Ancient Rainforests Resilient To Climate Change

ScienceDaily (Oct. 1, 2009) — Climate change wreaked havoc on the Earth’s first rainforests but they quickly bounced back, scientists reveal. The findings of the research team, led by Dr Howard Falcon-Lang from Royal Holloway, University of London, are based on spectacular discoveries of 300-million-year-old rainforests in coal mines in Illinois, USA.

Preserved over vast areas, these fossilized rainforests in Illinois are the largest of their kind in the world. The rocks at this site - in which the rainforests occur - contain evidence for climate fluctuations. During cold ‘ice ages’, fossils show that the tropics dried out and rainforests were pushed to the brink of extinction. However, rainforests managed to recover and return to their former glory.

Dr Falcon-Lang, from the Department of Earth Sciences, worked with colleagues at the Smithsonian Institution and Illinois Geological Survey. In their paper published in the journal Geology, they show that rainforest species all but vanished at the height of the ice ages. Yet they also reveal that the coal beds that formed shortly after, as the climate warmed, contain abundant rainforest species.

Falcon-Lang said, ‘These discoveries radically change our understanding of the Earth’s first rainforests. We used to think these were stable ecosystems, unchanged for tens of millions of years. Now we know they were incredibly dynamic, constantly buffeted by climate change’.

The research may also shed light on how climate change will affect the Amazon rainforest in the future. Dr Falcon-Lang commented, ‘If we can understand how climate shaped rainforests in the distant past, we can infer how they will respond in the future. We’ve shown that within certain limits, rainforests are resilient to climate change; however, extreme climate change may push rainforests beyond a point of no return’.

The work is part of a five-year project funded by the UK’s Natural Environment Research Council and aims to study how climate change affected the Earth’s first rainforests. These ancient rainforests date from the Carboniferous period, 300 million years ago, when most of the world's coal resources were formed.

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Changes In Earth's Ozone Layer Predicted To Increase UV Radiation In Tropics And Antarctica

ScienceDaily (Sep. 16, 2009) — Physicists at the University of Toronto have discovered that changes in the Earth’s ozone layer due to climate change will reduce the amount of ultraviolet (UV) radiation in northern high latitude regions such as Siberia, Scandinavia and northern Canada. Other regions of the Earth, such as the tropics and Antarctica, will instead face increasing levels of UV radiation.

“Climate change is an established fact, but scientists are only just beginning to understand its regional manifestations,” says Michaela Hegglin, a postdoctoral fellow in the Department of Physics, and the lead author of the study published in Nature Geoscience on September 6.

Physicists have discovered that changes in the Earth's ozone layer due to climate change will increase the amount of ultraviolet radiation hitting the tropics and Antarctica.

Using a sophisticated computer model, Hegglin and U of T physicist Theodore Shepherd determined that 21st-century climate change will alter atmospheric circulation, increasing the flux of ozone from the upper to the lower atmosphere and shifting the distribution of ozone within the upper atmosphere. The result will be a change in the amount of UV radiation reaching the Earth’s surface which varies dramatically between regions: e.g. up to a 20 per cent increase in UV radiation over southern high latitudes during spring and summer, and a nine per cent decrease in UV radiation over northern high latitudes, by the end of the century.

While the effects of increased UV have been widely studied because of the problem of ozone depletion, decreased UV could have adverse effects too, e.g. on vitamin D production for people in regions with limited sunlight such as the northern high latitudes.

“Both human and ecosystem health are affected by air quality and by UV radiation,” says Shepherd. “While there has been much research on the impact of climate change on air quality, our work shows that this research needs to include the effect of changes in stratospheric ozone. And while there has been much research on the impact of ozone depletion on UV radiation and its impacts on human and ecosystem health, the notion that climate change could also affect UV radiation has not previously been considered. This adds to the list of potential impacts of climate change, and is especially important for Canada as northern high latitudes are particularly affected.”

The research was funded by the Canadian Foundation for Climate and Atmospheric Sciences through the C-SPARC project. The C-SPARC project is a national collaboration between Environment Canada and several Canadian universities.

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The Concept Of Deionized Water

Deionization of water is a process which removes all salts dissolved in water. This process involves passage of water through ion exchange materials to totally remove salt content. There are two ion exchange materials for this purpose.

Another term for deionization is demineralization, thus, demineralised water and deionized water are two similar terms, although the latter is more appropriate. The principle of ion exchange has long been used. Scientists knew about this for ages but only quite recently that this principle has been used extensively for practical purposes. This process has been highly reliable and greatly effective to treat water from minerals, which make water hard.
This process uses resin beads or granules, referred to as ion exchange material or bed, which contains insoluble anions neutralized electrically by sodium cations. This system softens hard water by stripping off calcium and magnesium ions in the water and replacing them with sodium ions.

During the first ion exchange calcium and magnesium ions are removed. This follows the water softening process. Industrial deionization removes positive metallic ions and replaces them with hydrogen ions. Home equipment does not achieve the same process because it releases sodium ions instead. The cations adhere to the ion exchange material. Metallic ions replace a number of hydrogen ions depending on the charge they are carrying. A sodium ion (Na+) replaces one hydrogen ion (H+). Two hydrogen ions are replaced by a calcium ion (Ca++) from the exchange material. An iron (III) ion (Fe+++) displaces three H+ ions. This way the ion exchange material maintains a balance of electrical charges in itself.

The introduction of hydrogen ions into the water results to a higher acidity. This is when the second step in deionization process steps in. The water contains hydrogen ions and remaining anions (negatively charged ions) after the first process.

The second process lets water pass through another unit where an anion exchange occurs. The ion exchange material this time takes negatively charged ions in the water, chloride ions (Cl-) for example, and replace them with hydroxyl ions (OH-). The resulting water contains H+ and OH- ions, which are actually ions composing water. Thus, the two processes mentioned actually demineralise water.

There different types of equipment used in the process. There is single deionization or multiple deionization bed units. The former mixes positive and negative ion exchangers in one tank, while the latter have separate tanks for cation exchangers and anion exchangers.

Industries have wide applications for demineralised water. Pharmaceuticals, leather goods processing, chemical production, and electroplating are some of the industrial applications of this kind of purified water.

An alternative for deionization would be distillation which is a more complex and more expensive process of water purification.

The safety of available water in the world is never guaranteed. This is why purification of water has always been a concern. A large percentage of water available for the public is often contaminated. This contamination comes from industrial and environmental waste. Pathogenic bacteria, heavy metals, and chemicals make water unsafe for human consumption. The health risks of contaminated water cannot be ignored. Reports have it that some liver problems and cancer can be linked to contaminants in water. Contaminants can be microorganisms like parasites and bacteria, or substances, which can be organic or inorganic. Organic substances come from different sources as decaying matter. Inorganic substances come from lots of sources from synthetic fertilizers in farms and infiltrate waterways to toxic lead present in PVC pipes.

There have been issues about drinking pure water because some experts believe that purified water without minerals is harmful to the body. According to them, pure water devoid of ions can cause loss of electrolytes in the body. But that is a simple explanation because their research indicate that loss of bone mineral and essential minerals in tissues can be a result of deionized water consumption. In addition, minerals present in water are beneficial to the human body, that there is no need to demineralise.

However, lots of scientists do not agree. Humans take minerals not from drinking water, which supply extremely minimal amounts of minerals, if anything; and that "minimal amount" is at the point of negligibility. Minerals used by human body come from food.

By: joalesto

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Spotting danger from on high

Airborne instruments can scan the ground to quickly and efficiently detect rocks and soil that may contain naturally occurring asbestos, researchers report.

In many regions, particularly in the West, rock outcrops can host several types of fibrous minerals known as asbestos. Though generally known for its past use as insulation in building construction, asbestos can also be a health concern for people who live on or near land that contains the minerals (SN: 7/8/06, p. 26). Field geologists in California have been mapping outcrops that could potentially contain asbestos for more than a century, says Gregg Swayze, a research geophysicist with the U.S. Geological Survey in Denver. Now, a technique developed by Swayze and his colleagues and described in the August Geology may make mapping remote areas quicker and easier.

Minerals have distinct chemical compositions and crystalline structures. The amount of each wavelength of light that is absorbed or reflected from a mineral’s surface often has a distinct fingerprint as well, Swayze says. Many minerals in the asbestos family — and the minerals from which they’re derived, such as the nonhazardous serpentine — absorb much of the 2.3-micrometer-wavelength light that falls on them. So, viewed in near-infrared light near that wavelength, such minerals appear darker than those around them.

Using airborne sensors tuned to wavelengths ranging from ultraviolet through the near-infrared, the researchers scanned areas of El Dorado County and Plumas County in California that are known to host asbestos-bearing rocks and soil. Data suggest that the instruments can spot rocks that may contain asbestos even in areas that are 80 percent covered by dry grass, Swayze says. Because water also absorbs some of the key wavelengths used to identify potentially asbestos-bearing minerals, airborne scans for such minerals would need to take place when vegetation is dry or absent, he notes.

The team’s flight tests, which took place in August 2001, spotted many areas already known to host naturally occurring asbestos but also identified a few new ones, including an area about 1 kilometer long and several hundred meters wide in a pasture in northern Amador County, just across the border from El Dorado County. The technique could help scientists to quickly and easily fill in gaps on current maps of asbestos-bearing minerals, the researchers contend.

From

Sid Perkins

Web edition : Friday, August 7th, 2009

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