Fri April 26, 2013
Great Salt Lake Is No 'Dead Sea'
IRA FLATOW, HOST:
This is SCIENCE FRIDAY. I'm Ira Flatow. We're broadcasting today from the Grand Theatre at Salt Lake Community College. And, of course, just up the road from Salt Lake City is the city's namesake, the Great Salt Lake. Parts of it are 10 times saltier than the ocean. But this is no Dead Sea. It's teeming with microbes which can turn the water bubblegum pink.
My next guest has devoted her life to studying tiny creatures, these tiny creatures in the water. And believe it or not, these microbes may hold the clues for better sunscreens, hydrogen fuel cells, even life on Mars. So there's a lot to talk about. And if you ever wonder where the phrase red herring comes from - have you wondered that? Yeah. We may have a salty answer for you this afternoon.
So we won't be taking any calls this hour, but if you're in the audience, as I say, welcome - you're welcome to step up to the microphone and ask your questions. Don't be shy. Bonnie Baxter is director of the Great Salt Lake Institute at Westminster College here in Salt Lake. She's also a professor of biology there. Welcome to SCIENCE FRIDAY.
BONNIE BAXTER: Thank you, Ira.
FLATOW: Let's get - yeah - bring a fan club with you, today?
BAXTER: Yeah, I did.
FLATOW: Yeah. Let's get right to the question of why, for the rest of the country, everybody here knows the answer, but why is this huge, salty lake here? Why is it salty? Why is it here?
BAXTER: Well, you know, a lot of people actually locally don't know the answer to that. I get asked that all the time. This was a giant inland sea at the end of the last ice age. It was called Lake Bonneville, and northern Utah, southern Idaho, northern Nevada was all underwater, a freshwater lake.
But as the Earth warmed up, ice dams broke, and water evaporated, and all the water seeping out left behind this salty puddle in the bottom of the bathtub, and that's what we call Great Salt Lake.
FLATOW: You lovingly refer to it as the bottom of the bathtub?
BAXTER: Yeah, yeah, it's all the debris.
FLATOW: It's not really one lake, is it? It's divided in half, just about.
BAXTER: It's divided in half since about 1959. A railroad causeway was built across the middle of it. And for most of you, if you've seen Great Salt Lake, you've probably driven by on I-80, and that's the south arm of the lake. It's just a tiny little bit you get to see.
Most of the lake you can't circumnavigate by boat, and you can't drive around. It's very shallow, and it's marshy, and it's hard to get around it. So, actually, access to a large part of the lake is limited. So that north part has gotten super, super salty, because all of the freshwater rivers flow into the south part.
FLATOW: Mm-hmm. How salty is super-salty?
BAXTER: Well, the ocean is about 3.4 percent sodium chloride all around the Earth. And the south arm of Great Salt Lake is about - it's about 11 to 12 percent salt right now.
BAXTER: And the north arm, where I study, where I do most of my studies, is between 25 and 30 percent salt. So close to 10 times saltier than the ocean.
FLATOW: Is that dangerous?
FLATOW: If you fell in, I mean, into something that - you know we hear the Dead Sea you'd float a lot. Is it saltier than the Dead Sea?
BAXTER: You know, that's a good question, too, because there's something that affects how much salt can stay in water, and that's temperature. So if you want your hot chocolate powder to mix in the milk, you need to heat it up, right? So warm water will hold more salt. And so it turns out the Dead Sea is also saturated, but it gets to be more salty because it's warmer there year-round than it is in our alpine climate.
FLATOW: Now, you study the salt-loving microbes that live in the northern arm, the really salty part. Why are you studying them? What's there to be learned? What are they?
BAXTER: You know, I came out of the world of DNA damage and repair, and I was really interested in extreme organisms because I thought they might have some secrets for how to tell us how to survive damage from the sun, for example. So I went there looking for models for the laboratory, and I found this incredible environment that had never been explored.
So those microbes that deal with high UV exposure, they deal with high salt, they get dried up during, you know, part of the year and live inside salt crystals, and they - so they can deal with desiccation, be completely dried out. Those guys have some secrets to tell us. So I thought these would be great models for exploring life in extreme environments.
FLATOW: You mean they must have their own sun shade, because they're out there in the sun? Do they?
BAXTER: They do. In fact, organisms that live in sunlight, microbes all around the world that live in high salt, particularly in high-sunlight, will develop pigmentation. Even humans that live in high solar radiation will, you know, have evolved with higher pigmentation. So pigments are really important for helping from sun damage and oxidative damage.
