Undark Podcast #13: The Great Black Swamp

Join our podcast host and former NYT Science Times editor David Corcoran as he discusses Undark’s latest Case Study on the importance of wetlands and the legacy of Ohio’s Great Black Swamp, with writer Sharon Levy. Also: Seth Mnookin on why you should be skeptical of scientific studies you read or hear about, and reporter Nina Ignaczak on the fight to restore some of North America’s greatest rapids.

A full transcript of the podcast is provided below.

David Corcoran: This is Undark. We’re a science magazine published by the Knight Science Journalism Program at MIT and we’re this podcast. Hello again, welcome to Episode 13. I’m David Corcoran.

For our cover story, a visit to a major US landmark you’ve probably never heard of, I know I hadn’t, yet you might say it’s in the middle of Middle America. It’s called the Great Black Swamp, and our tour guide is science writer Sharon Levy, who joins us now. Sharon, welcome to the podcast.

Sharon Levy: Glad to be here.

David Corcoran: So I know I’m not alone in my ignorance because I looked in the New York Times news database and I found, dating back 30 years, I found exactly three references to the Great Black Swamp. Then I looked on Google Maps, and it wasn’t exactly sure either. So where is the Great Black Swamp, and why is it so obscure?

Sharon Levy: The Great Black Swamp is in the past and that’s why it’s so obscure. It was a formidable wilderness that covered about a million acres in northwest Ohio and eastern Indiana, but around the late 1800’s, turn of the 20th century, it was completely erased. All these old growth swamp trees were cut down, and the land was drained, and it is now all crop land in Ohio and Indiana.

David Corcoran: Tell us about the history of the Great Black Swamp because it really is a great story, just the whole how it came to be in the first place, and then how it disappeared.

Sharon Levy: Well, the Swamp came to be around the end of the last Ice Age. As the glaciers were receding, Lake Erie as we know it was revealed, as the glaciers rolled back. The Great Black Swamp was kind of a long, shallow extension of the western basin of Lake Erie. It had been there for a few thousands years, so a lot of huge sycamores and elms and burr oaks that could live with their roots under water, and it was just this vast, wet forest. There were some areas that were tall marsh grass.

It was such an intense deal trying to make your way through the Black Swamp that even the native people who lived there only went in there to hunt. They lived outside the edges of the Swamp because it was not an easy place for humans to hang out.

David Corcoran: So the colonials arrive wide end of the 18th century and on into the War of 1812 era, and they endured some really striking hardships.

Sharon Levy: Yes, they did. Settling the Black Swamp … I think that to modern people like us, the life of an American pioneer on the frontier would seem very difficult no matter where they were, but in the Black Swamp it was super hard. Before the War of 1812 there was just a handful of white settlers because being there was so difficult, and a lot of the records that we have from the people who first experienced the Black Swamp are from soldiers, US soldiers, who were ordered out there at first in the 1790’s to fight the Indians who had formed an alliance to try to protect their lands. Of course, inevitably, they lost. They were defeated at a battle called The Battle of Fallen Timbers in the 1790’s.

After that, the Indians were kind of pushed out of the area, but settlement in the Black Swamp was very, very slow because you had to just slog through. Depending on the time of year, there are records from soldiers talking about passing through there in winter, walking knee or thigh-deep in water, and under the water was a layer of ice, but it wasn’t real solid. So they’d be slogging along in winter, in the cold, and every now and then the ice would break, and they would just be dropped in the swamp up to their necks. It’s not surprising that you had to be in the military, you had to sort of be ordered to go through there. People didn’t volunteer for it.

David Corcoran: And then come winter, I’m sorry, come summer, mosquitoes.

Sharon Levy: Right. Malaria was a huge problem in the swamp. This is a time, the early 1800’s, when America’s western frontier was in what we now consider the Midwest – Ohio, Indiana, Illinois, Michigan and Wisconsin. It’s a little startling, I didn’t realize this until I started researching it, but malaria came across the ocean with settlers from Britain. So as early as the 1600 there were settlers in Virginia who had come from marshy places in England, like Kent and Sussex, and malaria was endemic there. They brought the malaria parasites with them, and when they got to the American coast there was a species of mosquito that could carry the parasite, and so settlers brought malaria to the US. Then as people started waves of migration of settlers moving west, they carried the disease with them.

By the time people started trying to settle in the Black Swamp, or even more than settling there were a lot of people who just needed to pass through the Swamp to get to Illinois or Indiana or Michigan, which were all considered more desirable places to settle because they weren’t quite as mucky and difficult, pretty much everyone who passed through there suffered from malaria.

David Corcoran: So the Swamp was drained, and we’ll talk about that in more detail in a minute. But it’s pretty much gone now, and yet it’s much more than a historical curiosity. Why write about it now?

Sharon Levy: The reason I discovered the Black Swamp is that I am working on a book that focuses on the intertwined histories of wetland loss and water pollution. I grew up on the Great Lakes, I’m from Chicago, and in the ’60s I remember as a kid going to the beach and there were just mats of dead fish laying on the beach because the lakes were so polluted back then. This was before the Clean Water Act.

There was a lot of poorly treated sewage, or untreated sewage, and industrial waster going into all the Great Lakes, and the syndrome that I witnessed as a kid is called eutrophication. Basically there’s an overload of nutrients, it causes a big bloom of algae, and as the algae die off they settle to the bottom, and all the bacteria on the bottom decompose those algae, and in the process they drain all the oxygen out of the water, and so you get a dead zone, an area under the water that is so deoxygenated that most aquatic life can’t survive there. So I was very familiar with how polluted Lake Erie had been in the ’60s and ’70s, and it was infamous back then.

When the Clean Water Act passed in 1972, the cities around Lake Erie, like cities all over the US, got funding to build improved treatment plants and the pollution from point sources, that is sources like sewage treatment plants or industrial discharges, that kind of pollution got treated and decreased dramatically. And so in the ’80s and ’90s, Lake Erie had a renaissance. The water got much healthier, the beaches were no longer quarantined, you could go in and swim. The fish populations that had really dwindled away began to bounce back. And that was where I had left Lake Erie in my own level of awareness. I left Lake Erie in the ’90s thinking it was this great success story.

Well, what I found out as I was researching my book is that in about 1995 Lake Erie started sliding back into eutrophication. People who study this refer to it as the re-eutrophication of Lake Erie. The cause this time is not point sources like sewage plants, it’s what’s called non-point source pollution, and the major cause in western Lake Erie is very nutrient-rich runoff from all the farm fields in the watershed of the lake.

David Corcoran: Fertilizer.

Sharon Levy: Fertilizer. And also the way that the landscape has essentially been turned inside out. That area of northwest Ohio was a huge swamp. Wetlands, including swamps, really hold on to nutrients. They retain nutrients like phosphorus in the soil, in the sediment, and nitrogen, which is another major nutrient, is processed by microbes that live in the wetland. Those microbes can do a process called denitrification that takes nitrogen out of the aquatic system and puts it back in the atmosphere as a harmless gas.

We went from this huge swath, the Black Swamp was once about a million acres, of a habitat that retained and processed nutrients, and when people settled it and began to farm it, in order to farm successfully, they had to drain water off the land because crops like corn and many other crops people grow there now, as one farmer put it to me, “They can’t stand having wet feet.”

They don’t grow in wet soil successfully, and this is naturally a very soggy place. In order to farm it, over the history of settlement, people started by digging hundreds of drainage ditches, and even that wasn’t enough. The whole landscape there, starting in the late 1800’s, has tile drains placed through it.

David Corcoran: And the very way that they drained the swamp back in the 19th and early 20th century, they used a technique called tile drains. Can you tell us more about that?

Sharon Levy: Basically what tile drainage is is you dig a trench in the land, and they had back in the day, in the settlement day, they had these little chunks of ceramic pipe. You would lay them end to end in this trench and then you would cover them over, and it’s underground drainage. What it is is a series of buried pipes that are under the field, and in the winter, in the wet season, it just makes water flow out of the field much faster. Basically it’s a way of lowering the water table, which is what they wanted to do.

And the vast majority of the landscape in what was the Great Black Swamp is now tile drained, so it’s just hemorrhaging water with dissolved nutrients in it. That’s why when I was saying the landscape’s been turned inside out, it went from a landscape that takes up nutrients to a landscape that not only is losing nutrients real fast, but we keep adding fertilizer to it. So it’s really a huge source of both phosphorus and nitrogen now.

David Corcoran: Yeah, it’s kind of a double whammy there. They’re putting the fertilizer into the farmland, and that fertilizer is running off into the watershed because there’s no swamp to filter it out.

Sharon Levy: That’s right.

David Corcoran: Coming back to the history lesson, there’s really a kind of heritage that the settlers and farmers have passed down to succeeding generations, and you’ve got a real anti-swamp attitude. Do I have that right?

Sharon Levy: From what I experienced when I visited there, I spent about a week in northwest Ohio meeting farmers and researchers and land managers, and, yeah, from what I could tell the culture of northwest Ohio is not into wetlands. At all. It’s interesting because many of the farmers I met are fourth generation. They’re descended from families who settled the Black Swamp, and settling the Black Swamp was a backbreaking, intense labor. If you think about what they went through, in retrospect you can see it as kind of an environmental disaster, but to them it was an incredible accomplishment that they won through a lot of blood, sweat and tears.

The swamp was full of these huge, old-growth oaks and sycamores. Heartwoods, they had to cut through them with axes, and then they had to dig by hand the drainage ditches. They used horses that pulled big scrapers, but mud in the Black Swamp was a constant, it was just a constant battle to deal with the mud. The horses would sink into the mud, and they developed wide wooden horse shoes to put on the horses’ feet to stop them sinking into the mud.

Digging the trenches to lay drain tile was a backbreaking job. There was a young guy in the 1860’s and ’70s named James Hill who was a drain tile layer, that was his job. He got so tired of breaking his back doing it that he invented a steam-powered tile laying machine called the Buckeye Traction Ditcher, and it was hugely successful. It started out as a steam-powered gizmo, and it went on to be used to drain a lot of Louisiana and Florida.

But because it was such a struggle, and because people did all this labor while they were living through malaria, defeating that swamp, I think that people generations later still see wetlands as a really negative thing, an obstacle to a farmer making a living.

David Corcoran: Some of these techniques have been tried out in the real world, not just experimentally, and I’m thinking of the Florida Everglades. Can you talk about the wetlands restoration effort there?

Sharon Levy: Yes. There’s an area in what was once the northern part of the Everglades that is now called the Everglades Agricultural Area. The entire hydrology of Florida has really been re-plumbed since the late 1800’s. There’s a whole series of canals and pumps that have entirely changed the natural flow of water there.

David Corcoran: Not unlike the Great Black Swamp.

Sharon Levy: Not unlike the Black Swamp. Florida is a bit more so because they actively pump water from here to there, but it’s the same basic concept. In any case, the southern part of the Everglades was maintained as a wilderness and is now Everglades National Park, and there are also a couple of wilderness conservation areas adjacent to the park that are still functioning as wetland, but much of the northern part of what was once the Everglades is now farmland.

As in Ohio, there’s a huge nutrient load coming off the farmland. In Florida, the major crop there is sugarcane. There’s also a lot of dairies. By the mid-1990’s, people were realizing that this nutrient load flowing from the farms downstream into the Everglades was completely changing the Everglades’ ecosystem.

When this very heavy load of phosphorus and nitrogen started running off the fields, cattail invaded the Everglades, and when the cattail invaded, a lot of the water birds, the herons and egrets and spoonbills, that forage in the native vegetation couldn’t really make it in the cattail. It’s just so dense, they can’t hunt in there and find their prey. So the population of water birds in the Everglades began to really decline, and in the 1990’s conservationists really started demanding that the Everglades be protected.

After that point, there was a committee established of wetland scientists and engineers, and they got together and worked on the best way to handle this problem. What they came up with was that they built some huge constructed wetlands, so there’s now more than 60,000 acres of constructed wetlands in lands that were once being farmed as part of the Everglades Agricultural Area, and these wetlands are doing a really good job of hanging on to phosphorus.

David Corcoran: “The water is cleaner, the birds are back. Even the alligators are back,” you write. What’s the outlook for the Great Black Swamp, Sharon? Is there any prospect that something like this could be done in northwestern Ohio?

Sharon Levy: I think it’s a very difficult, uphill battle. I think what happened in Florida was that there was a political moment, and there were some leaders like the Governor, Lawton Chiles, who were willing to say, “Okay, our water’s polluted, let’s figure out how to get this under control and improve the situation.”

David Corcoran: Sharon Levy is a science writer based in northern California covering the environment and natural resource issues. She’s at work on a new book, “The Marsh Builders: The fight for clean water, wetlands and wildlife”. She joined us from the studios of public radio station KHSU in Arcata, California. Listeners, you can find Sharon’s article about the Great Black Swamp in our magazine at undark.org. Sharon, great story. Many thanks.

Sharon Levy: Thank you.

David Corcoran: We’re joined by Seth Mnookin who covers science in the media for the podcast. Hello, Seth.

Seth Mnookin: Hey, David. How are you?

David Corcoran: I’m good thank you. So today, a study about studies. What did we learn?

Seth Mnookin: Well, there was an interesting study and an interesting writeup from Ivan Oransky and Adam Marcus who do Retraction Watch and write for STAT among other places. The study looked at the number of times that newspapers cover positive studies as opposed to negatives studies.

David Corcoran: Scientific studies.

Seth Mnookin: Scientific studies, yup. And then also how often they covered follow-ups to those. It was essentially an effort to look at whether the media overhyped positive results when they were then communicating them to the general public.

David Corcoran: And what did they find?

Seth Mnookin: I think probably not surprisingly to anyone who has spent any time in science journalism, they found that, yes, the media does overhype studies to a very large extent, although there are a couple of things that I think are worth pointing out in this. This paper looked at six areas, psychology, neurology, breast cancer, rheumatoid arthritis, glaucoma and psoriasis, which at first blush might seem to be a kind of random collection of studies, but I think actually those are studies that all involve conditions that can be in some cases life-threatening, certainly painful, and so I think you’re more likely to see the media hype positive results about studies in those areas than you would for a study in some aspect of chemistry or physics. I think you’re more likely to see the media engage in this kind of coverage.

David Corcoran: That being said, the researchers, who are from the University of Bordeaux in France, did their study in a very interesting way I thought. Can you talk a little bit about how they did their analysis of studies in the media?

Seth Mnookin: They looked at thousands of journals and studies in those six areas, and what they found was that news outlets were far, far more likely to report both on initial studies than follow-up research, which I think is especially interesting and crucial to note because oftentimes follow-up research indicates that the initial studies might not have held up. News outlets covered the initial studies roughly at 13% and follow-up studies at 2%. Journalists did cover a very small percentage of negative follow-up studies, but a pretty small percentage.

David Corcoran: Yeah, I guess if the finding was really, really hyped in the first place, you might be more likely to run a second story that says that subsequent studies debunked the results or found they were over hyped or whatever.

Seth Mnookin: I think actually not always because what you’re seeing is that journals are also much more likely to hype positive results. To the extent that we’re losing specialized science reporters, and news releases from these journals are more likely to end up the desk of someone who doesn’t have extensive background, I think even if it’s a really big, hyped study, you’re less likely to see a release about a follow-up study that disproves that, just as across the board you’re less likely to see studies that do tout null or negative findings. So I’m not sure that the extent to which the initial coverage was studied has an enormous impact on the follow-up.

David Corcoran: So, wait a minute, Seth. You’re saying that these respected scientific journals, which are kind of the gold standard of what we look to for authoritative coverage of cutting-edge research, what you’re saying is that they sometimes hype their results? How do they do this and why?

Seth Mnookin: We should make some distinctions here between … We shouldn’t treat all journals the same, and the study looked at thousands of journals. I think you’re more likely to see a sober analysis of studies the more high-profile the journal is. So in Cell or Science or Nature, you’re probably less likely to see press releases that way overhype or go way off reservation. However, the press releases about these studies are not just coming from the journals themselves. Oftentimes they’re coming from the researchers, either if they’re at a university, a university press office or a lab press office, and I think anyone who has been involved in science writing, especially over the last couple of years, knows that there’s this real tension between in many cases the scientists themselves and the people at their institutions who are writing releases about that work, and how oftentimes the releases, oftentimes might be an exaggeration, but it’s not unusual for releases to go much further than the study itself did.

David Corcoran: Also, these universities, or whoever’s promulgating the research, will hold a conference call for favored journalists who might be expected to write about the results. And something that we haven’t talked about, at least on this podcast, is the whole institution of the embargo.

Seth Mnookin: Of the embargo. Right.

David Corcoran: Yeah. Talk a little bit about embargoes and how they work.

