Podcast: Cannabis cultivation in Canada and the Sun’s place in history

Host: Shamini Bundell

Welcome back to the Nature Podcast. This week, we’ve got four-and-twenty ways science could help a budding industry…

Host: Noah Baker

And a potted history of the Sun. I’m Noah Baker.

Host: Shamini Bundell

And I’m Shamini Bundell.

[Jingle]

Host: Noah Baker

Around the world, more and more governments are relaxing legislation on the use of cannabis both for medical and recreational purposes. But how much do we know about how to grow this formally black-market crop? To find out, reporter Elie Dolgin headed over to a cannabis factory in Canada, only the second country in the world to legalise the stuff. His goal – to find out how science could help.

Interviewer: Elie Dolgin

In a suburban Toronto strip mall, past the barbed wire fence and layers of electronic security, sit rows upon rows of cannabis plants. Welcome to TerrAscend, one of 129 licensed cannabis producers in Canada. Ari Unterman, the company’s Head of Business Development, shows me around.

Interviewee: Ari Unterman

The first room we’re going to is our mother and veg room.

Interviewer: Elie Dolgin

This is where the company keeps its stocks of different cannabis plants. The varieties each have distinctive names like ‘CBD God Bud’ and ‘Shishkaberry’.

Interviewee: Ari Unterman

The yield on the Shiskaberry is about 15% better than the CBD God Bud, but as we grow there’s more time for learning the right food recipe, lights, environmental controls, amount of time in each phase, etc.

Interviewer: Elie Dolgin

Those aren’t the only scientific studies happening here at TerrAscend. A few months ago, the company teamed up with a few local academics to run a series of experiments altering the plants’ genetics. One of those academics, Shelley Lumba from the University of Toronto, normally studies a parasitic plant called ‘witchweed’. But with cannabis getting legalised, she jumped on the chance to study a different kind of weed instead.

Interviewee: Shelley Lumba

This is a natural place for us to try to maximise our skills into a commercial plant.

Interviewer: Elie Dolgin

She and her team are now exposing cannabis seeds to chemical mutagens and looking for DNA changes that benefit the plant in some way. Those mutations may confer disease resistance or they might yield chemical profiles that are better for patients. It’s a fairly basic experiment but one that could have a huge impact for an industry that has lacked a solid scientific foundation.

Interviewee: Mike Dixon

The industry struggles mightily for just real information, reliable information.

Interviewer: Elie Dolgin

Mike Dixon is a plant scientist at the University of Guelph, home to the largest agricultural college in Canada. He laments the fact that many growers continue to operate as they’ve always done, cultivating cannabis in much the same way as they did in basements and warehouses during the plants black market days.

Interviewee: Mike Dixon

They’re basing a lot of what they do on what they know, which is not founded in sound scientific principles and some of it is just remarkably silly.

Interviewer: Elie Dolgin

That’s beginning to change though because of the global trend towards legalisation, and nowhere is there more money and opportunity for cannabis science than in Canada where starting on October 17th the plant will legal for all medical and recreational purposes. Legalisation has bought with it government support and financial services both of which, says Shelley Lumba, put the country in a very unique position.

Interviewee: Shelley Lumba

Canada is perfectly situated to be pretty much a driving force when it comes to research and development for cannabis.

Interviewer: Elie Dolgin

The goal for scientists and companies alike is to produce high quality, industrial grade cannabis that is consistent from plant to plant. This should ensure patients get the same dose from one cannabis prescription to the next, and that recreational users know what they’re putting in their bodies. Some researchers like Lumba are focused on meeting these goals through breeding and genetics, but others like Dixon think that here are better places to focus their scientific efforts.

Interviewee: Mike Dixon

We can take genetics and blow it out of the water.

Interviewer: Elie Dolgin

For the past 20 years, Dixon has worked with the Canadian Space Agency to develop systems for growing food on other planets. Now, he’s applying some of those same technologies to cannabis, starting with fine-tuning the lighting conditions.

Interviewee: Mike Dixon

The spectral quality of the light is imperative. You really do have to figure out what the physiological response of the plant is to this colour because it’s different than it is to that colour, and the implications in interpreting the medical benefits are profound.

Interviewer: Elie Dolgin

In addition to light, Dixon is also testing how best to modulate temperature, humidity and ambient carbon dioxide levels.

Interviewee: Mike Dixon

If you homogenise those four major environment variables, you can’t lose. The plant must do what you tell it to.

Interviewer: Elie Dolgin

Back at TerrAscend, Ari Unterman walks me – somewhat backwards – through the last two steps of the cultivation process. Amidst hundreds of plants hanging upside down, he explains the three key elements that affect the quality of cannabis.

Interviewee: Ari Unterman

The genetics going into the plant, the growing conditions and then the drying and packaging conditions.

Interviewer: Elie Dolgin

Finally, Unterman takes me into the grow room, where I’m immediately struck by the glow of the high-pressure sodium lamps. Wow!

Interviewee: Ari Unterman

You can tell a nice healthy plant – nice colour green, pretty robust and yeah, that’s pretty much it.

Interviewer: Elie Dolgin

But really there’s so much more. With advances in genetics and agriculture, the cannabis industry is entering a new phase of science-driven of R&D and after years of black-market breeding, this weed is becoming a true horticultural crop.

Host: Noah Baker

That was Elie Dolgin reporting from Canada. If you want to read more about the science of cannabis production, check out Elie’s feature-length story over at nature.com/news.

Host: Shamini Bundell

Speaking of news, we’ve got a mission to Mercury and a climate disaster brewing for brewers. That’s coming up in the News Chat, but first it’s the Research Highlights read this week by the newest member of the podcast team, Ali Jennings.

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Interviewer: Ali Jennings

Scientists in the States have constructed a purpose-built microscope to study early mouse embryos in unprecedented detail. After a mouse embryo implants in the uterus, it undergoes a staggering transformation, ballooning to 250 times its initial size in just 48 hours. During this time, embryonic cells divide, expand and reshuffle as they rush to build the mouse’s basic body plan. Up until now, researchers had only seen snapshots of this staggeringly complex process. The embryos are easily damaged by light and their rapidly evolving size and shape can make it tricky for microscopes to keep the image in focus and at the right resolution. This new microscope automatically tracks the embryos growth and uses single sheets of laser light to illuminate this transformation for the first time. So, if you fancy brightening up your day, check out their stunning images in Cell.

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Interviewer: Ali Jennings

Now, are you sitting comfortably? Well, if you’re listening to this podcast from Jupiter’s moon, Europa, the answer is probably not. A team in the UK have suggested that ice on the surface of Europa could form 15-metre-tall frozen blades around its equator. Ouch! On Earth, these spikes form when a steady stream of sunlight repeatedly reflects back and forth inside small pits in cold, dry snow. The sunlight’s heat causes snow from the pits’ edges and bottoms to sublimate from solid straight to gas, so the pits grow wider and deeper until only their edges remain, forming spine-like structures called penitentes. And if that pricks your interest, you can read about it in Nature Geoscience.

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Host: Shamini Bundell

Now, here in the UK, autumn is currently getting serious and reminding us all that the record-breaking Northern Hemisphere summer of 2018 is well and truly over. Despite worries about the warming climate, we will miss it, so we’ve sent Lizzie Gibney off to remind us all of warmer days by exploring the story of the Sun.

Interviewer: Lizzie Gibney

Solar physics is something of a hot field of research right now, if you excuse the pun. In August, NASA launched the Parker Solar Probe, which is going to get closer to the Sun than any craft has done in history. The European Space Agency is launching its own probe in 2020 so why the interest? Well, despite being the very hub of our solar system, as well as an influencer of life and culture on this planet, the Sun is still something of a mystery. To learn more, I’ve come to London’s Science Museum where a new exhibition is opening this week on our nearest star – the Sun – and humans’ relationship with it. I’m going to meet curator Harry Cliff for a sneak preview. Hi, Harry, is it?

Interviewee: Harry Cliff

Yeah, hi Lizzie, nice to meet you.

Interviewer: Lizzie Gibney

Nice to meet you. So, what’s the motivation then behind this exhibition? What made you want to do it?

Interviewee: Harry Cliff

Well, the exhibition is all about the Sun and the Science Museum has a great collection that kind of relates to the Sun in all kinds of different ways. The problem with Sun, in a way, is that it’s so big, it attaches to almost every aspect of human history so trying to distil it down to something manageable was the real challenge at the beginning. And the story we’ve gone for is the way that our relationship with the Sun has changed through history from the Bronze Age right up to the Space Age but through the lens of science, technology and medicine.

Interviewer: Lizzie Gibney

So where do we begin?

