Kerry: Good morning, we're coming to you live from NASA Ames Research Center in Mountain View, California. We'll be talking about the Mysteries of Microbes -- Fascinating Fieldwork. This broadcast has been brought to you by NASA Quest and NASA's Astrobiology Institute. My name is Kerry Littlejohn, and I'm a member of the Educational Technology Team here at NASA Ames Research Center.

We will answer questions from the chat room near the end of the program, so be sure to listen for your answer. We are happy to have as our guest Dr. Brad B. Barrett, astrobiologist, biochemist, marine microbial ecologist, and Mary Hogan, astrobiologist here at NASA Ames Research Center. Thank you for joining us.

Mary: Hi, Kerry. Nice to be here.

Back to Kerry.

Kerry: We have a slide about what we will be discussing today. May we show that slide?

Today we will review the scientific question of the Microbial Mats investigation that was done during the Baja field work, and we'll describe the types of organisms being observed and studied, and what is done after each investigative fieldwork, and Mary will discuss the Winogradsky Column results and conclusions.

Last month, Dave explained the importance about the procedure in data collection and the scientific inquiry process. Brad, could you please review the scientific inquiry process and provide some examples for us?

Brad: Sure. What we are going.

Kerry: We have a slide for that, too, and you can discuss each point on the slide.

Brad: Yeah, if we could go ahead and show that first slide.

What we were going to do is discuss the data collection results and some of the conclusions using the example of the field trip that we've just come back from. We were in Baja in October, so what we are going to use. We are going to use that field trip as examples of some of these kinds of things.

Kerry: Mary, what if long-term studies are needed? I'm sorry.

Mary: Actually, I think we were going to talk about why we got to Baja.

Kerry:: Oh, yeah. Why do you go to Baja?

Mary: That's all right.

Kerry: Please review why you went to Baja?

Mary: Okay. We've found that there's an area there that has developed a living nice bacterial, microbial community, and I've brought a couple of slides, so if you can bring up the first slide, it will just show us.

In this slide, you can see in the upper left hand corner is a map, and in that map, in the upper right hand corner of that is showing the border between the United States and Mexico. On the left hand side is the Pacific Ocean and traveling down between those two is what's called the Baja Peninsula.

The Baja Peninsula is separated from Mexico by the Gulf of California. And we traveled about half way down on the Pacific side of that peninsula to kind of a cup shaped area, and that's where our field site is located. It's at the end of the arrow there. And that's a coastal the lagoon, and if you look at the right-hand side, there's a satellite image, and that's showing you the Pacific Ocean up in the left hand corner and then as you look at, we go there. There's the world's largest salt manufacturing company is located there. And they've developed this series of ponds that take water in from the Pacific Ocean and they pump it in through this series of ponds.

They've diked these ponds off, and as you travel from the ocean up through the series of ponds, the salinity increases. It's a very high wind area and high temperature, so it's causing evaporation and as you travel up through the ponds, the further you get, the salt increases until it finally precipitates out and they collect the salt.

And what we do is, we work mostly in that bright green area in the lower right hand corner, and there's a large pond there that we like to work in most. And as you can see, in the bottom left corner, there's a photograph of some vans.

So, if we can go to the next slide, we drive the vans out on roads that separate the ponds one from the other, and we mostly work in the pond that in this photograph is on the right-hand side, and, in the van, we bring out all equipment and all the sampling items we need and we’ll take water samples and microbial mat samples.

The microbial mats glow in the bottom of this pond, and this pond has the salinity that's maybe three times the salinity of sea water, and with that, we've got higher salinity. It very discourages the growth of larger organisms, like worms or snails that normally would feed on the bacteria.

So, without organisms larger than those that would be there feeding on the bacteria, nobody's there to eat them. They have this great chance to grow and really flourish, and so, that site's been chosen because the large microbial mat community has developed there over the years, and not too many large organisms are there to disturb them.

Kerry: Great. Brad, please briefly discuss what was done during the Baja field work and how did you collect the samples?

Brad: Okay.

What we do when we go down to Baja is we do a lot of our sampling work actually under water. If I could go to the slides, I'd like to show you a couple of pictures of what it's like to work underwater in the Baja system.

Okay? So this is a couple of divers headed out to one of our flux chambers. Dave mentioned flux chambers during the last webcast. If we could go to the next slide, we basically use an acrylic box made out of a kind of plastic.

If we could go to the next slide, please.

Here's a diver sampling from one of our acrylic flux chambers, so this is a box that doesn't have a bottom that we put over the microbial mat, and as Dave mentioned in the last webcast, we basically see what that microbial mat does to the water that's inside that flux chamber. We take both water samples and gas samples.

If we could go to the next slide, it shows a close-up of the divers sampling gases from that box.

And you can see there are some motors on the tops of the boxes that are used to stir the water inside the box so that we have conditions that are similar to those that exist outside of the box in the pond.

Kerry: Oh, thank you. Mary, what longer-term studies are needed? What do you do?

Mary: So, usually, we do need longer term studies, and you can look at that in two ways.

What we've been doing over the years is about every since months, we drive down to Baja, and we stay there for two weeks, and that gives us data and information on those two weeks and every six months. But what we like to try and do is see, could we look at it day to day over a number of months, so what we've done is, if we could go to slide. I don't know if it's the next one; I think it might be number 14, so if we could go to that slide, it would be great, and if we can't, I can just talk through it.