Seth Mnookin: Sure. I guess most people who probably are listening to the Undark podcast know what embargoes are, but just really briefly, if there’s a big study coming out, a journal will send that study to reporters under embargo until the date when it’s actually published. The effects of embargoes I think are especially pernicious in a very specific type of embargo called a close-hold embargo, which means that reporters are not free to contact anyone but people involved in the study beforehand, which means that they have no ability to get a skeptical perspective, or even just to run the sort of basics of the study by another expert in the field and say, “Is there anything here that seems like a red flag to you?”

This is something that has been manipulated at different times. It’s something that the FDA has used as a way of ensuring that the coverage of studies funded by the FDA don’t receive initial coverage that’s skeptical. I think, again, it raises questions about what the purpose of the embargo system is, and who it’s supposed to help, and who it’s serving, and if the ultimate goal of covering studies and of embargoes is to hype the journals in which those studies are appearing or if it’s to do a good job informing the public. If it’s to do a good job in informing the public, my perspective would be that even in a close-hold embargo, reporters would be better off, better served, by taking a couple of hours after that embargo is lifted and getting more perspectives, talking to more people, and making sure that they’re not helping to propagate a credulous take on a study that actually should be viewed much more warily.

David Corcoran: So, Seth, I can’t let you go without talking about an actual study, and this one is reported in an online publication called Live Science. The headline is, “Spiders Eat Up To 880 Million Tons of Insects Each Year”. What about it?

Seth Mnookin: Yes. It’s a study that Ron Weasley undoubtedly would not be a fan of. It’s a pretty shocking study, although with very huge numbers it’s I think initially hard to know what it means to consume 880 million tons of insects or 440 million tons. As a point of comparison, the amount of food that whale species eat annually is supposed to be between 300 million and 550 million tons, so spiders eat a lot more food than whales do potentially. It’s a very interesting study. A couple things that jumped out at me was that anytime you have a study where the result is either X or 2X, that’s a pretty big variable area, and that’s something to file in the back of your head and be aware of.

David Corcoran: So if it says 440 million to 880 million tons of insects, that’s potentially a disparity of about 100%.

Seth Mnookin: 100%. Exactly. You don’t see a lot of studies where you have a disparity of 100% between the ranges. The other thing that struck me in reading the coverage of the study was that this was a study that was done largely by extrapolation. There was estimates of the weight of all the spiders in the world, and then estimates of the amount of food that each spider consumes, and then some variable is added to account for whether it was a desert spider, which is going to consume less food, but it’s a study that’s based overwhelmingly on these types of extrapolations. When you’re doing extrapolations on that scale, small changes in the initial set of numbers can result in huge changes once you get all the way down the line.

David Corcoran: So on top of all those tons of insects, maybe you want to also have a grain of salt.

Seth Mnookin: Yes. Well done, sir. Have you ever eaten a spider?

David Corcoran: I can’t say that I have. And you?

Seth Mnookin: No, I’ve eaten cockroaches.

David Corcoran: Not knowingly anyway.

Seth Mnookin: And grasshoppers.

David Corcoran: Right, yeah, there you go.

Seth Mnookin: But I have not eaten spiders.

David Corcoran: Okay. Well, that’s for the next podcast. Seth Mnookin covers science in the media for the Undark podcast. He’s the author of a number of books including “The Panic Virus”, and he’s the head of the graduate program in science writing here at MIT. Seth, thanks a lot.

Seth Mnookin: Thanks as always.

David Corcoran: Few people may know it, but the Soo Locks in far northern Michigan are a linchpin of America’s economy. They’re an engineering marvel that allows passage of iron-ore-laden freighters between Lake Superior and Lake Huron along the St. Mary’s River. They’re also aging and in need of repair. At the same time, there’s an effort underway to restore rapids that were destroyed by the construction of the locks. The restoration project has the support of the native tribes whose ancestors fished in these waters. Reporter Nina Ignaczak has the story.

Nina Ignaczak: That’s the sound of Lake Superior rushing in to the St. Mary’s River at Sault Ste. Marie, a town straddling the border between northern Michigan and Ontario, Canada. The water here drops 21 feet into the river on its way to Lake Huron. This place was once a summer gathering spot and fishing grounds for Native American tribes across the upper Great Lakes. It’s said that the thunder of these rapids could be heard from miles away.

