Ecology articlesNo safe ground for life to stand on during world's largest mass extinction
The world's largest mass extinction was probably caused by poisonous volcanic gas. The research, published in the journal Geology, reveals vital clues about the mass extinction at the end of the Permian period, 250 million years ago, when mammal-like reptiles known as synapsids roamed the earth.
New maps reveal true extent of human footprint on Earth
As global populations swell, farmers are cultivating more and more land in a desperate bid to keep pace with the ever-intensifying needs of humans. As a result, agricultural activity now dominates more than a third of the Earth's landscape and has emerged as one of the central forces of global environmental change, say scientists at the Center for Sustainability and the Global Environment (SAGE) at the University of Wisconsin-Madison.
What is a cloud?
All through the ages, humans have dreamily gazed at those shape-shifting cotton-balls floating gently across the sky-the clouds. Atmospheric scientists-Earth's professional cloud-gazers--have learned a great deal about clouds over the decades, particularly with the advent of satellites during the 1960s and 70s. But despite years of research and the emergence of increasingly sophisticated tools, scientists are still at odds over one of the most basic issues of all: how to define a cloud.
Why the Amazon rainforest is so rich in species
Tropical areas of south and central America such as the Amazon rainforest are home to some 7500 species of butterfly compared with only around 65 species in Britain.
NASA satellites yield best-ever Antarctic maps
Scientists using satellite data have now created the most detailed maps ever produced of the vast snow-covered Antarctic continent. The maps reveal unprecedented views of surface features that provide clues to how and why the continent's massive ice sheets and glaciers are changing.
Models show growing more forests in temperate regions could contribute to global warming
Planting trees across the United States and Europe to absorb some of the carbon dioxide emitted by the burning of fossil fuels may just outweigh the positive effects of sequestering that CO2.
Getting ready for the 'Big One', researchers make most detailed survey ever of San Andreas Fault
Researchers have completed the most meticulous survey ever made of the San Andreas Fault, and they've found detailed features that nobody could have seen before.
Mountainous plateau creates ozone 'halo' around Tibet
Not only is the air around the world's highest mountains thin, but it's thick with ozone, says a new study from University of Toronto researchers.
Global warming could halt ocean circulation
Absent any climate policy, scientists have found a 70 percent chance of shutting down the thermohaline circulation in the North Atlantic Ocean over the next 200 years, with a 45 percent probability of this occurring in this century. The likelihood decreases with mitigation, but even the most rigorous immediate climate policy would still leave a 25 percent chance of a thermohaline collapse.
Large Himalaya earthquakes may occur sooner than expected
While the rupture zones of recent major earthquakes are immune to similar-sized earthquakes for hundreds of years, they could be vulnerable to even bigger destructive temblors sooner than scientists suspect, according to analysis by University of Colorado seismologist Roger Bilham.
Mercury in atmosphere could be washed out more easily than earlier believed
Scientists for years have been at a loss to explain unexpectedly high levels of mercury in fish swimming the rivers and streams of areas like eastern Oregon, far away from industrial sources of mercury pollution such as coal-fired power plants.
Changes to land cover may enhance global warming in Amazon, reduce it in midlatitudes
New simulations of 21st-century climate show that human-produced changes in land cover could produce additional warming in the Amazon region comparable to that caused by greenhouse gases, while counteracting greenhouse warming by 25% to 50% in some midlatitude areas.
Earthquake 'pulses' could predict tsunami impact
The magnitude 9.2 earthquake that triggered a devastating tsunami in the Indian Ocean in December of 2004 originated just off the coast of northern Sumatra, but an "energy pulse" – an area where slip on the fault was much greater – created the largest waves, some 100 miles from the epicenter. Seismologists have mapped these energy pulses for Sumatra and are trying to learn more about them to predict better when and where tsunamis may occur.
First-ever observation of squid caring for eggs
Squid have always been considered poor parents: they lay their eggs on the seafloor and leave them to develop on their own. But a University of Rhode Island scientist has made the first observation of parental care by squid when he used a remotely operated underwater vehicle in the deep sea to watch as five squid each carried thousands of eggs in their arms.
Movement of Earth's north magnetic pole accelerating rapidly
After some 400 years of relative stability, Earth's North Magnetic Pole has moved nearly 1,100 kilometers out into the Arctic Ocean during the last century and at its present rate could move from northern Canada to Siberia within the next half-century.
Glacial pace of erosion was not so slow
Glaciers, rivers and shifting tectonic plates have shaped mountains over millions of years, but earth scientists have struggled to understand the relative roles of these forces and the rates at which they work.
Function of "unicorn" whale
Harvard School of Dental Medicine (HSDM) researcher Martin Nweeia, DMD, DDS, answers a marine science question that has eluded the scientific community for hundreds of years: why does the narwhal, or "unicorn," whale have an 8-foot-long tooth emerging from its head, and what is its function?
Researchers discover trees in Amazon much older than assumed
Trees in the Amazon tropical forests are old. Really old, in fact, which comes as a surprise to a team of American and Brazilian researchers studying tree growth in the world's largest tropical region.
Ancient glaciers still affect the shape of North America
Long after the disappearance of the glaciers that once covered much of North America, the land they rested upon is still recovering from their weight – and the slow movement of this recovery includes horizontal motion never seen before, say Purdue scientists.
Ability to capture large prey may be origin of army ant' cooperative behavior
Scientific insights come at the darnedest times. Animal behaviorist Sean O'Donnell was having an afternoon cup of coffee when a giant earthworm exploded out of the leaf litter covering the jungle floor in an Ecuadorean nature preserve. The worm, later measured at nearly 16 inches long, was pursued by a column of hundreds of raiding army ants that quickly paralyzed or killed it.