Short Wave - Air Pollution May Be Increasing Superbugs

Episode Date: September 8, 2023

Today on the show, All Things Considered co-host Ari Shapiro joins Aaron Scott and Regina G. Barber for our science roundup. They talk about how antibiotic resistance may spread through particulate air pollution, magnetically halted black holes and how diversified farms are boosting biodiversity in Costa Rica.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, shortwivers, Aaron Scott here. And me, Regina Barber. Oh, and I'm Ari Shapiro. Yes, you are Ari Shapiro, and we are grateful that you are stepping away from your hosting responsibilities at all things considered. I mean it when I say anytime. Oh. Any time. Thank you.

So we brought you here to chat about some of the recent science headlines that have grabbed some attention over here at the shortwave. desk. When I heard that a connection between drug-resistant germs and air pollution was on the docket, how could I have resisted that? I had to show up. Well, and mysterious eating habits of black holes. And to take us out a feel-good story about how farms and even people's home gardens can play a big role in supporting biodiversity. You're listening to Shortwave, this science podcast from NPR. All right, let's start with the dark stuff, as if drug-resistant germs, were not good enough. They're riding on air pollution? Yeah, but not any germs. We're talking about superbugs, like bacteria resistant to antibiotics. A lot of these come from places like farms,

hospitals, sewage treatment facilities, and over a million people died globally in 2019 from drug-resistant bacterial infections. And it's estimated this problem is just going to get worse decades to come. Yeah, and we've long known that these bacteria lurk in the soil and in waterways, but what is new is that it turns out air pollution could also be a major contributing factor to the spread of these antibiotic-resistant germs. Our colleague Gabriel Spitzer just wrote about a recent study in the journal Lancet Planetary Health that found that globally the rates of particular air pollution and antibiotic-resistant infection are closely linked. They're both on the rise overall, and low-income regions of the world tend to face the highest rates of both of them.

That sounds really unpleasant, but do we know that one causes the other, or is there a chance that anti-microbial resistance is just more common in the same kinds of places that have a lot of air pollution? Right. We should say that this study does not establish a causal relationship between air pollution and antibiotic resistance or examine the actual biological mechanism that might be at play here. But researchers did adjust for factors that could affect the rate of antibiotic resistance like socioeconomic status, health expenditures, and education. And it still does show this really strong and interesting association between the two. So how does this actually work? I'm imagining a drug-resistant bacteria riding side saddle on an air pollution particle. Like paint a picture for me. It's actually a good image, ARIA.

One of the researchers, NPR talked to, didn't use the equestrian metaphor. or they actually went with islands, that these are like islands that the bacteria can hitch a ride on and can actually set up little communities that are kind of floating around on the particulates through the air. And what we don't know much about is whether these little floating islands can actually spread antibiotic resistant infections to people. So we're not yet ready to say that air pollution does spread antibiotic resistance. Sounds like there's more work to be done here. Yes, there's more study that needs to be done. But the thing is, if it turns out there is a link, this could give countries more incentive to reduce air pollution, given that we already know that pollution itself can damage your health.

All right. From the microscopic to the astronomical, tell me about the feeding habits of black holes, please. Yeah, so when people think about black holes, they think of like these stellar vacuum cleaners that suck up everything. But in reality, they only suck up stuff that are right next to it, like dust and gas from like a nearby star. And now a team of scientists led by astronomers in China has observed something that has only been theorized or seen in computational models. A black hole where that dust and gas is no longer getting sucked in. It's halted. And the gravity from the black hole is no longer winning. This is all detailed in a paper that was published last week in science.

Are there pictures? What does this actually look like? There isn't pictures of this black hole. What you want to picture is, you know, the black hole is sucking that dust and gas from the nearby star towards its center. And that creates a disc around the black hole. So if you want to imagine something, Ari, it's imagining a bright donut in space with a black hole at the center. It's like everything everywhere all at once, the everything big. Yes, yes.

