Ecological Recovery from Bottom Trawling

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From bright, energizing mornings to soft, relaxing evenings, makeake the invisible unforgettable this season Visit pure. com to find your new favorite summer scent We're all at sea on inside science from the BBC World Service this week, pererhaps because Tom Whipple has temporarily vacated the bridge and left me Roland Peace at the helm But also because we've ended up with a bit of a maritime theme. Ranging from the origins of animal life in the ocean depths six hundred million or so years ago But when we look back in the history of Earth, the Ediacaron this period of time and these fossils that I study are the first evidence for the emergence of our animals. to a call for a ban on bottom trawling fisheries to preserve the critters that inhabit the seabeds today. Bottom trarawling is this crazy form of fishing where you drop heavily weighted nets You drag them through the ocean floor, picking up pretty much everything in your path and honestly laying waste to the habitats behind to start with the stirrings in the surface of the Central and Eastern Pacific towards the equatorial coast of South America But hereralds, according to all forecasts now, a strong if not extreme El Nino later this year, stirring memories of global weather impacts from previous El Ninos in twenty twenty three and a really strong one in twenty sixteen. This one might be stronger still. Some headlines are turning to the adjective super But it's not in the technical lexicon and nothing to discussion. putting it to one side. Science journalist Gareth Mitchell will be explaining shortly some of the technologies used to detect the shifting conditions in the vastness of the Pacific. Thanks for joining us, Gareth. No worries. Nice to be here, Roland. And also on the line is climatologist Amanda Mayok of Leeds University to help us understand how this basin wide movement of surface waters is likely to have near global impacts on the climate from October till early next year. Welcome to Inside Science Amanda. Hello, good afternoon. Lovely to have you. Perhaps if I can put my own crude understanding of what goes on in the Pacific climate system and you can either correct me or amplify. The way I understand it, normally the warm surface waters of the Pacific get blown westwards by the trade winds towards the Philippines and Australia. until they fail and The beginnings of that breakdown is what's happening now. Yes, that's pretty much spot on. So typically in the Pacific, the winds blow from the east towards the west and drive the warm waters towards the what we call the warmpool region near the Philippines And in the eastern side, we have the upwelling of cold deep waters, which are very nutrient rich But when we have the onset of an El Nino event, like we're seeing at the moment, those winds slow down. and so that blowing of the waters is reduced We've also seen over the last six months or so a build upp of very warm waters underneath the surface of the ocean, about a couple of a hundred meters below the surface. We've now got a very large body of water, which with temperatures that are more than six degrees above normal So that's kind of sitting there waiting to emerge up to the surface. And so as that spreads towards the coast of America, two things I guess. it's one a huge extra sort of radiator putting moisture and heat into the atmosphere. and it's also a redistribution of where it's actually happening Exactly. So the strong evaporation and convection activity in the atmosphere. so those are storms within the atmosphere that are being driven by the exchange of heat normally are centered to the western part of the Pacific Basin where those warm temperatures are. As those warmer Ocean temperatures spread eastwards that shifts the location of that strong atmospheric energy and the convection moves with it, which is where the rainfall occurs. So we see the rainfall moving further east than would normally occur. There's also I think a sort of a lot of momentum in the system, which is why it's been talked about for several months that this may happen, but it's now taking off. I've got a toilet at the moment that doesn't flush properly. I have to keep on pulling the chain several times until it catches And I feel that it's a bit similar with the rain the windstorms that sort of drive and Albenia they need to keep pushing and that's been historically quite difficult to forecast. So there's something that we call the sppring predictability barrier, which happens Around the time that we see a transition between the different phases of the Enino cycle. So last winter we had what we call a Lanino event. That was when the surface waters were colder than normal And in the springtime, that previous event has died away. It's decayed. We're back to near normal conditions, but we're ahead of starting to see the build upp of the next event, which is coming this year. So that spring predictability barrier makes it more difficult to make forecasts around the sort of early part of the year However, as we move beyond that, and we're now starting to see the onset of the event, our forecasts are much more confident And we're now seeing a very high chance that the E Nino will be present at the end of this year. So it's pretty well locked in, but not necessarily how strong it is That's right. So at the moment, the forecast suggests there's about a two in three chance that it's going to be a strong or a very strong event this winter But there is still a little bit of uncertainty there and we'll be watching closely over the coming months. The prerevious Alinos, I remember particularly in twenty fifteen, early twenty sixteen Massive wildfires across the Philippines and Southeast Asia, floods across some parts of Peru. Those are sort of the Basin wide sort of effects, I think That's right. So the Pacific is a bit like an engine house for the climate system. All of that strong convective activity and that heat exchange really drives the whole global climate system So yes, we would typically expect to see flooding in parts of Northern Peru and southern Ecuador. We would have droughts in Indonesia and in the Amazon Basin But even further afield, we see changes to rainf in Africa, we'd expect to see