Interviewee: Harry Cliff

So, we start off with this rather beautiful screen. So, this is showing a live feed of footage of the Sun over the last 24 hours. What you can see here is the Sun in extreme ultraviolet light and as soon as you look at this, you see that the Sun is not a sort of static source of light. It’s dynamic, you can see there’s all kinds of things going on on its surface. There’s magnetic field lines bursting up from sunspots. The atmosphere is constantly sort of moving around and changing. You can see around the edge of the Sun this kind of hazy halo which is the corona, which is a region of superheated plasma. You can see sunspots which are the sort of regions where you have these bright, magnetic filaments looping out from the surface of the Sun.

Interviewer: Lizzie Gibney

Fantastic. It looks very dramatic. So how long have people been studying the Sun as the centre of our solar system?

Interviewee: Harry Cliff

You can find evidence of ancient Greek philosophers who argued that the Sun was the centre but they never really gained much traction. It was Aristotle’s view of the Universe, with the Earth at the centre, that really became the dominant model. So, the idea that the Sun was the centre of the solar system only really starts to become widely accepted from the 16th century onwards, when Copernicus publishes On the Revolutions of the Heavenly Spheres in 1543, but it’s not this instantaneous change in our view of the Universe. It takes a century for his ideas to become refined and accepted, ultimately with the contributions of other people like Galileo and Kepler and Newton. So, the next phase of the exhibition is kind of actually saying something that in a way is quite obvious but also which we’ve totally forgotten, which is that time is solar. So, our very concept of time really ultimately comes from the Sun and for most of history, if you wanted to know what the time was you looked at the sky and you looked for where the Sun was in the sky. And because we’ve surrounded ourselves now by machines and by digital devices, we’ve kind of forgotten that basic fact.

Interviewer: Lizzie Gibney

Is there still any link at all or do we just measure time digitally nowadays?

Interviewee: Harry Cliff

Well, so one of the objects we have over here in this showcase is an atomic clock. So, in the 1960s, the global time standard moved away from astronomical time based on the Earth’s rotation and moved to atomic clocks which are much more precise. That’s because the Earth actually doesn’t rotate perfectly. It wobbles and it changes so you find that the Earth will lose or gain certain amounts of time depending on what’s going on at the surface. The only link that’s maintained is that we have these things called leap seconds, so every six months people compare the time according to atomic clocks to the time according to the Universe, to astronomy, and if they find that things have drifted by more than a second then they add or subtract a second from atomic time to keep it in step.

Interviewer: Lizzie Gibney

Ah, so this looks like we’ve leapt a little bit further forward into the future.

Interviewee: Harry Cliff

Yeah, so this is quite an interesting story and it really begins at the end of the 19th century when Robert Koch and Niels Ryberg Finsen discover that sunlight has bactericidal properties, in particular that it can be used to kill tuberculosis bacteria. And you get special hospitals, sanatoria, set up where children and patients can be put out on to a sundeck and they were actually left out in the sunshine, so TB lesions on the skin are then treated using natural sunlight.

Interviewer: Lizzie Gibney

So that wasn’t an old wives’ tale? That actually did have an impact.

Interviewee: Harry Cliff

No, it does have an impact, but you also get a certain amount of quackery that comes out of this. So, this really strange object which is a big wooden human-sized box with mirrors on the inside and lightbulbs, this is an artificial light bath, electric light bath. It was invented by John Harvey Kellogg of Kellogg’s Corn Flakes for his sanatoria in the 1930s and 40s. So, the idea is you sit inside this box, the doors close, the lights are switched on and it blasts you with light, and that’s supposed to treat all kinds of ailments from a bad back to diabetes, whatever you like. There’s very little evidence it did anything apart from warm you up and possibly risk electrocution. I’m not sure I’d want to get in it to be honest.

Interviewer: Lizzie Gibney

Me neither. It looks a bit like a torture chamber. So of course, the Sun is not all good for people’s health.

Interviewee: Harry Cliff

No, and this was only really realised in the 50s, 60s and 70s. You get a huge increase in melanoma cases as a result of everyone being told in the 30s and 40s to go out and get as much Sun as possible. So, this section is all about our attempts to harness the Sun to drive machines, to power our industries. So, in the 1870s, particularly in France, you have engineers who are already thinking what happens when coal runs out, how are we going to power this world when this is a finite resource? And they start to build solar-powered machines. And there’s a big exhibition in Paris where very famously Augustin Mouchot and Pifre display this large solar engine which is used to power a printing press that prints of this solar journal, and it amazes the crowds, turning light into mechanical power. So, we’ve got here we think the oldest solar-powered machine in existence.

