Astronaut James B. Irwin scoops up lunar soil during Apollo 15, 2nd August 1971.
When Neil Armstrong made his giant leap for humankind in 45 years ago, he got covered in Moon dust. Throughout the Apollo missions, dust was an issue. Fine but rough, it caused problems with the space suits, and created mini dust storms in the cabin once the landers launched back into space.
On Earth, mineral soils are formed from the underlying rock by weathering, which is a collection of natural processes that gradually break down the rock. Weathering can be mechanical (through atmospheric conditions such as heat, water, ice and pressure) or chemical (when the surface rock reacts with water, oxygen or chemicals produced by plants). The rock particles then combine with organic matter to form what we know as soil.
On the Moon, that doesn’t happen. Lunar dust is formed from lunar rock (regolith) when small meteorites hit the Moon’s surface and pulverize the rock. Some of the rock melts and then cools, coating the dust with a glassy shell. There’s no organic matter for the dust to combine with. UV rays by day, and solar winds by night, create charged particles and give lunar dust ‘static cling’. Oh, and tiny specks of iron make it magnetic. So it’s not your run-of-the-mill Earth soil.
But would anything grow in it? The short answer is no – the minerals it contains are locked up in a form that plants can’t access. Whilst it might be possible to use Moon rock as a ‘substrate’ for hydroponic growing (essentially there merely to hold the plants up), all of their nutrients would have to be supplied with a fertilizer.
But that’s not the final word on the subject. NASA did some plant experiments with Moon rock at the time of the Apollo missions (mainly as part of their quarantine procedures to make sure they hadn’t imported health risks with their souvenirs). They didn’t attempt to grow plants in lunar soil, but they exposed plants to it. Not only did they find no negative effects, the experiments seemed to show that the plants benefited from the Moon dirt – results that have not been replicated. Since then the Moon samples have been considered a precious commodity and have not been made available for destructive research such as grinding them up to grow plants. So researchers have to use ‘simulants’ – Earth rocks that are similar in type to those found on the Moon.
Early in the new millennium, a team of researchers led by Natasha Kozyrovska and Iryna Zaetz from the National Academy of Sciences in Kiev, conducted a series of experiments with French marigolds (Tagetes patula) in one such simulant – anorthosite. They published their results in 2006.
Unsurprisingly, seeds sown in plain old crushed anorthosite didn’t grow into plants. But they were the control group. A second set of seeds was inoculated with a microbiome (bacteria and fungi known to promote healthy growth), whilst the crushed rock was also seeded with bacteria – and in this more complex ecosystem the seeds were able to germinate and grow into flowering plants. The microorganisms present were helping the plants to extract nutrients from the rock, and the authors suggested that this might be a way of starting to grow plants on the Moon.
Reading through the paper, I got the impression that what the authors were proposing was a kind of space permaculture. Lunar regolith is sterile, which not only means that plants can’t rely on microorganisms to release nutrients, but also means that any soil made from them would be a blank canvas for microbes accidentally brought from Earth. Rather than fungi and bacteria that promote healthy growth, you could end up with an imbalance – an environment that is harmful to plant growth. The idea of inoculating the seeds and the regolith was to promote a healthy soil environment that could protect plants against pests and diseases.
The selection of French marigolds was not random. The scientists wanted to grow ‘pioneer’ plants that would not to be too fussy to grow in the nutrient-deprived lunar soil. These ‘first generation’ plants would then be composted to create organic matter and real soil, but the goal was also for them to be multipurpose. They were looking for plants to recycle waste products and produce oxygen, which had potential nutritional and medicinal benefits, and that flowered and so could improve the psychological well-being of the astronauts. Providing all these benefits, whilst kick-starting a sustainable ecosystem that makes use of local resources, is a tall order – but apparently French marigolds fit the bill!
The paper mentions another problem with growing plants on the Moon – the Sun is up for about two weeks, and then down again for the same period of time. If you don’t want to go to the expense of supplementary lighting, it reasons, the only solution is to chill your plants so that they are dormant until the Sun comes out again. In the meantime, I guess those long nights are perfect for forcing vegetables and sprouting seeds! Or perhaps mushroom cultivation….
