August 15, 2007, 9:21 PM CT

Ocean 'supergyre' link to climate regulator

The new research confirms the current sweeping out of the Tasman Sea past Tasmania and towards the South Atlantic is a previously undetected component of the world climate system's engine-room - the thermohaline circulation or 'global conveyor belt'.

Wealth from Oceans Flagship scientist Ken Ridgway says the current, called the Tasman Outflow, occurs at an average depth of 800-1,000 metres and may play an important role in the response of the conveyor belt to climate change.

Published this month in Geophysical Research Letters the findings confirm that the waters south of Tasmania form a 'choke-point' linking the major circulation cells in the Southern Hemisphere oceans.

"In each ocean, water flows around anticlockwise pathways or 'gyres' the size of ocean basins," Mr Ridgway says. "These gyres are the mechanism that distribute nutrients from the deep ocean to generate life on the continental shelves and slopes. They also drive the circulation of the world's oceans, creating currents and eddies and help balance the climate system by transferring ocean heat away from the tropics toward the polar region".

He says the conventional picture of the Southern Hemisphere mid-latitude circulation comprises basin-wide but quite distinct gyres contained within the Indian, Pacific and Atlantic Oceans. However model simulations had suggested that these gyres are connected......... Posted by: Tyler      Read more         Source

August 15, 2007, 9:05 PM CT

Heading for Antarctica

Its been more than 100 years since anyone has journeyed to this section of Antarcticas Amundsen Sea, but that is about to change. Next month five UTSA scientists and a Boerne High School science teacher will join a crew of 22 scientists from several countries to set sail on a two month expedition.

The trip, funded by a $533,000 National Science Foundation (NSF) research grant to UTSA, is designed to study the relationship of sea ice and the Antarctic environment. UTSAs research team will depart Sept. 1 from Punta Arenas, Chile.

The expedition, sponsored by the Arctic Research Consortium of the United States (ARCUS), is one of 20 annual trips planned involving a teacher accompanying a research expedition. ARCUS coordinates NSFs PolarTREC educational program, designed to bring educators and scientists together to explore, collaborate and experience life in the Polar Regions.

We hope that once these teachers get this hands-on experience they will be better equipped to teach science in the classroom and convey their sense of excitement to their students, particularly after going through this amazing experience, said Janet Warburton, PolarTREC program manager.

Leading UTSAs efforts is world-renowned sea ice expert Stephen Ackley, research associate professor of earth and environmental science, who has made more than a dozen trips to the Arctic and Antarctic regions. Ackleys outstanding contributions to sea ice research were recognized in 2004 when the Antarctic geographic feature, Ackley Point, was named after him by the U.S. Board of Geographical Names......... Posted by: Tyler      Read more         Source

August 10, 2007, 7:15 AM CT

Man-made soot contributed to warming

New research shows that industrial development in North America between 1850 and 1950 greatly increased the amount of black carbon--usually known as soot-- that fell on Greenland's glaciers and ice sheets. The soot impacted the ability of the snow and ice to reflect sunlight, which contributed to increased melting and higher temperatures in the region during those years. This discovery may help researchers better understand the impact of human activities on polar climates.

In an article published recently in the online edition of Science magazine, a team led by Joe McConnell and Ross Edwards from the Desert Research Institute (DRI) in Reno, Nev., report that these increased levels of soot deposits were the result of human activity and in some years were as much as eight times larger than naturally-occurring soot deposits measured in the years before 1850.

The research, funded by the National Science Foundation and NASA, indicates that these elevated levels of soot decreased the snow and ice pack's ability to reflect sunlight. This decreased level of reflectivity, or albedo, in scientific terms, allowed the surface to absorb more energy from the sun. These changes may have resulted in earlier snow melt and exposure of darker rocks, soil and sea ice, leading to warming throughout Greenland in the late 19th and early 20th century when soot levels were at their highest......... Posted by: Tyler      Read more         Source

August 8, 2007, 8:41 PM CT

Conventional plowing is 'skinning our agricultural fields'

Traditional plow-based agricultural methods and the need to feed a rapidly growing world population are combining to deplete the Earth's soil supply, a new study confirms.

In fact, long-established practices appear to increase soil erosion to the point that it is not offset by soil creation, said David Montgomery, a University of Washington professor of Earth and space sciences.

No-till agriculture, in which crop stubble is mixed with the top layer of soil using a method called disking, is far more sustainable, he said.

"Soil loss through conventional agriculture is in a range of 10 to 100 times greater than the rate at which soil is created. No-till agriculture brings it into the ballpark, surprisingly close to being balanced with soil creation," he said.

Montgomery looked at data from more than 1,650 measurements published in more than 200 studies examining various aspects of farming practices, soil creation and erosion. His findings are being published this week in the online edition of the Proceedings of the National Academy of Sciences, and will be published in a print edition later in the year.

Long-term erosion rates worldwide average less than one-tenth of a millimeter per year, which is similar to the rate at which soil is produced through mechanical, chemical and biological processes that dissolve rock and mix the grains with organic matter. The research shows that erosion rates consistently exceed 1 millimeter a year less than a half-inch per decade only in steep alpine terrain, and plowed fields erode at about the same pace as the Himalayas, home to the highest mountain peaks in the world......... Posted by: Tyler      Read more         Source

August 7, 2007, 10:43 PM CT

Stability and Diversity in Ecosystems

Is biodiversity important for predicting human impacts on ecosystems? If diverse ecosystems were as a consequence more stable, the answer would be yes.

However, stability is not one, simple property of an ecosystem and there is no one, simple relationship between diversity and stability, say ecologists Tony Ives and Steve Carpenter of the University of Wisconsin at Madison.

In the last 20 years, ecologists have performed experiments on diversity and stability, manipulating diversity (number of species) at small scales, then measuring one of several kinds of stability.

While these studies have taught us a lot about how diversity affects some types of stability, they don't necessarily tell us how stable ecosystems will be against human impacts, say Ives and Carpenter.

Ecologists should turn the question on its head, the scientists believe: rather than focusing on how diversity affects stability, researchers might make faster progress by focusing on stability first.

"Humans don't change 'just' biodiversity," said Ives. "Humans cause major environmental changes to ecosystems, like acidifying lakes or cutting down forests, with changes in biodiversity often a by-product.

"Rather than how biodiversity affects stability, we should be asking how environmental change affects the stability of a number of aspects of ecosystems, including diversity"......... Posted by: Tyler      Read more         Source

August 6, 2007, 5:24 PM CT

Can hemp help the everglades?

Within Southern Florida, soil and water conditions indicate potential for leaching from the use of atrazine-based herbicides in corn crops. Researchers from USDA-Agricultural Research Service (ARS) and University of Florida conducted studies to evaluate the specific groundwater risk from atrazine use by focusing on a specific cover crop that seems to have the potential to greatly reduce that risk. The crop is called sunn hemp. Its a tall, herbaceous annual that grows rapidly to a height of 6 to 7 feet.

The regions aquifer provides drinkable water for nearly all of the rapidly growing population. Agricultural practices that impair water quality may also stunt a massive project intended to restore the Florida Everglades ecosystem. A number of investigations have shown that cover crops can reduce herbicide leaching; however groundwater quality has not been widely observed and the effectiveness of cover crops on water contamination has not been documented.

The studies revealed that atrazine and some of its products may seep into the groundwater and impair water quality. Climate, cropping patterns, high dilution rates, and high chemical degradation rates limited the contamination levels. Measurements also showed that cover crops significantly reduced contamination in groundwater. The studies focused on sweet corn production and included whether fields with a highly vigorous cover crop would reduce impacts. Sunn hemp planted during uncultivated summer periods was the most focused upon. Crops such as these can be effective in reducing weeds and leaching while enriching soil. Sunn hemp can be grown to prevent soil erosion, as high-protein forage, and in older plants, it can be used to make cloth, twine, and rope......... Posted by: Tyler      Read more         Source

August 6, 2007, 5:13 PM CT

Tracking North American Climate Change

Gene Takle begins talks about climate change with some strong statements.

"There is no question now that the climate is changing on a global scale," says Takle, an Iowa State University professor of geological and atmospheric sciences and agronomy. "The evidence is so overwhelming".

But what does that mean on a smaller scale? How are greenhouse gases changing the climate in North America? In the United States? In Iowa?.

After all, "You and I are not affected by a few tenths of a degree of temperature change on a global scale," Takle said.

Takle is working with Bill Gutowski, an Iowa State professor of geological and atmospheric sciences, and Ray Arritt, an Iowa State professor of agronomy, to find some answers about regional climate change.

The three have worked together on climate studies for 15 years. And now they've joined an international group of researchers collaborating on the North American Regional Climate Change Assessment Program. The assessment program is led by Linda Mearns, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo. The National Science Foundation is funding the Iowa State work on the project with a $353,000 grant.

The project calls for six teams of scientists (four from the United States, including the Iowa State group, one from Canada and one from Europe) to run their own regional climate models using at least two sets of identical data from two research groups studying global climate change. The research groups will see what their models say about regional climate change and compare the results. Ultimately, the scientists will create data sets that will help them study the impacts of climate change on a continental or even statewide scale......... Posted by: Tyler      Read more         Source

Sun, 05 Aug 2007 21:06:09 GMT

Lake Superior Losing Water, Getting Warmer

Be it big industries or small farms, the deteriorating source of a livelihood always kicks up concerns with the same magnitude. So, is also with those depending on the mighty Lake Superior be it a scientist or industry or a farmer.

Yes, Lake Superior — the lifeblood for ones living near its shores — is losing water and getting warmer!

It is a significant sign of climate change?

Though, this has not been known, — that it is causing significant damage to itself as well as its dependents can quite clearly been seen.

The giant Lake has reached to its alarming lowest level in last eight decades! And, if the trend does not change, with its level dipping three more inches, it will set a record this fall!

To add to the lakes misery, the average water temperature has also considerably surged. Since 1979, it surged 4.5 degrees! This is above the 2.7-degree rise in the region’s air temperature during a similar period.

This sudden and severe changing phenomenon of the Superior has left scientists puzzled and environmentalists worried. Not long ago 27-foot vessels could easily make their way up the eastern Upper Peninsula channel from the lake’s Brimley Bay, but has gone useless this year.

With the ferry services disrupted, boats along Superior’s shores can’t reach many of its mooring sites, leaving the marina operators begging for shallow-harbor dredging. Is the Lake disappearing?

Image Posted by: Irani      Read more     Source

August 3, 2007, 10:27 PM CT

Sensors Help Africa Tackle Water Shortage

Zambian water authorities are integrating information based on satellite imagery to alleviate water shortages. With inadequate information causing a number of water-related problems, an ESA project has generated a variety of environmental maps to provide local policy makers with the necessary tools for effective water resource management.

As part of the IWAREMA (Integrated Water Resource management for Zambia) project, funded through ESA's Data User Element, data from ESA's multispectral MERIS sensor aboard Envisat was used to create maps depicting existing water resources, suitable dam locations and land cover. The project is carried out by the Belgium Company GIM (Geographic Information Management) in partnership with the University of Zambia and the Zambian water authorities.

"The results of the IWAREMA project can be used to protect Zambia's ecosystems especially in the Kafue flats where wildlife, agricultural activities, fisheries and tourism compete for regulated water resources," Jack Nkhoma of Zambia's Department of Water Affairs said.

Having access to these maps allows authorities to determine the expansion of urban areas and loss of forest and agricultural areas as well as calculate the risk of erosion, change in water availability and percentage of surface water, which will allow for early flood warnings......... Posted by: Tyler      Read more         Source

August 3, 2007, 10:20 PM CT

European heat waves double in length since 1880

The most accurate measures of European daily temperatures ever indicate that the length of heat waves on the continent has doubled and the frequency of extremely hot days has nearly tripled in the past century. The new data shows that a number of prior assessments of daily summer temperature change underestimated heat wave events in western Europe by approximately 30 percent.

Paul Della-Marta and a team of scientists at the University of Bern in Switzerland compiled evidence from 54 high-quality recording locations from Sweden to Croatia and report that heat waves last an average of 3 days nowwith some lasting up to 4.5 daysin comparison to an average of around 1.5 days in 1880. The results are published 3 August in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union. The scientists suggest that their conclusions contribute to growing evidence that western Europe's climate has become more extreme and confirm a previously hypothesized increase in the variance of daily summer temperatures since the 19th century.

The study adds evidence that heat waves, such as the devastating 2003 event in western Europe, are a likely sign of global warming; one that perhaps began as early as the 1950s, when their study showed some of the highest trends in summer mean temperature and summer temperature variance......... Posted by: Tyler      Read more         Source