There are numerous claims that rechargeable batteries are the way to go, but are they that much better than our everyday alkaline batteries? And are they truly worth all that extra money?

It’s a guarantee that batteries will die. After providing power to everything from cameras, to remote controls and your kids toys, there comes a point when batteries must move on to battery heaven. This year alone, one person will throw away an average of 8 batteries and Americans together will purchase close to 3 billion dry-cell batteries. So how do you stop yourself from following the crowd of battery tossers and buyers? RECHARGEABLE BATTERIES! Not only will you save money, but you will be taking advantage of renewable energy.

Clearly it is cheaper to reach for our old friend alkaline (whether it be those AA, AAA,C,D or 9-volts that we love so dearly), but once you pay the initial expense (Best Buy offers a Duracell 4 pack of AA batteries and charger stand for $12.99) for rechargeable batteries, there is no more expenses to owning these batteries. Rechargeable batteries can last up to 1,000 charges (longer if stored in the fridge) saving you about $80 a year, on average.

As for the environment, batteries can and will leak harmful chemicals (mercury, lead and cadmium) into landfills. Probably the best news is that rechargeable batteries are easy to recycle. And, because batteries can be recharged and reused numerous times, they contribute less waste to landfills, overall.

Nickel Cadmium (NiCd) - known for its long life but lower voltage potential than its competitors.

Nickel-Metal Hydride (NiMH) - higher voltage that the NiCd, but requires more charges.

Lithium-ion-more expensive than other rechargeable batteries, but stores more energy and lasts longer between charges. They’re perfect for battery-operated tools and they’re better for the environment because they don’t contain harmful toxins. And lithium is a natural metal therefore available in great quantities.

And even though rechargeable batteries live longer than alkaline, there comes a time when they will die as well. But don’t go throwing them away, check out the Rechargeable Battery Recycling Corporation (http://www.rbrc.org/call2recycle/) or call 877-273-2925. If there is not a site in your area to recycle your other rechargeable batteries, like those old cell phone batteries, check out EarthWorks website (http://earthworksboston.org/page/home) and they can send them off for you.

TAKEN FROM greenopolis.com

The most complex, “mind-boggling” crop circle ever to be seen in Britain has been discovered in a barley field in Wiltshire

APEX PICTURES

The circle is a coded representation of pi to the 10th significant figure

The formation, measuring 150ft in diameter, is apparently a coded image representing the first 10 digits, 3.141592654, of pi.

• Google Earth: Top 10 British crop circles

It is has appeared in a field near Barbury Castle, an iron-age hill fort above Wroughton, Wilts, and has been described by astrophysicists as “mind-boggling”.

Michael Reed, an astrophysicist, said: “The tenth digit has even been correctly rounded up. The little dot near the centre is the decimal point.

“The code is based on 10 angular segments with the radial jumps being the indicator of each segment.

“Starting at the centre and counting the number of one-tenth segments in each section contained by the change in radius clearly shows the values of the first 10 digits in the value of pi.”

Lucy Pringle, a researcher of crop formations, said: “This is an astounding development - it is a seminal event.”

Mathematics codes and geometric patterns have long been an important factor in crop circle formations. One of the best known formations showed the image of a highly complex set of shapes known as The Julia Set, 12 years ago.

TAKEN FROM www.telegraph.co.uk 

Photo credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University

These images were acquired by NASA’s Phoenix Mars Lander’s Surface Stereo Imager on the 21st and 25th days of the mission, or Sols 20 and 24 (June 15 and 18, 2008).

These images show sublimation of ice in the trench informally called “Dodo-Goldilocks” over the course of four days.

In the lower left corner, lumps disappear, similar to the process of evaporation.

June 19, 2008 — Dice-size crumbs of bright material have vanished from inside a trench where they were photographed by NASA’s Phoenix Mars Lander four days ago, convincing scientists that the material was frozen water that vaporized after digging exposed it.

“It must be ice,” said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson. “These little clumps completely disappearing over the course of a few days, that is perfect evidence that it’s ice. There had been some question whether the bright material was salt. Salt can’t do that.”

The chunks were left at the bottom of a trench informally called “Dodo-Goldilocks” when Phoenix’s Robotic Arm enlarged that trench on June 15, during the 20th Martian day, or sol, since landing. Several were gone when Phoenix looked at the trench early today, on Sol 24.

Also early today, digging in a different trench, the Robotic Arm connected with a hard surface that has scientists excited about the prospect of next uncovering an icy layer.

The Phoenix science team spent Thursday analyzing new images and data successfully returned from the lander earlier in the day.
TAKEN FROM http://phoenix.lpl.arizona.edu/index.php

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2008 June 19  

The Star Streams of NGC 5907
Image Credit & Copyright: R Jay Gabany (Blackbird Observatory) - collaboration; D.Martínez-Delgado(IAC, MPIA),
J.Peñarrubia (U.Victoria) I. Trujillo (IAC) S.Majewski (U.Virginia), M.Pohlen (Cardiff),Explanation: Grand tidal streams of stars seem to surround galaxy NGC 5907. The arcing structures form tenuous loops extending more than 150,000 light-years from the narrow, edge-on spiral, also known as the Splinter or Knife Edge Galaxy. Recorded only in very deep exposures, the streams likely represent the ghostly trail of a dwarf galaxy — debris left along the orbit of a smaller satellite galaxy that was gradually torn apart and merged with NGC 5907 over four billion years ago. Ultimately this remarkable discovery image, from a small robotic observatory in New Mexico, supports the cosmological scenario in which large spiral galaxies, including our own Milky Way, were formed by the accretion of smaller ones. NGC 5907 lies about 40 million light-years distant in the northern constellation Draco.

TAKEN FROM apod.nasa.gov

Image by Hoyasmeg

Last Tuesday, seemingly out of nowhere, a huge lump of cement hurtling from the sky crashed through a suburban Moscow home, creating a large hole. But what was the cause? Why, it was the Russian Air force attempting to change the weather of course!

Yes, the relatively common practice of cloud seeding ended in an unfortunate yet hilarious example of how sometimes we shouldn’t mess with the weather. The Russians have been using cloud seeding as a way to prevent rainy weather during important national holidays. On June 12th, the Russian Air Force sent up 12 planes carrying silver iodide, liquid nitrogen and cement powder to seed clouds above Moscow and empty the skies of moisture.

Ground Based Silver Iodide Generator by Esteban9

“A pack of cement used in creating … good weather in the capital region … failed to pulverize completely at high altitude and fell on the roof of a house, making a hole about 80-100 cm (2.5-3 ft),” police in Naro-Fominsk told agency RIA-Novosti. Weather specialists said this is the first time in 20 years that this has occurred. The homeowner was not injured, but their pride was. They refused a $2,100 offer from the Air Force to fix the damage, but the home owner declined and stated she would sue for damages and compensation of moral suffering instead.

This wasn’t the first time that cloud seeding failed in some way. In 2006 during the G8 Summit in Russia, Russian President Vladimir Putin dispatched fighter jets to seed the skies over St. Petersburg so that it wouldn’t rain on the city. Putin was hoping that the seeding would push the rain towards Finland instead, yet alas, the G8 Summit was drenched anyway. Organizers showed their lack of confidence by supplying rain coats beforehand, which proved popular when the rain came pouring down.

Cloud Seeding is extremely popular in places like the People’s Republic of China which uses the method to produce rainfall in usually arid areas. China also plans to use cloud seeding in Beijing just before the 2008 Olympic Games in order to clear the air of pollution.

The United States also uses cloud seeding to increase precipitation in areas experiencing drought, to reduce the size of hailstones that form in thunderstorms, and to reduce the amount of fog in and around airports. Several countries have looked at cloud seeding as a way to increase snowfall on mountain ranges so that ski seasons can be more sustainable.

While cloud seeding has shown to be effective in altering cloud structure and size, and converting cloud water to ice particles, it’s more controversial, as to whether cloud seeding increases the amount of precipitation at the ground. Part of the problem is that it is difficult to discern how much precipitation would have occurred had the cloud not been “seeded.” In other words, it is hard to ascertain additional precipitation from seeding from the natural precipitation variability, which is frequently much greater in magnitude. Nevertheless, there is more credible scientific evidence for the effectiveness of winter cloud seeding over mountains (to produce snow) than there is for seeding warm-season cumuli form (convective) clouds.

Cessna 210 with cloud seeding equipment by Christian Jansky

Silver iodide can cause temporary incapacitation or possible residual injury (e.g., chloroform) with intense or continued but not chronic exposure. However, studies by Sierra Nevada of California have shown that the exposure to silver iodide from cloud seeding is less dangerous than exposure from tooth fillings. Notwithstanding this, cloud seeding can be dangerous in other ways. The USAF proposed its use on the battlefield in 1996, although the U.S. signed an international treaty in 1978 banning the use of weather modification for hostile purposes. After the Chernobyl disaster, Russian military pilots seeded clouds over Belarus to remove radioactive particles from clouds heading toward Moscow. So while the current environmental impact is limited, cloud seeding can be used as a hostile measure.

While this method has proved successful in various roles, we should acknowledge that areas that would normally be receiving precipitation won’t because of man-made weather patterns. Using cloud seeding to increase precipitation in usually arid environments can change ecosystems and cause damage to the local habitat for a number of animals. While it is nice to spend the day outside in the sun, we also need those dreaded rainy days as well. I’d rather it rain water than cement on my house, how about you?

TAKEN FROM

Solar System Powers Donggwang Green Village on Semi-Tropical Jeju Island

Donggwang is on the western half of Jeju-do, the largest of South Korea’s semi-tropical southern islands. Near the village, Halla Mountain, a volcano and the tallest mountain in South Korea, rises from the island’s center amidst a patchwork of small farms.

Donggwang has achieved what even the most powerful countries in the world are still struggling to accomplish: total energy independence with clean technology.

On the roof of each of the 40 houses in Donggwang lies a large beds of solar panels. Even the small, local elementary school runs on free electric energy from the sun. The photovoltaic panels produce enough energy to power the entire area. Amidst cattle and fields, Donggwang is a state-of-the-art renewable energy village.

I spoke with Choo Chan Lee, who lives in Donggwang. Mr. Lee, a Seoul native, retired to Donggwang green village after operating a successful grocery store in New York for many years. He and his wife invited my in for tea to talk about the solar system and their life in Donggwang.

“Dongwang is a solar town,” Mr. Lee says. “[The solar systems] are a lot of help for us. Mine is 2.1 kW.”

In 2004, the government helped to install solar systems in Donggwang, paying 70% of the installation fees.

“They told us this is your town,” recalls Mr. Lee. “Do you wand them or not? We said that we would like them.”

When asked whether he is concerned about environmental issues, Mr. Lee replies casually, “Yeah, the environment is a very important issue. In Jeju we don’t have many factories, so the air is very nice. Very nice environment. The motto is a clean city - clean island. They’re trying to do this solar and then the windmills. My favorite part of living in Jeju is the fresh air. The clean air.”

Taken from ecoworldly.com

Editor’s note: We’re pleased to welcome Max Gladwell, of MaxGladwell.com, as a regular guest writer on sustainablog. Max Gladwell covers the nexus of social media and green living. We feel that these two trends and technological developments hold tremendous promise for improving quality of life for everyone on the planet.

If you’re reading this blog, then you’re on board with social media. There’s a good chance you belong to social networks like Facebook or MySpace. It’s likely that you Digg stories and even possible that you Twitter. These technologies and services, together with a growing number of others, make up the social web. It’s much like the regular web, but more interactive. More…social. It invites and even demands active participation from everyone. It has a global reach with viral capacity, and yet it’s bringing local communities closer together. It enables people to connect, organize, and make a difference as never before. Indeed, social media is a powerful force, one that the world’s CEOs are starting to acknowledge and take seriously.

Many entrepreneurs, activists, and marketers are leveraging the social web for positive change. In the process and by its very nature, they are giving each of us the tools to change the world and make it a better place. There are thousands of examples, which is precisely why Max Gladwell exists. Here are 10 worth exploring.

1. Do-Good Widgets: If you’re Facebook page was a car, these would be your bumper stickers. Only these do more than spread the message. Widgets are standalone web applications that can run inside any web page. They take many forms, ranging from the absurd to the truly useful and socially valuable. The best ones engage us in ways that lead to action, awareness, and even fund-raising. Facebook was the first to offer them, and MySpace recently followed. Other social networks offer widgets, but these two have a scale that gives them unrivaled potential. Causes is the 800-pound gorilla in the do-good widget space with millions of daily active users on Facebook alone. If you support a cause, chances are you can find it in Causes. We support 14 ranging from “Recycle not Waste” to “Ride Bikes” and “GREEN“. Each Cause enables you to recruit others and make donations.