And so it’s time, once again, for you to choose the next leg of our space blog adventure! Would you like to know more about growing fungi in space, how scientists choose which crop plants will be grown in space, or the Moon trees (grown from seeds taken into orbit around the Moon during Apollo 14)? Cast your vote below, or if you have a suggestion for a different topic, leave a note in the comments :)
And you’ve chosen…
NASA’s Dirty Secret: Moon dust
Kozyrovska, N. O., Lutvynenko, T. L., Korniichuk, O. S., Kovalchuk, M. V., Voznyuk, T. M., Kononuchenko, O., … & Kordyum, V. A. (2006). Growing pioneer plants for a lunar base. Advances in Space Research, 37(1), 93-99.
Gardening on the Moon
Posted in Blog on Aug 2, 2014 · ∞
Last modified on Aug 17, 2014
Tags: science & space.
Photo credit: Steve Wall
In my occasional series, “When Plants Attack” we’ve seen some of the ways in which plants can defend themselves. So far I’ve covered the chemicals they produce to discourage other plants from growing in their space (allelopathy) and the conventional weaponry they use to guard against a physical attack. I am planning more posts to continue the series, which will include a look at the chemical defences plants have evolved to protect themselves against being eaten. But as soon as a plant evolves a defence mechanism, predators will begin to evolve or develop a way to counteract it. For example, some insects can collect poisons from the plants they’re munching on, and use them as part of their own defences. But until now it has seemed as though plant-eating mammals change their behaviour to cope with toxic plants – e.g. by changing how they forage for food, or by eating dirt (geophagy) to detox.
On Wednesday a paper published in Biology Letters put forward what the authors believe is the first evidence of large mammals evolving to combat a plant’s chemical defences. The researchers collected saliva samples from moose (Alces alces) and European reindeer (Rangifer tarandus) in Canadian zoos, whilst the animals were anesthetized to undergo necessary medical procedures. These two animals are known to feed on red fescue (Festuca rubra), a grass which occurs around the world. Red fescue uses a common defensive strategy: it forms a mutually-beneficial relationship with a fungus (Epichloë festucae), which produces toxic alkaloids.
By applying the animal saliva to grass samples, the researchers demonstrated that both moose and reindeer saliva slowed down the growth of the fungus, and so reduced the amount of toxin that was produced. Moose dribble also appeared to directly affect the levels of the toxin in European samples of the grass (the deployment of chemical defences depends on the environment in which the plant is grown), and the scientists theorize that the saliva is preventing the plant’s defence system from activating, by disrupting its signals.
So it seems that moose and reindeer aren’t just coping with the toxins produced by their diet of red fescue, but have evolved to actively combat them. “Plants have evolved defense mechanisms to protect themselves, such as thorns, bitter-tasting berries, and in the case of certain types of grass, by harbouring toxic fungus deep within them that can be dangerous or even fatal for grazing animals,” says York University’s Professor Dawn Bazely, who worked with University of Cambridge researcher Andrew Tanentzap and York University researcher Mark Vicari on the project. “We wanted to find out how moose were able to eat such large quantities of this grass without negative effects.” This interesting discovery (which will have to be verified by further studies) may seem a little esoteric, but you never know when you might need an enzyme that deactivates a toxic alkaloid (and this particular one also appears in ergot), and when you do it’s good to know that moose happen to have one handy.
You may also be fascinated to learn, as I did during the course of my research for this blog post, that whilst the common usage of “ungulates” refers to hoofed mammals (such as moose, reindeer, cattle and camels), cetaceans (whales, dolphins and porpoises) are also ungulates, sharing a common ancestor with the other species in this large group of mammals.
Tanentzap AJ, Vicari M, Bazely DR. 2014 Ungulate saliva inhibits a grass–endophyte mutualism
. Biol. Lett. 10:20140460.
Posted in Blog on Jul 26, 2014 · ∞
Last modified on Aug 25, 2014
Tags: science & fungi.
In this video from the University of Cambridge, Rox Middleton shows us a ‘nanoscale’ image of gum arabic, taken with an electron microscope. Gum arabic is the hardened sap of an Acacia tree; this sample was probably collected in Sudan. If you want to see what it looks like on the everyday scale, I took a photo of a chunk when I visited the Oxford University herbarium. Gum arabic is a food additive, E414, used as a stabiliser. It’s also used in paints and pigments.
Posted in Blog on Jul 16, 2014 · ∞
Last modified on Jul 9, 2014
This isn’t a fantasy alien landscape, its an image of a mint leaf, taken with a scanning electron microscope by Annie Cavanagh. This low-res version is available from Wellcome Images with a Creative Commons license, which allows me to show you how awesome plants are. The spike is a trichome (a hair, essentially). The blobs are oil, sitting on oil glands, and are what gives mint is delicious flavour. The oval structures that look a bit like seeds scattered on the surface, are stomata, the holes that the plant can open and close to regulate its intake of carbon dioxide and the expulsion of oxygen. You can just see the slits along the centre, which is where they would open up.
Posted in Blog on Jul 12, 2014 · ∞
Tags: science & herbs.
In this video from Cambridge University, Dr Beverley Glover uses a Scanning Electron Micrograph to explain the ‘trick’ that makes daisy-family plants more attractive to pollinating insects.
Posted in Blog on Jul 9, 2014 · ∞
Last modified on Aug 2, 2014
Tags: flowers & science.
As I mentioned a few weeks ago, NASA astronaut Steve Swanson has been doing some gardening on the International Space Station, growing ‘Outredgeous’ red romaine lettuce in the new VEGGIE gardening system. This inaugural experiment, called Veg-01, is partly a test of the hardware and partly to see whether space-grown crops will be safe to eat. After all his hard work, Steve doesn’t get to eat his lettuce – it has to be returned to Earth for testing. If the lettuce is proved safe, a second batch of lettuce can be grown and eaten later in the year. This would be the first mouthful of ‘homegrown’ food to be consumed in space, and NASA have produced a great video explaining the VEGGIE project:
Posted in Blog on Jun 11, 2014 · ∞
Last modified on Jun 11, 2014
Tags: science & space.
Astronaut Steven Swanson tending to the Veggie garden on the International Space Station. Image credit: NASA
If you’re currently tending lettuce plants, then you have something in common with the crew on board the International Space Station (ISS). They’re testing NASA’s new Vegetable Production System – affectionately known as ‘Veggie’. At 11.5 inches by 14.5 inches, Veggie is the largest plant growth chamber to have been blasted into space, and was developed by Orbital Technologies Corp.
Veggie was delivered to the ISS onboard the dragon capsule of SpaceX-3 in April, and installed in the Columbus module at the beginning of May. It has red and blue LEDs to supply the plants with the light they need for growth; it also has green LEDs that the astronauts can turn on to give white illumination, so that the plants don’t look funny colours.
Veggie’s first experiment, Veg-01, is mainly a hardware validation test to check everything is working properly. It has been ‘planted’ with six ‘pillows’ – each one contains the growing medium, a controlled-release fertiliser and calcined clay to improve aeration and plant growth. Water is supplied via a root mat, and wicks for the plants (which also help ensure they grow the right way up in microgravity!).
Veg-01 will be growing ‘Outredgeous’ romaine lettuce, a very red lettuce that will be familiar to US gardeners (I don’t think it’s available in the UK). An astronaut will thin the seedlings down to one plant per pillow, and the experiment lasts for 28 days. Photos will be taken each week, and microbial samples will be taken as well. At the end of the 28 days, the lettuce will be harvested and frozen and stored until it can be returned to Earth on SpaceX-4 in August.
The lettuce harvest will be analysed on Earth to ensure that it’s safe to eat. If so then a second set of pillows can be started on the ISS, with the crew able to tuck into homegrown lettuce 28 days later. While they’re waiting to hear whether Veggie produces edible plants, they have some pillows sown with ‘Profusion’ Zinnias to brighten the place up.
As well as proving that edible vegetables can be produced in space, and that the Veggie system works, it is hoped that the astronauts will enjoy tending their garden – which will also make it easier for them to mark the passage of time. A source of fresh food would also be very welcome – fresh produce is eaten almost as soon as it arrives in every cargo run, leaving long-life rations to provide the bulk of astronaut cuisine.
Crops tested in VEGGIE plant pillows include lettuce, Swiss chard, radishes, Chinese cabbage and peas. Image credit: NASA
A control experiment is taking place on Earth, so that proper plant science can be done with Veggie’s results. An Earth-bound Veggie has already grown a range of crops – including lettuce, Swiss chard, radishes, Chinese cabbage and peas.
Have you grown Outredgeous lettuce? Is is a variety worthy of being grown in space?
I am submitting this to VP’s Show of Hands
Chelsea Fringe project, although I think she might have trouble marking these gardening hands on her map ;)
If you’d like to know more about how humans carry useful plants across the world (and beyond it!) then check out my latest book – Jade Pearls and Alien Eyeballs – which includes a potted history of plant hunting as well as interviews with gardeners trying to grow edible plants outside of their native habitat.
Posted in Blog on May 22, 2014 · ∞
Last modified on Jun 11, 2014
Tags: space & science.
Mars in Hawaii. Credit: HI-SEAS
In Jade Pearls and Alien Eyeballs I talk about the journeys plants have made with us – criss-crossing the globe and leaving Earth entirely for missions in space. I talk about it a little bit more in the latest episode of the Alternative Kitchen Garden Show – Plants in Space.
One of the missions I mention in the show is going on right now. There are currently 6 scientists living in a habitat dome 11 metres in diameter. They can only go outside if they’re wearing a space suit, they have strict water-saving regimes that allow them only 12 minutes under the shower each week and some of their meals are dehydrated astronaut rations. But these scientists aren’t astronauts; they’re part of a Mars simulation project, HI-SEAS 2, and they haven’t been blasted into space. They’re spending the next four months on the side of a mountain in Hawaii.
One of the scientists, Lucie Poulet, is researching three different sets of LED lights that could be used to grow food in inhospitable environments. She’ll be looking at which lights provide the greatest efficiency, and how much time a crew might need to spend tending their plants. But it’s hoped that the presence of the plants might also help to foster a sense of well-being – the psychological effects of greenery are under the spotlight as well.
Astronauts on long term space missions, such as a trip to Mars, would need to be able to grow some of their own food – but it’s still unclear how feasible that will be. There are numerous obstacles to overcome, and questions to answer. How will the plants be affected by different gravity? How do you keep them watered whilst avoiding leaks that put delicate equipment at risk? Will the harvested produce be safe to eat without washing? Or safe to eat full stop…?
Gardens in space are likely to be a far cry from the bountiful ‘hanging gardens’ seen in sci-fi movies – space and weight are at a premium, and the plants have to give a good return on the investment. Lucie Poulet will be growing lettuce, radishes and tomatoes in her little corner of ‘Mars’.
It’s the space-age equivalent of asking what you’d take to a desert island, but which crop would you want to take with you on a space mission?
Posted in Blog on May 19, 2014 · ∞
Last modified on Jun 11, 2014
Tags: science & space.
Given the showery weather we’ve been having recently I thought you might like this lovely infographic from Compound Interest, which examines the chemicals behind ‘petrichor’, the distinctive smell of rain or wet ground :)
(Click through to the original image if you want to see it larger!)
Posted in Blog on May 15, 2014 · ∞
Ryan went to the Gadget Show last week, and brought me back a present. He bought me three notebooks made from Parax Paper, which (according to the label) is made from stone. He knew I’d be intrigued, and I had to investigate. It turns out that Parax paper is tree-free, made from calcium carbonate (the active ingredient in agricultural lime, and the stuff that makes water hard) and some plastic (HDPE). Its manufacture doesn’t use any water, requires less energy than conventional paper, and the finish is naturally white. It has a lovely, smooth writing surface and can be recycled (as plastic, not paper). It has won all kinds of eco awards.
Parax paper is water-resistant, and hard (but not impossible) to tear, which should make it an ideal allotment notebook. It won’t mind being used in the rain. In theory, I could write on it underwater, if I had a pen that would write underwater. As the paper doesn’t yellow over time, it could be good for archiving. I will give it a go. If you fancy trying Parax paper for yourself, Amazon is one possible retailer as they have a good selection.
Parax paper isn’t the only stone product to have come into my life recently. We have also acquired some whisky rocks, designed to cool your drink without watering it down. Of course, they can be used with anything, not just whisky. Ours are made from soapstone (they’re Chill ‘N Rock, which we ordered from Amazon). You pop them in the freezer, and then into your drinks as necessary. A quick wash and dry and then they can go back into the freezer for next time.
Now, I’m an ethnobotanist, interested in the way people make use of plants. And occasionally I stray into ethnobiology (mainly due to an interest in edible insects, entomophagy), the way people make use of animal products. And I my stone implements set me wondering – is there such a thing as ethnomineralogy? It turns out that there is, it’s the “study of the interrelationships between people and the minerals, or inorganic resources, in their environment”. So, whether you’re in to the animal, vegetable or mineral, there’s an anthropologist out there who wants to know about it!
Posted in Blog on Apr 14, 2014 · ∞
Last modified on Apr 25, 2014