The teeth hold evidence of the type of vegetation that grew in a particular location at a particular time, and that in turn provides information about climate fluctuations occurring on the plains, said Kathryn Hoppe, a UW acting assistant professor of Earth and space sciences.
"Bison eat mostly grass, so they provide a good way to measure grassland productivity," Hoppe said. "Much of the rangeland and farmland in this country was originally native grasslands, so if you want to measure how the productivity of agricultural lands has changed over time, bison seem like a good way to go."
Hoppe and colleagues Adina Paytan and Page Chamberlain of Stanford University found climate evidence in the enamel from third molars of bison, the equivalent to human wisdom teeth. Those teeth form after young bison no longer depend on mother's milk for nutrition, and so carry clearer signals of what types of grass the animals consumed.
The researchers used bison teeth collected in Montana, Wyoming, North and South Dakota, Nebraska, Kansas and Oklahoma. They pulverized enamel from tooth surfaces and dissolved samples in acid to release small amounts of carbon dioxide. Then they used a mass spectrometer to examine the ratio of the isotopes carbon-12 to carbon-13. Different grasses, those that grow in warm and cool seasons for example, have different isotope ratios.
The results provided a means to reconstruct temperature patterns for particular locations at particular times, Hoppe said. Tooth enamel also carries evidence of changes in carbon dioxide levels, which helps scientists to see how levels of that greenhouse gas changed over time.
Bison roamed North America from Alaska to Mexico going back 200,000 years. They were the most abundant herbivores following the last ice age until Europeans began to settle the continent. Because there were so many over such a large territory, Hoppe said, bison are an ideal means to study how climate and vegetation fluctuated over thousands of years.
Scientists know there have been major periods of climate change on the Great Plains numerous times in the past, typically on a much greater scale than the conditions that created the Dust Bowl in the 1930s. But questions remain about how sensitive the plains are to climate change, and how much of a change might trigger their conversion to desert.
"We know from looking at evidence of past climatic conditions that we currently are in a warm period and that climates have changed dramatically. There have been times in the past, for example, when the climate was so dry that northern Nebraska was a desert with sand dunes. The Sand Hills are a remnant of that time," Hoppe said. "The better we understand what happened in the past, the better we can predict what will happen in the future," she said.
The work also provides a way to test current climate models, she said. As scientists develop a more precise understanding of past climate, they can add those conditions as variables to see if the models correctly show what happened. If the models are successful in correctly showing past climate, there is much greater confidence that they are accurate in showing what future climate is likely to be.
Vince Stricherz | EurekAlert!
Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union
UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences