We Don't Know What We Don't Know
Professor Timothy Bromage (photo by Kate Lord)
And Biomaterials Professor Timothy Bromage Is Working to Change That
By Alison Gwinn
Ask Timothy Bromage—a hard tissue biologist working in the fields of paleontology, biology, and anthropology—to describe his scientific philosophy, and he quickly cites his reverence for Charles Darwin: “He read economics, geology, the social, biological, and physical sciences—everything. Nothing was irrelevant.” Bromage brings that same voracious, all-encompassing curiosity to his work as professor of biomaterials and head of the Hard Tissue Research Unit in the College of Dentistry. “We endeavor to know what we don’t know we don’t know,” says Bromage, who recently developed a new method of testing liquids for inorganic elements in a much faster and more efficient way. “We open ourselves to everything, not being closed to any aspect of the world that could possibly have some purchase on what we’re interested in.”
Bromage’s recent water-testing discovery, published in the Royal Society of Chemistry’s RSC Advances, came about from a “What do I not know I don’t know?” question: How can all the periodic table’s elements in a liquid be measured instantaneously? “No one had ever done such a thing,” Bromage says. “Even a simple glass of water had never been evaluated that way.”
So Bromage’s team of scientists started reading all the literature they could find on ecological stoichiometry, the subject’s scientific name, and discovered that nothing they encountered had ever been tested for more than four elements: carbon, oxygen, nitrogen, and phosphorous.
“Knowing the distribution and concentration of those four elements could tell us a lot about the environment,” says Bromage. “But I asked myself, ‘How can that be anything like the reality?’ Because the inorganic spectrum includes 92 elements, most of which are required for life. I thought we really had to break that open.”
It was, he says, a perfect example of “perceptual bias” in science: “The reason some people thought they could explain the whole environment by only four elements was that they only had the technology to do that.” Knowing he needed to find a “bigger picture” technology, he tracked down a company that manufactures a mass spectrometer capable of measuring the entire periodic table. “After the machine arrived in our lab, we asked the company, ‘So how do we do it?’ They said, ‘Are you crazy? We don’t know! We just said it was possible.’ Our jaws dropped. We realized we had run into a brick wall.”
But Bromage sees brick walls as opportunities, so over the next two years he and his team developed (and patented) the measuring method, which detects 71 inorganic elements in about 90 seconds. They then applied it to a variety of liquids—“If we could pee into the machine or spit into it, we did. We looked at wine, beer, milk, bottled waters, seawater, lake water, river water. And guess what? The freshwater sample that had the most elements in the highest concentrations was a sample of snow collected at 14,000 feet in the Italian Alps.” In testing samples from all over the world, from Mongolia to national parks in Oregon, the scientists were able to create “fingerprints” to trace the liquids back to their origins.
Why is that important? Because it helps us “understand the metabolism of a place,” says Bromage, whose undergraduate degree, from California State University, Sonoma, is in biology, geology, and anthropology, and whose master’s and PhD, from the University of Toronto, are in biological anthropology. “If you consider the scaling of metabolism, it works like this: there are cells in your body. We can take, say, a single cheek cell with a swab, look at it under a microscope and actually evaluate its metabolic output. You add up all of the cells in all of the tissues in all of your organs, and it finally becomes you. But you live in a neighborhood that has trees, grass, dogs, cats, and people, who all have metabolisms of their own. You add all of those up, and you get the metabolism of your neighborhood, and then the metabolism of your city, your country, and the continent.
“At every scale, there is a metabolism; we’re doing global ecological stoichiometry by collecting water samples from all over the world. You choose at what scale you want to interrogate, and you learn about the metabolic ecology of a place, how it works in every single way, and that provides a foray into climate change science, nutrition—a million subjects. It’s a completely new field.”
So far, the NYU machine is the only one in the world that can do this examination, but the method has innumerable uses. “For instance, the United Nations fully funded us to do a project on the water chemistry of Samoa in the South Pacific,” Bromage says. “The coral reefs there are dying, and they thought perhaps there was some element contamination coming from chemicals used in agriculture. Another forensic scientist used our method and machine to sample the chemistry of the bones and teeth of people whose life history is known, and then go to the places where they lived and sample the water there to determine to what extent their consumption patterns are imprinted into their own tissues.”
The new water-testing spectrometer—what Bromage describes proudly as “a perfect ‘I don’t know what I don’t know’ machine”—dovetails with his other work in paleoanthropology. To study the 3.2-million-year-old bones dubbed Lucy—the oldest and most complete remains of a previously unknown ancestor of mankind—Bromage invented a portable confocal microscope, since Lucy could not be moved to an existing large microscope from the Ethiopian National Museum, where she resides. His goal: to look at the orientations of collagen in her bones to confirm that she did, indeed, walk upright.
Bromage is also known for his own paleontological discoveries: in 1991, he unearthed a jaw from the oldest known sample of the human genus, Homo rudolfensis, as well as its contemporary, Paranthropus boisei, both 2.4 million years old, at Africa’s Lake Malawi. He hopes to use the new water-testing method to examine the ecology of that same lakeshore habitat. “Doing the metabolic ecology of a 2.4-million-year-old habitat takes us into the time dimension,” he says. “Now we’ll be studying climate change not by predicting the future but actually going into the past, where we can measure climate change quite clearly and absolutely.”
“After the machine arrived in our lab, we asked the company, ‘So how do we do it?’ They said, ‘Are you crazy? We don’t know! We just said it was possible,’ ” Bromage recalls.
Bromage with the mass spectrometer that can instantaneously measure the periodic table. (Photo by Kate Lord)
Bromage creates abstract art from hard tissue samples, such as (from left) a gnarled wisdom tooth root from a medieval human, a zebra tooth, and a human molar with enamel-deficient tufts.
Bromage has also turned work from his lab—specifically, microscope slides of hard tissue samples—into art and exhibited it around the world, including a permanent installation at the American Museum of Natural History. “We have an adage in the lab: every image we produce must have all of the aesthetic and scientific properties that our proficiency allows,” he says. “I started looking at the images we had created in the lab and realized that if I optimized their scientific and aesthetic properties, it became extremely abstract. You don’t know if you are looking at something close up or an image of the galaxy taken by the Hubble Telescope.” Consider that another unusual discovery by Bromage: that the left brain and right brain can collaborate quite beautifully.
| Video: More Than H20 |
NYU Spectrometer Measures 71 Elements in Water