I got to go out on a research vessel into the Gulf of Mexico to study life in the deep sea and ask questions about the deepest waters there that we don't already know.

Tom Rowland: And where did you leave out of?

Lorian Schweikert: Gulfport, Mississippi.

Tom Rowland: Okay.

Lorian Schweikert: I drove from South Florida all the way to Gulfport, and we went out on a hundred-thirty-five-foot research vessel, steaming out past all the oil rigs and oil fields — something I'd never seen. We steamed out about a hundred to two hundred miles south of New Orleans, which is about where the research area was.

Tom Rowland: Well, we fish there quite a bit. That's in range of the guys in Venice, Louisiana, and the sport fish fleet there — they'll go a hundred, a hundred-fifty, some people going two hundred miles out. So I'm somewhat familiar with that area, and what you find there might scare me, because I've been there. I want to know what lives down deep.

Lorian Schweikert: Oh my god, I want to go back purely as an angler because I saw things — miles and miles of sargassum floats, baby tripletail, huge tripletail. I'm there doing the science, and I see all these big pelagics come by, and it was amazing. So I understand why people go out there to fish.

Tom Rowland: It's incredible — that is the fish factory. The Mississippi River flows right in there and hits the Gulf of Mexico, and it creates an incredible inshore fish factory like I've never seen before. The amount of redfish and sea trout there is unbelievable. And offshore doesn't disappoint either — the tuna, the marlin, the swordfish, it's all happening. It's really good up there.

Lorian Schweikert: That's cool — and I got to hear some of those fishing stories from the crew on the ship, the captain and crew. They're just salt-of-the-earth gentlemen who had lived in coastal Louisiana and Mississippi their whole lives and had so many great fishing stories to tell. So I got to go out with a science party of twelve marine biologists, representing some of the most elite marine biologists on the planet, studying all different aspects of what might be going on in the deepest waters of the Gulf of Mexico. This was funded by NOAA, and it was very exploratory — we had a couple of ideas of what we might find.

Tom Rowland: That's what I was going to ask — what were the objectives? Let's talk about those ideas you thought you might find as you were leaving the dock, because there's got to be some kind of objective in taking twelve marine biologists out there. What were the things you or the team were hoping to find?

Lorian Schweikert: Great question. The biggest thing was understanding how life operates below the photic zone. Below a thousand meters there's no longer a trace of sunlight, but you still have this incredible biodiversity — all these fishes and invertebrate animals — and they have to communicate, find each other, find prey, and evade predators, mainly through bioluminescence, the biological production of light. So we were trying to understand the mystery of how life operates and the function of bioluminescence in those extremely dark, cold waters. We were also looking for new species and adaptations that occur in the deep — producing some of the most extremely dark, or black, biological material on Earth — and we were looking at the abundance and health of animals, and how that may have been tied to the Deepwater Horizon spill. And lastly, looking at whether we could find the giant squid, which had never been recorded live or observed living in the Gulf of Mexico prior to this trip. It was incredible.

The Mystery of the Giant Squid

Tom Rowland: So when you see all these reports of giant squid, where are those coming from? Has it been documented lots of times before?

Lorian Schweikert: We think of the giant squid as one of the most unbelievable animals on Earth, and they've been documented from washing up on shore dead — we find their bodies, or limbs, and so forth. But only one other time in history have we observed them and their living behavior, and that was in waters off Japan, from a manned submarine that was on the hunt for these animals. It observed one and videoed it for a short time, but mainly we only knew it existed from specimens washing up on shore.

Tom Rowland: Man, that is a crazy species. I want to talk to you a lot more about that, but let's walk through the trip — you're going out with these objectives, going two hundred miles out. How does the trip kind of unfold?

Lorian Schweikert: Good question. So the science leader, who has a ton of responsibility on his shoulders — Dr. Sönke Johnsen of Duke University — gets us all together and assigns our berthing. At the time I was just a postdoc, not yet a professor, so I got put down in the belly of the ship right by the engine, which was great — thanks, Sönke. We all get assigned our berthing, we learn the safety protocols, we hear the spiel from the captain, and you meet the chef in the galley, and you want to make friends with him because—

Tom Rowland: You're nice to him.

Lorian Schweikert: He determines your fate for the rest of the trip. And then the science begins — everyone talks about their objectives, gets their equipment out, and it's time to steam to the different locations where we need to start collecting data.

Tom Rowland: Okay, and what about the equipment you're using? With all those different objectives, I'd assume there's a big array of equipment — some you might be familiar with, maybe some new stuff. What were these people prepared with?

Lorian Schweikert: Some of the small stuff you'd expect, like benchtop microscopes and things like that. But there were three major methods employed on the ship. If you think about how vast the deep sea is, and the biomass — the abundance of animals, the amount of life down there — it's not very dense per unit area. It's a huge area, so it's hard to explore, hard to know where the animals are, and hard to get down there safely and collect data. So we needed three pretty amazing pieces of technology. The first was an ROV, a remotely operated vehicle — an unmanned submarine tethered to the ship. It gets deployed and goes down thousands of meters — there's approximately three feet in a meter, so you can imagine the depths — and we motor around with that instrument, taking video, looking for life. It actually has suction arms, so we can capture deep-sea animals and return them to the surface. The second was a giant trawl net, about a twelve-by-twelve-foot net on a winch of metal cable that we deploy into the ocean. The max depth we did there was about fifteen hundred meters, and we'd tow it for hours at a time, then bring the net up — it funnels all the life into a little tube at the end. So now we've captured animals by sampling the water. And the very last technology, which I'll expand on more when we talk about the giant squid, was developed by Dr. Edith Widder and Dr. Nathan Robinson — they deployed this thing called the Medusa, which is kind of the newest technology for this kind of research. It's remotely deployed — we dropped off this insanely expensive piece of equipment and steamed away, trusting that the buoy with the transponder would stay attached to it, and it silently and remotely senses and videos the surrounding life. We put in a lure to try to bring in animals to that silent instrument, and it changed everything.

Tom Rowland: What does the lure look like? What kind of lure?

Lorian Schweikert: Good question. So picture the Medusa as a box, a frame with a camera on it — a low-light camera — and a lure. The lure is essentially a ring of lights that glow in succession, over and over, like dots of light going around a wreath. This is a mimic of a naturally occurring bioluminescence behavior. There's a jellyfish — I believe a North American jellyfish — that, when attacked, glows in a circle like that in nature. The reason it starts to glow when attacked is that it's trying to tell bigger predators from far away, "Hey, I'm getting eaten — come over here and eat the thing that's eating me." It's called a burglar alarm. Dr. Edith Widder, who's had all these incredible experiences and is one of the first and most amazing women oceanographers, had seen this phenomenon in nature and had the idea: what if I put a lure that looks like a jellyfish being attacked onto the Medusa and send it down thousands of meters — what's going to happen? We had a very large predator come to that lure, thinking there was a fish or a tasty snack in the area, and it changed everything.

Tom Rowland: What was the very large predator?

Lorian Schweikert: The giant squid.

Tom Rowland: That was it? That's what brought it in?

Lorian Schweikert: That was it, that's what brought it in. What's amazing is that ROVs — and probably manned submarines — are being used in the Gulf of Mexico all the time, for finding artifacts of sunken ships, for studying biology, and guess how many times we'd seen the giant squid with an ROV?

Tom Rowland: Zero, in the Gulf of Mexico — you already said that. So how did they see it in Japan if it wasn't with an ROV?

Lorian Schweikert: In Japan, they came across the animal — I don't know exactly how they got it to stay in frame, I'd have to look into that more. There's video on YouTube that's amazing. But I'll say it's not really Japan versus the Gulf of Mexico — it's the use of technology that made the difference.

Tom Rowland: But that's what I was wondering — if they saw it, was it with an ROV, or some other type of camera or technology?

Lorian Schweikert: It was with a manned submarine.

Tom Rowland: Okay, alright.

Lorian Schweikert: I think they basically snuck up on the animal — that's how they were able to do it. And this was the problem with using ROVs to look for giant squid in the Gulf of Mexico — they're loud, and they have a lot of lights on them. Despite that, there have been probably thousands of deployments looking all around. The squids are smart, fast, and have big eyes, so they've never let us get into their view — they just zoomed off. But within the third deployment of this new technology that was silent and looked natural, we were able to see the giant squid. It was brilliant.

Tom Rowland: That's cool. So how is it silent — what changed, if the old technology was loud and this one's silent?

Lorian Schweikert: The ROV has motors, propellers, and bright lights on it, and it's motoring around down there, so you have the buzz of all that. Whereas the Medusa is just passively floating.

Tom Rowland: Oh, and you're pulling it with the main ship?

Lorian Schweikert: No — the Medusa was remotely deployed, so it's just floating on its own.

Tom Rowland: Oh, okay, so it's totally silent.

Lorian Schweikert: Totally silent.

Tom Rowland: So that could be one factor, but it seems like if that was the whole factor, you guys would have seen lots of giant squid on this trip. So you saw some — why do you think we don't see them more, besides the fact that the technology we typically use is loud and cumbersome, and the squids are fast? It seems like there'd be something else too — like the early days of permit fishing, where you'd see them but almost nobody was catching them, and then somebody figures out how to do it and it becomes regular. Or bonefishing, where a fly was developed and it changed everything. So hopefully scientists will figure out what it is about the giant squid. In your opinion, what's the biggest challenge to finding these animals? Or do we even know?

Lorian Schweikert: That's such a great line of thinking. Beyond the fact that we've been using loud, cumbersome things to try to find them, I think the biggest thing is that they're not surface-dwelling animals, as far as we know — they live and thrive in the deep sea. The fact that they're maybe not surfacing very often means we just wouldn't get the opportunity to know where they are or how they even exist. But they have been seen in the historical past — you've seen reports from fishermen of monsters, mermaids, whatever, out there. I'm sure they've been seen in nature.

Tom Rowland: Like the kraken — isn't that in Moby Dick and all that old literature, taking ships down? When a legend like that sticks around, there's got to be something to it. And you hear about sperm whales with scars on them that look just like a giant squid's marks — is there something to that? Are they really attacking those large animals, and maybe they breach and fishermen see it? I mean, there's got to be something to it — it goes through history. You could say the same thing about Bigfoot, I guess — people have said they've seen Bigfoot-like creatures, but nobody's ever caught one. So is there really something to it, or is it just legend?

Lorian Schweikert: I think there's something to it. A paper came out just after our trip from one of the scientists in our party, Dr. Heather Bracken-Grissom and her colleagues, looking at sharks with marks — suckers, or some indication that they'd been attacked by large squid, very likely the giant squid. The giant squid gets up to sixty feet in length, so it's a massive animal, and I suspect that in times past, you'd have to get lucky to see a giant squid wrapped around some prey.

Tom Rowland: I mean, people made their living on the ocean and would be gone for years at a time, just out there exploring or fishing, and that's just where they were, way more than they were on land. I'm sure people are doing that today too, but the giant squid is interesting — it's almost like Bigfoot, this mythical creature, but now we have a couple of real pieces of evidence, like what you collected, what they collected off Japan, and these long tentacles and pieces of squid that show up on a beach somewhere. So you're like, well, this is obviously real — we're not finding Bigfoot's arm. That's what separates this mythical, legendary creature from something else that may or may not exist but still captures people's imagination just the same.

Lorian Schweikert: Exactly. We have empirical evidence that this animal exists. It has a profound impact on the ecology of that system, and we have so much to learn from it. If you look on YouTube you'll see the video from Japan — the giant squid was kind of sitting there in the water column in all its glory for a while, then it goes away passively. Because we deployed this lure, we got the first video of a giant squid going through an entire attack sequence. In the video, it's darkness, and you see the lure going over and over, and all of a sudden you see this bunch of arms pressed together into a single limb, coming like a serpent from the side toward the lure. The animal goes away and comes back in, very cautious, very smart, and all of a sudden, when it decides, it gets brave enough to attack — the arms open up and encapsulate the lure, trying to catch the animal that's supposedly feeding on that jellyfish lure. Once it realizes there's no animal there, it retreats, sucks those arms together, and explodes out of frame. Scientists can now build what's called an ethogram — a graphical representation of a sequence of behavior — for the first time, to understand this predation behavior from the giant squid. So needless to say, I'm super passionate about this.

Giant Squid Anatomy and Deep-Sea Species

Tom Rowland: What's interesting is the way you describe that squid coming into the lure — we study smaller squid too. Is it the same kind of thing, just larger? Is that how they attack what they're going to eat, like squid we see on a regular basis?

Lorian Schweikert: That's a great question, and I don't know the specifics, so I wouldn't want to say wrong. But what I can say is the broad anatomy of a small squid versus a giant squid is the same. If you think about a squid used for bait, there are two tentacles used for reproduction, and then the arms, which are shorter and make up all those extensions at the bottom. If you peel those back, you find their mouth, in a very powerful beak — that's the area where they attack prey. So that gross anatomy is conserved between the smaller and larger species. Whether they do that same serpentine stalking, I'm not sure.

Tom Rowland: That's super cool. So just to be clear on what we know and don't know — there's this creature we're calling the giant squid, and then we have regular bait squid, and probably something in between. I know guys jigging for squid in California catch them at six feet long — pretty big — and there are squid lures with bent wires you jig up and down, and the squid attacks it. So is a giant squid just a larger version of these, or a completely different species?

Lorian Schweikert: It's a different species. There are many different species of squid, and the giant squid is one of them.

Tom Rowland: Yeah, so that would be the biggest one. That's cool. So how much time — or what was the scene like when this was happening? You're exploring a part of the ocean that receives no sunlight, so it doesn't seem to matter if you're doing this at night or day. What are your research hours?

Lorian Schweikert: It's twenty-four-hour operations. I'm just looking at the depth here — we actually saw the squid at about six hundred meters depth, so there is light there, but very little, because we were sampling a comparison between absolutely no light and up into the water column where there is some. Good science requires those comparisons to know what's true. So it's twenty-four-hour operations, absolutely brutal sleep schedules, but you collect a ton of data. The trawling nets were going all day, the ROV was going all day tethered to the ship, then we'd pull that in, the net would go all night, and the Medusa was remotely deployed floating by the ship. It was no joke — we'd have to pull in six hundred meters of rope by hand. Brutal.

Tom Rowland: You're pulling that in by hand? Not on a crane or a winch?

Lorian Schweikert: There was an insanely small winch that helped us mainly just not drop the instrument to the bottom of the ocean once we unhooked the buoy, but the Medusa itself we pulled in by hand — it was on a rope system, not something that could be winched. Whereas the nets were on a huge metal winch.

