Surprising Shortages and Shaky Supplies

From bananas to helium, we're uncovering the science behind some of our favourite at-risk resources
05 October 2021
Presented by Chris Smith, Eva Higginbotham
Production by Eva Higginbotham.




As the UK struggles with a lack of fuel in petrol stations and fresh food shortages in the supermarket, we ask: what else are we at risk of running out of? Plus, in the news, why we might be destined to succumb to the ‘worst cold ever’ this winter; signs that air pollution causes millions of premature births each year, and scientists peer into the past and read previously-hidden parts of Marie Antoinette’s love letters...

In this episode

A person with a cold, sneezing into a hacky

01:06 - Will the "worst cold ever" come this winter?

Why some scientists are predicting a particularly bad cold and flu season this year

Will the "worst cold ever" come this winter?
Ron Eccles, Common Cold Centre at the University of Cardiff

As COVID retreats, will it be replaced by an epidemic of coughs, colds and flu viruses? Well, it's already happening, says Ron Eccles, who spent over 3 decades running the Common Cold Centre at the University of Cardiff. Chris Smith caught up with him to find out a bit more about the common cold and whether, in his view, we're all destined to succumb this winter to what some are dubbing "the worst cold ever", and if so why…

Ron - Common cold is one of the most complicated diseases because it's caused by over a hundred different types of viruses. The respiratory viruses, as they are called because they enter the respiratory tract through the nose, are changing all of the time. And we don't have a single vaccine against any of the common cold viruses.

Chris - And that means that you don't have long-term immunity then?

Ron - You have immunity perhaps for a few months, but the immunity doesn't protect you against variations of the virus. The rhinovirus changes its coat so rapidly that we can't really develop immunity to it. There are over a hundred different types of rhinoviruses in circulation at present.

Chris - And is it possible to catch more than one of them at once?

Ron - You can and certainly now that we have such good techniques to identify the viruses, we know now that it's not uncommon to be infected with two viruses, sometimes even three at the same time.

Chris - People are saying we're destined to suffer our worst cold ever this winter. Is that hyperbole, or do you think that there is some risk of that happening?

Ron - I think it's already happening, Chris. During the pandemic, we suppressed COVID, but we also suppressed all those common cold viruses that are transmitted in the same way as COVID. And now we've released from lockdown, we're getting an epidemic of common cold viruses, wherever you look around you, there are relatives and friends and media saying the epidemic of colds are upon us. There is a particularly nasty, common cold virus that is circulating at the moment that tends to cause a lot of cough and chest infection and can have a serious effect on babies and the elderly.

Chris - Why should the fact that we've kept these germs at bay for the last 18 months owing to our response to the COVID pandemic mean that they're coming back with more abandon now?

Ron - Normally we would have these common cold viruses circulating all of the time. They're much more common in winter because our noses are colder in winter and they like a cold environment, but we've suppressed them. And it means that amongst the community, nobody has any resistance to these viruses. No one has been exposed to them and they are spreading very rapidly throughout the community.

Chris - From what you're saying then, in an average year, we catch a cold or whatever, but we've got a sort of baseline level of immunity or resistance then to colds. And because we haven't caught any for the last 18 months as a result, we've lost some of that immunity. And that's enabling these viruses that caused the colds to become more common again.

Ron - That's right, Chris. No one has got any immunity to these common cold viruses. So they've got 100% of the population that they can attack. And in normal circumstances, you know, perhaps 20-25% of the population would have had colds fairly recently. That is why they are spreading so rapidly.

Chris - Is there any evidence that these colds actually compete with each other and could they provide some competition for coronavirus infections? Because there was some suggestion last year that perhaps the common cold might reduce the risk of COVID because your body's busy fighting off the common cold and puts itself into a state where it's harder for COVID to gain a toehold.

Ron - That's correct. We know that there's been a big surge of rhinoviruses when lockdown has been reduced and the rhinoviruses have crowded out some of the COVID viruses. As you say, our immune system is alert, it's activated and it makes it more difficult for the COVID viruses to get in.

Chris - I guess what's interesting is that despite our efforts to suppress coronavirus, these colds - although their numbers went down - they didn't disappear and people have repeatedly come to me during the lockdowns and said "I've taken enormous steps and been very, very diligent about hygiene and everything to stop myself catching COVID, I've still managed to catch colds."

Ron - Well, the colds have been in this game a lot longer than COVID. We've probably been interacting with the common cold viruses for millions of years, and therefore they've got lots of tricks to get past our immune system. COVID will eventually evolve into what I would expect would be like a common cold virus. These new variants are more infectious than the earlier variants and common cold is worldwide all of the time. And therefore it's almost impossible to eliminate the common cold viruses.


Drawing of human embryo

07:18 - Air pollution affecting millions of births

Millions of developing babies exposed to air pollution will be born prematurely or with a low birth weight

Air pollution affecting millions of births
Rakesh Ghosh, University of California San Francisco

Around this time last year, researchers in London reported that they had found particulate matter from air pollution in the placentas of women giving birth in the capital. They concluded that what pregnant women breathe in can sometimes end up in their developing baby. They didn’t look at the impact on the children in that study. But now University of California, San Francisco epidemiologist Rakesh Ghosh has taken things a step further and married up data from exposure to small particles of airborne pollution - termed PM2.5 - with the risk of a baby being born either too early, or weighing less than it should. He told Cameron Voisey what he found...

Rakesh - So the main finding of this study is that there are almost 6 million preterm babies and 2.8 million underweight babies born every year that are due to PM2.5 exposure during pregnancy. These are very small particles, less than 2.5 micrometres that can travel deep into the lungs and pass into the bloodstream.

Cameron - And how is it that these particules affect babies?

Rakesh - So there could be three possible ways that we can think of. One: by effecting the development of the placenta and the umbilical cord. The second could be these particles induce some kind of inflammation of the membranes and cause the baby to be born early. And the third possible pathway could be by causing oxidative damage to the DNA.

Cameron - And what are the problems associated with preterm birth?

Rakesh - Preterm birth is the most important cause of neonatal mortality, which is death in the first four weeks after birth. And those who go on to survive, it is often observed that these preterm babies develop long-term disability because their body, including the brain, was not fully mature when they were born.

Cameron - So what are the main sources of this particulate matter? What leads to this pollution being in the air?

Rakesh - In many of the countries, the main source, particularly the high-income countries, is traffic and industrial sources, for example, coal-fired power plants. In other countries, such as Sub-Saharan Africa and the Indian sub-continent a major source of PM2.5 is household air pollution. So in many of these places wood, dung, even coal are used as fuel for cooking. And my results show that huge amount of these 6 million that I was talking about is happening in these parts of the world where pollution levels are very high.

Cameron - So how did you actually carry out the study? What data did you use?

Rakesh - So first I started with compiling the evidence from the studies that have been conducted so far. And I primarily did this to examine critically whether the relationship between PM2.5 exposure and the adverse outcomes like preterm birth and low birth weight is causal. And once I was convinced that this association is causal, then I estimated along with the team, the magnitude of the risk at different levels of exposure.

Cameron - So looking forward, where would you say we go from here?

Rakesh - Outdoor air pollution, as we all know, is ubiquitous. It has to be acted upon by different authorities. For countries where indoor air pollution is a problem, I think a message should be part of the prenatal care. Do whatever you can to minimise exposure to indoor air pollution or household air pollution. It is high time to realise that air pollution is not just about premature deaths, but it is harming the babies and our future generations even before they are born.


A needle and bottle of the COVID-19 vaccine.

12:27 - Flu and COVID booster jabs work together

A study giving the flu and COVID jabs in one go is a success

Flu and COVID booster jabs work together
Rajeka Lazarus, University of Bristol

A booster programme for the COVID-19 vaccine has been implemented in the UK. But, doctors are predicting a worse-than-usual flu season this year, so we’re being urged to grab a jab for flu too. And the current guidance is that this can safely be given alongside a COVID booster. Chris Smith heard from Rajeka Lazarus at Bristol University who has been a part of the ComFluCOV study, which has been testing this and has just announced their results...

Rajeka - By giving the vaccines together, you can prevent any delays while getting protection for one infection or the other, and also, hopefully, make it easier for people to get both vaccines just by having one appointment. Also, it makes it easier, hopefully, for the healthcare services, by reducing the number of appointments they need to deliver.

Chris - Indeed, because the JCVI, our Joint Committee on Vaccination and Immunisation, have said that this should be done where it is clinically expedient to do so, but obviously people shouldn't wait to get both vaccines. If they can have one sooner, they should just go and get that one a bit sooner, shouldn't they? But how did you actually do your study? Because critically one wants to know, if we are going to give two vaccines at the same time, that both are going to work equivalently well.

Rajeka - That's right, and I think it's important to say that giving two vaccines at the same time is very common. People will get a pneumonia vaccine or a shingles vaccine alongside their flu vaccine. But when there's a new combination, it does need to be tested. So we invited volunteers who were due to have their second dose of the COVID-19 vaccine, and then randomised them to have that second dose alongside a flu vaccine or a placebo, which was just a salt solution. And then compared the responses of those volunteers to how they react to the vaccine, and also their immune response in blood tests that we took.

Chris - Let's start with the first of the points you make about the reaction. This is side-effect profile, I presume: sore arm, feeling a bit achy and tired. What happened there? Did people get a double whammy with the side effects if they had both at the same time or were they okay?

Rajeka - We know that with the COVID-19 vaccines, depending on which one you had and whether it's a first, second dose, that you can get kind of a more general flu-like symptoms with them. And those are the symptoms that we were most interested in, as well as to see whether having the flu would increase the number of people who got those symptoms. And it varied a little bit, but overall, we found that there wasn't a significant increase when you have them both together compared to having the COVID-19 vaccine alone. Where there was an increase, most of those side effects were still mild or moderate.

Chris - And perhaps most critically, when you followed up and tested people's blood for evidence of immunity against both flu and coronavirus, was there any difference in giving the vaccines individually or when they were administered together?

Rajeka - That's a really important question. Overall, there wasn't a difference when you gave the vaccines together compared to when you gave the COVID-19 vaccine alone, which means that the protection that you get from both those vaccines remains intact.

Chris - How long after the vaccines were administered did you look though, because one of the other key questions here is how long are people going to be protected for?

Rajeka - Yeah, that's right. So we checked three weeks after people had had the vaccination, because we're just looking at how people respond in terms of their antibody levels in the blood. And I suppose what's really important in terms of how long it lasts is really how long people stop getting disease for; how well the vaccine works. And that's not something that we tested in our study. At this time, we don't know what level of antibody or immune response you need to provide protection from COVID. So that's the kind of question that we need to answer by ongoing studies, looking at what happens in the real world.

The International Space Station (ISS)

18:20 - What happens to female bodies in space?

A new experiment has launched to study the effects of microgravity on female bodies

What happens to female bodies in space?
Angelique Van Ombergen, European Space Agency

Going into space changes people, and not just in a ‘perspective shifting, the earth is so tiny’ way: the lack of gravity in space affects bone density; makes people literally taller, and affects a host of organs, from your heart to your eyes. However, most of the data on what happens to the body in microgravity comes from studying men, as the majority of astronauts have been male. Now, a new experiment has been launched by the European Space Agency, ESA, to look at how female bodies are affected. Eva Higginbotham spoke with ESA scientist Angelique Van Ombergen ...

Angelique - We have started a dry immersion study with 20 females and the dry immersion is the sort of model in which we can simulate weightlessness or microgravity, which allows us to do some research that can help us to prepare human space flight. In essence, the idea is that you put people in, let's say a bathtub, if you want to imagine it like that, and you leave them there for five days. The fact that it's a dry immersion study means that, in essence, their skin is not in contact with the water. So they stay dry, but they are immersed in the water for five days. This induces changes that are very similar to what we see in astronauts, and that can help us to better prepare human spaceflight and to get a better understanding of these changes.

Eva - Five days in a bathtub just does not sound very comfortable, so how did you go about recruiting people for this study?

Angelique - It's not easy to find people to do it, especially now because we're only targeting female subjects. So, they can read the book, they can be on the laptop, but of course, they at all cases need to be in the bathtub. They also can only use a pillow to support their heads when they're eating, but for anything else, they're just lying. And, of course, they can hold something up, but yes, it's not going to be the most comfortable thing.

Eva - Does the weightlessness bit come from the fact that they're in water. So they're kind of being held up by water. Is that how it's similar?

Angelique - Yes, exactly. So, you have the immersion in the water, which creates something that we call supportlessness. Because, normally, when you're sitting on a chair, for example, you're always supported in one way or the other - either it's your feet on the floor, or it's your bum on a chair, or when you're lying in the bed, it's your back. So there's always something supported. And, of course, in weightlessness, you do not have that unless you really touch something. The idea of having somebody in the water basically mimics that in a certain way. And we know that it also induces similar changes to what we see in astronauts.

Eva - And what makes you want to focus on female bodies in this experiment?

Angelique - The dry immersion model has already been used, mostly in Russia and also in France, but the subjects that they have included were always male subjects. So there is already quite some knowledge on how dry immersion induces bodily changes and physiological changes, but there is no data available on female subjects. So that's why we wanted to include 20 female subjects to, let's say, address some of the knowledge gaps that we still have, and to get a better understanding potentially on how males and females differ in these changes that we see.

Eva - And what changes do you see? What do you expect to happen to the body? And why might it be different in a female body than a male body?

Angelique - We know that there's a lot of differences between males and females. Sometimes these differences are quite small, sometimes these differences are bigger. So that really depends. And we know also that, in general, there are a lot of differences between individual people, so if you have Person A and Person B, there's going to be differences between them, even though they might be considered both in a normal range. We know that, for example, we have loss of bone density, we have loss of muscle mass, the immune system is challenged, we can have vision changes. From the data that we have from astronauts already, we know, for example, that female astronauts seem to be less susceptible to vision changes, just to name one example. Now we need to be sure that this is indeed the case. And if so, then we want to understand better why they might be more protected. It might be, for example, hormonal, it might be cardiovascular changes - there might be something different and we need to investigate it.

It might also be that we do not see it in females yet, just because we don't have enough female astronauts to test. This is an important distinction, of course, and we can only address that if we have sufficient female subjects to actually do the testing on. By this dry immersion study, and some other ground-based studies that we do, we really hope to address that knowledge gap. There's really a broad scope. And what we, of course, want to do is find the counter measures that are best in mitigating some of the unwanted effects of space flights. Potentially we will come to a situation where this might be individualised to a certain individual and then to a specific astronaut.

Marie Antoinette love letters

23:22 - Marie Antoinette's love letters laid bare

Scientists are now able to see beneath the retractions made to Marie Antoinette's final few letters...

Marie Antoinette's love letters laid bare
Anne Michelin, Sorbonne University

Let’s step back into the past now to Paris in the late 1700s. It was the time when the French Queen, Marie Antoinette, was under house arrest during the revolution. She corresponded prolifically during that period with the Swedish Count Axel von Fersen, with whom she was alleged to be intimately involved. He kept many of her letters, which now sit in the French national archives, but, ever the tease, someone scribbled out key parts of the text - possibly the bits that might have got him or her into trouble. Now though, researchers have used an X-Ray technique to see through those redactions by subtracting the differing signals of the ink used for the scribbling-out from the one Marie Antoinette wrote with. Anne Michelin, from Sorbonne University, took Harry Lewis through the story...

Anne - This correspondence was separate correspondence between Marie Antoinette and Axel von Fersen in 1791 and 92. It's the end of the life of the queen. She's in jail. We are in the middle of the revolution and it's not really good for the Royal family in France. She realises the situation, she sees that it's not a good time for her and so she writes to Axel von Fersen, which is a very close friend and she writes about the political situation, but also on her feelings. This correspondence is special because some parts of it are redacted. It's very black. You can't see anything. It's impossible to read the text and so it was something that the curator from the national archives asked us if we can read the texts.

Harry - Anne do you have any of those words available? Would you be able to read a short part where something's been redacted?

Anne - It's something like, my dear friend I love you madly and I can't be a moment without adoring you. Something like that. Not exactly, but something like that.

Harry - The big question there is, how do you see underneath the reductions? How do you know what the letters are?

Anne - It's all iron gall ink. Iron gall ink are inks that contain iron sulfate but also other metallic elements like copper and zinc. There is some slight difference between the inks and we use techniques, x-ray fluorescence spectroscopy, that analyse the compositions of the inks. Just the sensor on the paper, and we record the spectrum in each pixel. In each pixel of the letters we record a spectrum.

Harry - Then when you transfer that x-ray to the screen and you put that into a digital format through looking at each pixel you can see where the spectrum changes and the different elements are present. You can build up a visual picture like that?

Anne - Yeah, yeah. Like that. We have some parts where we are only the writing ink, the original ink, and some parts where we are sure there is only the reduction ink. It's like that. We can see if we have the same composition or if we have something really different.

A bulldozer in front of a piled up sand quarry

29:15 - Sand in short supply?

We use a colossal volume of sand every year, but where does it all come from?

Sand in short supply?
Ian Selby, University of Plymouth & Louise Gallagher, UNEP/GRID Geneva

Throughout human history, humble grains of sand have played a crucial role in how we have lived. But, not all sands are suitable for our purposes, and this is putting considerable pressure on environments in some parts of the world. We need better sand logistics, otherwise what has powered our past could be our future undoing, as Eva Higginbotham has been hearing...

Eva - Whether digging into it with our toes or hoovering it up in the car after a day at the beach, we all have a relationship with sand. Actually, we are all far more dependent on those tiny grains than you might've thought

Ian - We've used sand actually since the Dawn of civilization. Essentially it satisfies our basic needs because we build homes with it. It's absolutely a foundation for civilisation.

Eva - That's Ian Selby from the University of Plymouth who spends his time thinking about sand from what we do with it...

Ian - Once we blend it with a mud or cement.

Eva - To what it's made of...

Ian - Sand is often dominated by quartz because it's such a hard medium.

Eva - So, how it's created...

Ian - Sand is essentially a natural product. It's created by geological processes. Rocks are formed off minerals. The rocks then across time are subject to all sorts of processes, whether that's: wind, rain, snow ice, essentially climate driven processes, it could be hot or cold, that basically break down those rocks after their formation and they break them down into their component parts and it can take a very long time. We can talk about millions of years, tens of billions of years, even hundreds of millions of year to break down the rock into these small particles, which we call sand.

Eva - Sand is an absolutely integral part of modern life. Think of cement roads and concrete buildings and plaster and glass and even paint. The thing is, although pictures of the Sahara desert might make you think we have a never-ending supply...

Louise - The big one that people I guess are starting with is do we have enough sand.

Eva - That's Louise Gallagher from UNEP/GRID Geneva, she's been tracking how sand is used and raising the alarm about a potential future, where there is a scarcity of the right kind of sand in the right places because actually not all sand is created.

Louise - People really liked river sand because it's a certain type of shape, it's coarse, it's angular, it grips well together w when you want to use it to make things like concrete and it has no salt in it, that's very important and you don't have to wash it. Nature has done all the work for you in grading and sorting and cleaning that sand.

Eva - As the population continues to grow. And as we build more infrastructure, more sand is needed, particularly in the global south. To ensure that we globally have the resources to meet this demand means that we need to keep track of how much sand we actually need both now and projected into the future. I asked Louise, if we know how much sand we use each year and...

Louise - Best estimate that's out there right now is 50 billion tons of sand per year, which is just massive.

Eva - That's a lot of sand. The thing is the world actually has a lot of sand, but we need to be careful with how we use it. For example, although very plentiful the round grains of Sahara sand have little use in construction, and we currently sometimes use high quality sand where low quality sand would do. Partly thanks to the fact that historically sand has been seen as a never ending resource as opposed to a vital component of life that took, in some cases, hundreds of millions of years to be created.

Louise - I guess if you live in an area which hasn't been impacted by sand mining, it seems like there's loads and that it's not a problem. If you lived in an area where you've seen sand being taken out of your local rivers or off your local beaches, it doesn't feel like there's a lot of sand let, and your water availability can become a problem in some rivers, you can impact upon your land, your rivers start to erode more quickly, you can have banks of the rivers collapsing, including then bringing in buildings that are built on the banks of those rivers. Tqhat's like the direct impacts on the site level. Then finally, if we have overall much less than entering into the marine environment and making its way to the coast, making its way naturally to beaches, you can have increased coastal erosion, when the big storms come you have much worse effects, much worse impacts on land, you have loss of property, loss of life. If we don't manage sand properly at that kind of big systems level, you not only don't have the right type of sand for building what you need when you need it, you might also, on top of that, create a ton of problems.

Eva - It's clear that we need to pay closer attention to those tiny grains. This starts with more sensitive resource mapping and tracking of sand use globally. From a technical standpoint there are some substitutes in the works for some uses and Louise and others are hopeful that we'll move forward with making our own sand by crushing up waste rock produced by mining. Importantly though...

Louise - It's going to take a big change in how we think about building, how we think about the material, how we train our engineers, how we design building projects. It's going to be a big cultural shift. The technical challenges is going to be one challenge. The social and cultural and political aspects also are going to have to really be thought about very deeply as well.

Eva - Next time you're at the beach or walking along a river or looking up at a new building. It's worth thinking about the history of the grains involved in creating the scenes that we know and love and how we might best protect them.

A peeled banana

35:12 - Bananas in trouble: a fungal pandemic

A deadly fungus is infecting bananas across the world, putting the globe's favourite fruit at risk

Bananas in trouble: a fungal pandemic
Fernando Garcia-Bastidas, KeyGene

Next up, it’s the world’s favourite fruit, bananas! But partly as a result of their popularity, bananas are at risk from a plant pandemic, which could see supplies dry up.  Chris Smith spoke to Fernando Garcia-Bastidas, a banana scientist from KeyGene...

Fernando - It's indeed an ongoing banana pandemic that has the potential to wipe out banana plantation. It is rapidly spreading and this situation really threatens global banana production. Mostly because all the bananas in the market are identical, meaning that all of them are susceptible to this disease. This already happened in the past and with another race of this disease and a different cultivar. So we know that it's something serious.

Chris - What is the cause of the banana plants dying?

Fernando - Yes, the pathogen is a fungus, which is called fusarium and causes the disease known as Panama disease. It's caused by a solver fungus. So that means that it lives in the soil. This fungus interacts with the plant and essentially kills banana plants. This fungus also produces lots of spores that are easy to spread. So for example, if you go to a farm in the Philippines, for example, and you use the same shoes in a farm in Colombia, you are bringing the pathogen with you.

Chris - Goodness. And how far afield is the pandemic now, where's affected?

