 Hello everyone and welcome to the Science Exchange series from the University of Western Australia. My name is Angela Rosson. I'm an artist and a biodiversity educator. And it's my good luck to work with scientists, which is fabulous for me because I get to learn what they're doing and I take their work out to the community and share it with children. In my work I also take young scientists out to schools and community groups so that people can connect with what's really the exciting science things that are happening right here at the University of Western Australia in the Faculty of Science. Let's get started with some introductions. I'd like to welcome our presenters, Dr Greg Schkebek and Dr Alexi Sadekov. Greg is a senior lecturer at the University of Western Australia and an expert in the field of stable isotope ecology and biochemistry. He uses these stable isotopes to trace water and nutrient fluxes in natural habitats and environments impacted by mining and agriculture. Alexi is a research fellow at the ARC Centre for Excellence for Coral Reef Studies at the University of Western Australia. His research interests cover a broad spectrum of the earth scientists with particular emphasis on past climate change, ocean chemistry and bio mineralisation. We'll start with Greg, who'll give you a 10 minute overview of how we use stable isotopes in various natural environments to record and observe changes. And then we'll move on to Alexi, who will discuss his research at using marine calcifers to investigate pollution in our oceans. Over to you Greg. Thank you very much, Angela. Thanks for introduction. So, as Angela said, I will start first with toolbox and a special tool, which are stable isotopes. Stable isotopes, which can be used for many different things, but I will focus here on stable isotope composition and how we can use this to understand our environment. So, if you will start with water and water chemistry, obviously water is just H2O, so hydrogen to collect the two atoms and one oxygen. However, if we would like to distinguish one molecule of water from another molecule of water, we need, in this case, something more. In this case, we need to understand also stable isotopes. We have two molecules of oxygen, two isotopes of oxygen, Oxygen 16 and Oxygen 18. This is allowing us to tell difference between, for example, source of water or processes which are happening in the environment. So, what is the difference? The difference is in the number of protons. One isotope has in the core, in this case, will have in this case two less neutrons than the other one. Still, number of protons is the same because this is still the same element, but mass is different and this is causing a small differences which are called fractionation. I will show you first couple examples and then go to case studies. If we will think about the cloud, cloud which is hanging above the continent, in the cloud we will have both 16 and 18 O. But because there is a difference in mass, if there will be any precipitation and rainfall, those which are 18 O will disappear quicker from the cloud and actually will contribute to the rainfall more than 16 O. Of course, both will be contributing, but in the rainfall we will have slightly more 18 O oxygen than in the cloud. So, this is called ray wave fractionation and actually this will depend on few factors and the most important are temperature and humidity and then eventually also distance from the sea. If we will think about surface water, in such case we need to think opposite direction. If we will have any puddle of water or a water hole like this one from Karogeny, you will have evaporation which will carry both water molecules, both those containing 16 O and 18 O as the vapor flux. However, vapor flux for 16 O will be slightly higher than for 18 O. Why? Because again, in this case, you need less energy to mobilize 16 O lighter molecule to the vapor phase than 18 O. This is explained by Craig Gordon model. This model is explaining how this fractionation is occurring. So, if you will think about the puddle of water, lake or ocean, doesn't really matter. What is going to the vapor phase is disappearing from the liquid phase. In this case, 16 O is disappearing quicker than 18 O. So, when evaporation is progressing, we will have finally in the residual water more 18 O than 16 O comparing to initial conditions. So, then we can basically collect two samples prior and after evaporation. And based on stabilizer composition, we can actually estimate how much water was evaporating. What we are looking for is ratio. How much is 18 O versus 16 O in water? In sea water, this ratio looks like this. This number is quite difficult to read. This is why we are using something what is called delta value. Delta value in ocean water by definition is zero. If we will have positive numbers, this will mean more 18 O than in ocean water. If we will have negative numbers, then it will mean less 18 O than in ocean water. Similar situation will be also for hydrogen stable isotope composition and hydrogen rational. So, let's go now for two case studies. I will give you two examples how this type of toolbox, this type of geochemical tool could be applied. Let's go first to Pilbara and I will show you here a couple of results for different type of research in the very arid zone where water is very important both for human as well for ecology and well-being of many different species. So, this is Fortescue River shortly after flooding by Cyclone Heidi. This Cyclone Heidi was contributing a lot. This Cyclone was happening eight years ago. Since then we had couple other Cyclones, but none of them was that large as Cyclone Heidi, which was contributing up to 200 millimeters over 48 hours. This was making many creeks to flow and this flooding which you can see here, this is upper part of Kundayna Creek, one of the creeks. The creek is usually ephemeral, it means it's not flowing at all or we have very little water in the creek. During flooding a lot of water is passing through the system, but this continuous flow stops after approximately couple weeks, sometimes couple days depending on the amount of water. So why we need to understand this? First of all to understand and apply stable isotope composition of water, we need to understand what is rainfall signature. We know this quite well because we are observing rainfall in Pilbara over several years. Here you have examples showing stable isotope composition of hydrogen versus stable isotope composition of oxygen. And you can see here several dots which are representing different rainfall events. Those different rainfall events are actually making a robust line which is called local metoric water line. So there is a strong relation between hydrogen and oxygen. Knowing this, we can actually apply this for different type of studies. What you can see here is a section of Kundayna Creek in Pilbara. You can see a few pools over here. Those pools are usually persisting in environment for several months after the last flooding to a couple years. Some of them are permanent. If we have any mining operation in this area, it's very important for us to understand which pool how long is holding water. Especially which pool is, for example, this number 6, 5, 2 or 1 connected directly to groundwater. Because if mining company will start manipulating water level, then likely this will impact pools which are connected to groundwater, but not those which are disconnected and are simply just puddles of standing water. But let's have a look on the regional scale, how we can apply stable isotopes. On the regional scale, what you can see here is flooded for the skirmish. On the regional scale, we would like in this case understand first what is recharge. Recharge means how much water from recent precipitation is infiltrating to the aquifact. Because this is our resource for future. Perhaps we would like to use this water in the future, so we need to understand what is the frequency of recharge and how much water is going there. So from our study, we know that large cyclones on average are happening every 4-5 years. We were studying about 100 years record. And we understand as well what is signature of those large rainfalls. And in this case, stabilized composition of large rainfalls is between minus 10 and 12 per million. We also know based on study of different locations, especially at mining sites, what is stabilized composition of groundwater. As you can see, there is a difference about 2 to 4 per million between minus 10 to minus 8. Why we can see this difference? This difference is primarily because of operation. So in one of our studies, we were trying to estimate how much water actually is evaporating before is recharging groundwater aquifact. We were using long term average time future for human humidity. And based on this stabilized composition, we are able to calculate that only 13 to 20% of precipitation from large cyclones is evaporating prior infiltration to groundwater aquifact. So this is quite important for us to understand that this infiltration is very rapid, very quick, but also is important to understand that it's not occurring every day. It's occurring usually every 4 to 5 years. So this will help us to manage water resources in this area zone. Let's move now to second example of stabilized application. I would like to introduce you to Neanderthals. Do you remember who are Neanderthals? This is a human species which extinct about 30,000 years ago. But really, if you are blondie and you have blue eyes, as me, from genetic perspective, you are Neanderthal up to 3% because you will have up to 3% of Neanderthal genome. But the species extinct about 30,000 years ago. So what do we know about Neanderthals? Okay, we don't know too much, but we know something. But the most important question in this case was how cold was for Neanderthals moving to Central Europe? It was about 50,000 years ago. How we can tell this? Actually, there are a few archaeological sites around the several countries which contain a lot of flint tools. Those flint tools made by Neanderthals, you can see here on this picture as a sea. And in some location, we can see also a lot of bones and skulls of animals which were how eaten by Neanderthals. So actually, those bone remains are sort of dining scarves of Neanderthals. Several of them have traces of cutting with stone tools. So investigating those locations, we actually can apply stable isotopes to tell how cold was Neanderthals. What is the process? How we can do this from scientific perspective? First of all, we need to have a good sample. The best one would be a teeth, especially LML, this glassy thing on the surface of teeth. And having this, we can eventually extract phosphates and analyze stable isotope composition, delta 18O or 18O to 16O ratio to tell what is temperature or actually it was temperature at the time when Neanderthals were leaving. So how does it work? I will show you here a quick procedure. You can see this blue cross. This is delta 18O for phosphate from mammoth bone, actually from mammoth tusk. And this is 50,000 years old. This in blue. This in red is for comparison, a stabilized composition of human teeth from medieval climatic optimum, which was the warmest period in Europe over the last 1000 years, except the current time. We can do it. Actually, we can calculate this way using a calibration curve for humans showing relation between bones, stabilized composition, phosphate stabilized composition and water drunk by mammoth. Doesn't really matter if this is human or mammoth. We need to use just different calibration curve. Actually, we can calculate what was stabilized composition available for those humans and for those human and this particular mammoth. Okay, so this is the stage number one, we can see that this stabilized composition is quite different minus 10.7 and minus 7.5. How we can relate this to current precipitation. If we will look map across the Europe, this map is showing a stabilized composition in annual precipitation sort of average. So if we will place those two samples, we can see that okay, this value minus seven is typical for more southern Europe. This value minus 10.7 is for northern Europe, but actually our sampling side is somewhere here. What doesn't tell us basically the climate medieval optimum was actually warmer than current average temperature at the sampling side. And at the same time, if we will compare this with minus 10.7 signature for mammoth, it will tell us that it was colder than currently is at the sampling location. So knowing this and having those two numbers actually we can use another relationship as well relationship which is showing us what is regression line between environmental water stabilized composition and air temperature. And we can use another calculation to calculate actually what was average mean average actually mean temperature weight by volume average for precipitation. Okay, so we can see this is 12.4 for medieval climate optimum and 6.8 for the time when the under tells we're moving to central Europe. 6.8 from Australian perspective is pretty cold because Perth would be somewhere here, but please remember we are in Europe so 6.8. It's not that cold. How we can tell this. If you will think about the under tells they were leaving lightly in the landscape like this one. Those are a few photos from Iceland, but actually wasn't that cold as is now on Iceland. Temperature 6.8 Celsius degree which we had 50,000 years ago when the under tells were moving to central Europe is actually higher than current temperature in Stockholm in Sweden or Riga in Latvia now. So it was cold. Sure, but not that cold as we would expect and initially anticipate just for macro fossil of different plants. So what is conclusion I was presenting you here a few application of stable isotopes for different research study for different research subjects. But what we can learn isotopes are extending our knowledge and extending our chemical toolbox, giving us additional dimension. So to quote Dobrzejski or actually changing his final sentence, we can say almost everything in environmental science makes greater sense in the light of the light stable isotopes. Thank you very much. We will leave questions to the second part, but first Alexei will be presenting his perspective on application on chemistry and marine environments. And yeah, thank you for introduction Angela and thank you for opportunity to present. Yeah, I'll continue on the similar path I just trying to explain how we use the chemistry in general to understand environment. And in my particular case, I'm going to present you results of how we use in the chemistry of marine calcifiers everything which build in shell to understand pollution in coastal and ocean environments. So first of all, I think it's not surprising what people are and being and always been worried about the pollution coastal environment because majority of us actually live in coastal zones. And this is particularly true for Australia where almost most of population live within 50 kilometers from the shore. So not surprising what for us is vital to keep this zone healthy and clean. And therefore a lot of efforts went into monitoring manager in this environment and preventing it from pollution. And when we talk about pollution is different types of pollution and I think we all were currently the plastic pollution is one of the hot topic. And, you know, I think just recently was a talk on through you w about plastic pollution. What I'm going to talk about chemical pollution. I mean chemical pollution mostly is related to heavy metal pollution. And I believe they are a bit more, how to say concerning for society simply not because we are kind of more dangerous or more kind of high impact, but because we're invisible and invisible means you don't see them until it's probably too late. And there are such a normal tools for normal citizen to kind of monitor this chemical pollution and monitor in this chemical pollution, even the scientific tools which I'm going to present here is quite challenging. And, of course, you know, the governments and environmental agencies been paying the tank quite, you know, quite a lot of attention to monitoring this pollution because, you know, because of that. And in Australia, for example, we have