FLATOW: Is there a general name you use to describe what's living in there?
BAXTER: We call them halophiles, and halo is a root that means salt, and phile coming from love. So halophiles, they love salt.
FLATOW: And how many species have you been able to find in the lake?
BAXTER: You know, it's up in probably 300s to 400s by now in terms of genetically identifying organisms. So sometimes we just look for their genes. It's hard to actually make all of them grow in the laboratory. So sometimes we won't go get the cells out of the water, we'll just take their DNA and basically look at their ID at the door and try to figure out who they are.
FLATOW: What do they eat? I mean, in such a harsh environment, what are they living on?
BAXTER: They use the sunlight, in part, but they're not truly photosynthetic. They really are ingesting nutrients from the water, from decomposition, and helping decompose the couple of invertebrates that live in the lake. It's a pretty simple ecosystem at the macro level. But the community of microbes, I think, it's a really complex community at the microbial level. So...
FLATOW: Do they have an energy source of some kind that they're using?
BAXTER: You know, they are producing their own energy, sometimes from sunlight, but sometimes just from the nutrients in the lake. So, yeah.
FLATOW: Yeah, a lot of questions. Let's go right to the audience, here. Yes.
AUDIENCE MEMBER: So I don't know if you mentioned this already, but how many chemicals are in the Great Salt Lake besides salt?
BAXTER: Oh, what an excellent question. Thank you. You know, this lake is a little different than the Dead Sea because it has - hey come back. Don't go away.
BAXTER: It has sodium, and it has chloride ions. And the Dead Sea has a lot of things like calcium and zinc and some things different than sodium and chloride. But Salt Lake has a unique chemistry in that it has a high sulfate concentration, and that turns out to be really important, too.
That's - we have a mercury contamination problem, for example, and the sulfate turns out to be important in the chemistry of that. So there are some other ions besides sodium and chloride that are in the lake. So that's an excellent question. Thank you.
FLATOW: Let's go to this question right here.
MEMBER: Thank you for being here, by the way. I'm just curious: Were they any human beings here when Lake Bonneville existed, or was it already gone by then?
BAXTER: That's an excellent question, and luckily I got to be a part of the planning of the Natural History Museum of Utah. There's a Great Salt Lake Gallery there, and you can visit it. And one of the most exciting things about that whole process was talking to the anthropologists and some of the other people and asking exactly that question.
So Duncan Metcalfe there at the University of Utah and some others who have been studying that, and they tell me the peopling of Utah happened about 13,000 years ago. And that's about when Great Salt Lake set its margins. So we think that no humans ever saw Lake Bonneville.
So there would have been mastodons and giant sloths, but no people. So people have only experienced Great Salt Lake.
MEMBER: Thank you.
Interesting. Let's go up there to the balcony.
MEMBER: Yes. I've driven out to Lakeside a number of times, and mostly to take pictures out there. And there's a foam that forms out there if it's windy.
MEMBER: In fact, it'll even form pinwheels, and it blows along - crazy stuff.
BAXTER: I think they look like tumbleweeds.
FLATOW: Is that the technical word for that, crazy stuff?
MEMBER: Well, it - yeah, it blows along. If you - depending on how much wind there is and how much wind there's been, it often looks like there's ice out there on the lake, that'll look like ice flows, but of course it's much too salty for that. But then it does form pinwheels.
FLATOW: Yeah. What is he discovering out there?
BAXTER: So, all around the world where people make salt, and the concentrate salt water to make it saltier and saltier, they report this foam that appears when you get super-salty water. And we see that in the north arm of the lake. So Lakeside is a point on the western side of the lake where the causeway intersects. It actually was where they set up camp to build the causeway for the railroad.
And you can see the north arm and south arm from one location, which is marvelous. So what you're probably describing is a north arm activity. When we go up to the north arm, where Spiral Jetty is, and we are doing our studies, if it's a windy day, there will be foam everywhere. It's like a giant bubble bath.
And what we think this is, there are some very special lipids and fats that are in these particular types of cells that live in that pink water. They're called archaea, as opposed to bacteria, and they have unique lipids. So we think that they're contributing their, basically, soap to the water, and it's causing this foam.
FLATOW: Wow. You can see - up on our website, we have some great pictures of the Great Salt Lake, including a pelican fossilized in salt, and you can go see it up there at sciencefriday.com/salt, if you want to go see some of these great photos. These archaea...
Archaea, could we use them to make fuel for us if we're - could we find the right kinds of things that might make biological...