Fernando - For more than 30 years, this pandemic was restricted to Southeast Asia. So it was present only in the Philippines in Malaysia, Taiwan, Indonesia, but then in 2012, we found it for the first time outside of this area, in Jordan, and lately, it was described by the other scientists also in Oman, in Mozambique, we discovered it in Pakistan, in Lebanon, then in Israel, Turkey, Myanmar, and like that, it's been spreading very fast. Currently there are more than 20 countries with the pathogen. And the most striking thing is that it's present almost in every continent. In 2019, for example, I discovered for the first time in Colombia and that's really bad news because if you go to the supermarket for example, and you check the stickers of the bananas, most bananas come from Latin America. And this, this is, has the potential to destroy all banana plantations. Recently, it was also discovered in Peru.

Chris - You mentioned that the reason bananas are susceptible to this is because they are all genetically identical because they're all effectively clones, a bit like the Irish potato famine was because potatoes are all genetically identical. Along comes something that it can attack one plant, so it can attack every plant because they're identical. How are you trying to tackle the problems?

Fernando - There are only a few options to control this disease because so far not even chemical controls can kill this pathogen because it's in the soil and in the soil is very difficult to tackle. So the most logical way to tackle this problem is to generate a new banana. So essentially there are two ways to generate a new banana either by traditional breeding, which is using the pollen of one plant and pollinate other banana plants or transgenics, which is taking the DNA of another plant, helpfully another banana, and introduce it into, uh, an edible banana

Chris - Bananas only very infrequently have plant flowers, don't they? So they're very, very hard to grow via the pollen route. So the transgenic sort of moving genes seems to be more promising. Is that what you're doing?

Fernando - No, actually I'm doing traditional breeding. I'm using the pollen because you know, it's more complex with transgenics in terms of acceptance of the, of the customers. So I'm using traditional breeding and of course the edible bananas, the bananas that we have in the supermarkets are very difficult to improve. But what we are doing is to go to the ancestors of the bananas and those ones are easy to cross, to mix and to generate new bananas.

Chris - And what do they taste like? Are they any good?

Fernando - Yeah, they taste fantastic. There are even different kinds of flavors. We have bananas that tastes like apples, for example, or sweet there or, or more, uh, less sweet. So the diversity of bananas is huge. If you go to the center of origin of the bananas in Southeast Asia, they are more than a thousand different cultivars, but they don't look as pretty as the Cavendish, the one that we have in the supermarket. So what I'm doing now is trying to combine different types of bananas. So far, we identified the ones that are resistant to that specific disease, but unfortunately they are not ready because they are not pretty. They are not big enough, the skin is too thin, they don't ripen at the right moment. So we need to continue with breeding. And that takes a lot of time.


Balloons in sky

40:41 - Rising worries for helium shortages

Beyond balloons, helium is vital for modern science and technology - which is why scientists are concerned...

Rising worries for helium shortages
Sophia Hayes, Washington University in St Louis

But first to an important resource that’s normally invisible, unless it’s filling a balloon, that is - that’s right, it’s helium. But squeaky voices and party balloons aside, helium is actually a crucial part of modern life - from running MRI machines to making the semiconductor chips in your smartphone, helium is vital, which is why scientists get nervous about the fact that its supply can fluctuate, and one day, we could literally run out...Eva Higginbotham spoke with one such scientist, Sophia Hayes, from Washington University in St Louis...

Sophia - Oh, you know, there are so many properties of helium that make it a very special element. Of course, many of us know that it's lighter than air. It can lift objects. And that's why we have helium balloons and weather balloons and the like, but it's also unreactive. And what that means to those of us who are chemists, is it doesn't change the composition of things when it touches another atom or molecule. If you think about oxygen around us, that turns iron into rust or steel into rust, what happens with helium is it just doesn't react with anything else. But then the really important property is that it's the coldest substance that one can buy on earth. And we scientists use that. And like you said, it's used in MRI machines.

Eva - So it doesn't like making friends with other molecules. And it's also very cold. Where do we actually get it from?

Sophia - Helium comes along when we mine natural gas and bring it up from underneath the earth. So there's a bit of helium that's stuck there fortunately for us. And so when we bring up that natural gas, we can separate the helium from that other methane.

Eva - And how much helium is down there - sort of as a percentage with the methane that we're bringing up?

Sophia - You know, in a good source, tt's only about a percent, maybe sometimes as high as 5%, but many, many natural gas sources have much less.

Eva - And is that why the supply can go up and down?

Sophia - Ah, yeah, that is a really complicated question and I'm so glad you said a just-in-case model at the start of the program versus just-in-time. Helium has a very hard time being stored. And so comes up with this natural gas mining, but occasionally there are geopolitical situations with Qatar or Algeria, and that will shut down an entire source. The US Source has a large inventory because we have a rock formation where we store it, and so we have a unique capability here, but even occasionally we have shutdowns for maintenance. So the whole market goes out of order when one of these supply sources goes down.

