Marine Month: In too Deep

When volcanoes erupt, huge amounts of carbon are released into the atmosphere. Historically, we have believed this carbon came from deep inside the Earth, however new research from Cambridge University has upended this notion. Georgia Mills spoke to Sasha Turchyn...

Sasha - We’re really interested in understanding how carbon moves around the planet. When we think about the carbon cycle you often think about the movement of carbon between the atmosphere, or into the biosphere, or into the oceans. On geological timescales, so tens of millions of years or hundreds of millions of years, we think about the carbon cycle as carbon that comes from volcanoes into the surface of the planet and, eventually, after a certain amount of time will become a rock or a mineral and return back down into mantle, or back down into a rock form where it’s locked up for a while. That geological carbon cycle that’s been an open question for a little while to understand exactly how carbon is coming out of the surface of the planet and how it actually gets removed from the surface of the planet.
Georgia - So you’re interested in where this carbon was actually coming from - the volcano shoots is out into the atmosphere but where is it from originally? So how did you go about looking into this?

Sasha - We used something called isotope ratios. When we think of carbon, we think of carbon having 6 protons and 6 neutrons, but actually 1% of all carbon has an extra neutron in the nucleus. So, because of that we can use that ratio of the heavy carbon to the light carbon to understand the source of that carbon.

We had this question a long time ago, maybe 7 or 8 years ago and there weren’t many measurements made just yet, and over the last 7 or 8 years there’s been many more measurements. There’s been an explosion in the number of measurements that are reported in literature. So, when we went and revisited this question with a Master’s student, Emily Mason, who’s the lead author of the study, we went back this past fall and we could see that there was enough data that had been developed of this isotope ratio, which is effectively a chemical fingerprint of where the carbon comes from to be able to say something that was significant.

Georgia - I’ll ask you where you found the carbon was from in a second, but I’m curious. I’m imagining someone with a test tube standing over a volcano - how do you get these samples?

Sasha - Well, there are some test tubes over volcanoes, but no-one falls in any more. One of the advances that’s happened in the last 7 or 8 years is that the analytical capabilities have meant that you need smaller and smaller samples sizes. And that has allowed people to take very small vials, either from fumeral gases or through bags attached to pumps on the ends of camping poles. I’ve sampled things like methane in saltmarshes, and there we can take a tent pole with a bag and you can swirl it using a small vacuum pump and you can sample it in about a minute or two. In a similar way you can do this, you don’t do this in super hot parts of the volcano, but in some of the more dispersed parts of the volcano you can sample the gases pretty easy.

One other advance that’s been great in the last few years is you can make some of these measurements on site, which has allowed for more measurements to be made.

Georgia - So what did you find? Where is this carbon that the volcanoes are shooting out coming from?

Sasha - A lot of it is coming from the surface. A lot of it is from other rocks that are very close to the surface and not from as deep in the mantle. It doesn’t have that characteristic sample of deep mantle carbon that we were expecting to find. But what was most interesting is the volcanoes that are putting out the most CO2 - things like the Italian volcanoes - they’re very, very big CO2 emitters, so is Papua New Guinea for example. Those ones had the most carbon that was coming from the surface. Whereas other volcanoes like the Alaskan Ark, they were putting out mantle carbon, they’re not putting out quite as much CO2. So once you did a weighted average of both the amount of CO2 and its chemical fingerprint, it was very heavily weighted towards the crustal recycling.

Georgia - Why is it important to know this?

Sasha - That isotope fingerprint is the primary tool that we use to reconstruct the carbon cycle over geological time. So if I’m interested in 500 million years years ago, or a billion years ago understanding how much carbon was coming out, how much carbon was going down, how was it going down, was it related to animals or not? I’ll use that carbon ratio. So if the ratio in volcanoes can change systematically over time then that implies that we can’t trust those measurements from deep in geologic time for understanding the carbon cycle.

Georgia - I see. So it’s kind of changing what we understand the history of the carbon cycle will have been?

Sasha - We’ll have to rethink some of our interpretations. We have interpreted changes that have been measured to be attributed to say changes in some process at the surface, but it may be a change in the type of volcanoes that are around.

In the Hitchhiker’s guide to the Galaxy, the supercomputer ‘Deep Thought’ was given the challenge of solving the meaning of life, the Universe and everything. The answer was, as fans will know, a rather disappointing 42. But now we may be getting closer to building such a computer ourselves. Because scientists from the University of Sussex have come up with a design for what would be the most powerful computer ever built. It’s a quantum computer and commentators say machines like it will transform the fields of medicine, e-commerce and, who knows, possibly tell us the real answer to life, the Universe and everything. Izzie Clarke met with Winfried Hensinger, who’s leading the project.

