 All right. Welcome to the May webinar of the NASA Night Sky Network. This month we welcome Jamie Foster to our webinar who will tell us a little bit of the story about the early Earth. But first here's Dave Prosper with an activity that you can use to engage your audience in helping tell the story. Dave? All right. So this is one of my favorite items from the Night Sky Network which is the Earth timeline. You may have you may already have this in your club. You may have seen it. It's also part of the whole on Watery Worlds banner. We're focusing again on the Earth timeline. Earth timeline and it's rather large but it's roughly about the size of the Earth's hands which I'll get to in a second. It's a very fun demo. You can set this up. It's great for the daytime especially. This actually you can fold the bottom up and which kind of lists when different life forms have popped up. Fold this up. You have to participants to sort of guess when which kind of kinds of life have evolved on the Earth. And you have a little sheet where you can cut out different sort of biological events types of creatures when they appeared and to kind of stick them up along the banner when everyone's kind of figured out where things they think should be. You can then flip it open kind of show the results as always as a prize for almost everyone. And the timeline is of course an approximation of what we understand at this time. Various discoveries may change specifics around a little bit kind of especially near the earliest section of the timeline as we might hear more about tonight. And you may notice on the timeline that there's a silhouette of a person with their hands outstretched. It's sort of the basis of how though we developed it how we kind of started. And so you can actually do the timeline with your arms if you want just as a quick sort of like a like Carl Sagan and Cosmo sort of doing that sort of demo. And just remember that it ends with filing your nails will on the scale erases all of overcorded human civilization. That's always the fun part. And I'll post a link to this in the chat as well. And that's it. And back to you Brian. All right thanks Dave. Well now for our featured speaker Dr. Jamie Foster is an associate professor at the University of Florida. And her research program is dedicated to examining the interactions between microbial communities and their surrounding environments. Whether it's stromatolites or squid, Jamie's working to improve our understanding of the molecular mechanisms that microbes use to adapt and respond to changes in the environment. Please welcome Jamie Foster. Thank you everybody. It's so wonderful to be here and I really appreciate you all taking an hour out of your time your very busy days to come listen to all things stromatolite tonight. I'm going to start sharing my screen and showing you the slides and hopefully start that process. That looks pretty good. And for those of you out there if it looks a little bit small up at the top of the screen you can change your viewing properties to make that a little bit bigger. So looks good. Thanks Jamie. Okay great. So again thank you all and thank you Brian. Thank you David for inviting me here today. So stromatolite. So it sounds like a lot of you already know what those are especially with that timeline that might be going around to your different organizations. Stromatolites are essentially living rocks, living ecosystems that that from this picture here you see this is a picture that hangs in the Smithsonian. It's an artwork done to represent the ancient earth. And what I'm going to tell you a little bit is about how they form. Where do they occur? Why do we care so much about stromatolites and why do we call them windows into the ancient earth? And if anyone is interested in learning more or has questions that didn't get quite answered in tonight's webinar feel free to email me. My email is at the bottom of this slide here presentation and you can always Google jfoster in University of Florida and my information should come pop right up. So let's talk about first what is oops sorry thought it would move it on itself. Okay so what is a stromatolite? And essentially what we're talking about are the stromatolite is actually the minerals left behind by the activities of microbes. So stromatolites are actually made by microbes and their interactions with the environment. Life is always affecting the environment and in return the environment is affecting the life on the planet. And this give-and-take this feedback system has really changed the face of the planet when stromatolites have played a role in that. And so here you can see in this photo here these are living stromatolites from Australia. They're found in a place called Shark Bay or specifically Hamlin Pool. And here's a cross section of a stromatolite and you see lots and lots of layers that are being formed. And so the microbes that have been forming these structures just lay each one of these layers used to be the surface community. And as they grew as the microbes here's a picture of some of those microbes here such as cyanobacteria. As they grow towards the sun they leave behind this structure this mineral structure. And here's just a this is a confocal microscope image of some of the sand grains this is from taken from the Bahamas actually and some of these microbes that are trapping and binding and grabbing on to the sand grains into the sediment that's coming into their environment. And we'll talk a little bit about how they form. They form these matrix as they grow towards the sun they leave behind this mineral through a process called biologically induced mineralization. So this is a process by which carbon is basically scrubbed out of their environment and turned into calcium carbonate. And through this process they've really had a big impact on the planet. And so carbonate mineralization is done in a lot of different ways stromatolites aren't the only things that can precipitate carbonate. Obviously we see shells on the shore and they are this process of sequestering or scrubbing out that CO2 and precipitating it as calcium carbonate is that is an incredibly key part of the global carbon cycle. And so this biologically induced mineralization that requires life you have to have life but it's not active it's not like a shell precipitation or skeleton precipitation it's a little different. It's where you're taking and you're manipulating the environment around you the microbes living in the stromatolite are changing their micro environment around them and forming all these very unique structures and the type of structure is dependent on what microbe is there what sugar is there and so forth. And each again each of these layers represented a past surface community and it's like a timeline going into the past. And then sometimes you don't you can get precipitation without without life present but this is the one that stromatolites use and that's what we're going to talk about for the rest of the presentation. So again what is a stromatolite these are layers of past communities and they're representing the past surface of that environment. And it's like a tree ring if you cut into a tree ring each ring of the tree is representing you know a hint or a history of what that tree went through over its history and the stromatolites can do the same thing each layer is almost like a footprint looking back into the biosignatures or in biomarkers or what was happening to that particular ecosystem at that moment in time. And again we've talked about the microbes that live on the surface that make these structures and we call those communities microbial mats. And microbial mats they're found all over the place all over the world in the modern earth not all of them make stromatolites only a few locations in the world and we'll talk about that a bit later. But microbial mats are essentially organized communities of microbes that form these very distinct layers. And here's a picture of one taken from a salt pond it looks a little different it's no there's no mineralization in this particular example but they have complex cycling of nutrients they're they're cycling carbon they're cycling oxygen and sulfur through a whole host of different metabolisms here and this is all happening within a very small region centimeters and all of these different metabolisms are working together to influence their environment specifically they can influence the pH of their environment and and shift things either towards something more acidic or shift things towards something more alkalinic and it takes a shift towards higher pH or a more alkaline environment in order to facilitate actual stromatolites to form so they need a slightly higher pH and they don't form well under acidic conditions. So what's the big deal so why should we any of us care about stromatolites I told you this they were very abundant in the past here but and here's just a picture of a modern example but why should we care and one of the key organisms that makes stromatolites that we'll talk a lot talk about a lot more are cyanobacteria and here's another confocal image showing all sorts of different types of microbes living in that environment predominantly cyanobacteria and stromatolites are important especially if we want to understand the history of the earth because they're the oldest known ecosystem on the planet that we know about and we'll talk about their age but the modern systems by studying living examples hopefully we can understand the processes that happened in the past now the microbes are no longer the same they have changed through evolution the microbes in them in the living examples today are probably not anything like microbes in the past in terms of their genetic structure and what genes they might have but the metabolisms that they do are probably ancient and we can learn a lot about how the living systems function work together communicate amongst themselves to understand how things might have originated or evolved on the past so understanding the living systems gives us a lot of information they serve as analogs to the past another important reason is these guys are little co2 scrubbers they are pulling co2 out of the environment and turning it into calcium carbonate they're scrubbing out that co2 so by understanding those processes and what are the environmental parameters so to speak what's the envelope of the maximum amount of precipitation that could happen that could also be very important to understand insights and how our earth is changing today and what are the effects of maybe anthropogenic climate change and how will that affect these traumatic reef systems and also these things are dominated by cyanobacteria which are tolerant to all sorts of environmental stress and we can learn a lot about how they're dealing with DNA repair UV stress and they can give us a lot of insights and how they communicate with other microbes within these systems so all these things together make them very insightful ecosystems to look at to understand how did life come to be on the planet now how old are the oldest trauma likes this is a bit controversial some people push it back to 3.7 some people you know say nothing younger than 3.3 or 3.4 billion years ago and I tend to use the geological term giga annum GA in terms to represent time so you'll see that on the future slides just 3.5 GA or billion years or 3,500 million years so that's kind of my safe number that I kind of throw out there of where stromatolites that are the least amount you know fossil representatives that are less controversial but there are some people that put that back push that back to about 3.7 billion years ago now that's a really long time here on this cartoon here we can just see this is the modern eon eon the Phanerozoic here and all of that on the right hand column here fits into this upper left hand portion here and that's like all all the dinosaurs land plants the rise of animals all of that happened around here the Precabian is everything else and stromatolites came very early on in Earth's history and they first formed in the Archean and we the boundary between the Hadean or the formation of the earth and then the first origins of life kind of marks that boundary between the Hadean and the Archean roughly three and a half three point seven billion years ago and these are just some times some guidelines to give or take a few hundred million years but this peak Precambian period was the when stromatolites rules the earth and they make up about 90% of Earth's history that Precambian period so what what was the Archean eon like what when stromatolites formed what did the earth look like well the big thing that was different well two big things first as you can see here in this little cartoon there weren't the continents that we think of today there would have this is the time when maybe some of the continents that oceanic crust might have been oozing out the continents are starting to form but life probably originated very early when there might have just been just these fledgling formations and the the other big factor what the Archean was like is there would have not been free oxygen in the in the environment it would have been probably enriched in CO2 and methane and probably some more hydrogen than there is now and another thing that was very different was the Sun was less luminous there's this thing called the faint young Sun hypothesis as the Sun as the Sun is aging it is getting brighter and so the the earth was probably the Sun was less luminous in the past so the earth probably relied more on greenhouse gases to keep it to keep it warm and to keep it from just freezing over but by the end of the Archean we have a very few remnants these are called kratons these are these remnants of the ancient continents that still exist that geologists study today and right around this so this is what would have what has survived from the Archean on the modern earth and these plate tectonics would have been very critical for nutrients to be cycling and moving around so you probably would have had plate tectonics by the end of the Archean so the earth looked very different from its atmosphere a lack of confidence or pronounced confidence as we think of today and you would have had to have a lot there would have been a lot more greenhouse gases in the environment but the oldest stromatolite fossils date back from this time and this is just a picture of some from australia and you can kind of see those layers and I know it kind of can look like white how do we know that this is a stromatolite and hence why there's a lot of controversy dating back to these but they're actually in a lot of these old and some of them are people's proposed that these are in fact cyanobacteria and this particular region in western australia is very close to the region that I work on today this is where the living ones are today and here's an example of a region where they were fossilized examples lit so they're very old and we have very good fossil record of them dating back to roughly three and a half billion years and I want to talk a little more about the cyanobacteria because these are so important to the the change that are the impact that stromatolites have had on the planet so cyanobacteria just as a refresher of what we call photo autotrophic bacteria that means that the photo part means where they're getting their energy from that means they're getting energy from the sun through photosynthesis and the auto part that tells you where the carbon is coming from and these guys are getting their carbon from fixing atmospheric CO2 they're just metabolizing it directly from the environment and here's just kind of a cartoon drawing of what a average cyanobacteria looks like cyanobacteria still have a dramatic impact on the planet today I live in Florida and we are dealing with a very bad cyanobacterial problem in some of our water wet areas big bad bloom happened in 2016 but they're also being targeted for biofuels spirulina supplements I have arthritis I take these and so their cyanobacteria still play a valuable role but in the past they had a pivotable role in changing the face of the planet so cyanobacteria dominates stromatolites but the key metabolism that occurs that they do is photosynthesis oxygenic photosynthesis and so the primary source of the free oxygen that you're so if you take a breath right now breathe in you have bacteria to thank you for that particular oxygen molecule most people think plants but it really is both cyanobacteria and algae in the oceans that are making most of the oxygen on the planet but free oxygen can't exist very long it's not it's so reactive that it can't hang out for very long so there has to be a constant resupply of oxygen in the atmosphere and it is so reactive that there has to be a regular replenishment if photosynthesis stopped today if we just stopped you know blocked out the sun and all photosynthesis stopped basically oxygen would be scrubbed out of our atmosphere in about two million years so I like to call it the best atmospheric biomarker as we search now for exoplanets beyond earth I would bet my house there's a webinar so there's proof of this that if we found an exoplanet with a with the oxygen atmosphere of 10 15 20% I would bet you my house that there's a there's life generating that oxygen but and hopefully someone will challenge me on that and find that exoplanet and so cyanobacteria are that rise in oxygen completely change the face of the planet so here's just a kind of a cartoon I call it rust and no rust but basically all that oxygen started to accumulate if you look at the rock record prior to around 2.4 billion years ago there's no odd there's no iron oxide in the rocks there's no of this quote-unquote rust but right around 2.4 billion years ago all of a sudden you start to see an accumulation of iron oxide in the rock record we call these the patterns this banded iron formation this is kind of patterns of iron oxide no iron oxide iron oxide it's kind of this this layered rock where a lot layered rock face here and you can get it by looking at this you can get and dating these rocks it all kind of dates back to around 2.4 billion years ago again giga anams is 1 billion years so something there is a clear rock record of the rise in oxygen right around this time that stromatolites are not only appearing but also taking over but there's a few other things that we have to think about with regards to the rise of oxygen so here again is the same little cartoon about the rise of oxygen and roughly here is where you start to see carbon fixation and the rise of stromatolite cyanobacteria fossils but you don't really see the rise it takes a few hundred million years for the for the accumulation of oxygen in the atmosphere and a couple things are happening there so what as I mentioned earth probably lost a lot of its primary atmosphere and hydrogen that would have been around during the formation of the planet probably escaped to space Jupiter Saturn they've kept their hydrogen atmosphere because they're so big but Mars earth Venus probably it just slowly lost all that hydrogen to space because we just aren't big enough to to to keep that hydrogen so as the planet is degassing carbons accumulating methane's acumen carbon dioxide excuse me as accumulating and so the secondary atmosphere or maybe tertiary atmosphere is slowly building up but as photosynthesis is emitting oxygen into the environment slowly that oxygen is oxidizing all the rocks that we just saw in those banded iron formations and basically the whole planet so you can think of the whole planet is like a sponge soaking up all that oxygen but at some point you're going to saturate your sponge and it's going to start overflowing and so that oxygen eventually after it has oxidized the cross the mantle that sink or the oxidation of the planet starts to slow down and that probably took maybe even a billion years for that process where the sources of oxygen out were larger than the sinks and eventually you start to accumulate oxygen into the atmosphere and we have a lot of evidence to about the timing of all of this again we have the banded iron formations