Eva - And so what happens when we have a low supply to all of those MRI machines?

Sophia - The MRI machines are less at risk because many of them are in a closed cycle, kind of like the radiator on your car, but other kinds of applications, the semiconductor industry, and even those of us who don't have those closed cycle systems, then they're all at risk. So semiconductor lines have to be shut down. And in the case of those MRI-like magnets, that puts them at risk because they need to be maintained in that cold state for their entire lifetime. So it puts them at risk because they might warm.

Eva - And do we have any replacements for helium when there is a low supply?

Sophia - Sadly there is nothing like it, it is a special substance, again with no other alternative that we can find. And so while we might come up with an alternative for one application or another, there's really nothing like it, it's quite special.

Eva - And if we get it from underground, do we know sort of how much is left underground? Will more continue to be created? Where does it come from?

Sophia - It comes from the decay of elements, such as uranium and thorium. And so we have some estimates of how much uranium is on the planet, but what that means is that we're making helium one atom at a time and it's a very slow process. You see, you know, the earth is estimated to be about 4 billion years old. And so luckily a lot of these crust formations have trapped helium underground, which means it's there for us to pull out. But that 4 billion years has given us a lot of time to produce that helium, one at a time. So estimates say something on the order of a 200-year supply.

Eva - And that doesn't seem like that long actually considering it so important! Seeing as it's lighter than air, does that mean that the helium we get just goes up into space?

Sophia - Yes, exactly right. And that's a problem because it doesn't stay here on Earth. As soon as we've let it go, it's truly gone forever.

Eva - Does that mean that we could go get some from space if it sort of all ends up there?

Sophia - I wish! Wouldn't that be terrific? It would be such a terrific solution, but of course out in outer space, it's just so dilute. And even though there's helium up there, it would be so hard for us to collect an atom at a time again.

Eva - So what should we do? Does this mean that it should be the end of helium balloons to preserve them?

Sophia - That's also complicated. Let's just say those of us who use a lot of helium, we really ought to recycle it in such closed cycle systems. For example, the semiconductor industry, to the best of my knowledge, doesn't recycle the massive amounts of helium that they use. They are also used for rocket propulsion and there is not really a good way to recycle that as well. But those of us with MRI and related strong magnetic equipment, they're called superconducting magnets. If all of us began to recycle, it would certainly be a better way to preserve that resource.


46:27 - Rare earths: where to find them?

Using a bacteria-inspired hack to optimise rare earth mining

Rare earths: where to find them?
Joseph Cotruvo, Penn State University

To another technologically important element - or rather, group of elements - the rare earths. These are a group of 17 chemical elements with special properties that make them well suited to all sorts of tech applications, from making the bright colours in your phone screen to fuel cell batteries and electric vehicle motors, which means we need a lot of them. But currently, the supplies are dominated by certain countries, China in particular, that have also used their monopoly over this market to exert political and diplomatic pressure on other nations. So is there a way around this? Chris Smith spoke with Joseph Cotruvo, from Penn State University. He’s working on techniques that make it easier to get hold of the rare earths we need...

Joseph - The rare earths are really not particularly rare. There's more of the most abundant rare earth, an element called cerium, then there is copper in the Earth's crust, but the problem is that they're not distributed very evenly. And so the rare earths are rare because they're usually present in rocks in very low amounts, they're mixed with other rare earths and they're mixed in with many more abundant metals like iron, calcium, and others. And so as a result, there are very few deposits that are economical to mine those metals

Chris - And hence we have the sort of geopolitical issue, and supply issues, just because of gaining access to where they're actually worth exploiting?

Joseph - Exactly. Right.

Chris - What are the possible solutions then?

Joseph - Well, so the solution that we have been working on uses biology, or biochemistry I should say. Really about a decade ago it was discovered that there are actually bacteria that need some of the rare earths, just like we need metals like iron or calcium or zinc, as vitamins, essentially. And so I thought that if we could understand how these bacteria have basically solved the problem of mining rare earths, the same problem that we want to solve, we may be able to do this more efficiently. And so my lab discovered the first molecule that these bacteria make that binds rare earths very tightly and very specifically. It's a protein molecule, and you can think of it as a person with arms that are flailing about. When the hands on those arms grab hold of a rare earth, the body curls up into a ball and they can hold onto the elements very tightly. But if the arms grab a metal that is not a rare earth, it tries to curl up, but it can't. And therefore it has to release those metals. And so essentially what we would like to do, if we can take the protein that's curled up into this ball, and when we want to recover the rare earths from the protein, we can tickle it so to speak to get it to release the metals, and then we can go on and use those metals for technologies.

