"Climate, Health and Complexity: Converging Frontiers"
Dr. Rita R. Colwell
National Science Foundation
Remarks at BioVision 2003, The World Life Sciences Forum
(delivered by videoconference from Arlington, Virginia)
April 9, 2003
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[title slide: "Climate, Health and Complexity: Converging Frontiers"]
Good morning to BioVision participants, and a special greeting to all distinguished speakers and guests. I am very grateful to be able to address you although I regret not being able to be with you in person.
The BioVision meeting occurs at a very serious juncture in world affairs. We all share a desire for a swift and humanitarian solution to the conflict in Iraq. In a deep way these events make BioVision's goal more urgent--to promote dialogue about cutting-edge issues in the life sciences.
The biological sciences hold fantastic potential to contribute to the well-being of humanity and to the planet we call home--if we can integrate the stunning discoveries of science and engineering within the broader framework of our global society.
I speak with you today as both an active researcher who has pursued the linkages between climate and human health, and also as director of the U. S. National Science Foundation, an agency responsible for the health of the nation's research enterprise, including a vibrant biosciences portfolio. Our extensive international linkages underscore that today's global scale of research is without precedent.
The publication of Watson and Crick's paper 50 years ago, revealing the structure of DNA, heralded a revolution in bioscience whose momentum continues to accelerate, now at an exponential pace. Our global society faces new challenges almost daily that need the discoveries of the life sciences-challenges such as infectious disease spreading around the globe through air travel.
As a framework for facing these challenges, I will cite three principles that characterize the life sciences today. Since the structure of DNA was discovered a half-century ago, certain truths have come to characterize my own research on climate and health, as well as our broader science.
- First is the reality that biology's almost miraculous applications-whether in the environment, agriculture or health-rest upon a wellspring of discovery in fundamental research.
- Secondly, many exciting discoveries in other scientific disciplines take place in convergence zones--where other fields encounter life science. The simple questions in biology have been answered. Now we need a systems approach; I call it biocomplexity, a perspective that spans scales and disciplines.
[Math /bio word slide]
Some convergence zones are especially rich. Where mathematics and computing meet biology, they serve as biology's new microscope, illuminating otherwise invisible entities.
Math and computing shed light on bioscience problems that are too big (the biosphere), too slow (evolution), too remote in time (early extinctions), too complex (the brain), or exceed our capabilities in other ways. (I thank the National Computational Science Institute and Joel Cohen at Rockefeller University for framing the math-bio links this way.)
- The third principle-I've alluded to it already-is the global sweep of bioscience. More scientific questions of all sorts are taking on planetary dimensions, and only international partnerships can address them. Both climate and health are global phenomena, and for the first time, we can bring a global perspective to bear.
[Satellite view of dust storm off North Africa]
Here we see graphic evidence of the free flow of natural forces. A dust storm, originating in West Africa, surges out over the Atlantic Ocean. The African dust carries with it billions of microorganisms- fungi, bacteria, and viruses, among them pathogens of both humans and plants, as well as beneficial organisms. Research on this transport is in its infancy, yet the phenomenon underscores the smallness of our world.
Bioscience of today's breadth and depth calls for new frameworks. I have mentioned biocomplexity-a way of thinking about the relationships between life and its environment that has emerged from a lifetime of studying the interactions between climate and health.
Ecosystems do not respond linearly to environmental change, nor do the pathogens that live in them. Here I use the form of a spiral, so evocative of life at every level, to underscore the point that understanding demands observing at multiple scales, from the nanoscale to the global.
The spiral of complexity begins to unfurl at the most minute scale of the atom, and curves up through successive levels of life. With the perspective of biocomplexity, disciplinary worlds, formerly discrete, intersect to form fuller, more nuanced viewpoints. The spiral curves both ways-outward, integrating the levels of life, and inward, back to the center.
[squid with bioluminescence]
Biocomplexity's synthetic perspective is demonstrated through examples of fundamental research. The first example, which begins with the squid, shows how ecology sheds new light on human disease. Shown is a bobtail squid from Hawaii, which exudes a ghostly blue glow on moonlit nights. Its secret is this: The squid ingests quantities of luminescent bacteria, which glow inside the squid and cause its shadow to disappear-perfect camouflage.
The real secret, however, are the whispers that animate this community of glowing bacteria-whispers of communication that take place through chemical secretion. Only when enough chemical builds up-indicating that a critical number of bacteria are present-do they light up.
[chart of all bacteria that have "signaling gene"]
Bonnie Bassler of Princeton University and others have discovered that this bacterial communication governs a wide variety of bacterial pursuits. E. coli and other bacteria responsible for human diseases use similar signaling.
