*In “The Great Dying” 250 million years ago, the end came slowly*
The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life–and it killed in stages–according to a newly published report.
It shows that mass extinctions need not be sudden events.
Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. (more…)
*Long-term study analyzes social selection and peer influence in online environments*
New research funded by the National Science Foundation and published this week in the Proceedings of the National Academy of Sciences by three Harvard University sociologists examines how we select our friends and the role that friendship plays in transmitting tastes and new ideas.
Relationships are basic building blocks of society, and understanding who befriends whom can therefore provide insight into patterns of social segregation, mechanisms for the reproduction of inequality, social support (including mental and emotional health), and access to job opportunities. Some have even viewed these relationships as a means to influence behavior whether to control obesity or target advertising. But is it really that easy, even on the Internet, to make friends with people who have different cultural upbringings, different interests, different backgrounds and different tastes in movies, music and books? (more…)
*Experiments on “slime mold” explain why almost all multicellular organisms begin life as a single cell*
Any multicellular animal, from a blue whale to a human being, poses a special challenge for evolution.
Most of the cells in its body will die without reproducing; only a privileged few will pass their genes to the next generation.
How could the extreme degree of cooperation required by multicellular existence actually evolve? Why aren’t all creatures unicellular individualists determined to pass on their own genes? (more…)
*Ecological changes from lakebed may have led to two different populations of once-related steelhead trout*
A catastrophic landslide 22,500 years ago dammed the upper reaches of northern California’s Eel River, forming a 30-mile-long lake which has since disappeared. It left a living legacy found today in the genes of the region’s steelhead trout.
Using remote-sensing technology known as airborne Light Detection and Ranging (LiDAR) and hand-held global-positioning-systems (GPS) units, scientists recently found evidence for a late Pleistocene, landslide-dammed lake along the river. (more…)
*Researchers study heat delivered by ocean currents to bottom side of glacier that releases more than 19 cubic miles of ice each year*
An international team of researchers, funded by the National Science Foundation (NSF) and NASA, will helicopter onto the Pine Island Glacier ice shelf, one of Antarctica’s most active, remote and harsh spots, in mid-December 2011–weather permitting.
The project’s mission is to determine how much heat ocean currents deliver to the underside of the Pine Island Glacier as it discharges into the sea. Quantifying this heat and understanding how much melting it causes is key to developing reliable models to predict glacier acceleration and therefore predict how much ice will be delivered from land into the ocean thus contributing to sea level rise. (more…)
*Disruption of wind shear enables stronger storms*
Pollution is making Arabian Sea cyclones more intense, according to a study in this week’s issue of the journal Nature.
Traditionally, prevailing wind shear patterns prohibit cyclones in the Arabian Sea from becoming major storms.
The Nature paper suggests that weakening winds have enabled the formation of stronger cyclones in recent years–including storms in 2007 and 2010 that were the first recorded storms to enter the Gulf of Oman. (more…)
