I: Hello my name is Jeffrey Lear. I am a student at George Washington University and I am here interviewing Dr. Sarah M. Glaser for the 2015 NASA Astrobiology Debates. Dr. Glaser is a research associate at the One-Earth Future foundation, a Denver based non-profit, and a scientist at the University of Denver. Dr. Glaser earned a PhD in Oceanography at the Scripps Institution of Oceanography and specializes in fisheries, food web ecology, and complex systems. Thank you for accepting this interview Dr. Glaser.
G: You’re Welcome. It’s my pleasure.
I: Dr. Glaser and I are here to discuss the following topic which was prepared in partnership with the NASA Astrobiology program. The topic reads as follows: Resolved: An overriding ethical obligation to protect and preserve extraterrestrial microbial life and ecosystems should be incorporated into international law. Dr. Glaser, to start how about you tell us a little bit about your area of expertise and how it relates to our topic.
G: Well Jeffrey as you mentioned in the introduction I am a fisheries ecologist and oceanographer, so in some ways my field of expertise is somewhat removed from the topic of extraterrestrial microbial life. However, I think one of the reasons I was asked to be a part of this interesting debate is because my studies also take a big picture look at food web ecology and our ability, our being humans, to make predictions in complex ecological systems and that has a lot of relevance for understanding the impacts that humans might have on microbial life. So for example, I have looked at food web interactions between predators and their prey, how changes in the resource base effect different populations, and how those have ripple effects throughout food webs and food chains, and in particular the effect that humans have when we start removing or tinkering with parts of those food webs.
I: So how easy do you think it would be for humans to go into an extraterrestrial environment and disrupt a food web?
G: Well I think it would be quite easy. I guess one of my questions posed for you is in the context of this resolution are we talking specifically about Mars? Or are we supposed to use our imagination and think about any particular planet that would be habitable?
I: I think for the sake of the debates the focus isn't particularly on Mars but it certainly can be. I know a lot of the literature referenced is focused on Mars, so with that in mind what would your perspective be in an environment like Mars?
G: I guess in an environment like Mars where we think there if there is life that it is quite small, I think there can be parts of the planet where we have a large impact and other parts where there would be no impact whatsoever. If I am letting my imagination run wild and thinking about a “science fictiony Battlestar Galactica” type of world or universe in which there are vertebrates living or even other human like colonies on other planets, I think that it would be very likely that our presence would have a big impact on the food webs if we decided to start harvesting. As some of the studies of marine ecosystems in particular show that humans, even at very small levels of harvesting, even 10,000 years ago had some pretty demonstrable impacts on the ecosystems on which they started tinkering. There was some work done by Jeremy Jackson and a lot of people in his lab at the Scripps institution of Oceanography show that even before the colonization of North America by Europeans that Native Americans had a huge impact on fisheries and even the non-fisheries ecosystems. So even small amounts of harvesting tend to have very large impacts on food webs, so there are some very strong connections.
I: So with that in mind would you say that the only way to preserve extraterrestrial microbial life would be no human interaction whatsoever?
G: I don't think that I would say that is the only way to preserve it. When I think of harvesting I think more of creatures that we are taking for resource consumption for ourselves like eating them for example which wouldn't be the case with microbial life. So in the case of microbial life, as far as harvesting goes, I don't think that we would be a risk to the survival of different species of microbes at least from a harvesting point of view. So if the question is whether the only way to preserve I guess I would have to say my definition of “to preserve” is that some of the species still exists so I would disagree with that statement and I think that there are ways humans could potentially interact with extraterrestrial life that could preserve those microbes, preserve the species, preserve the diversity. I think if we're talking about an individual microbe and we decided to do studies that there would definitely be loss of microbes in an individual sense but maybe not from a species perspective.
I: So then would you say that something like an environmental preservation would be an effective way for human and extraterrestrial microbial life to coexist?
G: Yes. And I think you hit on a key point when you mentioned the preservation of the ecosystem. So one of the challenges that we have here on earth is preserving large enough spaces of land so we effectively cover the entire ecosystem. So for example, something large like Yellowstone national park has had challenges in preserving some of its top predators because a breaking of their natural habitat and range. So to effectively understand how large a preserve would need to be we need to know the extent of different species. If we're just talking about microbes then I think an important consideration would be diversity and making sure we have systems for preserves that are large enough to maintain the diversity that exists in a place before we inhabit it. That introduces an interesting dilemma for us which is as soon as we arrive to a new area we are going to start changing it and so trying to have minimal, and when I say minimal I mean in an invasive sort of way, impacts on the ecosystem while we're able to sample it would necessarily be an important first step in understanding the diversity, the range, and all the needs of the different microbes in order to design preserves that would be large enough.