drought in South Afra in Australia as well.. I mean, these droughts and floods, they will have a pretty devastating impact on people's lives, on farmers, productivity and so on Is that what we should be preparing for? Yeah, so we do see at a global scale, we can see a decline in the global agricultural and food stocks that come from those regional impacts, particularly affecting the sort of bread basasket regions of the world where we have very large amounts of agriculture There's been some estimates made that the previous strong Al Ninos that you mentioned from twenty fifteen sixteen and The previous one before that nineteen ninety seven and nineteen ninety eight, they estimated that there were trillions of dollars of economic losses globally that were resulting from the impacts of that event. The first Elmino I was truly aware of was the one you mentioned in nineteen ninety seven ninety eight. At that time, I think global temperatures would have been about what zero point five degrees centre grade colder than they are now. How does this interact? Does global warming make the forecasting and the impacts of all this harder to understand Well what we know is that since the the last very strong Eino event about a decade ago from now The globe average temperatures increased by around another quarter of a degreree Celsius Now we tend to see in the year after N Nino event that there's a little spike in the global temperature can be about another point two degrees Celsius. So we're now adding that ero point two degrees Celsius from a strong El Nino event on top of that long term background warming So there's every chance that if the event does play out and become strong towards the end of the year, as the forecast is suggesting, we'd be looking at the potential for another record breaking global temperature next year The previous record temperature was in twenty twenty four The global temperature then was one point five five degrees Celsius above pre industrial levels So it's possible that that record would be broken next year. If I can just bring in Gareth for a moment, you've been looking at some of the systems which they use to measure what's going on in the Pacific Ocean. you have to remember this is an absolutely vast ocean and a lot of what's going on as Amanda said is actually beneath the surface, so you can't just see that from satellites. Yeah, absolutely. it's a huge challenge to gather the data that scientists like Amanda can use. But since the nineteen nineties, we've had these networks of boys that are tethered And they have all kinds of sensors on them, measuring things like temperature, salinity, water velocity. but they're getting a little bit old now, Roland. So they're rolling out a new system basically across these equatorial regions in the Pacific, and that's called the Tropical Pacific Observing systemystem. So this is an international effort and it's very much an ongoing project And the idea is just to make the most of this new fantastic technology that we have these days that we wouldn't have had in the nineties when we first started putting these things in. And this includes, for instance, having more autonomous robotic boys, almost like drones but on and within the water and combining that with satellite data. And the whole idea is to fill in the gaps now higher resolution data set from across, you know, much wider and indeed deeper area of the Pacific to really help these observations. Amanda, I mean you're always going to say, yes, we need more data, but is this kind of effort what's needed if we're really to understand the impact in well, they'll be further El Ninos in future decades. Yeah, I think it's really critical to emphasize that these types of observations that' being collected at the moment within the Tropical Pacific Observing system is a critical part of our ability to make these forecasts over many months in the future Amanda, thank you so much for joining us. and Amanda Maycock is at Leeds University. And Gareth, do stay with us? I think you've got more to tell us later in the programe. Yes, there's more where that came from Rin And before that from the ocean surface today to the ocean des six hundred or so million years ago, to a period called the Ediacron, the last stage in the pre Cambrian which in Darwin's day was also thought to be the time before fossils The period is named after the Ediacaran Hills in southern Australia where extraordinary fossil forms more recently showed how wrong this was White Sea of Russia, the Namib desert, the coast of Nova Scotia have further formations with extraordinary hints of evolution experimenting with weird, complex animal forms And now Scott Evamans of the American Museum of Natural History has been exploring the Mackenzie Mountains of Canada's Northwest territory, which he hopes will pull together the story of the gestation of modern life For billions of years, the Earth system was dominated by microbes, by things you needed a microscope to see that were mostly single celled This is the first time we really get things that are big enough to see. And so to understand that transition This is really the key record at where we go from those microbes to big abundant life that can do a whole bunch of different things. And this takes you to the north, quite remote parts of Canada. Tell me a bit about You know, what it's like working out there Yeah, it's very remote. So for this trip, we drove fourteen hours from Whitehorse to a helicopter pad. helelicopter takes us about thirty, forty minutes to this side of a hill drops us off and says, I'll see you in a week. Don't get hurt. And yeah, the landscape the landscape is mountains. We camp above the tree line. We use snow to keep our drinks and cheese and meat cold and to that's where we get our drinking water from And the nice thing about being above the treeeline is that that means there's just a whole lot of rock out there, which is really good for the work we do. just walking as much as you can over as much rock as you can looking for these really subtle Fosils. I mean, so this is a really rich size, is it? As far as we know, we were here for only five days Um, you know, it's expensive to get a helicopter out there and and you can only be there for so long But in that five days, we found one hundred fossils. We