A new suite of widgets from Dank Apps called Social Change offers widgets for three main initiatives: Stop Climate Change Now, which raises funds for The Nature Conservancy; Earn For AIDS, which raises funds for the Clinton HIV/AIDS Initiative; and Earn for Breast Cancer, which raises funds for the Breast Cancer Research Foundation. Each of these allows you to send karma points to friends and play games, all of which generate donations from sponsors.

I’m sure I’d get hate comments if I didn’t also mention Lil Green Patch, which has helped to save over 20 million square feet of rainforest.

2. Get a Green Job: The business networking space is currently dominated by LinkedIn, but JustMeans has a new social media platform that “rallies both companies and individuals around social responsibility.” As you make your way through the registration and profile-building gauntlet, you are posed with two unique questions: What kind of change do you want to create in the world over the next 12 months? How do you plan on creating this positive change? The site encourages networking between members by recommending matches based on shared interests. Plus, you can network with companies themselves as “stakeholders”. Companies as well as nonprofits set up their own profiles, similar to Facebook Pages, where they can post content about initiatives and CSR efforts. An entire section of the site is dedicated to job listings. This is business networking with a purpose.

3. Greenstream: Twitter is a way to stay in touch with friends and keep up with breaking news. It is a source of both cutting-edge news and unchecked banality. It all depends on how you want to use it. You can follow CNN, BBC, GreenOptions, and MaxGladwell as “micro-blogs”, where you receive bits of news and links in 140 characters or less. Or you can track the musings of iJustine and Aubs for pure entertainment value. Recently, we started a new Twitter channel called the “greenstream.” Whereas Twitter asks, “What are you doing”, this adds “that is green?” So if you’re shopping at a farmer’s market, drinking fair trade coffee, or carpooling to work, these qualify as Tweets for the greenstream. Just tag your Tweet with “#greenstream”, and it will be indexed for viewing by all. Alternately, if you want to Twitter a green tip, just enter “#greentip” and check the index page for those.

4. Hugg a Story: Hugg.com is the green counterpart to the wildly popular Digg.com. These are social news sites that enable users to vote and comment on what’s important (and what’s not). This process places the power in the hands of real people who, collectively, determine which issues get attention, rather than leaving it up to the major news organizations to tell us what’s important. The great thing about them, though, is that they get better and more accurate as more people participate. So it’s your civic and social duty to Hugg and Digg stories that matter to you.

5. Join the “Make The Difference Network“: Actress Jessica Biel, in a collaboration with her father and brother, just launched a social network that connects people and businesses with charitable organizations. Make The Difference Network already has a number of prominent celebrities signed up as members, complete with their favorite causes. Each of the site’s constituencies has a profile platform, and it’s free for all to participate. The “Find Your Wish” section gives people some direction in matching their personal interests or passions with charities ranging from addiction and animals to labor and literacy.

6. Go Shopping: Your purchasing decisions matter. Though presidential elections come once every four years, you vote with your wallet every day. Combined with the tools of social media, you get social shopping. Alonovo describes this as “the power of millions of informed, aware and caring people acting in concert. For a better world.” The company provides a platform in which to interact with fellow conscious consumers, to research products based on a range of social and environmental criteria, and ultimately make informed purchases through Amazon.com. You choose a charitable benefactor, and 50-100% of the commission paid to Alonovo is donated on your behalf.

OsoEco, which is currently in private beta, takes a different tact. Using a bookmark feature for the Firefox browser, you can pull products from any retail site and import them into OsoEco with one click. It’s much like a wiki in this way (more below). Then you review the product for others to see and rate. According to the company, they “created OsoEco to answer our own questions about what’s green, what’s sustainable, and what kinds of things we should buy and do that are good for our communities and, not to sound completely cheesy and cliche, our world.”

7. Contribute to a Wiki: Most are familiar with Wikipedia. It’s a fantastic resource for information and an even more incredible phenomenon of collaborative creation on a global scale. What’s incredible to consider, though, is that it’s just the beginning. As author Clay Shirky points out, it’s a drop in the well compared to the untapped potential of our cognitive surplus. PlayGreen.org is one example of how wikis are being built for specific topic areas. Anyone can contribute or edit articles such as How to build a green PC and RecycleBank. Imagine an entire Wikipedia of knowledge and human experience dedicated to specific issues like global warming, cancer, autism, and renewable energy. That’s where we’re headed.

