Scientists have discovered that elevated atmospheric CO2 (carbon dioxide) can suppress plant growth when increases of this important greenhouse gas are combined with a broad suite of already-occurring environmental changes. According to Christopher Field, project leader and director of the new Department of Global Ecology of the Carnegie Institution of Washington, "We are now getting a much richer picture of ecosystem responses to global environmental changes, and the traditional view that elevated CO2 always stimulates plant growth simply isn’t correct." The research is published in the December 6, 2002, issue of Science.
Many past studies of global-change impacts on plants and ecosystems have focused on responses to increases in atmospheric CO2. But realistically, global changes are much more than just elevated CO2. They include global warming, altered rainfall, and increases in biologically available nitrogen compounds produced during fossil-fuel combustion. These other global changes can have major impacts on plants and ecosystems. A new study by scientists at the Carnegie Institution of Washington, the Nature Conservancy, and Stanford University shows, for the first time, how these other global changes alter the response of a natural ecosystem to increased atmospheric CO2. According to lead author Rebecca Shaw, "In the third year of the experiment, plant growth increased in the plots treated with CO2 alone, as in many other experiments. It also increased in plots exposed to the other global changes--warming, increased precipitation, and fertilizing with nitrogen --alone or in combination. But, when we added carbon dioxide, the effect of the other treatments was suppressed. The elevated CO2 in this situation pushed the response back toward the initial conditions."
Over the last hundred years, the concentration of CO2 in the atmosphere has increased by more than 30%. The planet has warmed by about 1 ºF. Rainfall has increased in some regions and decreased in others. And human actions have more than doubled inputs of biologically available nitrogen. Elevated atmospheric CO2 increases plant growth in many experiments, but most past experiments studied impacts of CO2 alone or in combination with one other factor. The results of the Carnegie-led experiment reveal new dimensions of ecosystem responses to global change. In the California grassland studied by this team, elevated CO2 suppresses plant growth in many treatments, especially treatments where growth at normal CO2 is fastest. Field noted, "When we look at impacts of realistic global changes on whole ecosystems, we see a broad range of responses. We do not yet know whether responses will be similar in other ecosystems, but our wide range of treatments helps open the door to understanding global-change impacts on ecosystems not yet studied."
Rebecca Shaw | EurekAlert!
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy