Tag Archives: university of Alberta

Warum sich der Sauerstoff in der Erdatmosphäre nur langsam angereichert hat

Die Dosis macht‘s: Eisen könnte die frühen Cyanobakterien vergiftet und den Start der Evolution von sauerstoffatmenden Tieren verzögert haben

Vor drei Milliarden Jahren bestand die Erdatmosphäre zu weniger als einem Promille aus Sauerstoff. Dass es heute etwa 20 Prozent sind, verdanken wir frühen Lebewesen in den Urozeanen, die trotz ihrer Winzigkeit diese umwälzende Entwicklung herbeigeführt haben. Cyanobakterien, die es in ähnlicher Form auch heute noch gibt, haben wahrscheinlich schon vor 3,5 Milliarden Jahren mithilfe der Energie des Sonnenlichts Fotosynthese betrieben und damit einen kleinen Teil des vorhandenen Kohlendioxids der frühen Atmosphäre in organische Stoffe umgesetzt. Sauerstoff entstand dabei als Abfallprodukt. Er machte nach rund zwei Milliarden Jahren die Evolution der zahlreichen heute lebenden Tiere, die Sauerstoff benötigen, erst möglich. (more…)

Read More

What’s your story? Six strategies for entrepreneurs

ANN ARBOR — An entrepreneur’s backstory plays a critical role in the success or failure of a fledgling venture, says Lianne Lefsrud, a postdoctoral fellow at the University of Michigan Ross School’s Erb Institute.

“Especially for entrepreneurs with limited financial resources, stories are a way to create resources if you can make sense of the world with your stories,” Lefsrud said. (more…)

Read More

Nitrogen From Humans Pollutes Remote Lakes For More Than A Century

Nitrogen derived from human activities has polluted lakes throughout the Northern Hemisphere for more than a century and the fingerprint of these changes is evident even in remote lakes located thousands of miles from the nearest city, industrial area or farm.

The findings, published in the journal Science Dec. 16, are based on historical changes in the chemical composition of bottom deposits in 36 lakes using an approach similar to aquatic archeology. More than three quarters of the lakes, ranging from the U.S. Rocky Mountains to northern Europe, showed a distinctive signal of nitrogen released from human activities before the start of the 20th century, said Gordon Holtgrieve, a postdoctoral researcher at University of Washington School of Aquatic and Fishery Sciences and lead author of the report. The UW and a dozen other research institutions contributed to the research. (more…)

Read More

Species Extinction Rates Have Been Overestimated, New Study Claims

*However, researchers say, global extinction crisis remains very serious*

The most widely used methods for calculating species extinction rates are “fundamentally flawed” and overestimate extinction rates by as much as 160 percent, life scientists report May 19 in the journal Nature.

However, while the problem of species extinction caused by habitat loss is not as dire as many conservationists and scientists had believed, the global extinction crisis is real, says Stephen Hubbell, a distinguished professor of ecology and evolutionary biology at UCLA and co-author of the Nature paper. (more…)

Read More

Have We Changed Our Ways After the BP Oil Spill? Not Really

ANN ARBOR, Mich.—On the heels of last week’s federal recommendations to help prevent another BP oil spill disaster, a University of Michigan researcher says the tragedy has come close to acting as a catalyst for deeper change—but not quite.

“The BP oil spill is, potentially, a ‘cultural anomaly’ for institutional changes in environmental management and fossil fuel production,” said Andrew Hoffman, professor of management and organizations at the Ross School of Business and a professor at the School of Natural Resources and Environment. “But true change in our approach to handling issues related to oil drilling, oil consumption and environmental management have yet to occur.” (more…)

Read More