Mary: Okay. I'll wait a minute and see if it comes up.

Brad: Keep talking.

Mary: Okay, well, they might come up, but what we've developed is a flow through incubation chamber system. Okay, so go back one slide from there. That's where we are. Thanks. Sorry about that.

Picture of scientist working with mat

So what we've done is we've developed here at our research center at Ames in California, a flow through incubation chamber system and we need to bring mat samples back from the field to put them into that chamber system, so here you see in the background is the van. We've driven out to the field site.

Someone has swum out into the pond and gone down to the bottom and cut out a piece of mat, and the mat is an even stronger consistency than Jell-O, where individual organisms are, excrete different types of [exopolymers]. They're kind of slime and it holds them together really well.

So we cut out a piece of mat and we trim it off and, if you go to the next slide, you can see that

we've made small plastic trays that the pieces of mat will fit into, and these pieces of mat fit down into that tray, and we just want the surface exposed, and if you go to the next slide, we.

Once those pieces of mat -- we collect quite a few number of them -- once, those pieces of mat are in the tray, we'll add what we call plastic edge pieces, and, basically, they're there to hold the pieces of mat down into the tray.

If we go to the next slide, you can see. This is the inside of our cargo van. We've taken those plastic trays full of mat, loaded them up into larger plastic boxes, and put them into the cargo van. We then drive a day back from Baja. I'd say it takes two days to drive back, and they do pretty well. We've got them sealed in there, and we make the drive back, and, then, finally, we can go to the next slide and we arrive here at our site.

We have a greenhouse upon the roof of our building here at Ames, and in that greenhouse is our flow-through chamber system.

You can see in there that these are the pieces of mat in their trays. We've now put them into the flow-through chamber system and seawater is flowing over them. It's water that we've brought back with us from Baja, and it's going to flow over them continuously, and we now have here with us samples that we can work on.

So, the longer term studies we can work on them day to day. We can take samples. We can also, if we want to, try alternating conditions. Maybe increase the light or decrease the level of a certain nutrient that's in the water that's being disbursed into the mats.

Kerry: Great. Brad, what was done following the investigation when the samples were brought back to Ames Research Center?

Brad: Okay. We actually have a video that we brought along to show a little bit of what happens to the mats once they're in the in greenhouse, so if we could just start that video, I can show you some of what happens in the greenhouse.

This is the greenhouse on the roof of our building, and the camera is zooming in to show basically the flumes that Mary just talked about. In those flumes, we have water running over the surfaces of the mats. Here are the mats. Each of those channels holds a different set of mats. You can see the effects of the flow on the stuff that's moving around. Those bubbles there are produced by photosynthesis, so those bubbles contain mostly oxygen, some other gases, and you can see the things kind of moving around in the flow there.

Now, what we do is we have an XYZ positioning table, which we use to make measurements, basically, anywhere over the surface of those mats, and so, here I am bolting an instrument onto the instrument package which can be moved around to any location on that whole table.

The thing I was bolting in there is a fiber optic flowometer. Here's the table moving down and what you're seeing here is the readout from an oxygen microsensor, which shows you that basically for very little movement that you make in a vertical direction in this mat, you can have huge differences in oxygen concentrations. We've only moved about a millimeter here, and yet the oxygen concentration has jumped almost five fold.

Here is the machine coming back up out of the mats and getting ready to go to a new location on the table. We have this all automated now, and it's available to members of our team over the Internet, so that any member of the team can call up this package of instruments and get it to move to whatever location they'd like to make a measurement.

You saw a field of holes right there, right in front of the sensors, so there's some measurements that you need to actually take a sample out of the mat. Here I am taking a sample that's already been cut out using the piece of tubing,

and I'll pulling it out of the mat and what I wanted to do with this piece of mat is to just show you what some of the organisms that are inside the mat. Some of you might not have access to microscopes, so what I wanted to do is show you just a quick view of some of the organisms that are living in this mat, so from this section which I'm taking now, and we'll show you a cross-section basically made in exactly this same way.

Right after the video, we've got a little demonstration, but this is what it looks like under a microscope, starting from the top of the mat and moving down.

These are all of the various kinds of microorganisms that you can see in there, and you can see that there's a very high density of microorganisms.

There's things living right next to each other. At the very surface, these are diatoms, so these are [eucariotic] algae. You can see that they're moving.

Most of the organisms that live in the mat are able to move around, adjust their position. These are what we call unicellular [cynobacteria], so they are composed of single cells. This is a [filamentis] cynobacteria. The single cells are strung together in filaments. And then this is, running from left to right, the colorless sulfur bacterium over a sign of bacteria, and this is very hard to see even on our monitor here.

But that's a purple sulfur bacteria cluster down in the lower section of that,

so those are the kinds of organisms that we can see in our microbial mats when we look at it under the microscope.

Kerry: Okay. Well, so you have a demo for us, don't you.

Brad: Yeah.

Kerry: This is great.

Brad: It will take just a second to set it up.

Kerry: Okay. Brad is setting up the demo now.