Discovery of the "signaling gene" could lead the way to foiling drug-resistant bacteria. Here's a case in which the study of marine bacteria's luminescence-once considered "incredibly arcane, with no application at all"-produces a fundamental insight for human health.
[Map of North America with glacial extent in blue]
Here is another study--one that spans temporal and magnitude scales to bring insights into understanding our living planet. The large blue area on this map of North America denotes the glaciated region of Canada and the northern U.S. It turns out that, because of glaciation, the forests of Canada had no native earthworms, and the northern United States, as well, had very few or none.
[Minnesota forest: with and without earthworms]
Invading earthworms, it turns out, have a tremendous effect on forest structure and nutrient location. This Minnesota forest in the picture has no earthworms, and it has a brushy understory.
[Minnesota forest: with earthworms]
In this slide, earthworms have invaded the forest, pulling shrubs and leaf litter down into the soil, creating a park-like landscape, with a much more open understory.
[schematic cutaway of forest floor: with and without earthworms]
As invasive earthworms move north with climate change, they may alter the composition of species in a forest and change where carbon is stored. Carbon, of course, is the element so critical in global warming. Could invasive earthworms spur forests to store more carbon, or could they somehow cause more carbon dioxide to be released to the atmosphere? We gain a new perspective on invasive species and climate change.
[world spread of cholera]
The third example speaks very directly to climate and health. It is my own research on the links between climate and the disease cholera.
Cholera has plagued humankind since ancient times, but it is very much still with us today, as this global snapshot shows. Cholera occurs worldwide, and we are still in the grip of its seventh pandemic. Today we are beginning to trace the currents of complexity surrounding the mystery of cholera, from the smallest to the largest scale.
[Chesapeake Bay sampling sites]
In the 1970s we discovered that the ocean itself is a reservoir for Vibrio cholerae, causative agent of the disease, cholera, when we identified the organism in water samples from the U.S. Chesapeake Bay. You see sampling sites here. Earlier detection methods for this organism were developed strictly for testing clinical, infectious samples. In the environment, this organism is more difficult to detect-it may be viable but non-culturable.
[copepod with egg case]
Cholera's ecology is intimately linked with the copepod, a microscopic relative of shrimp. Shown is a female whose egg case-on the left-is covered with vibrios. We believe that cholera originally evolved commensally with marine animals such as copepods, which provided them a surface on which to grow, nutrition, and maybe other mutual benefits.
[SST and SSH-Bangladesh: cholera]
On a large scale, we have used remote-sensing to track sea surface temperature and height. We discovered that temperature patterns were clearly linked to the pattern of cholera outbreaks in Bangladesh and South America. As sea surface temperature and height increased, cholera outbreaks followed. We have even hypothesized that El Nino triggered the resurgence of cholera in Peru in 1991. Warm waters and plankton blooms may have helped amplify the population of cholera bacteria already in the environment there.
[Bangladesh: woman straining water]
In cholera-endemic areas, human beings are part of the ecosystem for the cholera bacteria. Yet there is a simple and inexpensive tool available, which we can employ because we now understand cholera's ecology. A sari cloth, available even in the poorest household, can be folded eight to ten times. This creates a 20-micron mesh filter, as we determined by electron microscopy.
[micrographs of old and new sari cloth]
The pictures show why old, not new, sari cloth is essential-because its holes are smaller and better able to trap the plankton on which the cholera bacteria rides. We tested the cloth filter in villages in Bangladesh-the incidence of cholera was reduced by more than 50% with sari filters. The severity of disease may also be reduced.
Sorting out cholera's story required insights from many disciplines. Connecting cholera to climate has required contributions from sociologists, physicians, field extension agents, ecologists, geneticists, statisticians, and remote sensing scientists. Only biocomplexity's perspective applied on a global scale could pull the pieces together.
[title slide again]
World headlines have been focusing on a new infectious disease-SARS, or Severe Acute Respiratory Syndrome. Besides taking lives, this disease is also hurting the transportation industry, especially airlines; we don't yet know its full effects.
Yet, I am encouraged by the words of David Heymann, director for communicable diseases at the World Health Organization. He said, "What we've seen from this outbreak is a solidarity within the world which has been unknown in public health.We're seeing an unprecedented global response."
In the context of this latest threat, I hope that the discussions at BioVision will consider how insights from environmental and ecological science enrich our understanding of human health. Our global society urgently needs the solidarity of life scientists in sustaining ourselves, our food supply, and our planet. Dialogue is critical so that the sparkling promise of bioscience will be realized to everyone's benefit.