a really strict guidelines about what kind of a level of pollution and talk about concentration how much of particular element in environment allowed to be I mean it just before it's become quite harmful. And all I mean this is available information over internet the quality guidelines. And here I just highlighted couple of elements for example led but what is important that we saw numbers don't, you know, is to keep in mind the units and I'll explain details of this unit, but he all the numbers on the PPB scale this is part per billion is basically if you dissolve one part in a billion of parts. So we're talking about very small concentrations, but at least small concentrations, these elements become harmful to environment. And there's a different tools to how we monitor these things is a chem catch is kind of for reasons you put in the in the water. Direct measurements, where you just take a little bit of sample of the water and use the specific instrument to measure these elements and also buy accumulators majority of these elements basically through their life they consume this element for the natural ways I mean for the food for us Moses through the water, but they don't have ability to get rid of them. So through the time, the same as humans we do accumulate this heavy metals. And that's why we're so dangerous because there's no way to clean our body from them. And yeah, so the PPB and this is important because when you go to natural environment and open ocean environment and we're trying to understand cycles of this heavy metals in an ocean natural cycles without humans and they are present they were originate from sediments from rivers and so on, but the concentration we're talking about in a natural environment are usually in PPT scale, which is a part per trillion, this is a thousand times smaller than what I was talking about the guidelines. And why it is important because let me just go to the scales and here's a small cartoon about the scales it's a right American kind of way of taking it on a penny since one, but I have sort of kind of visualized example of that. Imagine the lake by Carl. It's a largest body of fresh water on the planet. So if you want to pollute the lake by Carl to the natural environment okay not pollute but bring it to natural environment we fled. We just need to dissolve 20 wagons, the train wagons of lead into Lake by Carl. So that's will be on natural background of Lake of the of the lead. But if we want to highlight these things in terms of pollution, and then say let's when our environmental agency will read the alarm. What Lake by Carl is polluted with lead. We need to dissolve actually the train with wagons which spun in distance, almost across whole half of Australia, just to give it to you in skin in scale. Right. So this gap between what is actually environmental agency considered to be dangerous. And what is actually not natural environment varies in different places. But it's important because there's not many tools we have to actually measure this small concentration between natural environment and natural environmental level and environmental agency kind of guidelines. So what I was trying to summarize these things in one phrase before, you know, you know what you're polluted you already polluted this area by 1000 times. So, and that's where we kind of trying to develop novel tools, how we can use marine calcifies is the organisms which live in the ocean. Corals and what I study a lot is for a minute for the small protozoa unicellular organism, which calcify will build these small skeletons out of calcium carbonate and this calcium carbonate is the same mineral as forms in your cattle is a scale basically. And good things about them when they form this scale with these shells. They also incorporate elements heavy metals from natural natural from natural water into the shells. And therefore by studying this organism the skeletons, we can reconstruct deduct of what the concentration of this element were in the natural environment in the first place. Okay, it's kind of free monitoring tools for us. But to do so we need to do of course a quite a bit of background research we're trying to understand how this organization by minerals like how we build these things. So what we do for example in this case we use culture in facilities like we have in water months where we culture in this organism in particular conditions and we spike them with heavy metals. And then we analyze them with mass spectrometry laser relation mass spectrometry. Just to give you idea here there's a small video showing what's a laser relation look like. And it's probably a bit slow what you need to pay attention in this bright sport and look at the scale is tiny is less than the human hair. This is actually a laser firing on a fragment of the shell. The laser is firing it's evaporating a little bit of the shell, and this vapor with of the shell is transferred to the mass spectrometry this mass spectrometry is instrument, which measuring different concentration of elements. Therefore, by doing so, we can calculate these concentrations and understand environment and level of pollution. For example, here is the results of our some of our culture experiments below you can see this is for a minifra which grew in the nature and when we spike it with some heavy metals and this is logarithmic scale. This is natural background and this is 10 times up of natural background. And this is