Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny Creatures Point to Possible Climate Change

24.06.2011
Diatoms linked to solar activity, record increased storms in last century

A University of Arkansas researcher and her colleagues studied core sediments from a shallow boreal lake and found that storm activity has increased substantially over the past 150 years.

The rise in storm frequency appears to be linked to solar activity, but also may be linked to higher global temperatures resulting from increased amounts of greenhouse gases.

Sonja Hausmann and Falko Fye, professors of geosciences at the University of Arkansas; Isabelle Larocque-Tobler of the University of Bern, Switzerland; Pierre Richard of the University of Montréal, Canada; Reinhard Pienitz of Laval University, Québec City, Canada; and Guillaume St-Onge of the University of Québec at Rimouski, Canada, report their findings in The Holocene.

“We don’t really know if it is solar activity or if it is greenhouse gases because what we found correlates with both,” Hausmann said.

In the last 150 years, human activity has considerably increased the concentration of greenhouse gases in the atmosphere. Greenhouse gases trap heat in the lower atmosphere of Earth, raising the Earth’s temperature. Scientists have predicted that rising temperatures could lead to more frequent storms, and Hausmann’s evidence supports this.

However, Hausmann also compared the diatom-storm evidence to solar activity, which includes sunspots. Solar activity peaks and dips on 11-year and longer cycles. The diatom activity appears to fluctuate with the solar cycles, with stormy periods coinciding with high solar activity.

The researchers took core samples at Lac du Sommet, a shallow mountain lake in the Laurentian Mountains of eastern Canada. They were able to extend their climate reconstruction back 9,500 years.

Hausmann studies diatoms, unicellular algae with shells of silica, which remain in the sediments. Diatoms make excellent bioindicators, Hausmann said, because the diatom community composition changes with environmental changes in acidity, climate, nutrient availability and lake circulation.

By examining relationships between modern diatom communities and their environment, Hausmann and her colleagues can reconstruct various historic environmental changes quantitatively. In this case, they examined the residual effect of storms on the diatom communities in lake sediments. High winds cause the water column to circulate and mix the diatoms and nutrients in the water.

In the absence of wind, diatoms settle at the lake bottom where they have less light. The researchers compared the diatom community structures to wind records from a nearby weather station established in 1965 and found that they matched well. They then examined the diatom community structures for the past 9,500 years.

The diatom evidence shows that storms have increased substantially over the last 150 years, Hausmann said.

She and her colleagues compared these findings to other tiny proxies: non-biting midges and pollen. Midge larvae live in the lake sediment and act as good indicators of temperature changes in a given environment. At Lac du Sommet, the midge evidence shows that temperature, while variable, has not recently increased in the same manner. Pollen evidence tells a similar story.

“The diatoms do not show a temperature effect. They show wind,” Hausmann said. “We are looking at climate change, not just temperature differences.”

Hausmann will return to Lac du Sommet during decreased periods of solar activity to see if diatom activity shows a similar decrease.

CONTACTS:
Sonja Hausmann, assistant professor, geosciences
J. William Fulbright College of Arts and Sciences
479-575-6419, shausman@uark.edu
Melissa Lutz Blouin, director of science and research communications
University Relations
479-575-5555, blouin@uark.edu

Melissa Lutz Blouin | Newswise Science News
Further information:
http://www.uark.edu

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

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...

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

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>