Winfried - It’s really big. Right now it fills a huge laboratory and as we build a large scale machine it will certainly fill a whole building and maybe it will fill a whole football pitch. Think of it as a masterpiece of engineering; tremendously difficult engineering.

Izzie - For one day only, a large bunker was placed in the centre of London which displayed the blueprint to building the most powerful computer on Earth. But, this isn’t a computer as we know it. Using planes and planes of microchips, scientists can use charged atoms called ions to carry out enormous calculations using the laws of quantum physics...

Winfried - Quantum physics is a very, very strange theory and has really wierd predictions. An atom can be in two different places at the same time. So you could be standing here and you could be at home having breakfast all at the same time, and that actually exists in the world of quantum physics. We train these quantum effects in order to build a very, very powerful computer which is nothing like a normal, conventional computer.

Izzie - The key to this quantum computer is that its circuit can operate by not just being on or off like a switch, but by occupying a state that is both on and off at the same time. This is down to quantum mechanics, which allow very small particles to be in different places simultaneously, where they stay in these states until they are either observed or disturbed. It’s a bit like flipping a coin. The coin is both heads and tails when it’s in the air but it’s only heads or tails once it’s caught...

Winfried - What you actually see is a very authentic model of a quantum computer as we have it in our lab at the University of Sussex, which has a vacuum better than that of outer space. Inside this vacuum system there are silicon microchips. We’ve developed a new way where you apply voltages to one of the these silicon microchips and we use these to produce electric fields, and these electric fields make individual charged atoms, or ions, that levitate above the surface. What we’ve shown is a new type of approach to quantum computing.

Izzie - It’s on these small particles that information is encoded. Our standard computers carry information in bits with values of zero or one. Quantum computers use quantum bits or qubits, where they can be both zero and one. Previously, small scale quantum computing methods used lasers to help process the calculations carried out by these qubits. However, that provided some issues when upscaling…

Winfried - Imagine you wanted to build a large scale quantum computer which would require millions or billions of qubits. Imagine you need to align millions or billions of laser beams with the accuracy of a hundredth of the width of a human hair. What we’ve done is we’ve taken away all this requirement of using all these laser beams and instead replaced them that with voltages to apply to a microchip.

Izzie - Because these qubits can be in multiple values at the same time, more information can be encoded on them. We’re talking about calculations that even the fastest supercomputer would need millions of years to calculate. For such a powerful computer you’re going to need a pretty big circuit board known as a module. It’s a large, flat microchip that contains lots of routes for the ion to move across, along with control electronics that allow this movement. Their motion actually looks like a game of Pacman. And more modules means more ions and that’s what increases the computational power...

Winfried - We’ve developed a new way to connect modules. Traditionally, people thought you’d have to use an optical fibre, so we came up with a new approach to do this. We move ions using electric field connections from one module to another and with that we are going to be able to do this 100,000 times faster than the state of the art technology around right now. And this is the second exciting breakthrough we have.

Izzie - In some aspects a quantum computer works in a similar way to a standard computer running calculations based on an input. But, thanks to quantum, both the information a quantum computer can store and it’s power is incomparable.

Imagine you were looking for someone in a public phone book. The standard process would be to go through each entry individually until you found the right person. Because these ions can take multiple states, a quantum computer would be able to search every name and number, so that’s every single possible answer, all at the same time. But what can we use these quantum computers for?

Winfried - Quantum computers can tackle problems even the fastest supercomputer would take billions of years, so it’s a whole set of opportunities. For example, creating chemical reactions like creating new pharmaceuticals. Being able to understand how to make new materials; stronger materials but lighter materials. Think about optimisations in the the stock market - very quickly, classical computers just run out of computational power. It’s more like getting a new capability that you didn’t have before...

What's it like to journey down to the bottom of the ocean? Georgia Mills heard first hand from Wally Fullweiler, associate professor at Boston University, who has explored the seafloor...

Wally - We get into the submarine named Alvin. The pilot seals the lid and we’re lifted up and into the air and off the stern of the boat into the water. We stare out the window and see the sky, then water, sky, then water, as we bob up and down. The descent begins. First, we move through sunlit, blue waters seeing organisms swimming and dancing in the water. Salps swirl around the windows, gelatinous water column dwelling creatures –translucent, save for their dark orange stomachs and blue rib-like structures. Little, see-through pink shrimp and small jelly fish with hints of auburn slide across our view.

Before we know it the light is almost gone and the water is this amazing dark blue, green, grey – and then darkness. The light is gone at around 200 m. For a brief moment it’s pitch black - and the we see them. We see the light – all the flashing lights. Tiny sparks that are barely discernible and then big, bold, dramatic blazes. For just moments, we see the ghostly outlines of their bodies. We are descending too fast to know what they are - but likely they’re scores of bioluminescent fish, jellyfish, squid, and sea worms. We are falling through an ocean of stars.

Scared? Not at all. I’m in awe and I’m in love. The joy of seeing this is immense – it’s more beautiful and peaceful than I imagined. It’s like home. And then we’re on the bottom. A gentle landing on soft mud with lights turned on for illumination. There are legions of red crabs with arms raised ready to defend themselves against our weird metallic ship and scores of eels skidding slowly along next to them. In our fleeting hours on the bottom, we observe streams of methane bubbles, thick white microbial mats, and moon-like carbonate rocks with bacteria mats growing on them that look like thick coats of brown hair. We squeal with delight at large anemones the colour of intestines and a black urchin the size of a dinner plate. Alvin’s arm and hook-like hand, controlled by our pilot, deftly collects samples. Silvery fish with large bright eyes inspect our work, before, all too quickly, it’s time to go back to the surface again.

Georgia - Thank you for relating that - that sounds fascinating. And the thing you mentioned that you weren’t scared at all but it does sound quite scary and also quite claustrophobic. How big was this thing you were sitting in?

Wally - It’s super tiny and it only fits three adults. So there’s a pilot and he sits in the middle of you facing forward and then there’s a bench on either side of the pilot for one of the divers. You can sit there on the bench or you can lie down on it, but it absolutely is very tight and closed.

Georgia - How deep did you go?

Wally - We got to go to 11 hundred metres.

Georgia - How does that compare with how deep other people have gone?

Wally - Most of our ocean hasn’t been explored and the Alvin can go to a depth of 45 hundred metres right now. With its recent upgrades it’s really close to being able to go  to 65 hundred metres. So if it goes to 65 hundred metres, we can explore over 90% of the ocean. But right now it’s still rated at the 45 hundred metres.

The deepest anyone has gone is James Cameron, the movie director, and he went down in the Mariana Trench a couple of years ago and he went down over 10 thousand metres.

Georgia - You mentioned this submarine called the Alvin - what is the Alvin’s purpose?

Wally - The Alvin has been around since the 1960s and its purpose is to explore the ocean. You’ve often heard we know more about the Moon than we do about the ocean and the bottom of the ocean, and that’s true. It provides a really valuable opportunity for scientists to go and really experience first hand, and see first hand what the ocean floor looks like.

We have other types of vehicles that are unmanned, and they can also go deep and they can be down there for longer periods of time which certainly provide other benefits. But I think there’s nothing like actually being able to see it with your own eyes.

Georgia - I’m thinking now of when you fly on an aeroplane - it sometimes does funny things to your head with the pressure. Do you get anything like that but in reverse when you’re going down that deep?

Wally - Yeah, that’s a really great analogy to give because it’s basically the same idea as an aeroplane, just in a different direction. Sometimes I think people get kind of woosy and you can certainly, just because of the air pressure if there’s any change there. I did not notice any of that. I think the larger issue that people have is when you come up to to the surface, there’s a few moments where you’re bobbing around on the surface waiting for the boat tender to come get you to pull you back on the ship. And she’s not the most elegant ship at the surface of the water, so there’s a lot of bobbing and I think people get seasick.

Georgia - Oh no. In a cramped, three-man submarine!

Wally - Yeah. You become very close with your pilot and fellow diver.

Countless ships and planes have gone down somewhere in the ocean, and finding them is not mean feat. One such vessel was the SS Central America, which sunk in 1857. It was known as the Ship of Gold, and when it went down it had 14,000 kg of gold on board. Obviously a LOT of people were quite keen to find it, but it remained undiscovered. Until, that is, a team of people decided to use something called Bayesian Search Theory, which involves making a map of probabilities using all available data. Larry Stone from Metron Scientific Solutions was involved in this search, and he explained hwo they did it to Georgia Mills.

Larry - The way we went about this search was using this Bayesian Theory. The information available was the last recorded position form Captain Herndon, who was the Captain of the ship SS Central America, who actually went down with the ship by the way, but he hollered his position across to a passing ship about 6 o'clock at night. The ship went down at 8 o’clock. There were passing ships that saw the Central America. Survivors were recovered the next morning at about 8 o’clock. We had a position for that ship that recovered them.

So you put together all this information in this Bayesian framework and the way you do this is by quantifying uncertainties and terms of probability distributions. And then, combining the information into your probability map using something called likelihood functions and likelihood functions are the common currency of information in this Bayesian analysis. You put together all these clues, and that’s part of the trick here because the Bayesian approach is the principle approach for incorporating all the information available to you, both objective and subjective to produce a probability map for the location of the wreck. What the probability map tells you is those places that are high probability for the location of the wreck and those that are low. The high probability areas are where you want to search

Georgia - Let’s break this down. You’ve lost your favourite hat - you idiot! So how can Bayesian Theory help you find it?

Well, you know you often leave it in your bedroom so it’s quite likely to be in there. But you also sometimes wear it in your kitchen and a friend tells you he last saw it in your study. You draw up a grid of locations using all the data available to work out the probability of finding the hat in each location. Maybe taking everything into account it’s got a 70% chance of turning up in your bedroom but only 20% of being in the bathroom.

But what makes this special is you can update your data as you go. For example, another friend says they heard a rumour it was in the attic so you increase the probability of it being there. Or you search a room once and don’t find it so the probability it’s there reduces. And this is key, even if you’ve looked in a place, it can still have a higher probability than being somewhere else. So, according to your model, it sometimes makes sense to search somewhere twice before searching somewhere else.

Now, imagine you’ve got a lot more data, a lot more places to look, a few more computer processes to play with, and that’s largely how Bayesian Theory is used to find wrecks full of gold on the bottom of the sea. Speaking of which…

Larry - In the case of the SS Central America this worked out. We found the wreck and they recovered a ton of gold bars and coins and sailed back into the harbour in Norfolk. There were bands, and newspapers, and television showing their arrival.

Georgia - It’s the find of the century. Maths of all things is used to find a ship lost for hundreds of years. And everyone ends up rich and lives happily ever after…

Larry - Well, sadly it didn’t end quite that way.

Georgia - Ah. First off the old insurance companies who’d paid out when the original ship demanded, and were rewarded, in court a substantial amount of the gold recovered. And then it was up to Tommy Thompson, the team leader, to divvy up the rest between the investors.

Larry - But no. For some reason he didn’t do that. He didn’t sell the gold, he didn’t give the investors any information about what he was doing with the money. He borrowed a lot of money and finally the investors asked him to show up in court to explain what he did with the money. Instead of showing up in court in Ohio, he fled to Florida for a couple of years and was finally arrested down there, and he’s now in jail until he will tell people, the investors, what he did with the money. That’s the sad end to that story, unfortunately.

Georgia - Well, this story doesn’t have a particularly happy ending; Bayesian Theory is still used all the time in modern day search operations…

Larry - We did this, also, for the search for the Air France 447 flight that crashed on it’s way from Rio to Paris. The people in charge of that search were the BEA (the French Bureau of Enquires and Analyses) and they had, for two summer seasons, searched unsuccessfully for that wreck. Then they contacted Metron and me and said would you use all the information available from this search. Not only the last reported position of the aircraft, but the debris that drifted and was picked up, and all the unsuccessful search that was done. So we incorporated all that into a probability distribution for them and the next summer, beginning of the early spring season, they began a search looking in the high probability region of that probability map that we delivered to them and they found the wreck within one week of search. So that’s a big success story.

Georgia - Oh Wow!

Larry - It doesn’t always happen that way but it’s very satisfying when it does.

As we end our month of all things marine, we ask the final questions: what future awaits our oceans, and why should we care? Georgia Mills heard the last word from Southampton University's Jon Copley...

Jon - Our everyday lives are connected to the oceans in so many different ways. If you’re listening to this podcast elsewhere in the world, it’s actually coming to across a cable across the deep ocean. All of the internet, all of our intercontinental phone traffic uses the deep ocean. We use a lot of ocean resources, we can learn from the ingenuity of nature in the seas and, of course, our everyday lives are having increasing impact on the deep ocean as well.

Georgia - How is our ocean doing? How much should we be concerned about it?

Jon - Certainly the pressures from our activities on the oceans are increasing from pollution, from the waste that we generate, and our increasing use of resources. But there are also what I like to think of as islands of hope out there. There are examples of where our personal choices in our everyday lives have made a difference for the better.

In the UK, we’ve had the ban on plastic bags in shops and that’s substantially reduced the amount of litter on our beaches. This week in the UK, we’ve also heard there’s going to be a ban on microplastics in cosmetics and some sort of personal care products. So I think that as we become aware of how our lives are connected to the oceans and how a healthy ocean benefits us, then together we can choose the future we want for our blue planet.

Georgia - What are the biggest challenges ahead for the ocean? What is the future and what can people listening who love the ocean do at home to try and help?

Jon - I think we’re all becoming aware of the amount of plastic waste that we tend to generate. If we don’t pay attention to it in our everyday lives and an awful lot of that plastic ends up washed into rivers and so on and, eventually, in the oceans - billions of tons of it. Probably the lion’s share of it has been generated within the past decade or so.

Now people are starting to really wake up to this and we’re seeing some differences. We’re seeing pressure on manufacturers and that’s something that each of us can think about and that collectively will make a difference to the oceans for the future.