Exactly. And I mean, this is the closest we get to actually seeing a black hole in general, right? We're seeing the stuff. It's eating getting sucked in. But in this case, all that dust and gas has stopped getting pulled in. Do scientists know why? Like, what's actually happening? So not all black hole disks are created equal.

Like some feed black hole slowly, some faster, some discs are thin, some are fatter. And that's important, according to Yale astrophysicist Priyemvada Natarajan, who didn't work on this paper. So geometry is destiny in many ways for the gas that's falling into a black hole. And that geometry she's talking about are basically, you know, the shape of the disc, that determines how fast the material goes into the black holes. So the thicker the disc, the slower the dust and the gas fall in. And these thick disks can strengthen the magnetic fields present around black holes. That's what's happening here. Its disc is thick and now heavily magnetized.

Now this magnetic pressure is strong enough to push against the black hole's gravitational pull and win. It countervails the black hole's gravity. Nothing flows. The flow stops. So basically we have a massively constipated black hole. On that image, Aaron, let's pivot to our third topic. Some good news about how farms can help. tropical biodiversity. How does that work? Because often we hear about rainforests being chopped down

to make way for farms, which is a bad thing for biodiversity. Yeah, I mean, to be clear, Ari, of course, destroying tropical forests to create farmland does contribute a massive amount of carbon to the atmosphere and it eliminates habitat for a lot of animals. But there is a bit of good news for some tropical birds and they're kind of, I mean, the canary and the coal mine when it comes to biodiversity. Yeah, a new study out this week in the journal PNAS found that some birds that have been hurt by deforestation in Costa Rica, like the Great Green Macaugh, they've actually been increasing in numbers on what's known as diversified farms. Like farms that grow a lot of different crops, not just one. Exactly, exactly. In the tropics, there are a lot of these smaller family farms, and they plant just this big mix of crops, all interspersed with patches of forests and native plants and shrubs.

It's very different from the monocroped farmlands that we mostly see here in the U.S. And researchers at Stanford who have been tracking tropical birds in Costa Rica have found some of these diversified farms are actually great habitat for forest birds, which sort of goes against the conventional wisdom about farmland and wildlife. Now, this increase in tropical birds that they're seeing on these diversified farms is not fully compensating for all the population losses that researchers are observing in the forests. But it is something. And, you know, the thought is that these diversified farms are providing a habitat that will act kind of as a bridge connecting, shrinking forests that might otherwise end up fragmented. And that will help the birds hang on and some of them even thrive. Does this offer any lessons for farms in the U.S.? Yeah, I actually asked the lead author Nicholas Hendershot about that.

And he said it's tricky to think about doing this in the U.S. just because of that large-scale agriculture that dominates here. you know, think your Midwestern cornfield. But Nicholas says we could think smaller like people's gardens. And just trying to make that as friendly for wildlife as possible because I think what this work and other work shows is that wildlife are using everything.

And they're not just in these protected forests, but instead we need to create these resilient landscapes that they can move through and make use of so that they can persist into the future. And what's really cool about that is that there was also a study out last week in scientific reports that found in Germany at least, there's a lot of potential for gardeners to play a role in conservation by planting threatened plants in their yards or even something like a balcony pot. So anyone with a little space to plant native species can provide habitat for things like threatened birds and pollinators.

Okay, I'm going to Google right now where my cherry tomato plants count. I bet they do. Maybe if they're heirloom. Yeah. All right. Thank you so much for joining us on Shortwave. So good to be here. Thanks.

This episode was produced by Rachel Carlson, Viet Leigh, and Michael Levin. It was edited by Christopher Inteliata and our managing producer Rebecca Ramirez. Our fact checker was Anil Oza, and our audio engineers were Stu Rushfield and Maggie Luthor. Bet Donovan is our senior director and Anya Grundman is our senior vice president of programming. I'm Regina Barber. And I'm Aaron Scott. Thanks, as always, for listening to Shortwave from NPR.