that tell us that something really dramatic happened to the rock record around 2.4 billion years ago and we do have biomarkers these are residuals from micro fossils those cyanobacterium micro fossils that I showed you sometimes the cells degrade but a lot of times the the molecules survive much longer than an actual cell membrane so we have biomarkers and these fossils suggesting that photosynthesis probably happened a lot earlier than this change at around two and a half billion years ago so we have bio biomarkers that go back 2.7 billion years and we have things like hope anoints these are molecules only made by photo trope photosynthetic cyanobacteria and we think that this rise in oxygen enables it didn't it didn't coincide with the origin of animals but definitely have facilitated the rise of animals and definitely facilitated the rise of a whole diverse array of eukaryotes and plants and so forth and diversity of animals I should say rather than the origin of animals and we have things like sterian markers you know to to kind of get a lot of these timing of when eukaryotes started to appear all coinciding with again these increases in oxygen abundance so but that would have caused you know this rise in oxygen around two and a half billion years ago would have been a crisis for life there's a term coined by Carl Sagan called the oxygen holocaust and that would have been because oxygen is so reactive it can interact with organic molecules it can break different kinds of bonds and you it would have just started to oxidize different molecules and so it would have been a major pollution event so the cyanobacteria living in these little stromatolites really caused the first major pollution event on the planet and many species anaerobic species probably went extinct and they survived by either going deep into sediments or deep into the oceans and so stromatolites through their process through this the rise of photosynthesis and the rise of oxygen have really impacted the face of the planet and the evolution of life on earth because of this metabolism of photosynthesis now there are plenty other metabolisms in in stromatolites that are necessary to help form them and we'll talk a little bit about those later so let's talk about stromatolite formation and and again to me to understanding the past we need to study living examples of stromatolites the microbes might be somewhat different from the ancient ones their genomes might be rearranged but but a lot of the metabolism still exist that that were around for the past three billion years and so here's just a few pictures of some of the stromatolites I work on in the living examples and again you can see some of the ancient structures from the past so the living stromatolites that are found there this graph is is just showing you a few of the locations around the planet where they still form I work on two locations I work in the Bahamas and in Shark Bay these are two of the best examples of the laminated at the layered stromatolites there are many other types of what we call microbulates those are precipitation in that caused by microbes but they might have that see in the fossil record so I'm just gonna talk a little bit about some of the work that I've done from these two environments and the shot the shark Bay location in Western Australia was what was discovered in the 1950s there was a long time where people thought stromatolites were extinct and it really was until the 1950s when Phil playard playford and some of his colleagues discovered them and in 1991 it became a World Heritage Site in Western Australia and then there's another location that's pretty more accessible for us here in the United States to go visit in the exhumas of the Bahamas where they were more recently discovered in the 1980s but I'll talk a little bit about some of the work I've done in Shark Bay Western Australia specifically the part of Shark Bay called Hamlin Pool and these this is there are millions and millions of living stromatolites today over 120 that we can we guess to me and it's really the current the planet's most extensive spectacular living stromatolite system and they're just so many of them and you can visit them if you ever make it out to Western Australia and you can go take a look at these for yourself living ones so unfortunately in today's world stromatolites typically live in more extreme environments and that we think is mainly because of the activities of eukaryotes these are tasty morsels that fish and other organisms like to eat and so that for for an stromatolite ecosystem to really thrive they tend to be in very extreme environments and Shark Bay is is an extreme environment it's very hot there it's very sunny sometimes these stromatolites are spending half their day out of the water so they have to deal with UV stress desiccation high salinity Shark Bay is roughly anywhere from two to three or Hamlin Pool I should say is roughly two to three times the salinity and for us working in that environment there can also be too many snakes it's an extreme environment for us to because there's the dreaded sea snake here that if it bites you you're dead because there's only like one dose of anti-venom in the entire state of Western Australia so it's an extreme environment for all participants but how do we go about taking this gomish of microbes how do they organize themselves and how do they actually form these amazing interesting intricate structures and for me to do that this is what I work on is I want to know about the microbiome of this and of these communities and also what's happening in their environment again this give and take between life and the environment so how do I go about studying these stromatolites well first when it comes to the environment we have set up data loggers we've gotten permission from the Australian government and we've set up data loggers that have been going non-stop since about 2012 and we're constantly measuring changes in temperature salinity and the wave energy that's happening the water flow energy all throughout at all these different locations in the pool and we kind of just snooze here and put stakes into the ground and then we can just have these data loggers that we go periodically check on them and so we have always have a constant source of what's happening into the environment another more recent activity that we've been doing is we've been working with a vape charade at NASA Ames using drones to start making more highly detailed maps of the stromatolite the floor of Hemlin pool and trying to get an understanding of what type of stromatolites are where and how abundant they are and these maps can really be important guides to understanding where do we want to go and explore