The Planet Earth podcast - 'Fungi and grogs, hydrothermal vents and green buildings'.
2 April 2012
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Sue Nelson: Hello, I'm Sue Nelson and welcome to the Planet Earth podcast from the centre of England's capital city where you can find 760 species, a penguin beach and a gorilla kingdom all within roaring, squawking and grunting distance of Regent's Park. It's the world's first scientific zoo and you will find out why I'm outside the reptile house in just a moment. Later in the podcast why we've got to look at buildings differently if we want to reduce carbon emissions and the perils of working with frozen mud from one of the world's most mysterious ecosystems.
Clare Woulds: I have to ask you not to touch bits of this freezer because I've got nice blue insulated gloves on - if you touch it you will get stuck to it and then we have serious problems.
Sue Nelson: The Zoological Society of London was founded by Stamford Raffles, he of Singapore fame in 1828. A year later the society opened the London Zoo and since then it has run conservation programmes both here and in over 50 countries worldwide and I'm in front of the reptile house made even more famous by a certain Harry Potter because there's an increasing threat to a number of amphibian species around the world in the form of a fungus. Over 200 amphibian species are thought to have become extinct and the problem of fungal infections isn't restricted to frogs, toads and newts or other amphibians because during the 19th century it causes the potato famine in Ireland and according to new research it could affect food security today.
Well, I'm joined by Dr Trent Garner from the Institute of Zoology and Dr Matthew Fisher from the Department of Infectious Disease Epidemiology at Imperial College, London. Matthew, if we can cope with being hassled by a helicopter overhead it sounds a serious problem - why haven't we heard more about fungal infections actually affecting biodiversity?
Matthew Fisher: Well, fungal infections haven't really been a problem until the last two decades and what we've noticed is that there are far more infections now than there used to be. I mean we know about fungi driving frogs extinct but there have also been very aggressive emergences in bat populations in North America, bat white-nose syndrome, and we're also seeing dramatic emergencies in forests, so we all know about Dutch elm disease but also in crops too. There are new virulent forms of fungal lineages which can devastate entire crops, so UG99 has a demonstrated potential to wipe out a quarter of the world's wheat supply. So, we've been thinking very hard about why this is occurring and what these trends that we're observing actually mean.
Sue Nelson: Right, well, let's look at in particular at how a fungus affects one particular species and that's frogs. Trent, how bad have frog populations been affected?
Trent Garner: In some parts of the world they are thinking that species have actually gone extinct due to this fungus and that's a rather unusual thing to have a parasite drive toads to extinction. Not only has this happened in one part of the world but it has actually happened on multiple continents and that's the thing that is so worrying that such an unusual occurrence can actually be replicated on a global scale. Of course that's not just species extinctions that are happening we're seeing catastrophic population declines where the remanent populations are so small that they could go extinct at the blink of an eye for any reason because there's not just enough numbers there to maintain the population and again this is occurring at a global scale.
Sue Nelson: Right, well, I think it's time, listening to those helicopters, to actually go inside the reptile house, get out of the noise here, and perhaps go and see some of the frogs that have been affected .
Trent Garner: All right.
Sue Nelson: Through the doors – still noisy but it's a popular time, lots of school children and familiar glass fronted cases containing snakes and lizards, geckos on my left there, African Bull Frog and a Blue Poisoned Dart Frog – oh, that is beautiful, that is a vivid blue isn't it?
Trent Garner: They are beautiful aren't they? They come from a family of frogs that has been heavily affected by the fungus in Latin America. Some of the species within the family are presumed extinct due to the emerging infectious disease.
Sue Nelson: Is the fungus that affects these frogs the same, Matt, that affects all frogs around the world or are there different strains?
Matthew Fisher: No, there's one single strain that's emerged and we've dated that to the mid 1970s or perhaps a little bit earlier than that and that seems to have emerged pretty much simultaneously in five continents.
Sue Nelson: Trent, what other frogs here in this reptile house have been affected?