The Night the Giant Squid Was Found — and the Ship Was Struck by Lightning

Lorian Schweikert: So it was twenty-four-hour operations — let me set the scene for you. The Medusa was remotely recording the squid, and we didn't know it yet. A day later we picked up the instrument, and the video was being processed by the science party. Dr. Nathan Robinson was sitting there, probably very bored, watching tens of hours of video — this was during the day, while the ROV was being deployed, and I was in a shipping container at the front of the research vessel with six monitors, telling the ROV pilots where to steer. Inside the ship, Nathan Robinson sees the squid, tells Dr. Edith Widder, and pandemonium begins among the science party — we hear it over the radio. But we're dealing with serious, expensive equipment down there, so we can't go celebrate with the team, we have to keep working. And in the moments after we heard the giant squid was seen, the ship was struck by lightning. We were in bad seas out there — rough seas, and we were in the shipping container, which is a bit nauseating, but you power through. We heard lightning like you've never heard before.

Tom Rowland: It seems like that would be a pretty loud place inside a metal shipping container.

Lorian Schweikert: It was. One of the pilots was leaning against the metal container and jolted — he said he felt the tingling of electricity passing through the ship. We just powered through, recovered the ROV, went inside, and had half the team celebrating that we'd found the giant squid, and the captain and crew very concerned because the lightning had exploded a very expensive radio antenna on the pilothouse. Luckily we still had comms and could talk to shore, but the captain said that in his multi-decade career at sea, he'd only been struck by lightning twice, and this was by far the most damaging, harrowing experience. So, anyway, it was amazing — the squid, the lightning, it was really an experience.

Tom Rowland: Wow, what a day — that's a day you'll never forget your entire life, probably for the whole crew. A significant scientific discovery met with being struck by lightning, which is my biggest fear on the water. Did anybody else feel it, or just the one person?

Lorian Schweikert: That was the only report I heard. We were all in our quarters, either in the shipping container or the main house, so no one was outside. There was a waterspout, and four-foot seas — it was terrifying. But we were fine, it was a big vessel, and the captain was brilliant, so it was fine.

Tom Rowland: That's cool. I've had some pretty close calls too — my closest was trout fishing when lightning struck the bank in the Rocky Mountains, and both my clients almost immediately started throwing up. I don't know if it was fear or the electricity being that close, but they both threw up. I hope I never encounter that again — I don't like lightning. Florida's the lightning capital of the world, probably second only, by a few strikes, to where you were. That's a tough area for storms and lightning. But that's a heck of a day. So what about this net you were pulling around at forty-five hundred feet or so? What kind of stuff comes up in it?

Trawling the Deep: The Diel Vertical Migration

Lorian Schweikert: Great question. Slow-moving animals, because the squid and big fish can evade it — we're pulling it at a very slow speed. You can imagine the drag on a twelve-by-twelve-foot net with extremely fine mesh, and the pressure that puts on the ship and winch system is unbelievable. But you bring in all the animals doing their thing down in the deep. This is a good time to bring up something called the diel vertical migration — if you're an angler or just someone who values the ocean, this is something you'll want to know. It's the largest migration on Earth, and it occurs every single night. During daylight hours, all this life in the deep sea — fishes, crustaceans, all kinds of animals — stays down deep where it's dark, with fewer predators, and it's safe. When it's nighttime, that life comes up closer to the surface to feed, because the shallower waters have more nutrients and more prey. Then when daylight comes, they go back down deep. All this to say, where you deploy the net is critical if you're going to catch anything. We did nighttime deployments, up to about twelve to fifteen hundred meters, which was when all that life would come up from as deep as two thousand to five thousand meters, to where we could catch it with the nets. To specifically answer your question, we found gorgeous, giant crustaceans, different species of shrimp — shrimp redder than the reddest tomato you've ever seen, shrimp that vomit bioluminescence — we saw dragonfish and anglerfish.

Tom Rowland: I know what an anglerfish is. I don't know what a dragonfish is — what's a dragonfish?

Lorian Schweikert: It's another species of predatory fish, with giant, gnarly teeth and bioluminescent organs all over its body, used for different things including capturing prey. Just another gnarly, very cool species of fish.

Tom Rowland: That anglerfish — the reason they call it an anglerfish is it has a lure off its head that it dangles out like a little worm, and something comes to eat that, and then it eats the other fish. So does it use bioluminescence in that lure?

Lorian Schweikert: It does.

Tom Rowland: Yeah, that's what it's all about — there's video of those things doing their thing, though I don't know the shallowest depth they'd live at, and you can't really tell from the video that it's operating with bioluminescence, it just looks like it's moving the lure around. But that's interesting, because that's exactly what they did on the Medusa — she got inspiration from nature, like you said, with the jellyfish, and other things do a similar thing, like the anglerfish.

Ultra-Black Camouflage and Vantablack

Lorian Schweikert: Exactly. Instead of a burglar alarm, it's a lure, an attractant for prey to come and be consumed. This was another major finding of the research trip with the anglerfish — because if you're a predator hanging a glowing lure in front of your face to attract prey, you have to make sure your lure isn't illuminating your own face, or the prey will see there's a hungry face right there. So there's an incredible adaptation in the deep sea where many animals have become super black and super red — both serve the same function, to disappear into the darkness. Sönke Johnsen and his student, Alex Davis, at Duke, measured the skin of the anglerfish to see just how black it is.

Tom Rowland: So there's different degrees of blackness.

Lorian Schweikert: There's so much black — have you heard of Vantablack?

Tom Rowland: Yeah, I think so.

Lorian Schweikert: It's a material you can put onto things — a super light absorber, one of the blackest materials on Earth. It absorbs over ninety-nine percent of light — it looks like you've cut a hole into the universe and you're looking into a dark dimension. The anglerfish is blacker than Vantablack, absorbing 99.9 percent of the photons that strike it. So if you want to talk about the value of studying the deep sea, we now have a biological understanding of how some of the blackest material on Earth might be manufactured.

Tom Rowland: And how is it that it might be manufactured?

Lorian Schweikert: Through the biology — basically, they're filled with a super-black pigment, melanin, which we have in our skin too, but they have a lot more of it, and they also have structural components that make them super absorbers. That science is going on right now.

Tom Rowland: That's incredible — it says a lot about the evolution of a predator, but it also makes you realize the prey has pretty good eyesight down that deep, because if one shade darker makes a predator more or less effective, they're going to progressively get darker and darker. But we're already talking about virtually no sunlight at those depths — what's the depth you're talking about with the anglerfish?

Lorian Schweikert: Let's say twelve hundred meters or more — that's about six thousand feet.

Tom Rowland: Yeah, so six thousand feet deep, and the predator is still concerned with being one shade darker and still evolving toward darker and darker. So the things they're eating must be pretty wary, pretty shy — it's pitch black to us, we wouldn't be able to tell the difference between Vantablack and five shades lighter, it's all black, and anything even gray would probably not show up, but the prey can see that. That's fascinating, because last time we talked, we had a great discussion about how fish see, through their eyes and also through their skin, and how they adapt to their surrounding color — you mentioned mahi-mahi really do that, changing color right on the deck, partly because they get fired up about eating bait, but other coloration changes are probably to be a more effective predator. So are there ever any studies on the shrimp, the crustaceans, whatever these fish are eating — have we studied their eyesight?

Lorian Schweikert: Yes — in fact, that's a major aim of my current research. I just put out one paper on the visual abilities of the shrimp we collected from this mission, and I'm continuing that work. That's what makes this system so valuable — animals live and die by light in the deep sea, despite there being no sunlight; bioluminescence rules. It's pushing these animals to develop either larger and larger eyes, or to conserve energy, because it's so energy-limited down there, so cold, with so little prey — some animals are reducing their eyes, and we're looking at how light drives these differences. Just like skin color change in fish for camouflage or predation, bioluminescence also provides camouflage, predation, and social signaling. It's just another side of the visual world.

Bioluminescence Across the Ocean

Tom Rowland: Wow, so cool. Bioluminescence is super cool, especially at these depths, which only a very small percentage of people in the world will ever experience, like you did, witnessing bioluminescence at forty-five hundred feet. We don't have that technology on a regular fishing boat — maybe one day there'll be a deployable camera you drop off your boat that shows up on your screen. That seems far off, but twelve years ago a drone seemed far off too, and now every eight-year-old has one. But as of today, people like you, high-profile science teams with lots of funding, are the only ones experiencing this. Yet you see bioluminescence in places like Key West Harbor, or in bays where you swim and every stroke lights up. So tell us about the role of bioluminescence through the entire ocean, not just at these big depths.

Lorian Schweikert: Oh my goodness, bioluminescence is critical to ocean life. We believe it has evolved forty times independently, or more — meaning that across all the different strategies animals use to survive in the ocean, they independently keep arriving at the same solution: bioluminescence. Eighty percent of all bioluminescent animals live in the ocean. We see it from microscopic diatoms and dinoflagellates — when you move your hand through the water and disturb them, they glow — all the way up to squid, fish, and it's pervasive all over. In the evenings, during a break in operations, we'd go to the bow and look over, and as the ship cut through the water, you'd see this explosion of blue-green light. If you've ever experienced that — I know you have — it's amazing.

Tom Rowland: Yeah, it's super cool. There are places in the world with bioluminescent bays where you can swim or wade, and every time you take a step, it lights up. It collects in some sort of bay, and it's a big tourist attraction, swimming there at night. When you haven't seen it before, it'll take you off guard — you see it in waves, like a glowing wave, as you disturb it and it fires up, whatever the mechanism is. That's pretty cool. So when you're studying all these animals at depth, how does the swordfish stack up? One of the things I like about swordfish is that they can be at that super-deep depth and come right to the surface, even jump out of the water, and go right back down — with all the biology of how their skull handles pressure. Are there fish that don't do well with that kind of vertical range, versus a predator like the swordfish that's so awesome at doing it all the way down to three or four thousand feet?

Lorian Schweikert: Great point. They're amazing, and they have giant eyes relative to their size — billfish in general have these big, beautiful eyes that no doubt help them see from the surface all the way down to deeper depths, where they're probably visually attacking prey on top of their whole suite of sensory systems. Not all animals come up — I said the ocean because so much of ocean life does this vertical migration, though some animals don't. But it's funny you bring up billfish, because a swordfish was the second-biggest animal we saw on the Medusa. One time, while it was being recovered at about two hundred meters depth, we saw this beautiful billfish come in, circle it a few times, check it out, and swim off. It was awesome, really cool. They're formidable predators, just so suited to survival in the open ocean.

Night Life Around the Ship

Tom Rowland: Yeah, they're really cool. So when you were taking those breaks and looking out off the ship, did the ship have lights, and were you able to see fish doing their thing out there in the middle of the night?

Lorian Schweikert: Yes. You think about the lights surrounding a hundred-thirty-five-foot vessel calling in the life of the ocean — I'd go out at night and see spinner dolphins and spotted dolphins jumping next to the ship, mahi-mahi, and flying fish going through incredible battles, with flying fish being chased up onto the deck of our ship all the time. We'd pick them up and launch them back into the ocean because they'd die on the deck. It was phenomenal — they were always drawn to the light of the ship. During the day, in breaks between operations — retrieving one instrument, deploying another, steaming to other locations — we'd pass sargassum floats extending for miles and miles, with live schools of dolphin fish. Some of the crew had poles on board, caught some mahi-mahi, and the chef would cook them up overnight. It was amazing.

Tom Rowland: You got flying fish jumping up on deck and mahi chasing them — seems pretty ripe to get a good one out there.

Lorian Schweikert: Definitely, definitely. And just to see the ecology of it — I'd look at the sargassum and see baby tripletail, all kinds of larval fish way out there, and you realize those are little ecosystems critical for our fisheries, both inshore and offshore.

Tom Rowland: That's one of my favorite things when I have somebody on the boat, or my kids — a lot of times you get sargassum inshore, sometimes offshore. We were on the sandbar at Valhalla, right off Marathon, with lots of sargassum floating by, and I'd pick it up and shake it in my hand, and all these little shrimp and crabs and little fish come out — an amazing amount of life in a piece of sargassum the size of a coffee cup. Some of it decides not to stay with the patch and drifts offshore instead. It's fascinating, all the different things you can see in there, especially the shrimp, and then you see one of those lines that goes for fifty or a hundred miles — there's so much biomass in that, no wonder the fish are there too.

Lorian Schweikert: Yes — and I just Googled a photo to remind myself, the juvenile tripletail are bright yellow, probably camouflaged to match that bright yellow sargassum so predatory birds can't pick them out. I'm a visual ecologist, and light, life, and color are all connected in our ocean, so seeing the tripletail being neon yellow like the sargassum was eye-opening to me.

The Tripletail Mystery

Tom Rowland: That was cool. I wonder at what size they start to turn color, or leave the sargassum to float on their own, because then they look just like a black plastic trash bag — not a good comment on the state of plastic in the ocean, but maybe that's why a bird doesn't want to eat them either. You drive by one and think, was that a trash bag, or is that a big tripletail — or they sit right on buoys. We had a weird thing — I wonder if you know anything about this — we've had a couple of really good years for tripletail in the Keys, and one factor might be a change in the size limit, though maybe that's coincidence with other things like hurricanes. The last couple of years have been really good with numbers and size, especially from Cape Sable to Flamingo and probably further north, where we fish. We used to just run the crab-trap-buoy lines to find them, and now they're floating all over, and you can spot them from a long way off on the right day. But we were catching these fish, and almost all of them had a red spot in pretty much the same place — behind the eye, up toward the shoulder — so red it looked like a sore, like they'd rubbed it on the bottom. You could see the red spot from a hundred yards away, red as a Solo cup, and it was almost always on just one side — the side they float on. My mate Rich thought they were getting sunburned; I didn't think a fish could get sunburned, but they do lay on the surface for hours at a time. Have you ever run into that — not bad-water-quality sores, but this specific thing, on almost every single fish?

Lorian Schweikert: I did — I saw photos of it at the time, when it seemed pretty prevalent. Question for you: have you ever seen that before those years, or since?

Tom Rowland: Well, one of the things is that we saw more tripletail this year than we've seen in a long time, so we saw it way more too. I've certainly seen some with that kind of sore area since, and I've sent photos to some different people, and they didn't know what it was either.

Lorian Schweikert: I didn't know either. I looked closely at a lot of photos, and it did appear to be like an abrasion, like you mentioned, though the fish otherwise looked pretty good. I passed the information around to some ichthyologists, including Dr. Tracy Sutton of NOVA, and they didn't know explicitly what it was — they didn't believe it was part of known spawning behavior, as you'd suggested. I reported it to the FWC as something that needed to be looked into. Pure conjecture — these animals are floating right there, and one of their strategies is camouflaging to look like a piece of seagrass floating next to structure. They're now doing this on artificial structures — buoys, crab-trap floats, buckets — and you wonder if the side that's floating upward is abrading against that unnatural, artificial structure.