only two weeks spike. So the short leaf events and only 10 times as in reach as a natural background. We can see them with our methods, which is really great improvement before we can actually not only detect the small changes environmental pollution, but also short leaf events like spills or some kind of runoff and so on. On the right scale here there's a lot of curves, but this is the record of core from the corals. So this is different elements, and particular for example manganese and barriers very, very good indicators of a river runoff. So when the river flooding in the Great Barrier Reef, for example, then these elements are carried in the open ocean and recorded in the corals. So we can see how, for example, the management of a catchment in the Great Barrier Reef is progressing through the time by just analyzing the corals which been living there, you know, for last couple of 100 years. So that's the toolbox I'm kind of presenting. So it's a use of chemicals in calcifies to understand the pollution in ocean. So thank you. And I think I'm going back to the Angela. Thanks, Alexi and Greek. That was that was really interesting and gives us some insights into your very, very elegant processes. And whilst we're waiting to hear from you, I just want to just go back to some some basics and that is, it was very lovely to have that glimpse into these incredibly elegant processes that have been developed for understanding the natural world. And I think that that's the wonder of science that no idea stands out on its own. It's built on a long history of thinkers and people who've who've started with a premises. Stuart Feinstein, the neuroscientist says of the pursuit of ignorance. And I kind of like that he's he elaborates on it when he says what we don't know is the best question to start with. And I would just like to put it to you, Alexi. More generally speaking about your life as a scientist. Can you just kind of speak to that a little bit that idea that scientists start from the point of what they don't know. And, and that's how they uncover understanding. Well, I think, yeah, there's such as an expression as a scientific mind. I mean, nothing to do with scientists. I mean, all what it means is you have some kind of internal inquiry into different questions in your life. And you know, when you go have a kids and they grow up, you already can see what some people have. Some kids have more inquiries about life. We're really interested to know how does this things work. I mean, we want to pull apart the toy or you know, dig this hole deeper and so on and so forth. So yeah, this is really basic thing to kind of understand what the scientist is. It's actually this kind of set of the mind where you can just want to understand how things work. And I mean, and of course, you know, it's not just the kind of a hobby things, you know, we're trying to understand something which is important for society. And that's why, you know, it's, it's a not a hobby, but it's actually profession. And you know, you kind of been paid by taxpayer money, hopefully by the important research. Yes, that's true. It's very true. We've had an interesting experience with COVID-19 where our policy makers, our political leaders have actually listened to science in a very real way and and taken the the advice of scientists. And it's I find it very heartening. But when you think about the amount of time that the words of scientists have not been listened to, it's possible to lose heart a little bit. And Greg, I just like to ask you, I realize this is outside your area. And as a senior scientist, you will probably most likely to say, it's outside my area. I wouldn't comment on that. But but it's it's in principle. And that is, for example, the great spill of the deep water horizon in the Gulf of Mexico, when, you know, we're looking at pollutants that are diluted over huge areas of ocean and how we address that issue. It kind of passed under the radar a little bit where everybody said, well, we put lots of detergent in the ocean. So everything's fine. How is it? Do you think that without going into the great detail more as a kind of a policy thing, how the sort of work you do can be harnessed to address something as massive as that? Probably we need probably we need to think here about two, let's say approaches. First of all, is how science is made. Because what you are talking here about COVID, for example, application of scientific advice is sort of shortcut. Usually scientific process is more complex. And on the first stage, it's much more difficult to understand. Majority of science is done by researchers like me or Alexia, and we are publishing scientific papers in scientific journals. And those are highly technical papers, difficult to understand for non-scientists. So on some point someone is taking several of those papers if they are published and confirm the findings and publishing sort of review. When is this review published is sort of synthesis of what we know on this subject. And later those reviews actually are ending up in academic textbooks. And in the final stage, eventually they are ending up in the textbooks for high schools or primary schools. But the process is taking quite a while before knowledge is very well established. So this is why eventually why very new discoveries are not applied and fully appreciated straight away by the public, because the process is taking several steps before this is verified