found six species that had never been described from North America and probably some brand new species that we need to go back and find more to be able to describe This is mountainous Northern, you know, I guess almost Arctic Canada at the moment. What was it five hundred eighty, six hundred million years ago This was all ocean. So these are ocean rocks. And in fact, the rocks where we found these fossils are pretty deep parts of the ocean Maybe even below the photic zone, the depth where sunlight reaches And we also know But the continent was probably closer to the equator. so maybe a more tropical Definitely a more tropical location than today. Sounds like quite a nice location to be. Sometimes we get these lovely artists impressions rather than the flattened things that are on the rocks G me a sense of what kind of ecosystem you imagine this to be back then? It's a strange ecosystem and it's these are animals, so they are some of our earliest relatives, but they look very different from any of the animals that are around today We know, for instance that some of them could move around, and that's a very animal trait They start to do things like have an elongate body with a front in the back and a top and a bottom and a left and right That may seem very simple, but that's the way that most animals today build their bodies. That's exactly how our bodies arranged. We have front and back, top and bottom, and then we just repeat some things along the way. and that's how you build most animals You know, this isn't the only location in the world. I get the impression from your paper that there aren't many What's important about finding this bit of history here and another bit of history somewhere else? One of the surprising things about these fossils is that they're found in these deep water environments below the photic zone. And we know that from sedimentary structures. There are certain structures that form at certain depths of the ocean And so we can read those to understand where we are. And what we knew about some of the fossils we found that were familiar from places like Australia is that in Australia, they're may be ten million years younger and they're found in much shallower water environments, places where wave action can regularly impact them versus these fossils which are found in much deeper parts of the ocean. And so that suggests maybe that we have this progression from dee water to shallow water through time So in a sense, the deep conditions might have been more conducive to them evolving in the first place, but then they can start colonizing other parts of the ocean bed. Yeah, so that's one of the hypotheses is that the deep water, it seems very inhospitable. It's dark cold, there's not a lot of oxygen, which lots of animals use to breathe and move around But one of the things we know is that it's stable. The temperature doesn't fluctuate a lot. The amount of oxygen doesn't fluctuate a lot. There's not necessarily a lot of food, but the food sources are pretty regular. And so That might be that stable conditions allowed animal life to first appear And then as it got more complex and figured out how to deal with these things like fluctuating temperature, it was able to move into shallower environments where maybe there is more oxygen and more food and then really diversify. Scott Evans, who's laid out in science advances this week are kind of prospectus of how rich these Eidiacron seemes of Canada might be. A reminder you're listening to Inside Science from the BBC World Service Tell us what science you think we should be investigating. Our email address is inside science at bbc. coot uk. Close your eyes. Summer smells like sunshine, fresh citrus, and salty air. What if your living room could feel just like that? With Pura's new summer collection, it can restestore your sense of wellbe with fragrances designed to move with your day. From bright, energizing mornings to soft, relaxing evenings, makeake the invisible unforgettable this season Visit pure. com to find your new favorite summer scent A burst pipe, a dead water heater, the AC calling it quits. Who do you call Home Serve is an easy way to handle unexpected home repairs, with plans covering stuff basic homeowners' insurance usually won't. Instead of scrambling for a contractor, you make one call to get the repair process started. Join the millions of customers who trust Homeerve right now. Go to homeomServe dot com slash podcast for fifty percent less your first year. That's Homeserve dot com slash podcast savings compared to renewal price boid in Florida The seabed may be where animal life first flourished, but increasingly life there is struggling because of our appetite for fish, sustained in large part by the practice of bottom trarawling, dragging heavy nets over the seabed and ripping it up to maximize the catch. It's been going on for centuries in European waters But in a small marine protection area south of Aron, off the coast of Scotland, the practice was banned ten years ago. Marine biologists sampling the area report already a remarkable rebound of life in and on the sediments there It may be only a tiny part of the global fished oceans Amanda Vincent, professor at the Institute for the Oceans and Fisheries of the University of British Columbia, and founder of the International Project Seahorse Conservation Group. Wcomes' results as a demonstration of what bottom twl bands can achieve I think what makes this study really interesting is it's not looking at the glamorous species. It's looking at the you know the mucky muddy things, what we call the infauna, which is things that actually live inside the sediments. Sort of worms and things. Yeah and mollusks and things like that. And then we've got the epipauna, so things that actually live on that bottom, which could be crabs or Anything really mobile So Looking at that Bottom of the food chain, the constructors, the builders, the creators of the ecosystem is really interesting and not done very often. There tends to be a lot more attention paid to the more visible, more obvious species. So how big a difference has keeping the trawlers out from scraping those S bed stone. Well, it's becoming pretty clear that protection made a notable difference for the stuff that lives in the sediment. It's really rebounded rather well The stuff that lives on the sediment has done fairly well. The fish were're not seeing a clear response. It's a much more confusing answer. And I think that's partly because the area has only been protected for ten years So if you protect an area for ten years You're going to see the change most evidently, I think, in the bottom of the food chain. and it's going to take a while for that to make its way through the rest of the ecosystem. But am I right that it's a threefold increase in the number of creatures that they're seeing and an increase also of the amount of variety, the biodiversity. Yeah, Both are changing and the biodiversity is important because the more complex the biodiversity, the healthier, the more stable the ecosystem is, and both really experienced a considerable change in this area. And you know it speaks to the value of protection, but I want to point out it also speaks to the damage of bottom trarawling. You know we've plunged into talking about what this study shows us, but I think we need to go back and just remind ourselves what bottom trawling is This area, the major change has been to protect it from bottom trawing The bottom trawling is this crazy form of fishing where you drop heavily weighted nets You drag them through the ocean floor, along the ocean floor Picking up pretty much everything in your past and honestly laying waste to the habitats behind And so if you trarawl an area repeatedly, you create a mess And to the point where sometimes people say, it's not worth protecting. That's just we've trarowled it, we may as well keep trawling it. But what's nice about this study and what matters is this study says It is worth pausing to think. It is worth contemplating what could happen if we stop this bottom trarawling. All is not lost, my friends That's actually a really important message Well and I liked it in that sense because it is only ten years. It felt to me like quite a quick rebound. Let's give this place more time to you know see how much more there is. Yeah. and you know It's tremendously important to take our time and recognize we're on long timelines. Most of the waters around Britain have been trolled for hundreds of years. and so what we're seeing is the consequence of really aggressive damage to the ocean bottom And so as you say, kind of nice and exciting that there's enough residual life there. You know, if we give it a bit of a break, we can actually get some form of recovery And that offers, I think hope for what we do with the oceans. you know, we have our ways forward. And just to be clear, fishing is vital. Nobody's trying to get rid of fishing, but what we're trying to do is say there are better, more sustainable ways of capturing our food Do not so destroy our futures. I mean, the very idea of bottom trawling sort of makes me think of harvesting wheat by using a bulldozer It Well, no, it's worse than that, Roland, because you're taking a wild ecosystem So think of it as helicopters dropping heavily weighted nets onto your favorite hillside or forest and just dragging up everything in their path. So every bush, every bird, every bee, every butterfly, every bug, it's all being removed and you're digging into the sediment and removing what actually underpins it all And then you're reducing it, and this is the stunning thing, mostost of that catch goes to fish meal or fish oil because a lot of it you didn't mean to get and you have no way of selling as a product itself So why is it still being sustained I think The discussion of bottom trawling has been slow to emerge because Most research is happening in areas where we've trarolled for so long that consequent trolls make almost no difference But if we actually understand the full scale of the damage we wrought with those bottom trowlls, we would be a lot more serious about ending this practice. Amanda Vincent, passionate about conserving the oceans. Gareth, Amanda's worried about the life harmed by bottom trarawling, but you say technology is threatened there too? Yeah, absolutely. So there's another concern alongside obviously the very important s ecological damage we've just been hearing about, and that is these submarine cables that supply millions of people with their internet connections. And these trarawlers with their very heavy fishing equipment are exceedingly good at trawling along the bottom of the ocean on the seabed And then splicing these internet cables. This is quite frequent, is it? You're saying that there are act examples of when these cables have been broken by fishing. Yeah, I mean, for instance, around three years ago there was a disruption to the internet for the citizens of the Matsu Island. So this is an outlying territory of Taiwan And this is where indeed, a trarawler dragged across and then it severed the island's only two undersea communication cables. And that meant a two month communications blackout for those islanders. know It affected fourteen thousand residents and obviously it was very inconvenient, but it had real economic damage as well to businesses. That's not all you're here to talk about, Garetha. fromrom all the science in the air this week. Cught your eiron Yeah, fascinating study from NASA about the sun being up to all kinds of shenanigans last year, where it admitted a nineteen day radio burst. So it's a big burst of radiation It went on for nineteen days from august twenty first to September the night last year. and just to put that into context, you'd usually expect these kind of bursts to go on for a few hours. So this was a really big deal. And it is telling NASA and the scientists a whole lot more about what the sun is doing when it's sending out these huge bursts of energy.ese matter not just because it's interesting what goes on on the sun, but because up interfering with satellites and things like that, I think. Well, absolutely. Yes. They can disrupt satellites, GPS systems, power grids and so on. And what's exciting, I think about this NASA study is that because this was such an extreme radio burst and so long lived, they were able to observe it from three different satellites. and from that they'd been able to say, o, I think we can actually work this out. We can work out where to triangulate and go and find these energy bursts and these radiation bursts