Brad: Okay, so, what I've brought along today is just an example of the kind of equipment that we would use in the laboratory to make the same kinds of measurements that you saw on the greenhouse, so on this table here, we have an oxygen microsensor. That's the black thing in the very middle and I have a light which is shining onto a cross section of microbial mat, and if you could show a close up of that mat.

Oh, perfect. This shows the laminated nature of our microbial mats, what they look like from the side, if you were to make a cut exactly like the one that I just showed you in the video, and the little tiny sensor that you can see on the very center of that mat is an oxygen microsensor that has a sensing tip that is on the order of a few micrometers across. And the reason that I brought this in is to show you basically the kinds of equipment that we use and also the fact that for very little movement of that oxygen microsensor, we can get into zones of oxygen concentration that are either very high or very low, with only moving the microsensor about a millimeter.

In order to make these kinds of measurements, we need to move these microsensors with the precision of about 250 moves per inch. So, in one inch of this microbial mat, we would make about 250 measurements, and we would see different things every time we moved the microsensor. So, this is just some of the kinds of equipment that we use.

Kerry: Oh, great. What do the scientists do with the data?

Brad: Well, we're extremely fortunate in having a team of researchers at NASA Ames lead by Rich Keller, and his team is called Science Desk, that are actually helping us to design new and better ways to deal with the data that we bring back. I have just a couple of slides about that, if we could go to the slide about science organizer.

Rich Keller's team has put together a Web-based repository of information which we can all access. Any member of our team can access and, basically, we go to the field. We take a whole bunch of measurements. We all go back to our various labs and then we have data that we've collected in the field, and we have data that we generate in our individual laboratories once we get back.

Science organizer keeps all of that in the central location, which is accessible over basically a Web interface, so if you could go to the next slide please.

I don't expect that you'll be able to see too many of the words here, but, basically, what I wanted to convey with this was just to show you that the way that Science Organizer works is that we all have browsers that connect to this program that's been written by the Science Desk folks and just by pointing and clicking, we can link items. We can upload and download items. We can assign links to various portions of data and that data is all available to any member of our team, so that's what we actually do with the huge amounts of data that we bring back from the field.

Kerry: Great. Will you provide an example of a conclusion you may arrive at during a specific investigation?

Brad: Sure. One of the things that we found out on our last trip, for example, is that while it's a great thing to take these boxes out to the field and put them over the environments that we're working in, one of the things that we can't duplicate with those boxes are some natural density variations in the water that's in the ponds.

So, what we found out on our last trip using a device called the micro-electrode lander, is that there's a lens of very salty water at the very surface of the mat, which we just can't simulate in our boxes very well. That lens of very salty water is responsible for changing the conditions of the microbial mats so that they don't actually experience the same kinds of conditions that are in the water column itself. So, one of the things that we found out by making measurements in the field this time was that we really can't simulate everything in these boxes. We need to go out and use our microsensors really right at the field site.

Kerry: Great. Let's check to see if we have questions from the chat room, and we do.

Mr. Diego's class asks, are any of your hobbies related to the type of work you do? Mary?

Mary: For me, I love to swim and I've done some scuba diving, so that kind of hobby has gone right along with our work. As far as right down into the dirt, my father always said I liked to dig in the dirt, so I'll just leave it at that.

Kerry: What about you, Brad?

Brad: Yeah. I actually got into marine sciences in the first place by scuba diving, and I got so interested in scuba diving that I actually changed the school that I was at and went to a school that was a little closer to the ocean so I could scuba dive more.

Kerry: Wow. Mr. Johnson's class asks, what were your favorite subjects in school? Mary?

Mary: I always enjoyed science. I have to admit, though, I really enjoyed history as well, but science was, I think even if you read my bio, science was a fun class because right through grammar school, I had science classes, and it always just seemed to answer the questions of how do things work and what was going on, and I was kind of nosy, so any answers that I could get came from science class, and that was fun.

Kerry: Great. What about you, Brad?

Brad: My favorite subjects were also in science. I had a little bit more trouble with the math. Math is absolutely necessary for the science courses that were fun to me, but I had a little bit more trouble with the math in the science courses, but any kind of biology course was really exciting to me.

Kerry: Okay. Mrs. Taylor's fourth graders ask, Dr. B. Barrett, how deep have microbial mats been found in the ocean, and do they only live in shallow water?

Brad: Microbial mats, as far as I know, have not been found in the deepest parts of the ocean, but the kind of mats that you may have heard about at the deep sea vents are found in rather shallow parts of the ocean, because as vents are found on mid-ocean ridges, mid-ocean ridges are one of the most shallow parts of the ocean basin. So, the ones that are formed at thermal vents are actually rather shallow compared to the average depth of the ocean, which is around five kilometers, I think.

Kerry: Great. We have one other question. Mr. Diego's class asks, let's see, what special conditions must you maintain in the greenhouse in order for the mats to survive? Mary?

Mary: There are a number of things that we've tried to control. Number one is just the temperature of the greenhouse that the incubation chamber system is in. Then we maintain the temperature of that water in that exposure system. We also try and maintain the pH of that water, the salinity of the water in there, and right now, we've got it set up where there's six flow-through chambers. Three of those are under on set of conditions and three of those are under another set of conditions, and that's just one of the nutrients. Sulfate is at one concentration in the one set of three and at a higher concentration in the other set of three.

So, basically, those are temperature, light, and nutrient concentration. Right now. There may be other things that will change at a different date, but right now, that's what we're controlling.

Kerry: Great. Mrs. McDonald's class asks, what role models inspired you to pursue your career? Brad?

Brad: Oh, gosh. I guess that probably my biggest role model were my parents just because they told me to do what it is that I wanted to do. Aside from that, I liked a lot of the biology class teachers that I had in high school, and I think that probably I liked working with them enough to make the subject more interesting to me.

Kerry: Great. What about you, Mary?

Mary: I was working very similar. My parents were a big influence. My mom always, again, said try and do and find something that you'll like, that you'll be interested in, and I was always interested in sports, and especially outside sports, so I tried to find something that would let me work outside, at least part of the time.

Kerry: Digging dirt.

Mary: That's right.

Kerry: That's great. Brad, do you and your wife ever work on the same project together?

Brad: Oh, gosh. Hard question. Lee and I have been working together since about 1986, sometimes with our desks so close together that it was like working like this. I think that we do very similar work, and over the years we've worked on the same projects many times. I think that right now, we're tending to work on slightly different field sites, so we do very similar work, but Lee's work is primarily in the Bahamas with mats that are forming [stromatolites], so they're mineralizing mats. They're precipitating minerals, and I've been working in Baja more, so we do very similar work. We are working at slightly different field sites right now.

Kerry: Oh, how fun. The Bahamas. Okay. See, Jeannie has a question. Are microbes in all of the layers of the mats? Brad.

Brad: For me. Yeah. So, what you see when you look at the layers that I just showed you on camera are, you see lots of layers that are probably formed over time by wind events, we think, and so what you see there is probably microbial mats growing on top of microbial mats.

Only the top millimeter or so is going to be active in photosynthesis and that photosynthesis is providing the organic matter that basically is in the rest of those layers. So, it's a little deceptive when you look at the Baja mats, because each of those layers does hold different kinds of organisms, but those organisms are not necessarily doing what it is that they were doing at the surface.

So, what you see is that there is a separation of the microorganisms that are living in the different layers, but that separation does not necessarily correspond to the colors that you see in these mats, for example.

Kerry: Great. Mary, why do you study microorganisms on Earth? How are they important to finding life in the universe?

Mary: I think our beginning answer to that would be that we only know about life here on Earth, and so, for the longest time in Earth's history, the most abundant and widespread form of life was bacteria, so we're just trying to find out as much information as we can from bacteria of today, and we're seeing if we first can relate it to bacteria of the past because that was the most abundant form of life in Earth's history. So, if that's the one that has been here the longest and figured out the best ways of living here, maybe that will also be what we'll find as life on other planets, so let's learn about what we know and what we can find out, and then maybe be able to move that information to investigate life elsewhere.

Kerry: Great answer. Andrew would like to know what kind of microscopes do you have in the lab, Brad?

Brad: I have a very nice microscope I was fortunate to inherit from the last guy in the lab, so I have a big Nikon microscope with [Neumarski] interference contrast, and that's what those pictures in the video were taken with, and it just has a very nice sort of visual effect for looking at the microorganisms.

We use that one. We use fluorescence microscopes in order to be able to basically illuminate organisms with different pigment systems. We'll hit them with different wavelengths of light. We also have a range of dissecting microscopes that we use. They're called dissecting microscopes or low power microscopes, when we're taking apart the layers so we have all kinds of microscopes, and we use them for different kinds of things. We don't do a lot of electron microscopy on these mats, but that has been done in the past, too.

Kerry: Oh, great. Mary, how does it feel to be a female minority on this team, and what is your role?

Mary: Well, luckily, when we do our field trip there are a couple of other females who will go on the trip with us, so that's great. My role is mostly support role, working with Brad's lab, [inaudible] and Brad's lab and projects that he's developed. He's also, though, been very generous about if there's an idea that I'd like to pursue, I can go right with it. I haven't really had too hard of a time working with mostly the men that in this group. They've all been pretty good and they are always willing to help me with anything that I need help with.

Kerry: Oh, great. And that was from Mr. Diego's class. Ms. Levine's class asks Brad a question. Do any of the samples that are spoiled in the greenhouse? If so, what is done with them?

Brad: I don't know if they spoil. Basically, you've got something that's living when you bring it back. Those living organisms adapt or don't adapt to whatever conditions they're encountering at the time, and so, you don't have something that spoils so much as you have something that may not resemble what it is that you took out of Baja, and so we have sort of a natural…

Microbes have very short generation times, and so they will basically grow at the rate that they can in response to the conditions they're getting, so instead of thinking of it as spoiling, what you actually end up with rather is a different community of microorganisms or a community of microorganisms that's adapted to whatever conditions it is that they're experiencing.

Kerry: Oh, great. Thank you. Mrs. Taylor's fourth graders ask when we take microbes out of the thermal springs or the salty ponds, can you keep them alive back in the lab? I think that's what you do. Isn't that what you do?

Mary: Yeah. Often, we'll try and determine what's the temperature of the water from the field site that we've removed from. We will often try to also determine things like pH, salinity, and then we'll try and once we've brought them back to the lab, maintain them at the temperature or the pH, the salinity, the amount of light -- the conditions that they're used to in the field and try and keep them that way, because that's where they've grown naturally, and so we're trying to just let them have the situation, the environment that they're most accustomed to.

We'll also try to sometimes tweak that and change their light and see, okay, are they doing better or are they doing worse, or lower salinity and, again, try and make a measurement to see how they've adjusted to that change in their environment.

Kerry: Thank you. Stella would like to know, do you speak Spanish in Mexico? Brad?

Brad: Yes. Some of us speak Spanish; some of us speak Spanish better than others of us. I think everybody tries to speak Spanish. It comes in very handy. When I was a kid, I spent four years in Guatemala, and so I remember a little bit of the Spanish that I had down there and so I'm often one of the ones that ends up asking the questions. But I wouldn't say that my Spanish is great, but I think that there are enough people down there that speak English and enough of us that speak Spanish well enough to get by that we keep ourselves out of trouble for the most part.

Kerry: Oh, great. [Annbica] would like to know, do you wear white lab coats in the lab? Mary or Brad? Mary?

Mary: We often do, not all the time, but I mean you should be wearing a lab coat when you're trying to protect yourself from things that you're working with. We work with acids and bases and those can be caustic and so we'll wear gloves and we'll wear lab coats for that. As far as the field work, there's not too many things out there that are going to damage you. It's like going into the beach, or into the ocean at the beach, and so, we don't need lab coats for the field work, but in the lab, if you want to protect yourself from items that you're using, you'll wear a lab coat. And often, the other way of looking at it is that you don't want to contaminate some of the bacterial cultures or organisms that you're working with, so you might just try and keep a clean barrier between you and your organism.

Kerry: Great. Patricia would like to know what is your hypothesis? Brad?

Brad: Oh, gosh. We have all kinds. That's a great question. We have all kinds of hypotheses and it's the case that we're a rather large team, all the members of which interact on these field trips, but not all of us are interested in the same questions, and so, each of the principal investigators on the project will have their own set of hypotheses that they're interested in testing.

One of the things that we're doing in the greenhouse. I'll give you an example. One of the things that we're doing in the greenhouse now is that we are lowering the sulfate concentrations on one set of mats relative to the other. Our hypothesis is that because we know that sulfate is important for some kinds of bacteria, our hypothesis in this experiment is that, as the sulfate concentration goes down, bacteria that are able to use that sulfate, won't be able to do what it is that they do for a living in order to obtain energy, and we will see the emergence or we will see the other kinds of bacteria grow better and perform the kinds of processes that they're better at in the absence of sulfates, and so that's an example of a hypothesis from our greenhouse.

Kerry: Oh, great. Thank you. These are great questions, aren't they?

Brad: Uh huh.

Mary: Uh uh.

Kerry: Mrs. Taylor's fourth graders would like to ask Mary a question. Mary, did you find anything new or unusual in the thermal springs at Yellowstone National Park?

Mary: It was actually all pretty new to me. That was my first trip to Yellowstone, so just going there to see it, oh, it was beautiful. I think Tory had shown you in his video the [Grand Prismatic Spring], and that's a large spring with a bright blue color in the center pool of water and then as the microbial mats spread out from it, they have somewhat of an orange color and yellow color, so it was a beautiful place. In the photograph, I think of me in the beginning, is I'm in an area known as Angel Terrace and that's cascading down the water and you can see that different chemicals have kind of solidified out of there and bacterial communities have caused the different colors that you'll see there. So, it was a great trip. We also camped there, and in the morning, one morning, we were sung to by the coyotes.

Kerry: Wow.

Mary: So it's a great place to go, and I really enjoyed that.

Kerry: Great. Mrs. Taylor's fourth graders would like to ask another question. We've been learning about how people pollute the oceans and how that hurts the coral reefs. Could pollution hurt the microbial mats, too? Are they endangered? Brad?

Brad: That's a great question. It's actually the case that some of these microbial mats are able to use some of the polluting agents. That's not to say that it's a great idea to go polluting places where microbial mats live, but, again, microbes are so adaptable, and what you have, if you introduce a pollutant into a microbial mat system is you've made life better for something that eats that pollutant, and there are a lot of, there are microbes that eat almost everything, and so, it's actually the case that in, for example, the crisis that resulted from the Gulf War with all of the oil that got spilled there, there was some research that was done about what happened to the microbial mats that were polluted by all the oil in the gulf there. And it was found that in the case of some of the microbial mats, there were some organisms that were able to grow at the expense of that pollutant. And so, it's the case that I think these microbial mats don't grow in a lot of places that are really polluted, but in cases where they do, there are some microbes that will rise to the occasion and start working on that pollutant as a food source.

Kerry: Great. Thank you. Eric would like to know how long do microbes live? Mary?

Mary: Hum. I think that can vary depending upon the organism. I know that there's ones that are like a day and then there are ones, I think, that can go a lot longer. I think Brad would have a better answer for that than I would because he's just worked with more types of organisms.

Brad: It's a case that the life cycle of a microbe is to grow and then to divide, so, in one sense, the microbes live forever because basically they divide and then their DNA goes off in the cell of what it is that they just divided into, and so, unless you kill the microbe, if it has a chance to reproduce, you can think of them as lasting a very long time.

Kerry: Okay. Well, thank you very much. I'd like to have Mary review the Winogradsky Columns. What should the students have done during the procedures in data collection for the Winogradsky Column, because we do have questions rather than go back to [talk over]. Okay.

Mary: We tried to do just what the students were supposed to have done, so Brad's going to grab the ones that we made. We were to go out to a field site close by them, either a fresh water area or salt water area, and collect some mud, bring the mud back to the lab or the classroom, add some water, add some newspapers. The newspaper is a source of carbon and in newspaper is cellulose, and that's the type of carbon that can promote rapid microbial growth. They also added egg yolk.

That was a source of sulfate, and they also added powdered chalk, and that was another source of carbon.

So, those three things. They're basically food for the bacteria. The bacteria should have been in the mud that you found. It should have been in the mud that you brought back from the field sites. What we did, and one of the things that you'll notice is that they're quite smelly.

Mary: So, what we did was we tried to. So that would be one way to go is go and get your mud, the water, making a slurry, add the three ingredients, the newspaper, the chalk, and the egg yolk as food for the organisms. Set it up in a nice spot in your classroom. It's a pretty good, normal temperature. You don't want it to get too warm, and have a light source. You could either put it in a window ledge or have 40 to 60 watt light bulb shining on it.

So, we set up three of them, and we got some mud from three different areas. We went to a freshwater marsh here on base. We had some salt water mud that we brought back with us from Mexico, and then we did one that was salt water and sand that we mixed together.

So, I'm going to just show you once I get them uncovered here. This would be the saltwater one, and this seemed to turn out the best. If you can get a close-up of that.

What it's showing you is that at the surface, we have this almost light tan to gray layer, and then as you travel down through it, right about here, there's sort of magenta, like a purplish red color. Beneath that tan, there's a very thin green layer that we can see, and so, as you went down to the bottom, it gets pretty dark, and so what you're having is the layered system of different organisms. They each have their own set of pigments, and that will cause the coloration that you see, so the ones at the surface are kind of a tannish color, right beneath that is a green. Over here, by my finger, is another light tan, that as you travel this way, there's a reddish purple color. There's some tan down here and then black.

The things that can cause the different organisms to find the different spot is the amount of light that they receive, the amount of oxygen that they receive, the amount of sulfate that they receive. Usually, what you'll find is that there's more light and oxygen at the surface,

so you get a pretty well developed community of organisms there, and then as you travel down, the oxygen is depleted, the light is depleted, and you don't get various organisms at the surface. You get a different set, and so you might have different colors.

What we also did was we covered one side of ours with aluminum foil, to try and see, okay, this side is going to be getting light and this side isn't, and see, did it make a difference? And so, what you can see is, basically, the aluminum foil side is all black. There really isn't that much difference from top to bottom, so if I can move it again to the side, there's kind of the color line right there. Here's where it was dark and here's where it was light.

We had our freshwater one, just to show a quick difference, and the most striking thing

here is the grass at the surface, and so, in the freshwater areas, you're going to find grass, and in the salt water, it's such high salinity that the growth of plants is very discouraged. It's very hard for plants to grow there. There are some plants that grow in the salt water areas, but grass would have a very hard time growing there.

It's hard to see on this, but there was a slight development of color, different layers, and again, the difference between light and dark was somewhat available for us to see. I think it's hard to pick up there on the screen.

Kerry: Yes.

Mary: And then, the last one we did was just the mixture of the salt water mud with sand, and you can see it's a much less developed layered system.

It still does have that lighter colored layer at the surface, but you don't get the development of the lighter, that green color or that purple and tan color. And again, it was kind of darker on the dark side where there wasn't as much development, compared to the light side.

And we just one more that is a large one that I thought I'd show you. This is one that was made about two years ago by another fellow who worked in our lab. And it's mud from a salt water area.

Brad: No, the beach.

Mary: Oh, it's from a beach. And so, if you can bring the camera right in here close, you can see that, at the surface, there's a nice green layer that's developed and then, as you travel down through it, there's colors again, and it kind of.

Here you go. So, there's the colors. It really developed nicely. There's that green at the surface. There's a nice red purple area there. It goes to a light tan, and then as I can tilt it up, you can see that it's getting darker as you go down.

So, what you should see in your Winogradsky Columns, hopefully, is the development of some kind of colored layer at the surface, probably more so at the surface than further down, and maybe some colors down through it.

But it also takes an amount of time for these layers to develop. The organisms have to find where's there best spot. How much light they want. How much oxygen they want. And they kind of start hanging out there, and as a group, each one has a different pigment system, so they'll have a different color, and it'll develop over time. So, you can hold onto your Winogradsky Columns. Just keep them in the same place you've had them now, and see how they do over the months.

I think you had results. You should just be collecting the difference that you saw from the top to the bottom. If you did one in the light and one in dark, what did you see there? The way that you can record it is just the color change as you go down in depth.

You should record the temperature of the room, and just keep a notebook of those. And then your conclusions are, you made a hypotheses. What did you think you would see when you started this out? What would develop? And your conclusions should look at, did a change happen from top to bottom? Did you see a difference when you had ones in the light and ones in the dark? Is there anything that from what you did, you've now learned that you could do it a better way, or from seeing what I did that you could try it a different way. Maybe put the aluminum foil on and set it up in the light so that you have the dark and the light right there.

Kerry: Well, some of the students have received quite interesting results. And I'd like to share some with you. They have questions about their schools, okay? This is from Dwight School. None of the groups got too different colors. Why is that? I guess they tried two different experiments.

Mary: It could be that if they all started with the same mud, so they had three different groups and they all started with the same mud, it should have just developed the same way. If he's talking about that it didn't get colors as you travel down from the top to the bottom of the columns, it may just be a matter of time -- that it needs more time to develop that color pattern. As you saw on our three small ones that we did, we didn't have nearly the bright color development that you saw in our larger one that we've had for two years. So, it could take an amount of time to see visually those colored layers develop.

Kerry: Brad, do you have a little more on that?

Brad: The only other thing that I might suspect is that you're only likely to see the purple colors if there's some sulfur in there. So if you didn't see any purple develop at all, it's possible that the reason for that is that you don't have salt water. It could be a fresh water system, or you didn't have enough source of sulfur. The sulfur is necessary to make sulfide. The sulfide is used by those purple bacteria, so the absence of the purple bacteria might indicate just no sulfur.

Kerry: Well, thank you. This is from Dwight School again. One of the groups had worms in it, and they were moving. Ugh. How did they get there and why are they still living?

Mary: I think it may very well be the source of your mud. If you went to a fresh water area and collected your mud, it's very likely that there were worms already in there, and they would just come right along with you with the mud to the classroom, and they've now found a nice place to live. You added some light. You've added some heat -- the temperature of your room, and the bacteria have developed, and now that's a nice food source for the worms. Whereas, as you saw here, we had the grass develop in our fresh water, but not in our salt water. Because of the higher salinity, it discouraged the growth of the grass. Same thing that if you're in a fresh water system, you're going to have the worms, whereas as the higher salinity may have discouraged the growth of the worms, or they couldn't figure out how to live there.

Kerry: Do you have anything to add, Brad?

Brad: No. I think that Mary's pretty much covered it.

Kerry: Okay. Well, thank you, Mary. This is also from Dwight School. We put an extra egg and chalk and got orange microbes. Why was that? Did that affect it? That extra egg?

Mary: How about Brad taking that one.

Kerry: Brad?

Brad: What was the question?

Kerry: Oh, this is from Dwight School. We have. Let's see. We put extra egg and chalk in the Winogradsky Column, and got orange microbes. Does that affect it?

Brad: Does that affect it? I'm not sure what the orange microbes would be, and without having a sample of it and taking a look at it, I'm not sure if I could answer that question. There are a lot of things that make orange layers, and I'm not sure which of those it would be.

Kerry: Okay. This is another question from Dwight School. We have white powder in ours. Do you know what that could be? Brad or Mary?

Brad: Do you want to take that one?

Mary: I'm not sure. It could just be that in your mud again something has precipitated out to the surface. It could be a chemical. It could be the chalk has just decided to rise up to the top. It didn't dissolve all the way and so it's kind of worked its way up there. I don't have any other guesses than that.

Brad: I mean, if it dries out, I think a lot of these things would look like a white powder if they had a chance to dry out. I think that the surface of Mary's cores would probably look like white powder if they dried out, so it could be that it's organic matter that was possibly bacterial and it dried out.

Kerry: Oh, great. Thank you. We have another question from Dwight School. Why doesn't the newspaper decompose?

Mary: It may have been that you didn't break it up into small enough pieces. I was worried about that as well, so I really tried to break them up into tiny pieces, and really mix it in well with the mud, so, initially, I was looking for it and didn't see any, but I though, ooh, I had bigger strips, and then as I put the first one in, I felt that it wasn't going to break up too easily, so I really broken them into small, tiny pieces.

Kerry: Great. We have a couple more questions about the Winogradsky Column. From Dwight School, one group put their microbes under a desk and didn't get anything, why is that? Brad?

Brad: It's probably the case that you've got microbes living in there. It's just that they're not colored. When you see color in a microbe, the reason that you see color is because they're absorbing some wavelengths of the light that we're all getting all the time, so it's not necessarily the case that you don't have microbes in there. You just don't have microbes that are highly colored, and the reason that you don't have those is because there's not a source of light, so they're not synthesizing the pigments that they would need in order to capture that light energy. So, I would guess that you just don't have anything that's in there that's using photosynthesis, but that you do have a lot of microbes that are there.

Kerry: Okay. Great. Thank you. Felix asks a question. Is salted water good or bad for microbial mats? Do you study mats in fresh water, too? Brad, do you want to take that?

Brad: The kinds of mats that we're interested in, the saltier the water, up to a point, the better, and the reason for that is because mats occur almost everywhere, even on the modern Earth, but they're able to grow thicker and sort of more impressively in places where there's enough salt that the animals have a harder time living in the microbial mat, and so I'd say that the salt water is good for them and that it excludes the grazing organisms that would otherwise be there.

Kerry: Okay. Because they pretty much grow in like extreme.

Okay. Culbert asks, what is your recent research? Is it microbial mats?

Brad: Well, we've done all kinds of things with microbial mats. Now, the greenhouse is occupying a fair portion of our time right now, because we're getting to the point in the experiment up there where the sulfate concentrations have finally dropped to a really low level, and so, we're very interested in stuff that's going on in the greenhouse right now.