8. Start Your Own Social Network: Ning has made starting a social network as easy as signing up for an email address. For an example, see the Max Gladwell network or any one of more than 100 networks tagged with “green”. The platform guides you through the customization process, where you can add features like a blog, news feed, videos, calendar, and assorted gadgets (widgets) to give it more utility. This is perfect for organizations on a tight budget that want a place to aggregate information, organize, and keep its members connected. With a bit of coding skill and a premium account, you can customize however you’d like and integrate your own sponsors or advertising.

9. Get Sponsored: SocialVibe is leveraging the traffic we generate from our social networking pages to fund various causes. It works quite simply. You sign up and select from a list of sponsors to endorse, ranging from PowerBar and Cherry Coke to Adobe and Apple. Next, you select a cause to support. We picked an environmental index of sorts that includes “water quality, global warming research and preventative measures, wildlife, agriculture, rainforest preservation and sustainable production of food and building materials.” SocialVibe places your ad on your social networking pages and can also generate code that you can embed most anywhere. When it’s viewed, you generate donations for your cause and also earn points and other perks for yourself.

10. Broadcast Your Message: The cost of web broadcasting (webcasting) has effectively dropped to zero. A number of new technologies are making it possible for anyone to have their own live online TV channel. Indeed, signing up for Ustream.tv is like renting your own production studio. While you’re broadcasting live, viewers can communicate with you and other viewers through a chat interface, and you can even add a co-host. Your “shows” can be archived for later playback, and you can post them to YouTube or your personal pages for further distribution. Ustream also provides a social networking platform and a number of ways to promote your shows, such as through Twitter alerts.

Seesmic has a much different approach with “video conversations”. It’s similar to Twitter in many ways, only instead of posting text entries you record video clips. Other users respond, which forms a thread of video clips that become a video conversation. These clips can be embeded anywhere you want, such as your MySpace page or blog. In fact, Seesmic offers a plugin feature for blogs where you can leave video comments. While there’s nothing particularly green about these video technologies, they represent a next step in communications and an efficient means for producing and distributing green messages.

T6AKEN FROM /sustainablog.org

HOUSTON, May 12, 2008 — A new study of possible links between climate and geophysics on Earth and similar planets finds that prolonged heating of the atmosphere can shut down plate tectonics and cause a planet’s crust to become locked in place.

“The heat required goes far beyond anything we expect from human-induced climate change, but things like volcanic activity and changes in the sun’s luminosity could lead to this level of heating,” said lead author Adrian Lenardic, associate professor of Earth science at Rice University. “Our goal was to establish an upper limit of naturally generated climate variation beyond which the entire solid planet would respond.”

Lenardic said the research team wanted to better understand the differences between the Earth and Venus and establish the potential range of conditions that could exist on Earth-like planets beyond the solar system. The team includes Lenardic and co-authors Mark Jellinek of the University of British Columbia in Vancouver and Louis Moresi of Monash University in Clayton, Australia. The research is available online from the journal Earth and Planetary Science Letters.

The findings may explain why Venus evolved differently from Earth. The two planets are close in size and geological makeup, but Venus’ carbon dioxide-rich atmosphere is almost 100 times more dense than the Earth’s and acts like a blanket. As a result, Venus’ surface temperature is hotter than that of even Mercury, which is twice as close to the sun.

The Earth’s crust — along with carbon trapped on the oceans’ floors — gets returned to the interior of the Earth when free-floating sections of crust called tectonic plates slide beneath one another and return to the Earth’s mantle. The mantle is a flowing layer of rock that extends from the planet’s outer core, about 1,800 miles below the surface, to within about 30 miles of the surface, just below the crust.

“We found the Earth’s plate tectonics could become unstable if the surface temperature rose by 100 degrees Fahrenheit or more for a few million years,” Lenardic said. “The time period and the rise in temperatures, while drastic for humans, are not unreasonable on a geologic scale, particularly compared to what scientists previously thought would be required to affect a planet’s geodynamics.”

Conventional wisdom holds that plate tectonics is both stable and self-correcting, but that view relies on the assumption that excess heat from the Earth’s mantle can efficiently escape through the crust. The stress generated by flowing mantle helps keep tectonic plates in motion, and the mantle can become less viscous if it heats up. The new findings show that prolonged heating of a planet’s crust via rising atmospheric temperatures can heat the deep inside of the planet and shut down tectonic plate movement.

“We found a corresponding spike in volcanic activity could accompany the initial locking of the tectonic plates,” Lenardic said. “This may explain the large percentage of volcanic plains that we find on Venus.”

Venus’ surface, which shows no outward signs of tectonic activity, is bone dry and heavily scarred with volcanoes. Scientists have long believed that Venus’ crust, lacking water to help lubricate tectonic plate boundaries, is too rigid for active plate tectonics.

Lenardic said one of the most significant findings in the new study is that the atmospheric heating needed to shut down plate tectonics is considerably less than the critical temperature beyond which free water could exist on the Earth’s surface.

“The water doesn’t have to boil away for irrevocable heating to occur,” Lenardic said. “The cycle of heating can be kicked off long before that happens. All that’s required is enough prolonged surface heating to cause a feedback loop in the planet’s mantle convection cycle.”

TAKEN FROM www.eurekalert.org/

Princeton researchers have invented a method for turning simple data about rainfall and river networks into accurate assessments of fish biodiversity, allowing better prediction of the effects of climate change and the ecological impact of man-made structures like dams.

The mathematics behind the new method also can be used to model and predict a wide range of other questions, from the transmission of waterborne illnesses to vegetation patterns on land adjacent to rivers.

The researchers, who published a report in the May 8 issue of Nature, have created a computer simulation that allows them to predict — based on rainfall measurements and the structure of river networks — how many species of fish will occupy any given region.

“It is an extremely simple model but it predicts absolutely fantastically well all of the characteristics of biodiversity that we were interested in,” said Ignacio Rodríguez-Iturbe, the James S. McDonnell Distinguished University Professor of Civil and Environmental Engineering and the leader of the research group that published the report in Nature.

“Our model implies that water dynamics have a commanding effect on biodiversity in river basins.”

Paolo D’Odorico, associate professor of environmental sciences at the University of Virginia, called the research “exquisitely original and thought-provoking.”

 ”It is the first study I am aware of that provides a real quantitative framework for the study of river biogeography,” D’Odorico said.

In their research, the authors merged different sets of existing data from the Mississippi-Missouri river basin, an extremely large region that covers more than half of the United States. This network of rivers springs from the Mississippi River, which cuts down the middle of the country. The triangle-shaped basin stretches from Minnesota to Louisiana and from Montana to New York.

Using one set of data, the researchers were able to identify 824 distinct sub-basins and establish how the rivers within each sub-basin were linked together. Another set of data identified 433 different species of fish living in those sub-basins. A third set of data identified each region’s average runoff, which is the amount of rainfall that ends up in rivers or streams as opposed to water that is soaked up by the ground.

The figure at the top right represents average runoff (the amount of rainfall that ends up in rivers or streams) with the driest regions appearing in red and the wettest in blue. The middle figure is an abstraction of the Mississippi-Missouri river network. The figure in the foreground represents how many different species occupy different regions of the network, demonstrating a close correlation between the average runoff and the number of species. The areas with the fewest species are represented in red; the areas richest in the number of species are represented in blue. (Image: Enrico Bertuzzo, École Polytechnique Fédérale de Lausanne)

The researchers combined all these data and came up with a computer model that accurately predicts how many different species of fish will inhabit any given sector of the river basin. Their research shows that the habitats richest in the diversity of species are areas where multiple streams are close to one another.

“This will help identify which parts of a river basin are ‘hot spots,’ meaning they have more species than others and therefore should receive special care,” said Rodríguez-Iturbe, senior author of the paper.

To create their model for the Nature paper, the researchers disregarded the biological features of the fish in question — for example, which species might be tenacious predators or which might be well-suited to take advantage of available food in the area. The model tracks how many species will thrive in a given area but does not predict which species. It is what is known as a “neutral” model and thus treats each fish equally.

The lead author of the paper is Rachata Muneepeerakul, a postdoctoral researcher at Princeton who received his Ph.D. from the University in 2007. Co-authors are hydrologists Andrea Rinaldo and Enrico Bertuzzo of the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland, and Heather Lynch and William Fagan of the Department of Biology at the University of Maryland. The study was funded by the James S. McDonnell Foundation.

