Scientific American magazine Editor in Chief Mariette DiChristina talks with podcast host Steve Mirsky (pictured) about some of the articles in the February issue, including one on the ecosystems that arise around the carcasses of whales that die and fall to the ocean floor; the warfare between our cells, our allied microbes and disease-causing organisms; and ways to improve the internal combustion engine.
Podcast Transcription
Steve: Welcome to Science Talk, the weekly podcast of Scientific American posted on February 10, 2010. I'm Steve Mirsky. When a whale dies at sea what happens to the body? This week on the podcast, Scientific American Editor in Chief Mariette DiChristina talks about the long afterlife of whales as well as other articles in the February issue. We spoke in her office.
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Steve: So, Mariette!
DiChristina: Hi Steve.
Steve: Whale Falls!!! Why don't you explain what whale falls are?
DiChristina: This [is an] article by a paleontologist at the University of Leeds in England, Crispin Little, and whale falls are when whales actually fall.
Steve: They do not trip.
DiChristina: They do not trip.
Steve: These are dead whales.
DiChristina: They actually, I imagine they fall rather gracefully. After a period of time, you know, some whales surface and some don't, but after a period of time the carcasses begin to fall, and they eventually land in areas of the ocean where there's not a lot around them, and that's were it gets interesting.
Steve: It gets really interesting.
DiChristina: So, way back in 1987 some researches aboard the Alvin, which is a little research craft that's has been—actually a many-storied research craft because it's found some amazing things under the sea.
Steve: This is a submersible.
DiChristina: A submersible research craft.
Steve: It found the Titanic right?
DiChristina: Yes, and has been used to find many other things since then—dove under the water and found this very interesting sight in the middle, of a kind of an, I would call it a desertlike area, which most of the deep ocean bottom, well I wouldn't say most of it; many areas are not [chock] full of life like when you look at the ocean [reefs or] something like that. There, life is spread out over more disparate areas wherever life can find good reasons to cling on and here in is the segue to the whale falls. Because here is a good way for life to cling on; this is what those whales become is [the] foundation of whole ecosystems of fantastic creatures that lasts for decades under the seas.
Steve: Yeah, that's an awful big parcel of food basically, for other creatures when a big old whale dies and then falls down to the seafloor.
DiChristina: Right, a multi-ton parcel right; Steve [and] I were just talking about how big are these whales are, you know, about a, even a bus and a half of length or even more that; if you can image this mass or as Steve, you put your measurement.
Steve: Right, my measurement was that any of these large whales that we're talking about, they're longer than the distance from home plate to the pitcher's mound, to the pitching rubber, maybe to the back of the mound or even longer than the back of the mound. Or to put it in another way, to go to in a completely different direction with this [as a] way to envision the distance: It's about two thirds [of the way] from home plate to first base, on a major league field.
DiChristina: Which, you know, gives you a sense of the scale of the oasis in some of these really barren areas of the ocean for these sea creatures. And the sea creatures that arrive on them, I mentioned, can take decades to process these whale carcasses that have [gone] down, through a series of stages.
Steve: Yeah. You have basically between 50 years and a century's worth of digestible material down there when a good size whale goes down. One of the really great stats in the article talk[s] about the first stage of the colonization of the whale carcass, is some of the bigger fish come in—sharks and…
DiChristina: Hagfish for instance.
Steve: Hagfish, and they'll start going at the meat of the whale, and they may take from the carcass, anywhere from 40 to 60 kilograms of meat on a given day. Well, they can do that every day for two years before they run out of the meat.
DiChristina: Right it takes a couple of years to strip an enormous whale carcass of meat and then the next colonies begin. So there's a series of life stages. The next one is animals that are smaller than those larger fish, and they start feeding on remaining scraps of things in the little nooks of the bone and begin to process the bone itself to bring it down to sedimentary level. And these are things like little shrimp something with the terrific name of the zombie worm, which lands on the carcass, and a bristle worm, which really is like its namesake; you know, if you can imagine a comb with the spikes on both sides, that's what the bristle worms looks like, and they work over the carcass then for another couple of years to bring it to the next stage.
Steve: In the next stage, you're left with nothing but bone.
DiChristina: Right and this is the stage called—I'm going to use the fancy word and then I'll tell you what happens— the sulfophilic stage.
Steve: Sulfophilic, not "self-fulfilling".
DiChristina: Not, although I imagine it's quite filling for the creatures that are involved.
Steve: But it is the sulfophilic, meaning sulfur.
DiChristina: Right.
Steve: Sulfophilic stage.
DiChristina: Because this is where anaerobic bacteria, which produce sulfur, in the course of their processing get involved. And there are other animals as well such as mussels, a tube worm which looks like a pipe-cleaner pipe, kind of bent up and around, a little hollowed out, if you can imagine that; clams, limpets then scamper across the remaining bone mass of the carcass and really bring it down to the sea floor, and this is the part that can take up to 50 years to complete. And another thing I find fascinating is not just the scale of the individual whale itself, but how many whales, you know, in various sizes of carcasses are down there; the estimate in the article is there may be as many as 690,000 scattered all around the world forming these ecosystem oases. And these animals that, you know, float in between them cling onto one, and then the next, they're, sort of, I think of them islands of life on the bottom of what can be really nutrient-poor areas of the ocean floor.
Steve: And these organisms that live off them, as you say, kind off scamper from one island of safety, of nutrients, to the next, so there's this whole community that's living down there on these.
DiChristina: Right and I want to tell you also, I'm, that's fascinating enough, but another thing that really appeals to me personally I mean—this is a point of interest in how life evolves in general—is that this isn't some modern thing that has just happened with whales and current life forms. Indeed back in 1992, there was the first discovery of ancient whale falls; you know, it was in Washington State rocks from the Oligocene.
Steve: They're really old.
DiChristina: Really old—this is from 34 million to 23 million years ago and even earlier than that, they were marine—I almost said mammals, I had to stop myself because they're not marine mammals, they were marine-life plesiosaurs and others, large marine creatures of the Mesozoic Era. This is the [era] area that encompasses the entire span that the dinosaurs were on earth; and there's evidence that there were large marine-animal falls way back then. So millions and millions of years back further.
Steve: That set up similar kinds of communities that would take advantage of their carcasses when they hit the seafloor.
DiChristina: Right, and how we know this is we find the evidence of the old fossil bones and the old fossil creatures that had attached themselves to the bones that are similar enough in characteristic and lifestyle that we can stay, well this look[s] like the life stages that we're similarly seeing today with descended creatures.
Steve: It's really interesting because it's been going on there clearly for millions of years, and we just found out about it.
DiChristina: I love that about it, that it is recent and new, but also it's in keeping with other things we know about life. Steve, if you and I think about when we went to high school—now we didn't go together, but I think we were trained in a similar way—I remember so clearly after learning about ecosystems and after a forest might have been felled by lightning bolt and fire, then there would be a succession of stages of that forest, you know, from early [seedlings and so on]. So if you think about it, it makes perfect sense that life would have successions of stages for ecosystems in any place.
Steve: I have to say, I was thinking about the same thing, the forest succession after a forest fire, that came to my mind as well when I read the article. I don't think that is actually mentioned in the article, but the analogy is so clear that it hit both of us.
DiChristina: Right, I think it just shows also that life has evolved a series of strategies that are effective for propagation of itself, you know, from various ecosystem evolution, to the stages that they go on, and I love these kinds of lessons–they help me see the context in which life forms on our planet evolved.
Steve: Speaking of which, [since we're] talking about evolution and the interactions of living organisms in their communities, we have this other article in the magazine about the warfare that goes on constantly among and between the microbes that exist within us; and us, they're fighting each other, we're fighting some of them, our immune systems.
DiChristina: Right. Yeah, let me make the connection for the listeners a little bit. You're speaking of warfare. But what we are both speaking of is evolution of creatures in cooperation or in battle with each other for survival. And so this article that you are talking about, we call it "The Art of Bacterial Warfare", it's by Brett Finlay. And he writes about how bacteria actually get into life forms, whether they are, you know, ours—I think we're most immediately concerned with ours because infectious diseases are as a group the second killer of people of all the diseases that we face. So it's very interesting to [us] how we can learn to conquer these bacteria that have been battling with us in our body chemistry for years and years.
Steve: Worldwide, infectious diseases kill second most number of people every year.
DiChristina: Right. For instance, a lot of our major concerns today are bacteria source infections—tuberculosis, for instance, which people worry about, way back in the Dark Ages we had bubonic plague, that was also bacteria related.
Steve: We still have bubonic plague.
DiChristina: You're right.
Steve: [It just] usually doesn't kill people in large numbers any more, because we have antibiotics.
DiChristina: Right. We have therapies, antibiotics, and drugs to fight them. So what the scientist is talking about in this article is getting a better understanding of the ancient interplay between bacteria and their hosts, whether human or otherwise. What are the tricks that bacteria use to infiltrate your body to then trick a cell and to bring in the bacteria into itself, to then use cellular machinery to you know replicate toxins or other things that bacteria seek to produce for their own survival; and then what clues can we get; finding those mechanisms, what the bacteria are actually doing, how can we then stop them at each front?
Steve: So what are some of the ingenious tricks that the bacteria have come up with to get inside the cells [an wreak havoc], and what are some of the equally ingenious tricks [our] cells have come up [with] to try to fight that, and what are we trying to do to, you know, to learn from that so that we can come up with faster, better ways, you know, with actual drug treatments or other therapies that would alleviate some of these problems?
DiChristina: Well, let me answer the last question first, which is, as with many things we seek to copy stuff that nature has figured out over a millions or even billions of years sometimes. So our drugs will seek to replicate kinds of things that our body already might do, but maybe needs to do a better job of, through immune stimulation or others, but also through mechanisms of blocking. Let me give you a couple of first examples of things bacteria do. One would like it call it ingenious if the bacteria were really thinking about it.
Steve: Right. No anthropomorphizing. The bacteria do not plan to do these things; they have evolved these techniques that we think of as ingenious.
DiChristina: So here is one E. coli. Everybody has heard about E. coli and some of the problems that can happen with E. coli. E. coli produces a kind of protein [that] acts like a docking clamp on to your [cells] so it can attach itself. So this is the one way that it approaches and at least gets connected with a cell. salmonella uses a similar kind of mechanism and it causes the cell to produce, sort of, ruffles in its membrane—the membrane is the outer surface of the cell— and these ruffles, if you can imagine them coming out like arms that hug, almost embrace the bacteria and draw it inside the cell's anterior.
Steve: So it forces the cell to consume it.
DiChristina: Correct, by making the cellular membrane change in a way that benefits the bacteria. Shigella bacteria has another interesting trick. It has something called effectors that induce something called actin polymers inside the cell—they're chemical compounds inside the cell—that create something that is described as a rocket tail, and it really kind of looks like that, that then propels the microbe into the cell cytoplasm, the liquid material inside the cell, to help invade a neighboring immune cell on top of but it's already done. I wish humans [knew] as much about how to manipulate cells as bacteria already do with their one cell.
Steve: Well, that's true. We have some lovely artwork in the article. So if you actually look at the article either in the magazine or online you will see illustrations of [some of] these things that we are talking about.
DiChristina: Right, so one set of illustrations is some of the things I have described, which is how the bacteria manipulate the cellular responses to benefit their own [nefarious] purposes and then another one is how do they then get around your immune system? What are ways that bacteria shield themselves, you know, so that they look invisible to immune protectors or to otherwise get around existing systems in the body that are set up to defeat them? And [an] answer to your question about how we are going to use this, is we're actually testing on some substances that could be built into drugs. A lot of these [are] really [in the] early days; so preclinical work, we are just trying to determine, is it even possible on the cellular level, as you know, have we actually figured it out the mechanism that is being used by the bacteria and the cells to evade it, and then could we take that and express it in some kind of either synthetic or naturally produced material that we could use to, you know, [create an] effective defense.
Steve: And there's also the issue of helping the neutral or good bacteria. We are just swimming in it, and people should understand that the cells that we think of as being us, your skin cells, your kidney cells, your brain cells, are outnumbered 10 to one by the cells of everything else that's living on and in us. So we are talking about the whale falls. We are host to this elaborate community of other organisms that are part of us, and we don't really even think about it. But people mostly know that your intestines and your stomach are filled with bacteria.
DiChristina: Right; everybody is eating yogurt.
Steve: Right.
DiChristina: With the right kind of bacteria in it.
Steve: And so one of the strategies is to assist the bacteria that are there in large numbers doing you no harm, assist them in fighting off these invading nefarious bacteria.
DiChristina: Right I mean, and I think one thing a lot of us are familiar with from taking antibiotics is we know that they then disrupt our digestive systems after that because [it wipes out the fauna that would] normally be in the body and help you digest. So yes, this is one area, and another thing I like that the article mentions at the beginning actually, is the next time you're feeling lonely, you'll realize that you are not by yourself ever; you know, indeed as you mentioned 10 times, you know, 10 to one of your [cells] is bacteria I or others that are living on, in and around. And one of the amazing things about those, you mentioned the neutral cells, is that only maybe 100 types of them are virulent to us; most of them are quite cooperative and good neighbors.
Steve: We have domesticated them very successfully.
DiChristina: Right, or they us.
Steve: Right or they us. Good point. So indeed the next time you're feeling lonely remember you are surrounded. The next time you're feeling paranoid, remember you are surrounded.
DiChristina: Some of the bacteria do [mean you ill].
Steve: They're watching you. We are running out of time, but we have another piece in there that I wanted to just discuss briefly, and it's about internal combustion engines. We are all looking for electric vehicles, hydrogen fuel vehicles, alternative vehicles that will help us get off the oil dependence. But one of the ways that we can really improve things now in the meantime before we are all driving the all-electric, all-hydrogen, all-solar fleet of cars, you know in 2050—I'm keeping my fingers crossed—is take the vehicles we have now the internal combustion vehicles; lets make those internal combustion engines more efficient. The amount of fuel that could be saved just by increasing the efficiency of internal combustion engines is really impressive. And what I did know until I read the article was that this is a process that has been ongoing, I think the figure was between 1987 and 2006, fuel efficiency has increased 1.4 percent every year on average. Now for you fans of compound interest out there, that works out to be quite an impressive total after two decades. The problem is, we squandered it all by going in for these larger vehicles that just burn all that extra gas that we would've saved.
DiChristina: It's actually, we have been working on internal combustion engines and making them better for 100 years.
Steve: Right.
DiChristina: You're right, and in the last couple of decades we've made a number of advances, but the sad fact is that today internal combustion engines only give us, for each gallon you put in, about 20 percent to 25 percent of the work back out that we would like to see. So there's an enormous area of potential improvement still.
Steve: Right, the chemical energy is converted to work incredibly inefficiently.
