Forum for Science, Industry and Business

Silica algae reveal how ecosystems react to climate changes

Rapid and extensive climate changes have taken place on several occasions in the past. For example, the latest ice age (lasting from about 115,000 to 11,500 years ago) is characterized by several rapid and dramatic climate swings.

These swings recurred in cycles of roughly 1,500 years and were originally discovered through studies of ice cores from Greenland in the early 1990s. These cycles started with an extremely rapid rise in temperatures, over just a few years or decades, of as much as 8-16o C over Greenland.

Linda Ampel studied how these rapid cycles in the climate affected ecosystems in an area in continental Europe. The study was based on analyses of sediment cores from an overgrown lake named Les Echets in eastern France and focuses on a time interval between 40,000 and 16,000 ago.

The findings are based on analyses of fossil silica algae, diatoms. Various species of diatoms prefer different water conditions relating to physical and chemical parameters such as temperature, salinity, access to nutrients, light, water depth, or available types of places to grow. These parameters, in turn, are affected by climate. Different species of diatoms can therefore indicate how the water environment changed as a consequence of the climate in the past.

Diatom analyses of the environmental archive from Les Echets, together with further analyses of chemical and biological parameters such as content of organic material and pollen grains from trees and other plants preserved in the lake, show that the ecosystems in the lake and its surroundings underwent marked changes during the latest ice age as a consequence of these 1,500-year cycles. The adaptation of the ecosystems prompted by the recurring warm periods took place as quickly as within 50 to 200 years.

"These findings show that ecosystems have changed rapidly in reaction to climate changes in the past, which indicates that quick adaptations could also take place in the future as a consequence of global warming, for instance," says Linda Ampel.

Contact: Linda Ampel, linda.ampel@geo.su.se, phone: +46 (0)8-674 75 95 or cell phone: +46 (0)70-366 32 82

Pressofficer Maria Sandqvist: maria.sandqvist@kommunikation.su.se;+46-70664 22 64

Pictures are available of diatoms, the landscape in France, and Linda at http://www.su.se/pub/jsp/polopoly.jsp?d=5833&a=59203

Maria Sandqvist | idw
Further information:
http://www.vr.se
http://www.su.se/pub/jsp/polopoly.jsp?d=5833&a=59203

Im Focus: MOF@SAW: Nanoquakes and molecular sponges for weighing and separating tiny masses

Augsburg chemists and physicists report how they have succeeded in the extremely difficult separation of hydrogen and deuterium in a gas mixture.

Thanks to the Surface Acoustic Wave (SAW) technology developed here and already widely used, the University of Augsburg is internationally recognized as the...

Im Focus: Better thermal conductivity by adjusting the arrangement of atoms

Adjusting the thermal conductivity of materials is one of the challenges nanoscience is currently facing. Together with colleagues from the Netherlands and Spain, researchers from the University of Basel have shown that the atomic vibrations that determine heat generation in nanowires can be controlled through the arrangement of atoms alone. The scientists will publish the results shortly in the journal Nano Letters.

In the electronics and computer industry, components are becoming ever smaller and more powerful. However, there are problems with the heat generation. It is...

Im Focus: First-ever visualizations of electrical gating effects on electronic structure

Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.

Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...

Im Focus: Megakaryocytes act as „bouncers“ restraining cell migration in the bone marrow

Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.

Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...

Im Focus: Artificial neural network resolves puzzles from condensed matter physics: Which is the perfect quantum theory?

For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.

Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...