Again, we're back fairly recently from Yellowstone and had some exciting results from there, as well.

Kerry: Okay. This is another question for Brad, and we'll get to you, Mary. How did you become interested in becoming. This is from Mrs. McDonald's class. How did you become interested in becoming an astrobiologist biochemist marine microbial ecologist?

Brad: I got interested in being in oceans sciences because of scuba diving, pretty much. I just thought that the ocean was an incredible place to be. Then I started looking around for ways to study that more and got interested in more projects in oceanography, got into school in a place that studied oceanography. And then, I became an astrobiologist just because NASA at that point in time when I was just getting out of graduate school or actually after a post-doctoral fellowship that I had, NASA was interested in hiring some more biologists, mostly because of the excitement about the Allen Hills meteorite and trying to find out more about what life might look like on other planets and what life might have looked like on early Earth.

And because I'd worked on microbial mats, NASA was interested in the kind of research that I did, and so I've been here through sort of the creation of the new sub-discipline of astrobiology and have become an astrobiologist that way.

Kerry: Okay. Great. Are you interested in microgravity? Mary?

Mary: I haven't done anything with microgravity. I know that there's others in our building that are doing some work with it.

Brad: In fact, my wife, Lee [Profert] Bebout has got a project now, and what she's raising microbial communities and trying to create communities that we can send into space if we ever have an opportunity to, because of the fact that these are intact microbial ecosystems, we could maybe learn a lot about microgravity on an intact ecosystem on a very fine scale.

We know something about the way certain kinds of mammalian cells, for example, respond to microgravity. We know very little about how ecosystems, and so some of her really exciting research is trying to grow communities that we can look at to look at changes in those communities, the kinds of changes that we've been talking about happening in response to a pollutant or sulfate concentrations. This is an intact community that occupies very little space, which is at a premium on the shuttle and on the International Space Station, and I think that she could get some really exciting results out of that.

Kerry: Oh, great. Well, this kind of leads into the next question. That question's from Becca. This one is from Felix. Do you think there is intelligent life in outer space? Mary? First.

Mary: That's a hard question. I mean, you know, here we are and the human population has developed here on Earth, so if you think of the magnitude of the universe, out there are, you know, billions and billions of planets, and could there be life elsewhere? I don't know if it would develop the same way as it did here. Would it be a carbon-based life system as it is here? I just think that the possibility is very real because of the numbers of opportunities just of the numbers of planets.

And yet, then you have to look at it the other way. For all of the things to take place that ended up with life developing here, there were a lot of things that had to happen, and it went step by step of, first, the chemicals all came together, and the planets formed, and then we needed water and we needed those chemicals to come together in the right way to start forming organisms, and how they then became very complex organisms. It almost seems serendipity. It was very good luck we had to develop life here on Earth. So, I want it to be so that there's life elsewhere. I flip-flop back and forth between the opportunity is there because of the number of planets and stars in our universe, but it's a very hard thing to do to develop life, so I'm not sure.

Kerry: What about you, Brad? Do you have anything to add to that.

Brad: No. I really don't. I have the same kinds of questions about it, but I think that everybody does. I think there's probably a very good chance that there's life out there somewhere. Whether it's intelligent or not, I really don't know.

Kerry: Okay. Thank you. Rachel would like to know where else are people studying microbes? Besides, I guess, NASA.

Brad: Oh, what other kinds of institutions. Almost every university is going to have a microbiology department, so I think that people are studying microbes all over. I think that the field that we're in is more microbial ecology. There are fewer places where you can go to study that, but I think that there are, again, departments at most major universities where people are doing microbial ecology, and since microbes are everywhere, there's always something to study about the way that the communities work.

Kerry: Great. Thank you. Mrs. Terry's fourth graders would like to know about research. Do you ever collect dangerous microbes? Mary?

Mary: In all my time here and as well as at a couple of other labs that I've worked at was bacteria, I've never worked with anything dangerous. Even if you wanted to call it like human pathogens or things that could get you sick, I've never worked with anything like that. Mostly. Some of them I think that if you drank a bottle of it, you wouldn't feel too good for a little while, but nothing that we would consider that could cause human disease, and that's what I would consider a dangerous bacteria.

Kerry: What about you, Brad?

Brad: I've never worked with any kinds of pathogens on purpose at any time.

Kerry: That's great. Well, these are great questions.

Mary: They really are.

Brad: They are.

Kerry: We're going to wrap up. That's the end of the questions, and we'll review what we've learned today. We have a slide about that.

So, what did we learn today? We reviewed the scientific questions of the microbial mats investigation, and we reviewed what was done during the Baja field work. We learned about the types of organisms they observed and studied, and what was done after each investigative field work. Brad focused on results of data collection and as well the conclusion, too. And Mary did a thorough review of Winogradski Column procedures and data collection.

And thank you for participating with the Winogradski.

That was quite a nice surprise, and, thank you for joining us today and our very special thanks to Mary Hogan and Dr. Brad Bebout.

Mary: Thanks for having us. This was really fun.

Kerry: And we hope you will join us in the near future from NASA Quest's Marine Technology's channel webcast. Please fill out the survey that Laurie has posted in the chat room. Thank you.