“The authors have combined sophisticated ecological theory and sophisticated hydrological theory,” said Simon Levin, the George M. Moffett Professor of Biology at Princeton. “This is work not only of practical importance, but [it] also stretches the boundaries of biogeography.”

Biodiversity characterizes the number of species within an ecosystem. Biogeography is the study of how biodiversity changes across space and over time.

“If because of climate change you have an increase in rainfall, our model can tell you how that will affect biodiversity,” said Rodríguez-Iturbe. “Or if you have a change in the connectivity of rivers due to human activity — for example, the building of a dam — our model can also measure how that will affect the numbers and distributions of species.”

River networks act as ecological corridors and as such the model will be useful not just for understanding the biodiversity of fish in rivers but also for understanding such things as the dispersal of seeds or even the spread of cholera. Rodríguez-Iturbe, Bertuzzo and Rinaldo also collaborated on a paper that recently appeared in an American Geophysical Union publication on how river networks affect the spread of cholera epidemics.

“Seeds and bacteria are different from fish — obviously they can’t swim upstream,” said Rodríguez-Iturbe. “But like fish, their distribution is dramatically impacted and controlled by the river network.”

In order to construct the model, the researchers created a mathematical representation of river systems that went far beyond simple volume calculations. They drew upon an advanced area of geometry known as fractals.

River networks are examples of fractals, fragmented geometric shapes whose parts are, mathematically speaking, smaller versions of the whole. Fractals occur widely in nature. For example, the branching structure of trees — from trunk to branch to twig — are fractals, as are clouds and lightning bolts and snowflakes.

Unlike in a savannah, where wildlife move across an open plain, in a river basin fish have to move through the fragmented space of river networks, which like all fractals follow a predicable set of mathematical rules.

River networks have “a universal type of structure independent of scale,” said Rodríguez-Iturbe. “Some may be big or small, elongated or round, but they all follow some basic features regardless of their scale, regardless of their size, regardless of where they are located in the world.”

TAKEN FROM www.princeton.edu/main

Rural families can slash their energy costs, improve their health and help preserve local forests by harvesting natural gas from rotting manure, researchers argue.

They say the use of biogas plants, which store the decomposing manure and capture the natural gas it releases, could improve rural farmers’ livelihoods, while protecting the environment.

Biogas digesters are used across the Indian subcontinent, Africa, and Latin America, but few rigorous studies have been done of their overall costs and benefits. So Govindasamy Agoramoorthy of Tajen University and Minna Hsu of National Sun Yat-sen University, both in Taiwan, surveyed 125 rural households in India that use biogas plants.

These plants, also called digesters, typically take the form of a sealed brick-lined pit, in which the manure ferments. The biogas that escapes from the manure is half carbon dioxide, but about half methane, the main component of natural gas, and is piped off to be burnt in stoves or gas lamps.

Health benefits

Many families in these rural Indian areas own several cows and buffalo, supplying them with a few dozen kilos of manure a day – enough to keep the digester well supplied.

After investing in biogas plants, families were found to cut back consumption of both firewood and kerosene by about 60%, Agoramoorthy and Hsu found. The savings on fuel mean the plants, which cost about $250 to install, pay for themselves in about 2 years.

Before having a digester, many families scavenged firewood illegally. Afterwards, Agoramoorthy says, “villagers saved more money and also had less negative impact on the forests.”

Replacing kerosene and firewood with cleaner-burning biogas also greatly reduces indoor air pollution, a leading cause of death for rural villagers, especially women and children.

After starting to use biogas in the home, the study found, families made about half as many visits to the doctor for smoke-related problems such as respiratory infections.

Fertile ground

The farmers also spread the leftover slurry from the biogas plant on their fields, reducing their need for chemical fertilisers, and saving them even more money.

“The usage [of biogas plants] is still low in villages, so governments need to promote biogas in villages of not only India, but also in other countries,” Agoramoorthy says. “Even developed countries should promote this.”

The study is quite original, says Peter Haas of the Appropriate Infrastructure Development Group, a non-profit organisation that operates in Guatemala and Haiti. “I have not seen a study before that draws a solid link between installation of a biodigester and health improvements.”

“People want biodigesters because of the cost-savings benefits and energy production,” Haas says. “The health impacts are really just an added bonus.”

TAKEN FROM environment.newscientist.com