To track atmospheric change caused by human activity, researchers have long studied a variety of materials, from tree rings to air trapped in glacial ice. A problem has been "noise"-- natural variability caused by sampling and random events that affect atmospheric chemistry. Noise can make it hard to tease out trends from the data.
Joseph Bump, a PhD candidate in forest science at Michigan Tech, and his colleagues speculated that those trends would be picked up by top predators as well as by trees. And they further suspected that measurements from predators would show much less noise.
"Wolves consume many prey animals—a minimum of 150–200 moose contribute to an Isle Royale wolf’s diet over the course of its lifetime—and the prey consume a whole lot of plants," Bump explains. "Just by being who they are, wolves and other top predators increase the sample size, because they do the sampling for us."
The team studied moose and wolf bone samples dating back to 1958 from Isle Royale National Park, in Lake Superior, the site of the longest-running predator-prey study in the world. In addition, they looked at 30,000-year-old bones from the long-extinct dire wolf and prehistoric bison pulled from the La Brea tar pits in Los Angeles. They compared the trend found in the bone chronologies to trends already established for tree rings in North America.
They found that gray and dire wolves, provide a much clearer record of environmental change than either the plants, the moose or the bison.
"Since the widespread combustion of fossil fuels, we have put a human fingerprint on atmospheric carbon dioxide," Bump said. "That fingerprint shows up in trees, and it shows up in animals that eat trees, but it shows up with the least variation in the top predators."
That fingerprint has to do with the ratio between carbon-12 and carbon-13. While carbon-12 is always much more abundant in atmospheric carbon dioxide, burning fossil fuels releases even more of it. So in recent years, even more carbon-12 has been incorporated by organisms than carbon-13.
The scientists found that the carbon-12 signal improves the farther up the food chain you go. "It's noisy for trees, less noisy for moose, and even less noisy for wolves," Bump said.
"In a way, this whole study can be summed up by asking, 'How many trees does a wolf represent?'"
Their analysis opens the door to a new area of inquiry, since the bones of predators dating back dozens to thousands of years are available at natural history museums all over the world.
"Instrumental measurements of environmental variables are only available for about the past few hundred years, so this may help us understand paleo-environmental change better, and if we can understand ancient environments better, then our ability to predict future changes is improved," says Bump.
Their paper, "Stable Isotopes, Ecological Integration, and Environmental Change: Wolves Record Atmospheric Carbon Isotope Trend Better than Tree Rings," appears in the Proceedings of the Royal Society–B, published Aug. 7, 2007 .
The coauthors are Rolf Peterson and John Vucetich, of Michigan Tech; Kena Fox-Dobbs and Paul Koch, of the University of California at Santa Cruz; and Jeffrey Bada, of Scripps Institution of Oceanography, University of California at San Diego.
The study was funded by the National Science Foundation, the U.S. Environmental Protection Agency, the National Park
Jennifer Donovan | Newswise Science News
When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences