Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A resourceful approach to climate research: Alpine ibex horns and old hay shed light on how grassland reacts to climate change

09.12.2009
How do plant ecosystems react to rising concentrations of the greenhouse gas CO2 in the atmosphere over the long term? This fundamental question is becoming increasingly pressing in light of global climate change.

Researchers from the Chair of Grassland Science at the Technische Universität München (TUM) have now - for the first time worldwide - taken up this issue for grasslands. The scientists found their answers in two unlikely places: in horns of Alpine ibex from Switzerland and in 150-year-old hay from England.

Researchers studying the reactions of trees to rising CO2 concentration in the atmosphere have it easy. Since trees store the carbon they absorb in wood, all they need to do is take core samples from tree trunks. A centenarian oak will reveal how it coped with the incipient climate change over a period of a hundred years in its annual rings. "However, the grassland vegetation we work with is grazed or dies off in a matter of months and decomposes," explains Prof. Hans Schnyder, who is doing research in the field of grasslands at the Center for Life and Food Sciences Weihenstephan at the TUM. The Swiss scientist nonetheless wanted to establish out how economically grasslands deal with water when temperatures rise and the carbon dioxide concentration in the air increases.

Important in this context is that all plants absorb CO2 from the atmosphere. At the same time they transpire water vapor to cool their sunlit leaves. Both processes run via the stomata, tiny pores in the leaves, the opening size of which plants can regulate. During longer periods of drought plants close the stomata to curb water loss, albeit at the expense of CO2 absorption. Laboratory experiments show that, for a given stoma aperture, an artificial increase of ambient CO2 leads to a temporary increase in the absorption capacity for the gas. However, to ascertain the actual change of water use efficiency in grassland vegetation over the course of the last century, Prof. Schnyder had to find grassland time series comparable in length to those of trees.

This is where the team turned their sights to the Alpine ibex horn collection at the Museum of Natural History in Bern. Ibex store isotopic information in their horns that reflects the water use of the vegetation they consume. The TUM researchers went at the museum collection, which covers the years 1938 to 2006, with a carving knife, to remove tiny samples from the horns. Since ibex horns also have annual rings, the grassland researchers were able to use the samples to draw conclusions about temporal changes in the grassland vegetation of the Bernese Alps where the ibex had grazed.

A unique specimen archive at the research station Rothamsted in England eventually enabled a comparison with a second grassland region. The "Park Grass Experiment" - the longest running ecological grassland experiment worldwide - was initiated in Rothamsted over 150 years ago. Since 1857 specimens have been archived there to allow future generations of scientists to gain long-term insights into the local ecosystem using modern research methods. And indeed, the TUM scientists were able to benefit from the hay specimens dating as far back as 150 years. Once again analyzing the isotope signature, they could infer how the English grassland vegetation had utilized the water over the years.

The Weihenstephan researchers thus determined the individual isotope composition of the grassland vegetation in both the Bernese Alps and in the British lowlands over extended periods of time: more than 69 years based on the horns, and as far back as 150 years using the hay specimens. In a second step this data was lined up with climate data, e.g. air temperature and aridity, of the respective region. The result: In both locations the intrinsic water-use efficiency of the grassland vegetation rose over the years. This implies that the plants improved their water storage potential as temperatures rose and the level of CO2 in the atmosphere increased. Based on these results the TUM scientists have now, for the first time ever, managed to demonstrate the long-term effects of anthropogenic climate change on the water-use efficiency of grasslands.

There were, however, also differences between the two locations. In Switzerland the effective water-use efficiency of the Alpine meadows remained unchanged in spite of the increased intrinsic water-use efficiency of the grassland. This was because, overall, the air had become drier and warmer as a result of the climate change. In England the scientists found evidence for this effect only during the fall. In the spring though - which in Rothamsted is no drier today than it was 150 years ago - the water storage potential of grassland vegetation had a real effect. This insight will help to further improve climate simulations. In the past, complex simulation models that included vegetation had to rely on estimates where grassland was concerned. The scientists at the TU München have now succeeded in prying open this climate research black box.

Contact:
Prof. Hans Schnyder
Chair of Grassland Science
Center of Life and Food Sciences
Technische Universität München
Tel. 08161 / 71-5165
E-Mail: schnyder@wzw.tum.de
http://www.wzw.tum.de/gruenland
Free Pictures:
http://mediatum2.ub.tum.de/?cunfold=829388&dir=829388&id=829388
Literature:
Barbosa ICR, Köhler I, Auerswald K, Lüps P, Schnyder H (2009) Last-century changes of alpine grassland water-use efficiency - a reconstruction through carbon isotope analysis of a time-series of Capra ibex horns. Global Change Biology, DOI: 10.1111/j.1365-2486.2009.02018.x

Köhler IH, Poulton PR, Auerswald K, Schnyder H (2009) Intrinsic water-use efficiency of temperate semi-natural grassland has increased since 1857: an analysis of carbon isotope discrimination of herbage from the Park Grass Experiment. Global Change Biology, DOI: 10.1111/j.1365-2486.2009.02067.x

Barbosa ICR, Kley M, Schäufele R, Auerswald K, Schröder W, Filli F, Hertwig S, Schnyder H (2009) Analysing the isotopic life history of the alpine ungulates Capra ibex and Rupicapra rupicapra rupicapra through their horns. Rapid Communications in Mass Spectrometry (RCM) 23, 2347-2356.

Dr. Ulrich Marsch | idw
Further information:
http://www.wzw.tum.de/gruenland

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>