and help us put together some of these ideas of the morphology of some of these stromatolites and how the environment might be changing that and drone technology is a wonderful technology that I assume we will definitely be using to explore other worlds they might not be stromatolites on Titan but I'm sure the drone technologies will help explore some of the many methane or ethane lakes on the surface and other potential areas on other worlds so but I primarily focus more on the microbiome aspect the microbiology and to me the microbiome is not only the microbes that are present in these ecosystems but also the metabolism what are they doing what is their metabolic potential in these sites and also not only what microbes and what are their activities but how are they interfacing with the environment how are they actually precipitating that those carbonate molecules so all three of these I call it the three ends here the microbes metabolisms and minerals to me make up the microbiome and maybe some of you have heard about the microbiome of humans and how microbes are so important to human health and we're using many of the same tools that we use to study the human microbiome as the stromatolate microbiome and we call it omics omics technology there's genome metagenomics metatranscriptomics all these little omics tools it's our jargon for the molecular biologists to to study and look at the molecular fingerprints what are those microbes actually doing what are their genomes and what's happening how are they communicating and talking to each other and we can do metatomics for looking at the DNA the metabolites the proteins and we can look holistically at all of them together to see what are what are the patterns that we can within all these molecular signals and like Lego blocks we can put try to reconstruct and put them together to understand what were the sequences of DNA what were the different proteins that these are using to communicate and form so I kind of use these molecular toolkits and as I mentioned it we're doing an approach very similar to the human microbiome project understanding who's in the community what's the microbial diversity of that community what is what are their activities what are they doing in that environment and to do this we use what is called metagenomics we sequence the DNA of everything in the entire stromatolate ecosystem and then we look at something called RNA which is ribonucleic acid and that is actually what is being expressed that's what they're actually doing it and when they're doing it and we call that technique that omic is called transcriptomics and so we can put all of these together to start building a family tree or a map here's a really good example of what we're trying to do here this is an example of the human a map of the human microbiome but we're doing the same techniques and the same using the same tools for this project so for what we actually do for the who what when and where what we're looking at is there's a very common molecule called a it's a small subunit ribosomal RNA molecule okay what the heck is that so every organism on the planet makes well with the exception of viruses but every bacterium every eukaryotic cell every Archean all have ribosomes and these are the protein powerhouses of a cell and there's a small little piece of RNA molecule that is the backbone of your ribosome and it's it's essential it is absolutely critical to to in order for a cell to make proteins is to have this RNA molecule and so it's very conserved and we can use that molecule to make family trees of all the microbes living in that so we can look at the relationships of who is in the community and then we do a step further not just looking at one gene but we look at all the genes and we're now getting it's so cheap to sequence a genome I can sequence a bacterial genome in about two hours in my lab now and we can now start to sequence all the microbes within these communities and see how they're changing to their environment how they're changing their chemistry and then we can take a step further and start sequencing the RNA of the molecules to see okay they have all these potential genes how are they actually using them and so the big take-home messages of all these molecular tools is our three messages that I'm going to finish with for this talk first is that microbes make protective molecules and and we'll talk a little bit about what those molecules are and why that's so important for stromatolite formation then we'll talk a little bit about how microbes are they're never found or they're rarely found alone in nature and so we'll talk about how those community structures are essential for stromatolite formation and the other big thing you know it's not just photosynthesis there's other metabolisms and the waste of one is food for the other and we can learn a lot about these kinds of lessons that applies to ecology all across the board not just stromatolites so these are the three that my molecular toolkit these are the three messages that I'm going to follow up on and finish with so microbial microbes in these masks they're making protective molecules that's protecting them from the UV radiation that's serving as the glue that's holding these stromatolites together so here are just some sand grains I had in the lab and then I added some microbes from the stromatolite and in a month they start to fuse all of those sand grains together and we call that those that material that matrix exopolymeric substances it's the glue that's basically keeping those microbes together in that environment from hang on if you've got a wave coming and crashing on top of you and potentially the tide taking you out if you don't hang on to your environment you are lost from that ecosystem so it is so incredibly important for you to hang on stay in your community stay in your stromatolite and and create these these matrices these biofilms in order for you to to hang on into the stromatolite and they also serve as food it is sugar and so again the food of one is is the waste of another product these guys are making these sugars and helping feed their their their neighbors and in return their neighbors are making molecules that they can use for their own metabolism so again these protective molecules how they function in stromatolite formation is so you have all this gooey material the sugar material and it is literally here all the green here in this little picture here is that glue is that EPS that sugar material and the microbes are the cyanobacter in this case here's a light microscope image and here's a confocal image they're trapping them binding their adhering to these sand grains and producing all this EPS material and this EPS material the sugar is actually the nucleus of where the mineralization happens so it's happening outside the cell and here's just a picture this is what we call a thin section of the stromatolite and here's one of those layers being actively formed of how the carbon the calcium carbonate is starting to form and here's just kind of a little image here taken from this cross-section of the stromatolite and wherever you see these blue lines that's a layer that was formed inside that EPS material and then again that lithophies and hardens and the microbes living in here they just move ever ever closer to the sun and so again that's how we form these lamination and again each layer used to be a form of surface mat where that trapping and binding and all that EPS material is happening so again it takes a community we just talked about that 16S RNA gene how it's found in all organisms in bacteria and archaea they have what's called the 16S RNA eukaryotes we have what's called an 18S so we all have to have this essential ribosomal RNA molecule and we can construct trees or family trees from that information so this is a huge advantage because every living microbe or cell has this on the planet so we can reconstruct trees but if we just work with the DNA we don't know what's active because the DNA is a genetic blueprint it's the architecture for the whole cell but it doesn't tell you what's being expressed or what's being turned on at any given moment so that's why we also like to work with the RNA and that is like taking a snapshot a photograph of the activity of what the cell might actually be doing in the cell and so we can sequence those those express genes just it can be the 16S or it can be other genes as well and then you're able to actually see what what microbes are metabolizing what are they actually what we call transcribed what are they actually making and so when we do that I'm not going to go too heavy in the data but what you see here is it's not just one cyanobacterium or two cyanobacterium it is a very diverse community of cyanobacteria and other microbes present within these communities and we can create spatial profiles we can we can use our molecular tools and with a scalpel kind of literally reconstruct the microbial organization the spatial organization happening within these microbial mats and look even further of who might be the most important cyanobacteria in that community who's metabolizing the most in this case it's it's a relative of this guy called Seneca Caucus because these are circles have to do with relative abundance but what I wanted to show you is that we can use these toolkits to look at the activity of the different microbes within the stromatolite and reconstruct their metabolisms over time and when we do that basically what we can do is reconstruct yes photosynthesis is a major metabolism but it also takes other metabolisms like nitrogen fixation and oxygenic photosynthesis sulfate reduction denitrification all of these different metabolisms happen and by looking at when they're expressed we can see whether they're happening during the day or when they're happening at night and some of these metabolisms like photosynthesis help increase the pH and that helps promote percarbonate precipitation therefore promoting stromatolite formation whereas some metabolisms are actually being enriched at night and some metabolisms if the arrow is pointing this direction that decreases the pH so there's a constant pendulum that's happening in these environments going oscillating between high pH and low pH and it's the net productivity of these communities that determines whether or not you you get precipitation or not not all like I said microbial mats make stromatolite so it has to be a part of the environment is having a very big part so let's put all of these ideas together again stromatolites are so important to help us understand how life and the environment co-evolves how does all of this microbiome and how does all this environmental all our data loggers and all of environmental conditions how do they fit together and so all of these environmental conditions are feedbacking with the microbes in the community what does community composition mean for the environment what does the metabolisms mean they're creating micro environments and they're changing the environment which then might impact how many microbes could actually colonize on the surface and for mineral productions so all of this give and take the microbiolite the environment is maybe creating substrate that mineral structures can can attach to and all of this give and take affects the net production of whether stromatolite forms or disassociates and so together this production of stromatolites we call that the alkalinity engine this metabolism that are driving precipitation and but that organic matrix is so incredibly important that glue that's holding everything together because that can facilitate where the mineralization actually happens so that's I've given you a lot of information about the big picture of how stromatolites form but it's really this give and take between the environment constantly going back and forth with life and stromatolites have been around for as we've seen hundreds of millions of years they've seen 400 parts per thousand CO2 they've seen 10,000 parts per thousand PCO2 so by understanding how they react to these different environmental conditions will be a very important insight into how maybe other ecosystems or other other microbial ecosystems are going to adapt to an ever-changing atmosphere and ever-changing Earth and there's always speculation that there might be more stromatolites out there I don't know if they're ever you know Europa Titan and Salad is probably too far away for a photosynthetic driven system but I have seen microbes living in caves as with as low as with just hints of photosynthetic energy making their living through photosynthesis so I don't cross anything off but there have been some people who have hypothesized this is really just a hypothesis now that maybe some of the structures they're finding on Mars they call them microbial induced sedimentary structures on Earth anyway maybe these could be more morphologies that serve as a remote biosignature and maybe some some of the images that people have seen on Mars could be stromatolite like or microbialite like but this is I would not go out on a limb and say these are fossil stromatolites but I definitely think that the exploration of Mars is probably one of the best places to look elsewhere for stromatolite like morphologies because Mars and Earth had very similar origin stories so maybe someday Mars curiosity rover some of the other Mars 2020 missions might bring back some more smoking gun images to