Tom Rowland: It certainly could be, but you could get pretty good abrasions from a piece of driftwood too, and I've never seen that happen — though I guess plastic would keep a sharp edge longer than driftwood. It was a strange phenomenon. I sent you those pictures wondering what it was, but I never came up with anything conclusive. I've fished in places I wouldn't eat a fish out of — golf course ponds with fertilizer and pollution — and you expect tumors there, but the tumors are never in exactly the same place on exactly the same fish, they're spread out all over. Whereas with something like a largemouth bass bedding, or a trout or salmon doing something with their tail, they'll all have the same type of abrasions in the same places, because they're all doing something similar. That's what made the tripletail thing so strange — these red spots weren't happening in random places, they were consistently in the same spot.

Lorian Schweikert: It's very weird. But you guys are the eyes on the water — reporting stuff like this either helps further understanding of natural behavior, or catches something that's becoming a problem before it is. So I don't know — the mystery is still out.

Where the Research Goes Next

Tom Rowland: Yeah. So what about your research — where do you hope it goes in the foreseeable future? Did this trip spark new curiosities you want to study?

Lorian Schweikert: Yeah, great question. Having this kind of life-changing experience coincide with my new role at UNCW gives me a lot of freedom in the direction of my science going forward. Through this experience, I realized the importance of the deep sea — not only for future technologies, like these ultra-black anglerfish, but also for how it drives the health of the Gulf of Mexico and our broader ecosystem overall. I mentioned the diel vertical migration — animals coming up, consuming prey at night, and going back down deep — and that's one of the most important parts of the carbon cycle in nature. We've heard about too much CO2 in the atmosphere and climate change, and related to that is carbon in the environment from dead plants, decaying leaves, living organisms, and abiotic sources like gas emissions. The deep sea is so important because these animals, when they come up, consume so much of that extra organic matter and prey, and actively transport a lot of that carbon back down to the deep sea. The deep sea, in fact, is the largest carbon storage area in nature.

Tom Rowland: Really? And is that because dead things sink, or because of ocean currents pulling stuff out there? That seems surprising, that it would be the most carbon-dense place on the planet.

Lorian Schweikert: Yes, the storage of carbon. There are three ways we get rid of carbon, and that's why the ocean is so important. First is phytoplankton — microscopic plants photosynthesizing, using CO2 to create their energy. That uses a ton, and things float from the surface down to the deep sea passively. Then there's active transport — foraging at the surface and migrating down deep — which is recently predicted to account for maybe half of the carbon sequestering that occurs in the ocean. So the ocean is critically important for keeping carbon out of the atmosphere, and for keeping excess nutrients out of surface waters, which relates to algal blooms and those problems — the deep sea is a huge part of that. We also passed the decommissioned Deepwater Horizon platform, and Appomattox, one of the largest rigs in the world, with its flame visible just miles away from where we'd seen the giant squid. Basically, we have these amazing, elusive, super-important animals intertwined with our energy infrastructure, which really makes you consider different strategies for how we get energy, and how important ocean conservation is. That's my public service announcement. To answer your question directly — yes, I'm studying the visual abilities of animals in the deep sea, and continuing to study vision in other ocean life. We've collected mahi-mahi eyes and flying fish eyes from various work, and I'd love to compare the visual abilities of some of the most colorful fish on the planet and their predator-prey interactions. So a lot of cool stuff coming down the pipeline.

Tom Rowland: Yeah, that's super cool. So when you moved to your new university, were there studies already going on there that you might add to, or do you have the freedom to do what you want?

Lorian Schweikert: The beauty of this profession is that I have my own research laboratory, which I'm developing, and I'm recruiting graduate students and other personnel. UNCW wants to have one of the best marine bio programs in the country, so if you're interested in marine biology, come on to UNCW — there's world-class faculty here researching all kinds of things, and I get to develop my own projects while collaborating with my peers.

The Science Team Aboard

Tom Rowland: That's cool. Well, that's another thing I wanted to ask about — the team on this ship, the collaboration. What was the team like, what kind of individuals? How do twelve marine biologists get selected for this, what's the commonality between them, and who are these people?

Lorian Schweikert: Great question — and hopefully we can put their names in the description below, just to honor their contributions, which are far greater than mine. This was my first time at sea and I had a lot to learn, and though I contributed seriously to the science, there were some really fantastic scientists on board. The commonality was an interest and passion in deep-sea biology, and everyone was invited to bring a certain expertise. We had experts in cephalopods, like the squid — Dr. Heather Judkins, from USF. Dr. Megan McCall is an educator and science communicator — she wasn't doing biological research, but was writing and helping us author mission logs so we could communicate the importance of our discoveries to the public, since this is publicly funded research and people deserve to know what's going on. I won't go through all twelve — I have so much respect for all of them — ichthyologists, crustacean biologists, deep-sea biologists, just a phenomenal team of experts. And particularly Dr. Edith Widder, with her passion — she devised the Medusa device, and with Nathan Robinson, they deployed it and got that data. She heads up ORCA, the Ocean Research and Conservation Association, out of the Central Florida Space Coast area, and she's a tour de force trying to conserve the Indian River Lagoon and address issues around deep-sea conservation.

Tom Rowland: I'd like to talk to her — she'd be a great guest.

