August 9, 2006, 10:11 PM CT

Arctic Coring Expedition Yield New Clues

For the second time in as a number of months, the IODP Arctic Coring Expedition (ACEX) is making news with new analysis of ocean-floor sediments. In the Aug. 10 issue of Nature, an article authored by several of the expedition researchers summarizes their findings: more evidence that the Arctic was extremely warm, uncommonly wet, and ice-free up to the time the last massive amounts of greenhouse gases were released into the Earth's atmosphere - a period calculated to have occurred 55 million years ago, and known as the Paleocene/Eocene thermal maximum, or PETM.

Scientists have long recognized that a massive release of greenhouse gases, probably carbon dioxide or methane, occurred during the PETM. Surface temperatures also rose in a number of places by as much as 15 degrees Fahrenheit in the (relative) geological instant of about 100,000 years.

Arctic sediment samples were largely unavailable until 2004, when ACEX researchers recovered the first deep-ocean sediment samples from beneath the ice-laden waters near the North Pole. ACEX, only the second scientific expedition to be conducted by the Integrated Ocean Drilling Program (established in late 2003), recovered 339 meters of subseafloor sediment samples.

"Building a picture of ancient climatic events is a lot like putting together a jigsaw puzzle, and what ACEX allowed us to do was fill in a blank section of the PETM picture," said Gerald Dickens, a Rice University geochemist and co-author, who conducted the initial, shipboard chemical analyses of all the ACEX core samples.........

Posted by: Tyler      Permalink         Source

August 9, 2006, 7:15 AM CT

Landscapes and human behavior

On Arizona State University's (ASU) Polytechnic campus, graduate student families in the cluster of six houses abutting lush lawns and ornamental bushes spend time together talking while their kids play outside. Meanwhile, the families in a nearby cluster of six homes barely know each other. But that may be in part because their homes sit on native Sonoran desert, not nearly as conducive to recreation as the lush microclimate scientists created in the first neighborhood. Social researchers and biophysical ecologists are finding that environmental surroundings may play a significant role in human social interaction, serving either as a social lubricant as in the first case, or as a barrier.

David Casagrande (Western Illinois University) and Scott Yabiku (ASU) and his colleagues are part of the Central Arizona-Phoenix long term ecological research project. In 2004 and early 2005, the scientists installed residential landscapes at 24 of about 152 virtually identical housing units in the "North Desert Village" of ASU's campus. The researchers selected five "mini neighborhoods" (groups of six houses) and altered four of them, leaving the fifth as a control with no landscaping. The four landscaping styles were:

• mesic: shade trees and turf grass, dependent upon flood irrigation for their high water demands

........

Posted by: Tyler      Permalink         Source

August 9, 2006, 7:01 AM CT

Management Of Climate Change

Arctic nations have the wealth and scientific understanding to alter the course of global climate change, if they choose to do so, writes F.S. (Terry) Chapin III, of the University of Alaska Fairbanks, in a paper would be published August 9, 2006 in the journal Ambio.

Chapin, professor of ecology at the Institute of Arctic Biology, and co-authors offer local-to-global policy recommendations to manage Arctic conditions resulting from thawing permafrost, melting sea ice, and relaxation of thermal thresholds. "Nations that govern Arctic lands account for about 40% of global CO2 emissions and therefore have a substantial capacity to reduce the rates of Arctic change," write the authors.

Among the authors' recommendations are that Arctic nations should designate marine protected areas, designate co-managed reserve networks, foster economic adaptation to global change, and reduce greenhouse gas emissions. "A lot of the recommendations for policy change deal with enhancing the capacity of northern regions to be flexible and adaptable to cope with changes, some of which we can predict, and others of which will be surprises," said Chapin.

An increasingly ice-free Arctic Ocean could be zoned to include marine protected areas, designated shipping lanes, and fishing areas co-managed by local residents and government managers. If reserve networks were implemented, they would likely make important contributions to maintaining biodiversity, providing nursery stocks for adjacent fished areas, and ensuring against mismanagement or unexpected events outside the reserves. Economic adaptation is likely to be most effective if it includes incentives to encourage economic diversity and entrepreneurship rather than subsidies for traditional sectors adversely affected by Arctic change.........

Posted by: Tyler      Permalink         Source

August 8, 2006, 0:30 AM CT

System To Put Wastewater To Work

In the midst of the worldwide energy crisis, scientists at Washington University in St. Louis have been continuing their work on a microbial fuel cell that generates electricity from wastewater. Advances in the design of this fuel cell in the last year have increased the power output by a factor of 10 and future designs, already in the minds of the researchers, hope to multiply that power output by 10 times again. If that goal can be achieved, the fuel cell could be scaled up for use in food and agricultural industries to generate electrical power - all with the wastewater that today goes right down the drain.

Lars Angenent, Ph.D., assistant professor of chemical engineering, and a member of the University's Environmental Engineering Science Program, has devised a continually fed upflow microbial fuel cell (UMFC). In a paper published online in the Environmental Science Technology, Angenent describes how wastewater enters from the bottom of a system and is continuously pumped up through a cylinder filled with granules of activated carbon. A number of prior microbial experiments used closed systems with a single batch of nutrient solution, but because this system is continuously fed from a fresh supply of wastewater, Angenent's UMFC has more applications for industry since wastewater is continually outputted during industrial production.........

Posted by: Kevin      Permalink         Source

August 7, 2006, 10:09 PM CT

Mercury in Aquatic Ecosystems

Mercury occurs naturally in the environment and cycles among the atmosphere, water, and sediments. Human activities such as coal burning power plants and waste incineration increase the amount of mercury cycling in the environment. Since the industrial revolution, anthropogenic mercury emissions have increased atmospheric mercury levels about threefold, causing corresponding increases in mercury levels in terrestrial and aquatic ecosystems.

Mercury that is released into the atmosphere can be transported long distances and deposited in aquatic ecosystems, where it is methylated to methylmercury. Mercury is a neurotoxicant, to which the human fetus is very sensitive. Methylmercury is an organic form of mercury, the most toxic form, and the form that bioaccumulates in fish. Wildlife and humans are exposed primarily through consumption of contaminated fish. The factors that make some aquatic ecosystems susceptible to this bioaccumulation, however, are unknown, making protection of human health and the health of fish-eating wildlife a challenge.

Research focuses on the processes of mercury methylation and accumulation in aquatic ecosystems, factors that determine ecosystem susceptibility, and investigation of whether reduced emissions will reduce mercury accumulation in susceptible ecosystems.........

Posted by: Tyler      Permalink         Source

August 7, 2006, 10:01 PM CT

Storing Man-made Carbon Dioxide

Deep-sea sediments could provide a virtually unlimited and permanent reservoir for carbon dioxide, the gas that has been a primary driver of global climate change in recent decades, according to a team of scientists that includes a professor from MIT.

The researchers estimate that seafloor sediments within U.S. territory are vast enough to store the nation's carbon dioxide (CO2) emissions for thousands of years to come.

"The exciting thing about this paper is that we show that CO2 injected beneath the seafloor is sequestered permanently," said Charles Harvey, an associate professor in MIT's Department of Civil and Environmental Engineering. Harvey is a co-author of a paper on the work that appears in this week's issue of the Proceedings of the National Academy of Sciences.

"CO2 injected underground on land is buoyant, and hence has the potential to escape back to the surface," Harvey said. "This is not the case under the deep ocean. Because the ocean floor is so cold, liquid CO2 stored beneath the floor is denser than water and will not rise to surface. Furthermore, the top of the injected CO2 plume will form a hydrate, an ice-like solid that plugs up the pore spaces, 'self-sealing' the injected CO2 plume into the deep sea sediments".

The leader of the work, Daniel P. Schrag, said, "Supplying the energy demanded by world economic growth without affecting the Earth's climate is one of the most pressing technical and economic challenges of our time." Schrag is a professor of earth and planetary sciences at Harvard University.........

Posted by: Tyler      Permalink         Source

August 7, 2006, 9:53 PM CT

Kayaks Adapted To Test Marine Robotics

MIT researchers are working toward the day when a team of robots could be put into action like a team of Navy SEALs -- doing such dangerous work as searching for survivors after devastating hurricanes or sweeping harbors for mines.

Working in labs that resemble machine shops, these engineers are taking small steps toward the holy grail of robotics -- cooperative autonomy -- making machines work together seamlessly to complete tasks with a minimum of human direction.

The tool they're using is the simple kayak.

The researchers are taking off-the-shelf, $500 plastic kayaks and fitting them with onboard computers, radio control, propulsion, steering, communications and more to create Surface Crafts for Oceanographic and Undersea Testing (SCOUTs).

Much of the technology being tested is ultimately intended for use in underwater robots, or autonomous underwater vehicles (AUVs), but testing software on AUVs can easily become a multimullion-dollar experiment.

"I want to have master's students and Ph.D. students that can come in, test algorithms and develop them on a shoestring budget," said Associate Professor John J. Leonard of mechanical engineering. Leonard, together with MIT research engineer Joseph Curcio of mechanical engineering and an intern, Andrew Patrikalakis, unveiled SCOUT last fall in a paper for the IEEE Oceans Conference.........

Posted by: Tyler      Permalink         Source

August 4, 2006, 0:02 AM CT

A Summertime Air Quality Exam

Summer in the city can often mean sweltering "bad air days" that threaten the health of the elderly, children and those with respiratory problems. This summer the nation's capitol has been no stranger to such severe air-quality alerts.

But since early July Washington area skies have been put under a unique microscope as researchers from NASA and around the country assembled a powerful array of scientific instruments -- in space and on the ground -- to dissect the region's atmosphere. The result will be not only a better understanding of intense urban air pollution episodes but also a better toolkit to track and probe air pollution worldwide from space.

Two years ago NASA launched the third of its major Earth Observing System satellites -- Aura -- carrying a group of instruments designed to take global measurements of air pollution on a daily basis. Aura sensors can detect five of the six air pollutants regulated by the U.S. Environmental Protection Agency. But to make these 400-mile-high readings as accurate as possible, data from the sophisticated Aura instruments need to be in comparison to data from tried-and-true sensors on Earth.

NASA is sponsoring just such a "ground-truth" experiment this summer. Howard University Research Campus, Beltsville, Md., is hosting visiting scientists, graduate students and instruments for a six-week-long series of intensive observations. The experiment is also evaluating the next generation of instruments used in daily weather forecasting, as well as tracking one of the strongest greenhouse gases involved in climate change: water vapor, which at increased levels we feel as humidity.........

Posted by: Tyler      Permalink         Source

August 2, 2006, 11:51 PM CT

Power, Water, And Refrigeration

When hurricanes, wars or other emergencies force authorities to respond, three essentials top their list of must-haves: water, electricity and refrigeration.

Now, in a project funded by the U.S. Army, two University of Florida engineers have designed, built and successfully tested a combined power-refrigeration system that can provide all three - and, with further development, be made compact enough to fit inside a military jet or large truck.

"If you're in a forward base in Iraq, it costs you the same per gallon of water as it does per gallon of fuel," said William Lear, a UF associate professor of mechanical and aerospace engineering. "It would be better to just have to send fuel out there, particularly if you could get refrigeration and water out of it - which is what our system achieves".

Lear and UF mechanical engineering professor S.A. Sherif have published several academic papers on various aspects of the system, which is being patented by UF. In November, they will present a paper discussing the system's experimental results at the International Mechanical Engineering Congress & Exposition in Chicago.

Both the Federal Emergency Management Agency and the military now rely on large generators to produce electricity in hazard zones. For cooling, they either haul in ice or electricity-hogging refrigerators. Depending on the location and emergency, imported fresh water may be another major logistical challenge and expense.........

Posted by: Kevin      Permalink         Source

August 2, 2006, 9:20 PM CT

Wen To Research On Gravity

MIT Professor of Physics Xiao-Gang Wen has received a grant from the Foundational Questions Institute to fund his study of the relationship between quantum mechanics and gravity.

Wen is one of 30 scientists to receive funding in the inaugural round of grants awarded by the Foundational Questions Institute (FQXi).

FQXi, a new philanthropically funded agency, awards grants to scientists to investigate questions about the deep nature of the universe, including topics such as the fundamental constants of nature, the relationship between quantum mechanics and theories of gravity, the possible existence of other universes, time travel, extraterrestrial life and the ultimate theories of physics.

"Over the past century, researchers have discovered how the universe evolved and revolutionized our understanding of the nature of space and time, matter and energy. We're delighted to help give them a crack at new big questions and to see what they find," said Max Tegmark, MIT associate professor of physics and scientific director of FQXi.

The institute plans to help scientists focus on "big questions" that conventional funding sources are reluctant to support. FQXi is distributing $2 million in grants in its inaugural round. Wen will receive $94,924.........

Posted by: Tyler      Permalink         Source

Older Blog Entries   1   2   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17