Trent Garner: Well, if we go over here there's actually a salamander species called the axolotl and it's a member of the family of ambystomatidae salamanders and while we don't have any evidence of this species actually being affected by the disease they certainly are infected with the fungus.
Sue Nelson: I don't think I've ever seen an axolotl before. It almost looks like a missing link between a frog and a fish.
Trent Garner: Indeed. And it's a critically endangered species.
Sue Nelson: Now, Matthew mentioned about it spread over five continents, what has caused the fungus to be spread in that way?
Trent Garner: I think that's a really good question and I think we're still developing the evidence base to actually answer that question. Certainly, a lot of people invoke amphibian trade as being responsible for the spread and we do have some evidence that amphibian trade has been responsible for some spread of events. Exactly how it's been responsible for spread overall is yet to be determined.
Sue Nelson: Which brings us back to food security and the overall all view here is when you have a fungus that can effect and potentially devastate crops of wheat or rice that's extremely worrying. What can be done about this? Does this mean greater food security is needed or even greater, perhaps, environmental security?
Matthew Fisher: We would argue that much stronger international bio security is necessary. We see the doors to our country absolutely wide open for the trade of animals and plants in the nursery trade or in the pet trade and these hosts have the demonstrated potential to carry new infections into countries and we're witnessing the effect of that and manifest the potentially of these pathogens. So we need to quarantine more and we need to give the international organisations which control trade in bioactive material more muscle.
Sue Nelson: Do you think it's too late, Trent?
Trent Garner: No. I agree with Matt that we need to tighten up regulations and tighten up enforcement to reduce the risk of disease being transported around. But even if disease occurs in an area, even if disease does emerge in an area I do think that steps can be taken to reduce forcing of infection and potentially reduce the effects of the parasite without necessarily eliminating the parasite.
Sue Nelson: Trent Garner from the Zoological Society and Matthew Fisher from Imperial College, London, thank you both very much. This is the Plant Earth podcast.
Hydrothermal vents were only discovered in the 1970s but have turned out to be some of the most fascinating ecosystems on earth. These deep sea geezers are teaming with unusual life from weird pale octopus to the recently identified 'hoff' or yeti crab as described on our podcast earlier this year. But there are some fundamental questions scientists studying hydrothermal vents don't yet know the answers to. Clare Woulds at the University of Leeds, for instance, is investigating food webs, what does everything living in the sediments around hydrothermal vents eat. Richard Hollingham went to visit her lab in Leeds where she showed him the samples that she works on.
Clare Woulds: We're going to have a look at some of my samples from the Southern Ocean, they're sediment samples and they're kept in this minus 80 degree freezer there. They're kept at such a cold temperature because of some of the things that I want to look at in them.
Richard Hollingham: So we've got this towering freezer cabinet at the side that's about two metres in height, it says minus 80 degrees on it - ok, open it up.
Clare Woulds: Ok, here we go. And I have to ask you not to touch bits of this freezer, because I've got nice big blue insulated gloves on but if you touch it you will get stuck to it and then we have serious problems. Ok, here we go.
Richard Hollingham: You can feel the cold, it's like a slice of Antarctica just there - I'm not touching it.
Clare Woulds: Ok, I'm going to open this bottom drawer here – so this is the one that my samples are kept in and these are literally bags of mud, you can hear the crackle, that's just a plastic bag but because it's so cold it sounds really brittle. We will take these out and put them on the bench and have a quick look.
Richard Hollingham: So, what, we've got frozen sediment samples from where?
Clare Woulds: This site is called Hook Ridge, that's the name of the feature on the seafloor that we were studying and what's we call a defused hydrothermal venting site, so there was geochemical evidence in the water that there is hydrothermal venting going on there but there is also instead of this rocky bottom with chimney's there is actually a cover of soft sediment or mud over that, so the hydrothermal fluids are coming bubbling out through the mud and that's the type of site that these come from.
Richard Hollingham: I have to say if we can look through the bag, again, I'm not going to touch that it just looks like crisp sized bags of frozen mud.
Clare Wolds: That is actually what it is but they're very carefully labelled bag of frozen mud.
Richard Hollingham: Now we have to put these back pretty quick because you don't want them to get warm.
Clare Woulds: That's right. I don't want them to get warm. We also can't open the close the freezer too much because it forms a vacuum when you shut the door. So, we will put these back in and then we can keep the freezer nice and cold. Ok, and the big door - that's closed and we have to lock this now just to make sure that the samples don't get interfered with.
Richard Hollingham: So, we've come into the microscopy lab and appropriately enough. There is a microscope and under there you've got a sizable petri dish and this is some of the sample, but at room temperature now.
Clare Woulds: Yes, that's right. This is a sample that was preserved slightly differently. It was pickled, if you like, in formalin and what I've done this morning is I've taken the whole sediment sample and I've sieved it. So, all of the really fine particles, the fine muddy particles have gone through the sieve and they're in a bucket in the next lab waiting for me to put them back in the jar, and what we're looking at is the course of fraction greater than 250 microns in size, that's a quarter of a millimetre, so still quite small and we're going to have a look at it under the microscope to see what animals are living in the sediment that we can pick out for analysis.
Richard Hollingham: Let's have a look.
Clare Woulds: I believe I've left an actual worm or fragment of a worm in the centre of the field of view there.
Richard Hollingham: Oh, ok, yes.
Clare Woulds: That particular individual isn't very coloured, that's a clearish whitish colour. Some of the ones that we find have greens or reds in their colouring.
Richard Hollingham: And so what are you trying to find out?
Clare Woulds: I'm interested in carbon cycling. That really means where is the food coming from for this ecosystem and how does that food travel through the ecosystem, so who is eating what and who is eating who else and that's what I am trying to find out through my experiments.
Richard Hollingham: And how are you doing that? I presume it just doesn't involve looking down a microscope.
Clare Woulds: At a hydrothermal vent system we have really interesting phenomenon in that the biological community there has two different sources of food mostly in the deep sea there's only one source of food and that's food that falls down from the surface ocean from plant production in the surface ocean. At hydrothermal vents there are really interesting microbial communities that can also make food just like plants do at the surface and instead of using sunlight because there's no sunlight at 1500 metres in the ocean they use chemical energy. They use the chemical energy from all of these strange volcanic fluids seeping out of the sea floor. So this biological community has a choice of two different food types. It can eat algae sinking from the surface of the ocean or it can eat bacteria that are producing food in situ on the seafloor and the thing we don't know is to what extent is this community reliant on those two different types of food, so where is the carbon coming from and how is it being cycled.
Richard Hollingham: And how are you trying to look at that and investigate that?
Clare Woulds: I do some experiments where I collected sediment cores, I collected tubes full of sediment that had all of their natural structure and their natural biology in tact and I then added chemical labels to those cores. Some of that was chemically labelled algae and in different cores I added a chemical labelled that the in situ bacteria would take up. So I'm labelling the two different food types. I'm then going to pick out the animals from these sediment samples and see which animals eat which different type of food.
Richard Hollingham: And I suppose this is fairly fundamental stuff because you don't really understand these processes that are going on in these communities.
Clare Woulds: It is a very fundamental aspect of understanding an ecosystem to understand where the food supply and where the energy supply for that ecosystem is coming from.
Richard Hollingham: And is it quite exciting to be working on something that no one else has done in an environment that really we've only started exploring in the last ten to twenty years?
Clare Woulds: Yes, that's fantastically exciting. I feel very privileged to be in this position of doing something for the first time. Often in science we find ourselves adding details or refining hypotheses, in this case it's really exploratory and that's fantastically exciting.
Sue Nelson: Clare Woulds at the University of Leeds talking to Richard Hollingham and we will put some pictures of Clare on our Facebook page.