BAXTER: Well, we've been looking in the lake for hydrogen-producing particularly algae, maybe even some of the archaea, because hydrogen production by microbes turns out to happen when there's low oxygen. And because it's so salty, the water cannot hold dissolved oxygen very well. So there's very little water - very little oxygen dissolved in the water.
If you can think about the water molecules that would normally bind up and hold oxygen, they're engaging with salt, so they can't really hold the oxygen. And that turns out to be a place where you find that unique energy metabolisms. And so we think some of these archaea and some of the algae in Great Salt Lake maybe have some secrets that could be used for biofuels.
FLATOW: Huh. So are people looking into that, studying it? Yeah?
BAXTER: Yes, yes. Yes.
FLATOW: Yeah. Because we're all looking for that kind of bacteria that could do some work for us, making...
BAXTER: Exactly, because they're easy to grow in a vat, and if you could grow hydrogen, you could go to Mars.
FLATOW: What a tie-in. What a tie-in.
BAXTER: That was for you, Margie(ph).
FLATOW: We're going to take a break, come back, talk lots more with Bonnie Baxter, director of the Great Salt Lake Institute at Westminster College here in Salt Lake. Don't forget you can come up, step up to the mic there. You can also join us talking about it @scifri and Twitter and our Facebook pages. So stay with us. We'll be right back after this break.
FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY, from NPR.
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FLATOW: This is SCIENCE FRIDAY; I'm Ira Flatow. We're talking this hour about Utah's Great Salt Lake and some of the unusual life that thrives there with my guest, Bonnie Baxter, director of the Great Salt Lake Institute at Westminster College here in Salt Lake.
One of the things that I was reading about in your research is that - this is so fascinating to me - you can actually look inside ancient salt crystals to see stuff that's preserved for 100 million years?
BAXTER: Two hundred and fifty million years.
FLATOW: Two hundred and fifty million year, stuff that was living here 250 - is it still viable? What do you see? Tell us what it is that we're looking at.
BAXTER: Yeah, yeah, so I went with a collaborator, Jack Griffith, and some other folks to a salt mine that's north of Carlsbad, New Mexico, and that was a salt lake 250 million years ago, and it dried up. And we - it's a half-mile underground, if you can believe it. And we cored salt and took it back to the laboratory, and there are fluid inclusions that form in salt, particularly when it's under pressure.
And we pulled the fluid sterilely out of those fluid inclusions and did some electron microscopy on that, and we found DNA, and we found cellulose, which is, you know, what paper is made of. Cellulose on Earth, we know, is produced by things like trees, right, plants.
BAXTER: And some algae and cyanobacteria can produce cellulose. So there's no non-biological production of cellulose, you don't just find it in the environment. It's produced by biology. So we took some beautiful pictures of this biological molecule, and we published that in a journal called Astrobiology because if salt can hold biological molecules for 250 million years and preserve them, maybe salt's where we should be looking on Mars for the traces of life that used to be there.
FLATOW: Because there was a lot of water there back then.
BAXTER: That's right.
FLATOW: And so if there was life, it would still be preserved, or traces of it, in the salt beds on Mars.
BAXTER: That would be a good place to look. That's the...
FLATOW: Are we looking there, in those...?
BAXTER: You know, the Meridiani Planum is an area on Mars where one of the earlier Rovers was, the Rover Opportunity. And so they discovered, that Rover discovered, a salt playa that looks a lot like the Bonneville Salt Flats. So that - we say on Earth if you find a deposit like that of salt, you say hey, this used to be a lake, and it dried up, and it left behind the salt. And they're actually called evaporates by geologists because the water evaporated and left behind the salt.
FLATOW: And so that sounds to me like it's a great place to go mining for ancient water and life.
BAXTER: Exactly, exactly, if we could teach a Rover to look inside fluid inclusions.
FLATOW: Could we do that?
BAXTER: Anything is possible. Did you see the landing of Curiosity? I mean, anything is possible, yeah.
BAXTER: Yeah, that was beautiful, beautiful piece of work.
FLATOW: Of course other folks would say we need to send geologists there or microbiologists themselves to look into that.
BAXTER: That's right. And I'm signed up for the one-way trip.
FLATOW: That's two this hour, two - would you want to take the one-way trip to Mars, standing at the microphone there, you? Would you go? No, no.
FLATOW: Well, tell us what's on your mind. Go ahead. What would you like to ask.
BAXTER: What's your question?
MEMBER: Is pollution affecting the Salt Lake?
BAXTER: Oh, that's a really good question. So there's a mercury problem. It's probably the highest mercury pollution in water in the nation. And it hasn't gotten much attention because we don't eat fish out of Great Salt Lake, right. But the ducks are eating the brine flies, which may be bio-accumulating the mercury.
So - and, you know, we're in a migratory path here. Great Salt Lake is a migratory habitat for millions and millions of birds, right. So if they're going to ingest mercury, they're going to take it somewhere else. They're going to fly with it, right. So it's not just a local problem.
So I've been studying the microorganisms that can change the mercury into something far more toxic and try to figure out how they're doing that, and are there are microorganisms that can detoxify the mercury and make it less toxic. So there are some duck species from the lake that you shouldn't eat, and we're - we have some people at Westminster - at Great Salt Lake Institute, Frank Black and some other folks, who are studying the spiders of the lake because they might be eating the brine flies, and then birds are eating them.
And the mercury keeps getting concentrated. So mercury is one of the pollution problems that I'm actively involved in.
FLATOW: That's a good question. Let's talk about, before we run out of time, the phrase red herring.
BAXTER: Oh yeah.
FLATOW: Tell us about that.
BAXTER: OK. So, you know, the idea of if you follow a red herring, you're following, you know, the wrong idea, not the main idea, and that came from dragging a herring through the woods when they were training fox-hunting dogs in England. And the red herring is a salted fish.
So the fish - the herring would be salted, and because of the microorganisms that turned Great Salt Lake pink, those were associated with salt that was purified from places like Great Salt Lake. And those microbes would just grow all over the salt on the fish and turn it red. And so when they drag a red herring through the woods, a really stinky, smelly, bacteria-laden fish, the dogs, they tried to teach them not to follow the red herring but instead to follow the fox trail.
So it - those were halophiles that were causing...
FLATOW: Oh, is that right, the halophiles caused the red, pink color?
BAXTER: Yes, yes.
FLATOW: Something else learned.
BAXTER: So see, you already knew about halophiles.
FLATOW: There you go, it's a red herring. Let's go right here.
MEMBER: So I know that there was this causeway built in the Great Salt Lake, and now half of the lake is saltier. So why is that exactly?
FLATOW: She looks familiar.
BAXTER: Yeah, that's my daughter, Leila(ph).
BAXTER: And a shout-out to the Salt Lake Arts Academy, her school. I saw some other students from there today.
FLATOW: All right, it's good to have a lot of school kids here today.
BAXTER: And a shoutout to the Salt Lake Center for Science Education, where my son Landis(ph) is, those guys up there.
BAXTER: OK, Leila, I will answer your question. So there are these lakes - or these rivers that come in from the Wasatch Front into the lake, and they feed water into Great Salt Lake. And one of the things we haven't talked about is Great Salt Lake is a terminal lake. And that means there's no outlet to the ocean. So it's subject to how much precipitation we get, that lake level will change.
So evaporation and precipitation are the things that control it. And water comes in from the snow melt from everybody's ski mountains, in the spring and summer, into the lake, in the south part of the lake, and the causeway prevents that water from flowing up to the north. So the north just gets saltier and crustier and saltier.
FLATOW: Wow, that's a great answer, and thank you for that question. We've run out of time talking about this segment. Thank you, Dr. Bonnie Baxter.
BAXTER: It's sure been nice to be here, Ira. Thank you.
FLATOW: She's director of the Great Salt Lake Institute at Westminster College here in Salt Lake, also professor of biology there. Thank you very much.
FLATOW: Of course we can't talk about salt without a little reminder of how important it is to our taste buds, and a producer of this segment, Christopher Intagliata, went to visit local chef Elio Scanu to get a chef's perspective on this ancient kitchen condiment.
ELIO SCANU: There are thousands of salts: Maldon salt from England; Japanese salts; mock salts; truffle salt; kosher salt; Himalayan salt; Redmond salt. My name is Elio Scanu, executive chef for Cucina Restaurant Group here in Salt Lake City. Are there salts that are saltier than other salts? Definitely yes. For example, the Maldon salt, they are from the northern sea, the very cold waters, but they are flaky.
If you compare it with let's say kosher salt, if you taste both, you will think at the beginning that the Maldon is saltier because you get a texture effect. But then it eases. If you put a kosher salt, you will get, you know, very flat, salty taste. My grandmother, when she was teaching me how to cook pasta, she always said the water needs to taste like the sea. So it gives flavor to the pasta. You just put salt, and it will taste better.
It's the natural flavor enhancer. In Italy, for example, when someone is not an interesting person, we say that it is like a boiled egg with no salt, (Speaking Italian).
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