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Animal evolution: Hot start, followed by cold shock

Science Daily - Thu, 06/15/2017 - 07:45
The initial phases of animal evolution proceeded faster than hitherto supposed: New analyses suggest that the first animal phyla emerged in rapid succession -- prior to the global Ice Age that set in around 700 million years ago.

Ancient otter tooth found in Mexico suggests mammals migrated across America

Science Daily - Wed, 06/14/2017 - 08:29
An ancient otter tooth recently discovered in Mexico suggests certain mammals migrated across America during the Miocene geologic epoch, roughly 23 million to 5.3 million years ago. The new hypothesized route questions other theories such as migrations above Canada and through Panama, and has implications for a much larger biologic event -- the Great American Biotic Interchange, when land bridges were formed and animals dispersed to and from North America and South America.

Polar bears' declining mercury levels likely due to climate-related shifts

Science Daily - Wed, 06/14/2017 - 08:18
To understand how human activities are affecting the planet, scientists often study the health of animals in the wild. Now a new study finds that the levels of mercury in some polar bears are declining. But rather than heralding a drop in mercury in the environment, the decrease could indicate how climate change has led the animals to shift foraging habits, which has affected their diets and weight.

Large Canadian Arctic climate change study cancelled due to climate change

Science Daily - Tue, 06/13/2017 - 14:06
The Science Team of the Canadian Research Icebreaker CCGS Amundsen has cancelled the first leg of the 2017 Expedition due to complications associated with the southward motion of hazardous Arctic sea ice, caused by climate change.

Comets may have delivered significant portions of Earth's xenon

Science Daily - Thu, 06/08/2017 - 13:55
A new study suggests that roughly 22% of the element xenon found in Earth's atmosphere may have come from comets.

Sahara greening may intensify tropical cyclone activity worldwide

Science Daily - Thu, 06/08/2017 - 06:33
Future climate warming could lead to a re-greening of the southernmost Sahara (Sahel), with decreased dust emissions and changes in land cover. In a recent study, researchers have found that tropical cyclone activity may have increased during past warm climates in connection with a greening of the Sahara.

Finding new homes won't help emperor penguins cope with climate change

Science Daily - Wed, 06/07/2017 - 14:12
Unlike other species that migrate successfully to escape the wrath of climate change, a new study shows that dispersal may help sustain global Emperor penguin populations for a limited time, but, as sea ice conditions continue to deteriorate, the 54 colonies that exist today will face devastating declines by the end of this century.

Domes of frozen methane may be warning signs for new blow-outs

Science Daily - Mon, 06/05/2017 - 14:19
Several methane domes, some 500m wide, have been mapped on the Arctic Ocean floor. They may be signs of soon-to-happen methane expulsions that have previously created massive craters in a near-by area.

Antarctic ice rift close to calving, after growing 17km in 6 days, latest data from ice shelf shows

Science Daily - Fri, 06/02/2017 - 10:28
The rift in the Larsen C ice shelf in Antarctica has grown by 17km in the last few days and is now only 13km from the ice front, indicating that calving of an iceberg is probably very close, researchers revealed after studying satellite data. The rift is likely to lead to one of the largest icebergs ever recorded.

Massive craters formed by methane blow-outs from the Arctic sea floor

Science Daily - Thu, 06/01/2017 - 14:18
Hundreds of massive, kilometer-wide craters on the ocean floor in the Arctic were formed by substantial methane expulsions, new research explains.

Geoscientific evidence for subglacial lakes

Science Daily - Thu, 06/01/2017 - 07:22
During the last glacial period -- when the ice in the Antarctic was far thicker and extended further offshore than it does today -- it has been speculated that subglacial lakes existed beneath it. An international team of researchers has now successfully sampled the meter-thick sediment layers left behind by these lakes contemporary on the seafloor.

Human activity has polluted European air for 2,000 years

Science Daily - Wed, 05/31/2017 - 09:33
A new study combining European ice core data and historical records of the infamous Black Death pandemic of 1349-1353 shows metal mining and smelting have polluted the environment for thousands of years, challenging the widespread belief that environmental pollution began with the Industrial Revolution in the 1700s and 1800s.

Previously, on Arctic warming

Science Daily - Tue, 05/30/2017 - 13:48
Arctic warming occurred in the early 20th century due to the warming phases -- 'interdecadal variability mode' -- of both the Pacific and Atlantic oceans, suggests new research.

Death by volcano?

Science Daily - Tue, 05/30/2017 - 07:23
The discovery of anomalously high levels of mercury in rocks from the Ordivician geological period has led to a new interpretation of the ensuing mass extinction. A sequence of disturbances may have led to catastrophic cooling by reflective sulfate aerosols injected into the atmosphere by massive volcanism. The finding is important since aerosol cooling is under consideration as a way to temper global warming.

'Tiny clocks' crystallize understanding of meteorite crashes

Science Daily - Fri, 05/26/2017 - 13:37
Scientists are using new imaging techniques to measure the atomic nanostructure of ancient crystal fragments at meteorite impact sites. The end goal? To understand when impacts ended and life began.

Fossil beetles suggest that LA climate has been relatively stable for 50,000 years

Science Daily - Wed, 05/24/2017 - 12:11
Research based on more than 180 fossil insects preserved in the La Brea Tar Pits of Los Angeles indicate that the climate in what is now southern California has been relatively stable over the past 50,000 years.

Weathering of rocks a poor regulator of global temperatures

Science Daily - Tue, 05/23/2017 - 07:20
Evidence from the age of the dinosaurs to today shows that chemical weathering of rocks is less sensitive to global temperature, and may depend on the steepness of the surface. The results call into question the role of rocks in setting our planet's temperature over millions of years.

Antarctic has seen widespread change in last 50 years, moss study reveals

Science Daily - Thu, 05/18/2017 - 13:03
In 2013, researchers studying mosses and microbes growing at the southern end of the Antarctic Peninsula documented unprecedented ecological change over the last 50 years, driven by warming temperatures. Now, the same research group has confirmed that those striking changes in the Antarctic are widespread, occurring all across the Peninsula.

A recipe for concrete that can withstand road salt deterioration

Science Daily - Thu, 05/18/2017 - 09:41
Engineers have known for some time that calcium chloride salt, commonly used as deicer, reacts with the calcium hydroxide in concrete to form a chemical byproduct that causes roadways to crumble. A civil engineer is working on a new recipe for concrete, using cast-off products from furnaces, that can hold its own against the forces of chemical erosion.

Temperatures in the Arctic are

Science Daily - Thu, 05/18/2017 - 07:30
Temperatures in the Arctic are increasing twice as fast as in the rest of the globe, while the Antarctic is warming at a much slower rate. A new study shows that land height could be a 'game changer' when it comes to explaining why temperatures are rising at such different rates in the two regions.

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