Chris - Presumably the tickle is a chemical one -  you prise the fingers of the arms off of the metal chemically to make it surrender what it's grabbed. What though, I'm intrigued to know, are the bacteria. What are they and why have they got this extraordinary function?

Joseph - Yeah, most of the bacteria that use rare earths are a class of bacteria called methylotrophs. These bacteria are actually all over the place in the environment -  in soil, in water, they grow on plants, and they're present in more extreme environments too. And they're really special microbes because they can use very simple molecules like methane and methanol, molecules that we can not use as food. And so what the rare earths are doing in these bacteria is they helping to catalyse a very important chemical reaction, basically how those bacteria eat, the methanol that they use as food.

Chris - And would your plan then be, having discovered how the bacteria are able to grab and sequester these rare earths from very dilute, what will be very dilute sources in the environment, you could borrow from that biology and basically copy it so you'd have a very fine sieve specific for rare earths?

Joseph - Exactly. Yeah, that's exactly it. You know, we could use the bacteria on their own potentially, but biology is a lot slower than chemistry is. The protein on its own, if we can make it and we can make it on its own, it works very, very quickly. So we're using the molecules on their own.

Chris - And in practical terms, how would one deploy this? Would you go to, say, a mine site where someone's already moved - I would say heaven and earth but a lot of earth - and you could take the tailings and basically, you know, there's going to be tiny amounts of rare earth in there and they're not worth processing the traditional way. But you could put that through your very fine sieve, and therefore you would enrich for the rare earth from mess we've already made without having to make a new mess?

Joseph - Exactly. Yeah. There are actually many waste sources, such as the ones that you mentioned, where we have huge quantities of material, but very small amounts of rare earths. And so the mine tailings that you mentioned, coal fly ash, the very acidic water that spills out of mines, also electronic waste. All of these are sources where we have a very large amount of material that can be processed, but the current technologies just don't work. And that's where we can take advantage of the millennia and millennia of evolution, where the bacteria have devised ways of getting out these small quantities of rare earths.

Chris - It sounds incredibly elegant, and congratulations to you for this achievement, but if one tots up how much there is in the way of rare earths in these other sorts of sources that we've just been discussing, is there enough potentially recoverable in there to keep the likes of the makers of iPhones and Android phones and the magnets in electric vehicle motors happy?

Joseph - At the moment I think this isn't the full solution to the problem. Using sources where you're starting with very high concentrations of rare earth will be the best for the next few years. But the demand for rare earth keeps increasing and we have more and more of these wastes. And I think it's important to incentivise sustainability. The mining process of rare earths is one of the most environmentally damaging industrial processes on earth. And so if we recognise some of the hidden environmental costs associated with those methods, then I think, once scaled up, biotech methods like ours could really make a dent in the rare earth problem that exists.

A cold can cause temporary anosmia (loss of the sense of smell)

53:51 - QotW - why are some diseases infectious twice?

Why can we catch some diseases more than once, but others give us lifelong immunity?

QotW - why are some diseases infectious twice?

Sally Le Page asked author and infectious disease researcher at Imperial College, London, John Tregoning, to jog her memory...

John - The simplest answer is that some pathogens change and others don’t. Our immune system remembers what we have seen before and stops those pathogens infecting us again. Immune memory recognises molecules made by pathogens, mostly the ones on the outer surface that the pathogen uses to get into our cells. If these molecules change, then our immune system no longer recognises them, allowing the pathogen to infect us.

Sally - Seems like the immune memory is as bad at recognising people as me! If I’ve seen you before but now you’ve got a new haircut or are wearing a different pair of glasses, you might as well be a complete stranger.

John - Different types of pathogen use different methods to change how they appear to our immune system. Some viruses, like influenza and the coronavirus that causes COVID19 use a molecule called RNA to store their genetic information. When the virus replicates it makes copies of that RNA and mistakes occur which lead to changes in the structure of the molecules on the outside of the virus. Some bacteria also change the way they appear. The bacteria coat themselves in sugar to hide from the immune system. Each bacteria can make several different sugars and they can replace the one on their surface with a new one, improving their chance of not being seen.

Sally - The sneaky things! It’s almost like these bacteria don’t WANT to be spotted by our immune systems...

John - The pathogens to which we acquire lifelong immunity are more stable – they don’t change their surface proteins, so our immune systems can recognise them each time we see them.

Sally - So the next time you catch a cold, feel sorry for your immune system which is having the very awkward experience of not recognising someone they’ve already met. If the thought of that social anxiety is making you want to leave everyone behind and just live in space, this next question from Daniel might make you think again…

Daniel - If a crew on a mission to Mars has a death on board and the body was released into space, would that body ever decay?


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