Lorian Schweikert: She would be, she's great.

Tom Rowland: Hook me up, I'd like to have her on the podcast, especially with the Indian River Lagoon — Blair Wiggins is doing some interesting stuff there with clams, trying to grow them because they've been fished so heavily, then putting millions of them back out there, which should help water quality. I'm sure she knows a ton about that and lots else with the Indian River — it's a fish factory too, or it should be, and it has been. Anyway, she'd be a great guest.

Lorian Schweikert: Oh yeah, we've got to keep talking about the Indian River Lagoon — it's a resilient body of water, but it needs our attention.

Tom Rowland: Yeah, for sure. So what's next for you right now?

New Baby vs. Life at Sea

Lorian Schweikert: Oh man, well, I've got a ten-month-old who's teething, and we're so unsleeping.

Tom Rowland: Let me ask you this — did you sleep better at home, or did you get less sleep at home with a very small newborn than you did sleeping next to the engine in the berth of the ship?

Lorian Schweikert: That is the best question I've been asked in the foreseeable past — I think about this all the time. I got pregnant very shortly after the cruise, and I thought to myself, oh, I slept three hours a day on the ship, I'm cool, I've got this. Well, truth be told, when you're a mom, when you first have a newborn, you get three hours a day broken up in fifteen-minute increments, plus the trauma of actually birthing a child and the hormone tidal wave that happens afterward.

Tom Rowland: You want to talk about it — so appealing.

Lorian Schweikert: It is. It was the most profound experience of my life, and it makes this expedition seem like nothing. It has brought more meaning to my life than anything I could have ever imagined, and that says something, because I've had some incredible experiences. Birth moms, and there are so many ways to become a mother — it's not just through birth — but they are the real heroes. So, way more sleep on the ship, that's the honest answer.

Tom Rowland: Way more sleep on the ship next to the engine with muffler problems — still tranquil and peaceful compared to raising a child. That says a lot. I don't know if there's a single biggest challenge to parenting, but I sure remember the days when we had two in diapers at the same time, and I was guiding every single day, and my wife was doing ninety percent of the work, but I was doing some of it — changing diapers at two, then three, then four in the morning, and they won't go back to bed, and you're supposed to get up at five, so you're just up. I have friends who are young now going through it, and they'll tell me they didn't get any sleep last night, and I think, wow, that must be terrible — and then I remember, oh, I did that too, I've just blocked it out. My friend tells me that sometimes he sees people with little kids at the beach, and it makes him nervous, and I remind him he has three of his own, and he says, oh yeah, I forgot about that. But it goes away — I think that's one of our preservation strategies, that women in particular forget pretty quickly exactly what childbirth is like, because if it was always fully in your head, we probably would have stopped being a species a long time ago. Childbirth is a big deal, and that first year is a big deal, but somehow your brain just moves past it because there are so many positives that outweigh it. You jump across something and break your femur, chances are you never do that same jump again — you'll never forget that. But somehow with raising a child, we forget, and we do it again and again, and go back to it. It's a preservation strategy, and it's working.

Lorian Schweikert: Amazing.

Tom Rowland: But congratulations on your new family — that's just so awesome. That's been the best thing that ever happened in my life, and it sounds like the same for you.

Lorian Schweikert: Oh, yeah, absolutely.

Closing Advice: Watch Out for the Loop Current

Tom Rowland: Well, I'm really happy to have you back on the podcast, and want to have you anytime — anytime you do something cool and want to talk about it, you're more than welcome. You have a tremendous amount of information, and our audience wants to know about it. Super cool, especially the giant squid.

Lorian Schweikert: Can I give one parting piece of fishing advice from my experience out there? There were two days when we had the nets and the ROV out, and we saw no life — zero. And you know what happened? We'd accidentally steamed into what's called the loop current.

Tom Rowland: A little bit — yeah, I know a little about it, but tell us.

Lorian Schweikert: It's a super important current that moves from the Yucatán Peninsula, south of Mexico, around the Gulf of Mexico, creating a gyre, and some of that hot water goes out through the Florida Straits. It's very warm relative to the Gulf's waters, and animals don't like it — I've read that tuna and other pelagics steer clear of the loop current. It moves continually, it's a dynamic process, so to my friends out there steaming a hundred or two hundred miles to fish, look at some online data to see where the loop current is, because if you're fishing in it, you won't know — it's huge, you could be right in the middle of it and not realize it, and you're very unlikely to catch anything.

Tom Rowland: Well, I seem to have a lot of spots that are somehow within the loop current, because some days you go there and there's nothing, when there was stuff there before, and you know you're in the same spot. We need a t-shirt — I must be fishing in the loop current. That's a great t-shirt.

Lorian Schweikert: Only a few people would get it, but I'd pay for that shirt.

Tom Rowland: Yeah, okay, I'll sell one — one copy, one t-shirt. Alright, well, that'll do it for today. Thanks for coming on and sharing that experience, and the giant squid, and all that stuff — super cool. We'll definitely have you back, definitely have you back. Congratulations on your family.