Mike Ripley is a member of the Sault Ste. Marie tribe of Chippewa Indians. “Our oral history makes it clear that fish of all kinds were here before European contact. There’s stories of millions of passenger pigeons in flocks so large they would block out the sun, and fish so abundant that you could walk on their backs.” Today, fishing for species like walleye and whitefish here is still a big deal. The native people who remain in the area have what’s called subsistence fishing rights dating back to an 1836 treaty with the US government, and the commercial fishing industry in Michigan’s Great Lakes tops four billion dollars a year.

But the number and diversity of fish in the St. Mary’s River today is far less than in the stories of Mike’s Chippewa ancestors. “We don’t see that abundance today, and the question is why. Is it a matter of pollution, invasive species or destruction of habitat?” One thing that certainly doesn’t help is that the natural environment of the St. Mary’s River has dramatically changes over the last 150 years.

In the 1850’s engineers broke up most of the rapids to make way for the Soo Locks. That made this stretch of waterway one of the most important shipping routes in North America. The US manufacturing economy still depends on massive lake freighters to move raw materials, iron ore, coal, oil and gas, even grain, from the upper Midwest to steel mills and refineries in the lower Great Lakes, and every one of those freighters must pass through the Soo Locks. It’s a sort of water elevator for ships to navigate the 21 foot elevation difference between Lake Superior and Lake Huron.

“[inaudible 00:33:57]”. “[inaudible 00:34:01], sir.” “Thank you.” “Your welcome.” The pilot of the Manitoulin, a 662 foot long bulk carrier freighter is signaling to the lock master that he’s about to enter the Soo Locks from Lake Superior. These aging locks represent a choke point and an Achilles heel in the North American manufacturing economy. There’s no other way, not trucks, not railroad, to move this amount of raw material to where it needs to go.

Jim Peach is the assistant area engineer at the Soo Locks. “If the Soo Locks were to stop operating, it would be a big problem for industry, particularly for the steel industry, and so we would expect to see an interruption in production. These plants have a small stockpile and they’re able to keep going for a certain period of time, but inevitably there would be job loss, there would be layoffs, and production would be interrupted.”

In 2015, a faulty gate mechanism shut down the MacArthur Lock for 20 days in July and August, at the height of the shipping season. Ships were delayed all across the great lakes and so were factories waiting on product. It will cost an estimated 600 million dollars to upgrade the locks with new technology and to build a second lock in place of a pair of 100 year old locks that few people today even know how to operate.

But while many would like to see the Soo Locks updated to save an important part of the US manufacturing industry, Mike Ripley and the coalition of local, state and federal officials are focused on restoring rapids in the river to sustain the local tourism economy and native people’s fishing rights. There’s no way to restore the big rapids where the Soo Locks are today, but six million dollars in federal funds from the Great Lakes Restoration Initiative are going to restore fast-flowing water just downstream of the Soo Locks, at a place called The Little Rapids. Once that project is complete, the area will likely be removed from the list of 43 federal Great Lakes Areas of Concern, the worst of the worst places damaged by the industrial legacy in the Great Lakes.

That six million dollars in federal funds was not easy to come by. Some local residents fought the Little Rapids project, arguing that the money could be better spent elsewhere. Jeff Hagan is CEO of the Eastern Upper Peninsula Regional Planning Commission. “There was some questioning about, like why does the federal government spend money on these types of projects. This was really the last opportunity to really get some additional spawning areas and to really have some restorative work take place in a way that was economically possible.”

Mike Ripley knows there is no going back to the original bounty of his ancestral waters. “People here understand that we’ll never have the rapids, the big rapids, restored to the way it was, like we can’t go back in time. But certainly the Little Rapids is a piece of that that can be restored.”

Now it remains to secure funding to fix the locks. On a cool morning in the St. Mary’s River, a massive freighter glides by anglers casting for whitefish and walleye. In a river that is so important to so many, striking a balance here between nature and industry promises a future where both can coexist. For Undark, this is Nina Ignaczak.

David Corcoran: And that’s all for this episode of Undark, a project of the Knight Science Journalism Program at MIT. Our show is produced by Katie Hiler. We’ll be back next month with more news and interviews from the intersection of science and society. Until next time. I’m David Corcoran for Undark.

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