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!
Gas hydrate research: Advanced knowledge and new technologies
23.03.2018 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
New technologies and computing power to help strengthen population data
22.03.2018 | University of Southampton
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy