Tag Archives: geological past

Global warming led to dwarfism in mammals — twice

ANN ARBOR — Mammal body size decreased significantly during at least two ancient global warming events. A new finding that suggests a similar outcome is possible in response to human-caused climate change, according to a University of Michigan paleontologist and his colleagues.

Researchers have known for years that mammals such as primates and the groups that include horses and deer became much smaller during a period of warming, called the Paleocene-Eocene Thermal Maximum (PETM), about 55 million years ago. (more…)

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Scientists Identify Microbes Responsible for Consuming Natural Gas in Deepwater Horizon Spill

*Water temperature played key role*

In the results of a new study, scientists explain how they used DNA to identify microbes present in the Gulf of Mexico following the Deepwater Horizon oil spill–and the particular microbes responsible for consuming natural gas immediately after the spill.

Water temperature played a key role in the way bacteria reacted to the spill, the researchers found. (more…)

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Six Million Years of African Savanna

*Open, grassy environments accompanied human evolution*

Scientists using chemical isotopes in ancient soil to measure prehistoric tree cover–in effect, shade–have found that grassy, tree-dotted savannas prevailed at most East African sites where human ancestors and their ape relatives evolved during the past six million years.

“We’ve been able to quantify how much shade was available in the geological past,” says University of Utah geochemist Thure Cerling, lead author of a paper titled “Woody cover and hominin environments in the past 6 million years” on the results in this week’s issue of the journal Nature. (more…)

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