I: Based on your experience with preservation here, what would you say would be the best way to minimize that dilemma?
G: That's where my knowledge of microbial biology and protocols for landing on the moon and landing on Mars cuts against my ability to answer that questions very well because I think you're talking about some technicalities or precautions that we might take. I guess I would say that on the one hand that it’s just going to be a practical question. We're not going to be able to rapidly colonize another planet, our exploration would occur very incrementally, so if we have the Mars rover right now it is just one instrument on Mars doing some sampling. I don't think that carries a very large risk compared to landing say 1000 rovers on Mars and the risk that would carry with it. You also run into then the problem of ensuring that what you sample is representative of what is actually out there. So we know for example the lander that is on the asteroid right now is having a hard time collecting all of the data that we wanted it to collect. So we're naturally going to be limited by our technical capabilities to answer the question have we covered enough ground? Have we collected enough species to represent diversity? But as far as technical approaches to minimizing our footprint as we enter such a space, I would leave that to the experts, probably NASA, to know things about sterilization and certain protocols that would help in minimizing the impact that we have.
I: Aside from the idea of protecting the ecosystem itself how might human development impact the evolution of extraterrestrial microbial life, specifically the species rather than the ecosystem?
G: I think that is a question of time frames. I think that in the very short term, and by short term I mean weeks to months to maybe even a year or two, that we might not have a significant impact on the evolution of a species. That being said, microbes evolve very quickly so harkening back to what I mentioned before about the impact of excess amounts of mortality has on species, humans have an outsized effect compared to natural predators. There is a paper that came out just last week that called humans super predators and showed the effects that we have on fish is fourteen times bigger than any other natural predator. That is largely because the amount of fish that we harvest. So if we look at humans as an outside predator or an alien predator, and in the case of another world we would literally be an alien predator, I think that we would potentially underestimate our effects, or the effects that we would have would be greater than we might anticipate. So I think there is a significant risk that in the matter of say two or three years that the effects of harvesting or if we were to introduce disease or contamination to a species could have significant evolutionary impacts if we are talking about microbial communities.
I: Do you think those evolutionary impacts could be ultimately fatal for some species?
G: I think that there is definitely a risk especially with the introduction of things like contamination or disease. Without having any idea what is critical to the life of a certain microbe it could even be something that is relatively harmless on earth that we just didn’t have any idea would be poisonous to another species. There is also the question of special scales, so if there are say small pockets of microbes that are one species that doesn't exist anywhere else on the planet and that is where we have an impact we could certainly wipe out an entire species, and I think that if we're talking about a planet like Mars it certainly does not appear to have large amounts of life then we're talking about small areas of life that are very isolated from each other and those are the circumstances under which rapid evolution occurs. So you could think about say the lakes of Africa that used to be one large lake and they dried up and became a variety of small lakes and in those small lakes certain species began to evolve rapidly. It’s called species radiation. Something like that is probably happening in areas like Mars or planets like Mars that have very isolated communities. So I think it could easily be the case that we wipe out an entire species because they exist in a very limited location.
I: From a scientific standpoint do you think that wiping or even taking the risk of wiping out an entire species is something that is harmful?
G: Yes I think it’s very harmful if we're only talking about microbes I don't know if the question becomes an ethical one or not but certainly there is an argument that could be made that we have the prerogative to protect any form of life from extinction. I think that humans don't follow that prerogative here on earth. I think we wipe out species before we've even discovered them and some of those are vertebrate and invertebrate species that are much higher forms of life than microbes. But if you're talking about a planet that only has microbial life then you're talking about the highest form of life that exits on that particular planet and to take a risk of potentially wiping out a species given the way species interact with one another, given the way that keystone species and food webs are really critical to the function of an entire ecosystem, it could have consequences that go far beyond the extinction of that one species.
I: You said that the consequences could go beyond the extinction of a species, what kind of impact do you think there could be specifically?
G: It depends on the species that would go extinct. So there are, on earth anyways, what are known as keystone predators. Keystone predators are called that because when you remove them from a food web there are ripple effects throughout the food web and we tend to think of these as strong linkages. So if you image a food web as a spider web and each node has a species and its connected to lots of other species, keystone predators have very strong linkages to many other species or strong linkages to just one critical species like a critical prey item in that particular food web. There have been empirical studies here on earth that show that the removal of just one can have ripple effects and that can be either from a predator or a prey or even a competition point of view. So it doesn’t have to be a prey item, we tend to think of these sorts of ripple effects from the point of view of a food source being removed when in fact some of these ripple effects can occur when a predator is removed if that predator regulates the prey that live below it on the food chain and then that prey in turn regulates prey below it. What can happen is that the first set of prey can explode in population because its predator is gone.
I: What are the potential scientific benefits for future generations of maintain a pristine extraterrestrial ecosystem for scientific study.
G: Well I'm not sure the premise of your question is sound because on one hand you said pristine and on the other you said scientific study. Even scientists who try to have minimal damage in the place they are sampling, they will be killing organisms potentially or altering their environment. So I'm not sure that it can both remain pristine and be available for scientific study. To remain pristine we would have to avoid going there all together. To preserve a system for scientific sampling however it doesn't necessarily have to be pristine and once we go there and recognize it won't be, the best thing to do would be to try to map the area, understand where there is heterogeneity in landscapes, understand where there is heterogeneity in species distribution, and the real problem for us and this is true on earth as well when we have an unexplored area is we just don't know what that looks like and until we understand what it looks like we're just going to be invasive.
I: So then what would you say would be the benefits of avoiding human development in a particular ecosystem altogether and instead preserving it with minimal damage for scientific study?
G: We've already touched on some of the potential benefits which would be better understanding forms of evolution. I think that my resting assumption would be that the models that we have developed here on earth for things like population dynamics, the way that species interact with each other, I would assume that those mathematical models would apply to other systems. So to me the main benefits would be collecting data to try to see where our models don’t fit other worlds and in that case we might better be able to understand how evolution occurs here on earth by understanding how it is ongoing especially if we find a world in which say the only thing that has evolved is microbial life. In that case we can assume either that the conditions are not right to support higher forms of life like invertebrates and vertebrates we can assume that evolution hasn’t happened yet, or we can assume that evolution did happen and now the world has reverted back to microbial life only in which case we would expect to see fossil evidence of that. So finding planets that give us a snap shot into what evolution might have looked like in the past or will look like in the future will be important for us in finding our evolutionary models here on earth.
I: Does your experience with international regimes seeking to protect terrestrial life and ecosystems suggest anything about the idea of such a regime for extraterrestrial microbial life and ecosystems?
G: Well, I hate to be a cynic but they're not very effective for protecting life here on earth so I have to say I have my doubts. I also think that if we are talking about international bodies that have been created here on earth that at the very least that we have national boundaries that define different spaces, so nations have self interest in both preserving and exploiting their own resources and ecosystems. If we start expanding that now to outside of the earth the question becomes who has jurisdiction or authority? I think that it would be very challenging. I would think that we would have to set up a brand new body and I am not optimistic that forces of conservation that would win out against forces of resource use and exploitation. It would be an interesting debate in the public and I think that at least in our current political climate that a lot of the international bodies are so bogged down in being able to see the big picture on things such as climate change for example and there is so much national interest that is overwhelming the global interest so I am not optimistic for things to be any different for the discovery of life outside of our world.
I: So you would say that if humans went to an extraterrestrial environment that ultimately that environment would deteriorate?
G: Yes I do, and at the risk of sounding like every other science fiction writer I do believe that would potentially happen but I have to say that I don't imagine that happening quickly or in any short time frame. So given that my cynicism is partly a product of the current political climate and that marrying that with the idea that we're not going to be colonizing or harvesting resources from a planet for a very long time, maybe I'm optimistic that things get better here on earth and we come to develop better international instruments for dealing with these things. Maybe we have a climate crisis here on earth that brings us to some point of clarity and international bodies are able to work more effectively 200 years in the future. I suppose I could be optimistic about that.
I: So one final question. Looking back at the topic would you say that there is an obligation to protect and preserve extraterrestrial microbial life from a scientific stand point specifically?
G: Yes. Yes. I would most certainly say that there is an ethical and overriding obligation and the word protect if we're talking about individual organisms like individual microbes, I don't know if we have an obligation to protect an individual microbe but to preserve at both the species and population level absolutely we do.
I: Great. That's about all the time we have for today, Dr. Glaser I would like to sincerely thank you for everyone at the astrobiology debates for giving up your time to provide such useful and informative insight on your perspective on this issue.