DiChristina: And you can do a little better with diesel engines—25 percent to 35 percent—but they are way more costly and you have already mentioned, you know, things like hydrogen fuel cells, plug-in vehicles, which [we] will be seeing later this year [and] which I'm very excited about too, but in the meantime we can really move the needle a lot with some efficiency improvements on current technology.
Steve: Well, not move the needle actually.
DiChristina: Well.
Steve: The gas [gage needle]—we [don't want] it moving; anyway, go on.
DiChristina: I got it. So we can do this in a number of ways, but its sums up to this, these three, kind of, key things. You got to control the air fuel mixture going in; you got to control how it's burnt, so the more complete the burning the better; and then you have to control how that chemical, you know, how that energy that has been released is then run through the systems of the engine itself. So what this article talks about is the various specific technology things you can do; for instance varying the way you inject the fuel. Today its common to inject the fuel into an air stream and then it enters a combustion chamber where it is ignited. You could inject the fuel directly into the combustion chamber, for instance; you have to be able to control that injection very closely, and here is where good software and good engine design really enters into things.
Steve: And you can do it with even, we talk in the article about a sparkplug-free combustion chamber, where just the act of pressurizing the chamber causes the combustion and without that spark plug, [what] you wind up with is a much more even burn and a lower heat loss. And you would have the spark plug there for backup, but if you don't need it, you increase your efficiency.
DiChristina: Right, in case listeners want to know what the term for that is, it's called homogeneous charge compression ignition. So, that's fuel in; you also then can control the exhaust going out, which would normally just a kind of go out of the car, [but] if you circle it back in through means of either a turbo charger or supercharger you can create efficiencies there.
Steve: You could use that. That's heat, that's energy you can use that to recharge your batteries.
DiChristina: And you can improve the timing of when these things are done with software that can control, for instance, it's all well and good to have things exiting out the valve, but variable valve timing, which cannot just open and close the valves on some automated system, but can accommodate what's actually happening in the burn, could do a better job of it. And then there, you know, there are even ideas for the future such as a camless engine, which would eliminate belts that you commonly see in today's engines to help cut friction.
Steve: Right, friction is obviously one of your biggest enemies; just the friction of getting your tires moving from a dead stop, there's a huge energy sink.
DiChristina: And to engineers all of these energy sinks represent opportunities to do better. And, you know, as long as we are hitting on themes of evolution, [here's] another one, [where] we are talking about a certain kind of evolution for today's engines to make them serve us better; and, you know, we can make a lot of change in energy efficiency while we are waiting for the cost to come down, for the reliability to occur, and things like hydrogen fuel cell–powered vehicles, for instance.
Steve: We should say that this article was written by Ben Knight who is the vice president of automotive engineering at Honda R&D Americas in California. At this point let us turn to our favorite column other than mine of course.
DiChristina: Of course.
Steve: Lawrence Krauss's and Michael Shermer's…
DiChristina: I love all my children, too.
Steve: Equally. [Who did I leave out?] Jeffrey Sachs… "50, 100 and 150 Years Ago", brought to you by Daniel C. Schlenoff, who handles that every month.
DiChristina: Big shout-out to Dan.
Steve: 150 years ago—so great to be at a magazine [where] we can say, "150 years ago, we wrote this."
DiChristina: And also not have it be the earliest we can talk [about], because actually this year we are 165.
Steve: And we look great.
DiChristina: In August, and we look great.
Steve: And why don't we share this with you. We had in the magazine 150 years ago this month: "Within the past 10 years, there has been a revolution in making bread. The ancient leavened bread was made by the dough being left in a warm place till it began to ferment. The chemical progress is the starch into sugar, then carbonic acid and alcohol, which forms between the particles of flour and then swells them up. But great care was required in the operation lest it be decomposed, and therefore the modern process by yeast is much more preferable. Within the past 10 years, besides yeast in making bread, we have had 'baking powders'and 'self-raising flours'and such and 99 families in 100 use some of these." So bread-baking technology had improved 150 years ago to the point where Scientific American felt that it was obligated to cover [it]. Do you make your own bread, Mariette?
DiChristina: I do actually; I made some last week and I used yeast, the preferred method [of the] Scientific American editors of 150 years ago.
Steve: I will tell you without the yeast, we would be in lots of trouble.
DiChristina: I also really love the idea that the new, improved, modern way of making bread was to use yeast, which our ancestors were scraping off the walls years ago to make the very same bread.
Steve: By the way we said that infectious diseases were the number-two killers worldwide; number one is heart disease, although cancer could become the top killer in 2010. The February issue of Scientific American is available in its entirety for digital download at www.SciAmdigital.com. Individual articles can be found at ScientificAmerican.com, and check out the Web site for the article on how new maps from Hubble show a changing Pluto. Whatever it is—planet, dwarf planet, Kuiper Belt object, melon ball, cheese puff, whatever it is—it's changing. And check the Web site for info on how to enter our World Changing Ideas video contest. Next week, in honor of the Winter Olympics, we will look at the physics of curling—seriously. In the meantime, follow us on Twitter, where you all get a tweet every time a new article hits the Web site. Our Twitter name: @sciam. For Science Talk, the podcast of Scientific American, I'm Steve Mirsky. Thanks for clicking on us.
Steve: Welcome to Science Talk, the weekly podcast of Scientific American posted on February 10, 2010. I'm Steve Mirsky. When a whale dies at sea what happens to the body? This week on the podcast, Scientific American Editor in Chief Mariette DiChristina talks about the long afterlife of whales as well as other articles in the February issue. We spoke in her office.
Steve: So, Mariette!
DiChristina: Hi Steve.
Steve: Whale Falls!!! Why don't you explain what whale falls are?
DiChristina: This [is an] article by a paleontologist at the University of Leeds in England, Crispin Little, and whale falls are when whales actually fall.
Steve: They do not trip.
DiChristina: They do not trip.
Steve: These are dead whales.
DiChristina: They actually, I imagine they fall rather gracefully. After a period of time, you know, some whales surface and some don't, but after a period of time the carcasses begin to fall, and they eventually land in areas of the ocean where there's not a lot around them, and that's were it gets interesting.
Steve: It gets really interesting.
DiChristina: So, way back in 1987 some researches aboard the Alvin, which is a little research craft that's has been—actually a many-storied research craft because it's found some amazing things under the sea.
Steve: This is a submersible.
DiChristina: A submersible research craft.
Steve: It found the Titanic right?
DiChristina: Yes, and has been used to find many other things since then—dove under the water and found this very interesting sight in the middle, of a kind of an, I would call it a desertlike area, which most of the deep ocean bottom, well I wouldn't say most of it; many areas are not [chock] full of life like when you look at the ocean [reefs or] something like that. There, life is spread out over more disparate areas wherever life can find good reasons to cling on and here in is the segue to the whale falls. Because here is a good way for life to cling on; this is what those whales become is [the] foundation of whole ecosystems of fantastic creatures that lasts for decades under the seas.
Steve: Yeah, that's an awful big parcel of food basically, for other creatures when a big old whale dies and then falls down to the seafloor.
DiChristina: Right, a multi-ton parcel right; Steve [and] I were just talking about how big are these whales are, you know, about a, even a bus and a half of length or even more that; if you can image this mass or as Steve, you put your measurement.
Steve: Right, my measurement was that any of these large whales that we're talking about, they're longer than the distance from home plate to the pitcher's mound, to the pitching rubber, maybe to the back of the mound or even longer than the back of the mound. Or to put it in another way, to go to in a completely different direction with this [as a] way to envision the distance: It's about two thirds [of the way] from home plate to first base, on a major league field.
DiChristina: Which, you know, gives you a sense of the scale of the oasis in some of these really barren areas of the ocean for these sea creatures. And the sea creatures that arrive on them, I mentioned, can take decades to process these whale carcasses that have [gone] down, through a series of stages.
Steve: Yeah. You have basically between 50 years and a century's worth of digestible material down there when a good size whale goes down. One of the really great stats in the article talk[s] about the first stage of the colonization of the whale carcass, is some of the bigger fish come in—sharks and…
DiChristina: Hagfish for instance.
Steve: Hagfish, and they'll start going at the meat of the whale, and they may take from the carcass, anywhere from 40 to 60 kilograms of meat on a given day. Well, they can do that every day for two years before they run out of the meat.
DiChristina: Right it takes a couple of years to strip an enormous whale carcass of meat and then the next colonies begin. So there's a series of life stages. The next one is animals that are smaller than those larger fish, and they start feeding on remaining scraps of things in the little nooks of the bone and begin to process the bone itself to bring it down to sedimentary level. And these are things like little shrimp something with the terrific name of the zombie worm, which lands on the carcass, and a bristle worm, which really is like its namesake; you know, if you can imagine a comb with the spikes on both sides, that's what the bristle worms looks like, and they work over the carcass then for another couple of years to bring it to the next stage.
Steve: In the next stage, you're left with nothing but bone.
DiChristina: Right and this is the stage called—I'm going to use the fancy word and then I'll tell you what happens— the sulfophilic stage.
Steve: Sulfophilic, not "self-fulfilling".
DiChristina: Not, although I imagine it's quite filling for the creatures that are involved.
Steve: But it is the sulfophilic, meaning sulfur.
DiChristina: Right.
Steve: Sulfophilic stage.
DiChristina: Because this is where anaerobic bacteria, which produce sulfur, in the course of their processing get involved. And there are other animals as well such as mussels, a tube worm which looks like a pipe-cleaner pipe, kind of bent up and around, a little hollowed out, if you can imagine that; clams, limpets then scamper across the remaining bone mass of the carcass and really bring it down to the sea floor, and this is the part that can take up to 50 years to complete. And another thing I find fascinating is not just the scale of the individual whale itself, but how many whales, you know, in various sizes of carcasses are down there; the estimate in the article is there may be as many as 690,000 scattered all around the world forming these ecosystem oases. And these animals that, you know, float in between them cling onto one, and then the next, they're, sort of, I think of them islands of life on the bottom of what can be really nutrient-poor areas of the ocean floor.
Steve: And these organisms that live off them, as you say, kind off scamper from one island of safety, of nutrients, to the next, so there's this whole community that's living down there on these.
DiChristina: Right and I want to tell you also, I'm, that's fascinating enough, but another thing that really appeals to me personally I mean—this is a point of interest in how life evolves in general—is that this isn't some modern thing that has just happened with whales and current life forms. Indeed back in 1992, there was the first discovery of ancient whale falls; you know, it was in Washington State rocks from the Oligocene.
Steve: They're really old.
DiChristina: Really old—this is from 34 million to 23 million years ago and even earlier than that, they were marine—I almost said mammals, I had to stop myself because they're not marine mammals, they were marine-life plesiosaurs and others, large marine creatures of the Mesozoic Era. This is the [era]area that encompasses the entire span that the dinosaurs were on earth; and there's evidence that there were large marine-animal falls way back then. So millions and millions of years back further.
Steve: That set up similar kinds of communities that would take advantage of their carcasses when they hit the seafloor.
DiChristina: Right, and how we know this is we find the evidence of the old fossil bones and the old fossil creatures that had attached themselves to the bones that are similar enough in characteristic and lifestyle that we can stay, well this look[s] like the life stages that we're similarly seeing today with descended creatures.
Steve: It's really interesting because it's been going on there clearly for millions of years, and we just found out about it.
DiChristina: I love that about it, that it is recent and new, but also it's in keeping with other things we know about life. Steve, if you and I think about when we went to high school—now we didn't go together, but I think we were trained in a similar way—I remember so clearly after learning about ecosystems and after a forest might have been felled by lightning bolt and fire, then there would be a succession of stages of that forest, you know, from early [seedlings and so on]. So if you think about it, it makes perfect sense that life would have successions of stages for ecosystems in any place.
Steve: I have to say, I was thinking about the same thing, the forest succession after a forest fire, that came to my mind as well when I read the article. I don't think that is actually mentioned in the article, but the analogy is so clear that it hit both of us.
DiChristina: Right, I think it just shows also that life has evolved a series of strategies that are effective for propagation of itself, you know, from various ecosystem evolution, to the stages that they go on, and I love these kinds of lessons–they help me see the context in which life forms on our planet evolved.
Steve: Speaking of which, [since we're] talking about evolution and the interactions of living organisms in their communities, we have this other article in the magazine about the warfare that goes on constantly among and between the microbes that exist within us; and us, they're fighting each other, we're fighting some of them, our immune systems.
DiChristina: Right. Yeah, let me make the connection for the listeners a little bit. You're speaking of warfare. But what we are both speaking of is evolution of creatures in cooperation or in battle with each other for survival. And so this article that you are talking about, we call it "The Art of Bacterial Warfare", it's by Brett Finlay. And he writes about how bacteria actually get into life forms, whether they are, you know, ours—I think we're most immediately concerned with ours because infectious diseases are as a group the second killer of people of all the diseases that we face. So it's very interesting to [us] how we can learn to conquer these bacteria that have been battling with us in our body chemistry for years and years.
Steve: Worldwide, infectious diseases kill second most number of people every year.
DiChristina: Right. For instance, a lot of our major concerns today are bacteria source infections—tuberculosis, for instance, which people worry about, way back in the Dark Ages we had bubonic plague, that was also bacteria related.
Steve: We still have bubonic plague.
DiChristina: You're right.
Steve: [It just] usually doesn't kill people in large numbers any more, because we have antibiotics.
DiChristina: Right. We have therapies, antibiotics, and drugs to fight them. So what the scientist is talking about in this article is getting a better understanding of the ancient interplay between bacteria and their hosts, whether human or otherwise. What are the tricks that bacteria use to infiltrate your body to then trick a cell and to bring in the bacteria into itself, to then use cellular machinery to you know replicate toxins or other things that bacteria seek to produce for their own survival; and then what clues can we get; finding those mechanisms, what the bacteria are actually doing, how can we then stop them at each front?
Steve: So what are some of the ingenious tricks that the bacteria have come up with to get inside the cells [an wreak havoc], and what are some of the equally ingenious tricks [our] cells have come up [with] to try to fight that, and what are we trying to do to, you know, to learn from that so that we can come up with faster, better ways, you know, with actual drug treatments or other therapies that would alleviate some of these problems?
DiChristina: Well, let me answer the last question first, which is, as with many things we seek to copy stuff that nature has figured out over a millions or even billions of years sometimes. So our drugs will seek to replicate kinds of things that our body already might do, but maybe needs to do a better job of, through immune stimulation or others, but also through mechanisms of blocking. Let me give you a couple of first examples of things bacteria do. One would like it call it ingenious if the bacteria were really thinking about it.
Steve: Right. No anthropomorphizing. The bacteria do not plan to do these things; they have evolved these techniques that we think of as ingenious.
DiChristina: So here is one E. coli. Everybody has heard about E. coli and some of the problems that can happen with E. coli. E. coli produces a kind of protein [that] acts like a docking clamp on to your [cells] so it can attach itself. So this is the one way that it approaches and at least gets connected with a cell. salmonella uses a similar kind of mechanism and it causes the cell to produce, sort of, ruffles in its membrane—the membrane is the outer surface of the cell— and these ruffles, if you can imagine them coming out like arms that hug, almost embrace the bacteria and draw it inside the cell's anterior.
Steve: So it forces the cell to consume it.
DiChristina: Correct, by making the cellular membrane change in a way that benefits the bacteria. Shigella bacteria has another interesting trick. It has something called effectors that induce something called actin polymers inside the cell—they're chemical compounds inside the cell—that create something that is described as a rocket tail, and it really kind of looks like that, that then propels the microbe into the cell cytoplasm, the liquid material inside the cell, to help invade a neighboring immune cell on top of but it's already done. I wish humans [knew] as much about how to manipulate cells as bacteria already do with their one cell.
Steve: Well, that's true. We have some lovely artwork in the article. So if you actually look at the article either in the magazine or online you will see illustrations of [some of] these things that we are talking about.
DiChristina: Right, so one set of illustrations is some of the things I have described, which is how the bacteria manipulate the cellular responses to benefit their own [nefarious] purposes and then another one is how do they then get around your immune system? What are ways that bacteria shield themselves, you know, so that they look invisible to immune protectors or to otherwise get around existing systems in the body that are set up to defeat them? And [an] answer to your question about how we are going to use this, is we're actually testing on some substances that could be built into drugs. A lot of these [are] really [in the] early days; so preclinical work, we are just trying to determine, is it even possible on the cellular level, as you know, have we actually figured it out the mechanism that is being used by the bacteria and the cells to evade it, and then could we take that and express it in some kind of either synthetic or naturally produced material that we could use to, you know, [create an] effective defense.
Steve: And there's also the issue of helping the neutral or good bacteria. We are just swimming in it, and people should understand that the cells that we think of as being us, your skin cells, your kidney cells, your brain cells, are outnumbered 10 to one by the cells of everything else that's living on and in us. So we are talking about the whale falls. We are host to this elaborate community of other organisms that are part of us, and we don't really even think about it. But people mostly know that your intestines and your stomach are filled with bacteria.
DiChristina: Right; everybody is eating yogurt.
Steve: Right.
DiChristina: With the right kind of bacteria in it.
Steve: And so one of the strategies is to assist the bacteria that are there in large numbers doing you no harm, assist them in fighting off these invading nefarious bacteria.
DiChristina: Right I mean, and I think one thing a lot of us are familiar with from taking antibiotics is we know that they then disrupt our digestive systems after that because [it wipes out the fauna that would] normally be in the body and help you digest. So yes, this is one area, and another thing I like that the article mentions at the beginning actually, is the next time you're feeling lonely, you'll realize that you are not by yourself ever; you know, indeed as you mentioned 10 times, you know, 10 to one of your [cells] is bacteria I or others that are living on, in and around. And one of the amazing things about those, you mentioned the neutral cells, is that only maybe 100 types of them are virulent to us; most of them are quite cooperative and good neighbors.
Steve: We have domesticated them very successfully.
DiChristina: Right, or they us.
Steve: Right or they us. Good point. So indeed the next time you're feeling lonely remember you are surrounded. The next time you're feeling paranoid, remember you are surrounded.
DiChristina: Some of the bacteria do [mean you ill].
Steve: They're watching you. We are running out of time, but we have another piece in there that I wanted to just discuss briefly, and it's about internal combustion engines. We are all looking for electric vehicles, hydrogen fuel vehicles, alternative vehicles that will help us get off the oil dependence. But one of the ways that we can really improve things now in the meantime before we are all driving the all-electric, all-hydrogen, all-solar fleet of cars, you know in 2050—I'm keeping my fingers crossed—is take the vehicles we have now the internal combustion vehicles; lets make those internal combustion engines more efficient. The amount of fuel that could be saved just by increasing the efficiency of internal combustion engines is really impressive. And what I did know until I read the article was that this is a process that has been ongoing, I think the figure was between 1987 and 2006, fuel efficiency has increased 1.4 percent every year on average. Now for you fans of compound interest out there, that works out to be quite an impressive total after two decades. The problem is, we squandered it all by going in for these larger vehicles that just burn all that extra gas that we would've saved.
DiChristina: It's actually, we have been working on internal combustion engines and making them better for 100 years.
Steve: Right.
DiChristina: You're right, and in the last couple of decades we've made a number of advances, but the sad fact is that today internal combustion engines only give us, for each gallon you put in, about 20 percent to 25 percent of the work back out that we would like to see. So there's an enormous area of potential improvement still.
Steve: Right, the chemical energy is converted to work incredibly inefficiently.
DiChristina: And you can do a little better with diesel engines—25 percent to 35 percent—but they are way more costly and you have already mentioned, you know, things like hydrogen fuel cells, plug-in vehicles, which [we] will be seeing later this year [and] which I'm very excited about too, but in the meantime we can really move the needle a lot with some efficiency improvements on current technology.
