TORONTO, ON - In the remote desert highlands of southern Yemen, a team of archaeologists have discovered new evidence of ancient transitions from hunting and herding to irrigation agriculture 5,200 years ago.

As part of a larger programme of archaeological research, Michael Harrower from the University of Toronto and The Roots of Agriculture in Southern Arabia (RASA) team explored the Wadi Sana watershed documenting 174 ancient irrigation structures, modeled topography and hydrology, and interviewed contemporary camel and goat herders and irrigation farmers.

Mars once hosted vast lakes, flowing rivers and a variety of other wet environments that had the potential to support life, according to two new studies based on data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and other instruments on board NASA's Mars Reconnaissance Orbiter (MRO).

"The big surprise from these new results is how pervasive and long-lasting Mars' water was, and how diverse the wet environments were," says Scott Murchie, CRISM's principal investigator at the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md.

WEST LAFAYETTE, Ind. - According to a new study, global warming could lead to larger changes in snowmelt in the western United States than was previously thought, possibly increasing wildfire risk and creating new water management challenges for agriculture, ecosystems and urban populations.

Researchers, including a Purdue University professor of earth and atmospheric sciences, discovered that a critical surface temperature feedback is twice as strong as what had been projected by earlier studies.

MADISON - If a warmer Wisconsin climate causes some northern tree species to disappear in the future, it's easy to imagine that southern species will just expand their range northward as soon as the conditions suit them.

GAINESVILLE, Fla. — University of Florida and Florida Institute of Technology engineering researchers have narrowed the search for the source of X-rays emitted by lightning, a feat that could one day help predict where lightning will strike.

A type of wild rice that only grows in a small stretch of the San Marcos River is likely so rare because it plays the sexual reproduction game poorly, a study led by the Lady Bird Johnson Wildflower Center at The University of Texas at Austin has revealed.

NOAA-supported scientists from the Louisiana Universities Marine Consortium and Louisiana State University are forecasting that the "dead zone" off the coast of Louisiana and Texas in the Gulf of Mexico this summer could be the largest on record.

More than 7,000 large commercial vessels follow a major North Pacific shipping lane through Unimak Pass in Alaska's Aleutian Islands annually. That number is expected to climb with increases in vessel traffic between Asia and North America. Over the years, there have been numerous accidents, including in 2004 when the Selendang Ayu ran aground in a severe storm and spilled more than 300,000 gallons of heavy fuel oil into the Alaska Maritime National Wildlife Refuge. One of the largest spills in U.S. waters since the Exxon Valdez incident in 1989.

Palisades, N.Y., July 14, 2008—A group of scientists has used deep ocean-floor drilling and experiments to show that volcanic rocks off the West Coast and elsewhere might be used to securely imprison huge amounts of globe-warming carbon dioxide captured from power plants or other sources. In particular, they say that natural chemical reactions under 78,000 square kilometers (30,000 square miles) of ocean floor off California, Oregon, Washington and British Columbia could lock in as much as 150 years of U.S. CO2 production.

For the first time, researchers have taken a detailed look at what lies beneath all of Iceland's volcanoes – and found a world far more complex than they ever imagined.

They mapped an elaborate maze of magma chambers - work that could one day help scientists better understand how earthquakes and volcanic eruptions occur in Iceland and elsewhere in the world.