suggest these might actually be stromatolite like fossils but I just want to thank a lot of people this is my my collaborator Pam reading University of Miami who's helps me with a lot with the geology and of course all my graduate students that do a lot of the microbiology work and NASA for supporting me for a lot of this research so I'm going to open it up for questions and thank you so much for your attention and hanging in there throughout all this molecular stuff all right well this is really fascinating it really truly is an integrated science you have all kinds of different things there's geology there's atmospheric science there's biology chemistry you know a little bit of everything so who couldn't love stromatolites but it's the epitome it's the poster child for me for as astrobiology because it is so integrative and inherently multi-discipline that any I think we're all astrobiologists in some way but definitely if you work on stromatolites yeah well we've got a number of good questions here and and so I apologize we're not going to be able to get to all of them in all likelihood but we'll see if we can combine some of them so that we can get to as many as we can if anyone doesn't get their question answered feel free to email me okay great I'll actually leave my email up here that's that's fantastic um so well let me start I ended up here at the at the almost the bottom so Barry asked are there more or fewer stromatolites today than in the past definitely fewer um from the fossil record of what we see and where we see them uh basically during that pre-cambrian that really long period of time around five you know from the form formation of earliest life to about 500 million years ago stromatolites were probably a dot the dominant type of ecosystem on the planet so uh they probably were much much more abundant than we have today okay so uh Jay asked and this is an interesting question you alluded that they were kind of the these uh small layers and uh using tree rings we can get an idea of changes in the environment over time without knowing what the time span is involved with us uh can you get an idea of changes over I guess the life of an individual stromatoline yes you could go in and look at the you might not be able to get cellular fossils but you could probably you can definitely get bio-biochemical fossils going through and seeing what maybe the environment was like um on how when and how these minerals precipitated you can also get information I didn't talk about this at all but using what's called isotopes stable isotopes um life tends to prefer carbon 12 over carbon 13 there's an extra newton neutron and some carbon molecules and that ratio between carb the heavier carbon and the lighter carbon gives you a big hint on the metabolism photosynthesis isn't too particular it will tends to use up more of the carbon 13 so those ratios can look different from something that group heterotrophically or more or using chemical energy rather than carbon dioxide so um so you can get use use isotopes to and and within those carbon molecules within those organic molecules to help guide you with what metabolism might have helped create or we even maybe what even sugar was present by what microbe in those communities so you can really reconstruct the past within these layers so Gordon asked an interesting question and it kind of maybe speaks to the the fact that these termatolites have seen all kinds of concentrations of CO2 and so he wonders if the increasing concentration of CO2 somehow is is helping maybe increase instrumental formation well in some ways he might be right because there's what's called a molecule called rubisco and rubisco's found in all sorts of plants and they actually have their peak activity roughly around 1200 car CO2 parts per million so for it is conceivable that this might actually help them produce more and have increased their photosynthetic rates but after 1200 it kind of seems to flatten out and there's no real added value of more CO2 for these ecosystems but like i said they've been around they've seen it all and and i would be really interesting one of the projects that i've also been working on is how do you break instrumental like can you actually change the pH or change the environment to to inhibit this precipitation and so that's an avenue i've been kind of looking at as well so that's an interesting question about you know you know maybe you've meant it in a in a different way but um it kind of made me think stan asked the question here what do termatolites feel like they look kind of like rocks but they're kind of like look like mushrooms are they soft you know you you said that they're difficult to break and maybe you meant that in a different way oh i meant break and instead of disrupt the process oh how do you stop extrematolite formation that's what i meant but to get to that question is they are you can stand on them and in fact in some of these protected sites we have to protect people from standing on them um and because uh we they are you know these relics of the past so to speak but no they're pretty tough um you can you the the the softer part is just that top or up layer maybe it's only a centimeter long and underneath it's really hard limestone essentially it's just limestone rocks and made by back live by bacteria so you can they're pretty tough they've had to be to survive so many billions of years and so i guess that brings up uh david asks are these are the pools in Australia are they monitored by on-site scientists continuous monitoring to make sure that people aren't potentially damaging them how often the scientists visit them there's a continuously or seasonally monitor well we're trying to do a continuous monitoring we've gotten permission from the Australian government to put out our data loggers and we're working with an organization called the bush heritage organization in Australia as bush heritage owns um a wide range it's kind of like the nature conservancy for here in the u.s and we're working with them because they own um the what's uh the station it's called hamlin station and it's we're hoping to build a little research station to to work there um but there's a a wide range of of Australian researchers that work there so there's quite a few different groups there's researchers from woods whole university Connecticut other people who are working on these ecosystems and we want so for a long time the Australian government kind of treated it as a must mausoleum they just didn't let anyone take any samples and they wanted to protect it at all costs but hamlin pool is at high risk of seat for sea level rise and that hypersaline that unique hypersaline environment um is threatened by sea level rise and the flooding of regular seawater into that area that could completely bring in eukaryotes and cause the system to to fall apart so Australia has become much more open and to inviting more researchers to study it and um it's kind of unfortunately dependent on how many grants we can get and who will support the work but we're also looking at them as indicators for heat waves i don't know if you're aware of heat waves that has devastated the Great Barrier Reef on the other side of Australia and other parts of the world and so we're looking at them as indicators potentially to understand ecosystem health and so we are working very hard to try to get funding to keep monitoring these systems but right now our data lovers are at least in monitoring the environment and hopefully we can keep monitoring the microbes as well and their health okay this this i think is related and jeffrey's got a couple of different questions here and i'm going to see if i can you know somehow or another combine these he noted that uh he he read that shark may is perhaps and this might speak to a fluctuating sea rise and you know the sea level is far different now that it was 10 000 years ago and so he read that shark pays less than 10 000 years old um and how would the bacterial community find and colonize this and and i think that there is a way to relate this because any also notes that this was the major ancient habitat um but it didn't look like with the archaea and land masses that there weren't a lot of shallow habitats so and actually you know with sea level rise there might be more shallow habitats on the edges could be the new stromatolite was preserved you know so there's what was called the tethy sea you know a few hundred million years ago the there were the pretty much multiple north america would have been a shallow sea so there over time has been a lot of opportunities for shallow um areas to form and these to live they can live um we find them all the way down to 60 feet 30 meters maybe 20 25 meters so they can go pretty deep and you can get these actively forming but but true most of them are actually most of them are in the intertidal zone but yes there probably has been a lot of change but and opportunity for them to form in the past there probably were many shallow areas like i said north america was at one point mostly a shallow sea for a good chunk of time called the tethy sea so uh Jeremiah is um i you alluded to a couple so i think you might have seen these he's very interested in where we could you know potentially find these and you would alluded to cave systems and uh you know whether or not somebody could just casually come upon a stromatolite or or maybe even expand that if stromatolites are microbial mats and so you know how common are microbial mats but you know maybe we don't have stromatolites uh uh as often but maybe there's more opportunities just to see absolutely community absolutely so um stromatolite are what are called microbialites so i've just focused on stromatolites because they're kind of the poster child from microbialites but there are many types of microbial mats that make these carbonate structures they may some look more called others called dendrolites and there's some called leolites and and so they're formed all over the place and actually there's some that don't for carbonate they're formed silica or they're gypsum based um and that's all through south america and the chilean um bolivia and um argentina area there's quite a few so my my microbialites are actually quite common in a lot of different places around the planet and we're more keep being discovered all the time there's some in the pacific atolls and caribati there's some in south africa uh there's some in pavilion lake and freshwater ones in mexico so um there's some all over the place but that beautiful laminated structure that's a little bit more rare but microbialites in general are found quite often in microbial mats even more microbial mat is just essentially a bacterial biofilm but it's so thick that you can start to get um cycling of nutrients and and these more stratified layers to them i think i had a jar with one growing in at one hour yeah you probably don't have my microbial mats somewhere in your fridge well let's go with one more question here and we're right at the top of the hour now and so diane asks uh do stromatolites have a direct impact on human health and you know we might even think about you know uh indirect impacts and and and if maybe you want to make some comments about um you know how studying them can help us to understand uh our ability to you know have health as humans so i haven't published this yet but we started looking at the metabolites that stromatolites use and more than three quarters of them are unknown metabolites things that have never been found before so i think that there could be a lot of what we call natural products or natural materials that are being produced by these microbes that could be potentially used uh maybe there's new antibiotics maybe there's new um uh different pigments or sunscreens that could that could might potentially be used for human health and also just how microbes talk to each other what how are they communicating what cells what molecules are they using um uh and how are that what are their defense mechanisms so there is a huge black box associated with stromatolites we are just totally scratching the surface with our understanding of the the molecular the biology associated with these guys and we call it as you guys will appreciate this microbial dark matter it's not of course the astronomy dark matter but it's all this unknown material and even in our own genomes we only know what maybe at most you know half of what our genes do so we have such a huge frontier of exploration there just even here on earth and with these stromatolites so i think the stromatolites represent the epitome of the past understanding the past the present with climate change and maybe the future of helping us out of these messes that and helping human health so i think they're there for the past present and the future of for for life on earth all right well that's a great way to end up with looking at the future here so thank you so much that's uh absolutely wonderful so thank you for joining us jamey this is a very insightful thank you guys thank you again for your time so all of you uh you can find this webinar along with many others on the next guy network website in the outreach resources section each webinar's page also features additional resources and activities and you can find links to uh jamey's website and to her papers there as well we also post tonight's presentation on the next guy network youtube channel in the next few days