and very well described. The shortcut for this could be a good science communication. And this is we need people like you, Angela, or other science communicators, which are giving us this shortcut directly translating those papers or those new findings for common public. And what you were mentioning about the deep horizon spiel is a very good example. And there is a sentence which is saying, dilution is not a solution. And in this case we have primarily dilution as a remediation strategy, except of course collecting some oil from the surface. But this type of research which we are doing as Alexei or me are actually going into deeper details how to record this what was happening, even this is on the law concentration. So actually those traces are always remaining in the environment one or another way. The question is how we can decode this. And of course, if the problem is more complex, we need more sophisticated methods and in such case advanced chemistry or stable isotopes are offering some solution for this. Thank you. Thank you. That brings it together. I'm just looking up here to the question here by Kiran Kimister, who says, hi Greg and Alexei, have you guys ever combined your types of approaches, for example with laser ablation, IRMS, not sure if facilities exist in WA, thanks Kiran. Well, I don't know, I can probably try to answer on this. Yes, they're not a new WA, but they've been trial to apply this kind of combining stable isotopes mass spectrometers with laser ablation people did these things on the carbonates and many other materials. But what's for Greg was talking is they were called light stable isotopes. They are different isotope systems, and we have facility in UWA to study these isotopes with laser ablation, for example, isotopes of magnesium, isotopes of sulfur which Greg was saying, this all can be done already in UWA. So yes, research is kind of in this area been done before and actually actively been done in, for example, our laboratories. Some of this type of research were done also even in 90s when we are thinking about laser ablation of silicates. In this case, the systems are directly connected to IRMS dual inlet type of mass spectrometry. But yeah, Alexei is right. In this case, we have two separate sort of facilities, but we are frequently collaborating. For example, some samples of corals which are analyzed in Alexei lab using ICPMS are analyzed also in our lab using IRMS mass spectrometry. Paige Maroni says, thank you both for such a great talk to Alexei. Is there work out there similar to yours or have you ever worked with cartons, the radula in mollusks instead of calcified materials? Yes, thank you. Thanks for the question. Actually, the cartons, it's also calcifiers. We just calcified the different thing. So yes, there been studies in mollusks in the different parts, including the teeth of the mollusk radulus, where people look at the different chemical composition of this. None of them being actually applied for pollution directly for pollution studies, at least I'm not aware, but they've been usually used for tracer for different environmental parameters, like for example, temperature and salinity. So these studies do exist and people do use these things. Maybe also interesting is that some of those materials, like organic materials, type of height, for example, in whales are analyzed also for oxygen stabilizer composition to basically trace how much time animal was spending in different type of waters with different stabilizer composition respectively to contribution of ice. We might move to sign off unless Greg or Alexi had something in particular you wanted to add? I think I specifically like the quote which you gave on the beginning of your talk. Also Yuval Harari, the author of Sapiens bestselling books, was saying that the most, the major human discovery was actually that we don't know everything. And this was contributing to the scientific and technological revolution three, four hundred years ago. Because if we realize that we don't know everything, there is a room for development, for advancement, and actually the most important part of being scientists is curiosity. Do we know everything? Can we question something? Can we improve something? And probably this is the major, major driver for majority of scientific discoveries. Well, just follow up on this similar note. It's actually interesting, there is a line in Quran about more or less similar things what the humans, we don't know thing, we just assume what we know from our experience. So we only know the world around us through experience basically. We're all scientists in some ways by studying things by exploring how it works, we kind of understanding the world around us. So yeah, I think, you know, using the different toolbox, you know, you as a member of a public, every day you observe the world and seeing crime happening, something happening here and here in the reporting. And we scientists doing almost similar things. In our case we're using chemistry and we're trying to report to community what's happening to our environment here and there. That's great. I think that's a very lovely note to end on, that science is driven by curiosity and leads to the wonderful elegance of its processes. We'd like to thank everybody who's attended today's session. A special thank you to our presenters. Thank you for spending the time with us today. Stay safe and healthy. Goodbye. Thank you very much.