Well, I've come outside of the rather noisy reptile house to introduce our next report and it's about energy use in the home. It's one of the biggest sources of fossil fuel emissions round the world, and as the UK aims to reduce its carbon emissions by 80% by 2050 it wants to make all new homes zero carbon by 2016. But Dr Katy Janda from the University of Oxford's Environmental Change Institute think that it is more than just more than energy efficient buildings that are needed. She believes that the way we use buildings is an important as their design when it comes to energy use. So I became by asking Katie why she wants people to look differently at their homes.
Katy Janda: Buildings do respond not just to us but also to the external environment and so a lot of the work that's happening now on occupants and behaviour suggests that all you need to look at is the lights in the building or turn off your computer and while that is true there's also the dynamic system of the building responding to outdoors, so it's the heating which really makes the biggest impact on energy use and so if you don't think about the building constantly responding not just to you but also to the external conditions then basically you're missing a lot of the picture in terms of how the building is using energy to make your job possible.
Sue Nelson: What do you mean by a building responding to external conditions?
Katy Janda: If it's hot outside the building with heat up. If one side of the building faces the sun that will get hotter faster. One of the things that happened in the early part of the last century was something called the international style, which is basically the sealed all glass buildings which are air conditioned and if you look at those buildings they're the same all over the world, they're the same on all four sides but actually the sun which is the major source of radiation in our world that the buildings don't seem to respond to the sun differently but of course they absolutely are. The rooms that are on the north side of the building away from the sun, at least in our hemisphere, would get colder and the ones that are facing the sun will get warmer but the architecture seems to pretend that does not happen which I find to be very bizarre.
Sue Nelson: It's funny you should say that because I have actually been in buildings where that's been the case and actually some rooms were unbearable hot and you couldn't put air conditioning on because it was centrally controlled and it effects every room and people apparently in rooms on the other side of the building were frequently too cold and wanted the heating on. So is this an architectural problem? Is this a design problem?
Katy Janda: My architectural friends will not like me for this but I think that there is. There is often a tension between design and performance. People who do energy conscious design say that there is no tension and that a building should be like a sail boat and it should work together with the forces that it is responding to. And you can certainly imagine that that is true. However, that's not really the environment that we live in today mostly because of heating systems and particularly air conditioning.
Sue Nelson: So how do you make people look at energy use differently?
Katy Janda: I don't think you can make people do anything, to be honest, but I think you can invite them to think of things differently and this would be both for architects, so that the work that I do looks both at changing the nature of the architectural education, what is it that architects learn how to do when they are designing a building or in face redesigning a building which is what I think the next generation of architects needs to learn how to do that were not working with blue sky situation, the existing building stock needs a lot of help and I think architects are actually really well situated to provide some of that help and make things better but they need to learn how to do that and currently a lot of the architectural education is focused on building new wonderful exciting things, things that are exciting to architects but may not be the sail boat that we're looking and so I think that's the question on the professional side. I'm also interested in education for non professionals, so the analogy here would be thinking about how you learn how to drive a car and in every country - or most countries anyway - have regimes around how you learn how to drive a car but there is no such regimen around how you learn how to drive your building, and again you can't make people be good drivers.
Sue Nelson: So like an instruction manual for the house do you mean?
Katy Janda: It goes beyond instruction manual because people can always ignore manuals and that would be like if you learn how to drive a car just by reading the instruction manual for it. That's no enough. Buildings are - if you want to continue with the analogy not to over extend it but they can also be dangerous things, that's what we're finding with carbon emissions. They are just dangerous on a much slower time scale, so we don't recognise it in the same way but if you could come up with a, sort of, social understanding of appropriate use or appropriate driving of the building I think that would go a long way towards resolving some of the problems that we have.
Sue Nelson: Dr Katy Janda from Oxford University ending this edition of the Planet Earth podcast from the National Environment Research Council. My thanks to the London Zoo for letting me see their wonderful frogs. Don't forget to visit us on Facebook where you will find some of the photo's I've taken here today and do follow up on Twitter. I'm Sue Nelson, thanks for listening.