Steve: Well, not move the needle actually.
DiChristina: Well.
Steve: The gas [gage needle]—we [don't want] it moving; anyway, go on.
DiChristina: I got it. So we can do this in a number of ways, but its sums up to this, these three, kind of, key things. You got to control the air fuel mixture going in; you got to control how it's burnt, so the more complete the burning the better; and then you have to control how that chemical, you know, how that energy that has been released is then run through the systems of the engine itself. So what this article talks about is the various specific technology things you can do; for instance varying the way you inject the fuel. Today its common to inject the fuel into an air stream and then it enters a combustion chamber where it is ignited. You could inject the fuel directly into the combustion chamber, for instance; you have to be able to control that injection very closely, and here is where good software and good engine design really enters into things.
Steve: And you can do it with even, we talk in the article about a sparkplug-free combustion chamber, where just the act of pressurizing the chamber causes the combustion and without that spark plug, [what] you wind up with is a much more even burn and a lower heat loss. And you would have the spark plug there for backup, but if you don't need it, you increase your efficiency.
DiChristina: Right, in case listeners want to know what the term for that is, it's called homogeneous charge compression ignition. So, that's fuel in; you also then can control the exhaust going out, which would normally just a kind of go out of the car, [but] if you circle it back in through means of either a turbo charger or supercharger you can create efficiencies there.
Steve: You could use that. That's heat, that's energy you can use that to recharge your batteries.
DiChristina: And you can improve the timing of when these things are done with software that can control, for instance, it's all well and good to have things exiting out the valve, but variable valve timing, which cannot just open and close the valves on some automated system, but can accommodate what's actually happening in the burn, could do a better job of it. And then there, you know, there are even ideas for the future such as a camless engine, which would eliminate belts that you commonly see in today's engines to help cut friction.
Steve: Right, friction is obviously one of your biggest enemies; just the friction of getting your tires moving from a dead stop, there's a huge energy sink.
DiChristina: And to engineers all of these energy sinks represent opportunities to do better. And, you know, as long as we are hitting on themes of evolution, [here's] another one, [where] we are talking about a certain kind of evolution for today's engines to make them serve us better; and, you know, we can make a lot of change in energy efficiency while we are waiting for the cost to come down, for the reliability to occur, and things like hydrogen fuel cell–powered vehicles, for instance.
Steve: We should say that this article was written by Ben Knight who is the vice president of automotive engineering at Honda R&D Americas in California. At this point let us turn to our favorite column other than mine of course.
DiChristina: Of course.
Steve: Lawrence Krauss's and Michael Shermer's…
DiChristina: I love all my children, too.
Steve: Equally. [Who did I leave out?] Jeffrey Sachs… "50, 100 and 150 Years Ago", brought to you by Daniel C. Schlenoff, who handles that every month.
DiChristina: Big shout-out to Dan.
Steve: 150 years ago—so great to be at a magazine [where] we can say, "150 years ago, we wrote this."
DiChristina: And also not have it be the earliest we can talk [about], because actually this year we are 165.
Steve: And we look great.
DiChristina: In August, and we look great.
Steve: And why don't we share this with you. We had in the magazine 150 years ago this month: "Within the past 10 years, there has been a revolution in making bread. The ancient leavened bread was made by the dough being left in a warm place till it began to ferment. The chemical progress is the starch into sugar, then carbonic acid and alcohol, which forms between the particles of flour and then swells them up. But great care was required in the operation lest it be decomposed, and therefore the modern process by yeast is much more preferable. Within the past 10 years, besides yeast in making bread, we have had 'baking powders'and 'self-raising flours'and such and 99 families in 100 use some of these." So bread-baking technology had improved 150 years ago to the point where Scientific American felt that it was obligated to cover [it]. Do you make your own bread, Mariette?
DiChristina: I do actually; I made some last week and I used yeast, the preferred method [of the] Scientific American editors of 150 years ago.
Steve: I will tell you without the yeast, we would be in lots of trouble.
DiChristina: I also really love the idea that the new, improved, modern way of making bread was to use yeast, which our ancestors were scraping off the walls years ago to make the very same bread.
Steve: By the way we said that infectious diseases were the number-two killers worldwide; number one is heart disease, although cancer could become the top killer in 2010. The February issue of Scientific American is available in its entirety for digital download at www.SciAmdigital.com. Individual articles can be found at ScientificAmerican.com, and check out the Web site for the article on how new maps from Hubble show a changing Pluto. Whatever it is—planet, dwarf planet, Kuiper Belt object, melon ball, cheese puff, whatever it is—it's changing. And check the Web site for info on how to enter our World Changing Ideas video contest. Next week, in honor of the Winter Olympics, we will look at the physics of curling—seriously. In the meantime, follow us on Twitter, where you all get a tweet every time a new article hits the Web site. Our Twitter name: @sciam. For Science Talk, the podcast of Scientific American, I'm Steve Mirsky. Thanks for clicking on us.