Interviewer: Lizzie Gibney

And how does it work?

Interviewee: Harry Cliff

So, it’s a parabolic dish that focuses sunlight onto a heat engine that warms it up and then uses the heat generator to drive a little engine. Actually, there’s even an egg cup attachment so you can use it to boil an egg if you wanted to cook an egg.

Interviewer: Lizzie Gibney

You can do an awful lot with a bit of light if you concentrate it enough.

Interviewee: Harry Cliff

There was that famous incident a few years ago, where 20 Fenchurch Street in London, this huge skyscaper there, was built with a concave surface that focused the Sun’s light onto a guy’s BMW or something and melted the car. So yeah, the Sun’s very powerful and if you concentrate it you can cause all kinds of mischief. We’re trying with this exhibition to remind people that this thing is really fundamental and actually, so much of what we take for granted comes from the Sun.

Host: Shamini Bundell

That was Harry Cliff talking to Lizzie Gibney at the Science Museum in London, England. Read Lizzie’s review of the exhibition at nature.com/books-culture.

Interviewer: Noah Baker

And finally this week, it’s time for the News Chat and joining me in the studio is a voice you might have heard before, Anna Nagle, she’s our Chief Editor for Digital and Engagement. Welcome, Anna.

Interviewee: Anna Nagle

Hey there.

Interviewer: Noah Baker

So, listeners might remember in last week’s News Chat we discussed the new IPCC report and we have another climate change story here with some more bad news. This time it’s about what climate change could do to beer production. Anna, tell us, what’s the damage.

Interviewee: Anna Nagle

It’s bad. It means your beer is going to become more expensive.

Interviewer: Noah Baker

And why is that?

Interviewee: Anna Nagle

A lot of research has looked at the impact of climate change on more staple crops like wheat and rice, but these researchers looked to the production of barley, and they found that under pretty much any climate change scenario, global production of barley is going to go down and that will mean that the price of your pint will go up.

Interviewer: Noah Baker

And of course, barley is a staple crop in the production of beer.

Interviewee: Anna Nagle

Absolutely. So, what they did is they squished together sort of climate models, economic models and looked at the impact that the reduced production of barley would have on consumption and the price of a pint of beer.

Interviewer: Noah Baker

And they are showing some really direct tangible impacts.

Interviewee: Anna Nagle

I will throw some figures at you now. Are you sitting down because they’re not pretty numbers? So, it is China that will actually show the biggest national drop in beer consumption. Per year, they will be drinking over 4 billion fewer litres of beer. In terms of costs, it’s Ireland that will see the biggest absolute price increase out of all of the countries that they studied. The price of beer will go at almost US$5 per half-litre bottle, which triples the current cost which is pretty eye-watering by anyone’s standards.

Interviewer: Noah Baker

Now, these numbers are for the worst-case scenario. They do have numbers for different levels of warming, and some of them aren’t quite as eye-watering, but they’re still all increasing.

Interviewee: Anna Nagle

Yeah, even under the very best-case scenario, globally the model that they came up with predicted a 4% reduction in beer consumption but a 15% increase in price.

Interviewer: Noah Baker

So often we hear about how climate change is going to disproportionately affect the less-developed world, but this is a situation where those that may be sheltered from some of climate change’s effects in the industrialised world are still going to feel its impact.

Interviewee: Anna Nagle

That’s exactly why the researcher decided to focus on something like this. It might sound like a small thing, but he explicitly said that he’s trying to emphasise how climate change will impact people's’ lifestyle, and by showing the impact on that he’s hoping it will prompt people to take action and address it sooner rather than later.

Interviewer: Noah Baker

And of course, our beer consumption is one thing and that will have an impact on many in the developed world, but that does not really compare in many ways to the impacts which will be felt by many in the developing world.

Interviewee: Anna Nagle

Absolutely. I mean worries about our beer consumption pale in comparison to the kind of life-changing and life-threatening effects of climate change in the developing world. But if this kind of research can help reveal to people in the developed world the impact of our habits and our consumption, then it’s one way of getting that communication across that might encourage some people to make some changes in the long run.

Interviewer: Noah Baker

Okay, so from one long-running problem to another long-running mission. This is the BepiColombo mission to Mercury which is due to launch any day now.

Interviewee: Anna Nagle

Absolutely, so this is just the second ever mission to get into Mercury’s orbit and it is the most expensive mission from the European Space Agency, coming in at €1.6-billion.

Interviewer: Noah Baker

And it’s not just the European Space Agency involved here, the Japanese have got involved as well.

Interviewee: Anna Nagle

Absolutely. It’s Japan’s largest contribution yet to an international collaboration in space.

Interviewer: Noah Baker

Now, this mission has been in the planning stages for a long time - since the 90s. Tell me, what is it that they’re trying to achieve.

Interviewee: Anna Nagle

So, what they aim to do is they will be sending BepiColombo off on its mission. It will take seven years to get to Mercury and it will arrive in orbit hopefully in early December 2025, and then it will release two probes, one built by ESA (the European Space Agency) and the other by JAXA (the Japanese Space Agency).

Interviewer: Noah Baker

Now, there have been various missions by ESA and JAXA and others, to Mars, to comets, to asteroids that have dropped things on those asteroids. Why is this is a particularly tricky mission to get to Mercury?

Interviewee: Anna Nagle

Mercury is deep in the Sun’s gravitational well, so to get there the craft has to lose that initial momentum that it’s got from Earth’s orbital motion so that it can fall towards the Sun in the first place, but then it’s got to avoid overshooting. So, altogether, all these complex bits of the journey - which is 9 billion kilometres - it will take eight times more energy and several years longer than, say, an equivalent mission to get to Mars.

Interviewer: Noah Baker

So, tell me, what does the journey from Earth to Mercury look like? How is BepiColombo going to get there?

Interviewee: Anna Nagle

So, it’s using some really advanced technology. It’s using solar-powered ionic thrusters and combining that with some gravitational help with a total of nine fly-bys of Earth, Venus and Mercury itself.

Interviewer: Noah Baker

Now, Mercury, up until relatively recently, was considered to be a fairly dull planet that was hot and round and not much going on, but actually there’s maybe more things to look at than we at one point thought.

Interviewee: Anna Nagle

So yeah, in recent years there’s been a few surprises from what we thought was quite a dull planet in the context of all the other planets. It’s had an unusual magnetic field, water ice deposits found in some of its craters, but partly because of the difficulties in getting there, some of those things have made it one of the least explored of the four planets of the inner solar system. So, so far there’s only been one other mission that’s entered Mercury’s orbit which was NASA’s Messenger mission, which spent four years studying the planet a few years ago, but this will be just the second one ever apart from that one to enter the orbit and find out a bit more about it.

Interviewer: Noah Baker

And I have to ask, why BepiColombo? It’s a great name, where does that come from?

Interviewee: Anna Nagle

It is a great name. It’s named after Giuseppe 'Bepi' Colombo who’s a late Italian scientist who studied Mercury and he conceived of the trajectory that was used for a mission in the 70s known as Mariner 10.

Interviewer: Noah Baker

So, this is a collaboration between the European Space Agency and JAXA (the Japan Aerospace Exploration Agency) and this is a particularly busy time for JAXA because they have another mission that we’ve reported on the podcast recently called Hayabusa2 that is currently in a crux point and there has been some more news about that as well.

Interviewee: Anna Nagle

JAXA was hoping that they’d be able to make a landing this month on the Ryugu asteroid but they’ve had to delay that until January.

Interviewer: Noah Baker

And why has that delay occurred, has something gone wrong?

Interviewee: Anna Nagle

No, nothing’s gone wrong, it’s just that the asteroid that they’re landing on is considerably rockier than they were anticipating. So, what they’re trying to do is going to take a little bit longer to make sure that when they do make a landing, they can safely do it in a much smaller zone.

Interviewer: Noah Baker

Okay, so delay but no disaster, and we’re going to have to watch and see what comes out of that mission and watch and see over a longer time to find out what comes back from Mercury.

Interviewee: Anna Nagle

Absolutely.

Interviewer: Noah Baker

Thank you very much Anna and that’s it for this week’s show. As always, you can find even more of the latest science to peruse over at nature.com/news.

Host: Shamini Bundell

Now, there is sadly now show next week, but we will be back better than ever in two week’s time. And if you’d like to help us on our quest for continual self-improvement, why not give us some feedback? Tell us what you like, what you don’t like, what you want more of. Get in touch on Twitter (@NaturePodcast) or a good old-fashioned email (podcast@nature.com). I’m Shamini Bundell.

Host: Noah Baker

And I’m Noah Baker. Thanks for listening.