Saturday, June 16, 2007
Two articles caught my eye recently, and both have to do with carbon levels in the atmosphere. Forgive me if this seems a little redundant, but I must say again that carbon is the basic building block of life on earth. Many plants and animals depend on atmospheric carbon for their survival. Today's article features two champions of this sequestration: Boreal Forests and Phytoplankton.
The first is an article from Nature describing the effects of humans on the ability of a boreal forests to sequester carbon. Scientists have known for many years that plants gather carbon from the atmosphere and combine it with nitrogen to make plant tissues. What they didn't know was how nitrogen levels effect the ability of plants to gather that carbon. This information is key to understanding human effects on the forest through nitrogen runoff from nearby farms and human activity. What they found was that our inadvertent fertilizing increase the ability of plants to absorb atmospheric carbon.
"Through our forests, fertilization by nitrogen deposition is to some degree offsetting our carbon dioxide emissions - at least right now," said Beverly Law, Professor of Forest Science at Oregon State University, co-author of the study and director of the AmeriFlux monitoring network.
The second article is about the phytoplankton Phaeocystis globosa. It appears this tiny marvel is able to change from a single celled organism to a colony and vice-versa in response to pressure from predators. When encountering predators such as the shrimp-like copepods that can eat colonies, the Phaeocystis take on the single cell, free-swimming form. When predators of the single celled forms are detected, the Phaeocystis form into colonies. They do this through chemical detection. This information is quite valuable to science in that these Phaeocystis absorb enormous amounts of atmospheric carbon, and when eaten by larger animals, that carbon sinks to the bottom of the ocean in the from of fecal matter. That means if scientists can induce more colonial forms of the organism, more carbon can be sequestered.
Nature knows what to do with Carbon Dioxide, and it's just a matter of time before we figure it out for ourselves.
for Boreal Forest Article in TerraDaily
for the article on Phytoplankton at ScienceDaily
Friday, June 15, 2007
New genetic tests on species of arctic plants from Svalbard, an archipelago between Norway and the North Pole reveal parents from many different northern zones, even as far away as Russia and Canada. Scientist aren't yet positive how seeds from these places were transported hundreds of miles to rest on this land still 60% covered in ice. Many believe the scenario to be wind across frozen channels over the thousands of years of cooling between the warmer trends.
One thing for certain though, is that these tough alpine plants tolerate warmer climates than previously expected. This is good news, as Svalbard is rapidly losing its ice mass. Scientists expect these plants, like avens, will survive by moving into new melt territory. Efforts to preserve seeds are also being made, as global temperature may eventually reduce their territory to sheer memory.
for the whole article in Scientific American
Thursday, June 14, 2007
Last night I read a cute article in the NY Times about animals loose in Manhattan. First, a hawk fledgling made its way from nest to city streets. A couple of hours later, a young kestrel fell from the nest. Later, a sheep was sighted roaming the streets.
A sheep? Well, that's hardly a wild animal, so we'll just say she escaped the meat market and was rescued and named.
But the birds of prey are of great interest. Last spring when I visited Central Park there were t-shirts and a bird cam featuring a nesting pair of peregrine falcons on a high-rise apartment building overlooking the park. It seems that areas of high human density are also home to the pigeons, sparrows, and rats that these winged predators hunt for food.
These predatory animals aren't alone in their ability to live near human dwellings, even seek them out. Last night I walked through the shipping district of my neighborhood in Sausalito, 3 miles North of San Francisco across the Golden Gate Bridge. It was just getting dark when I spotted my coyote friend. A coyote, in Sausalito? Yes, indeed. Last time I saw it I thought it must be lost. But this time I followed it from a distance, and watched it slink through the gaps in fences like a kid in its own neighborhood.
Herons are other predators that seem to thrive here along the Bay, despite the industry and human density. Both the coyotes and the herons are here because they eat the small animals that in turn live here because of humans. Coyotes are known to eat rodents, cats and even small dogs if the opportunity strikes them. Herons love the rats, and have been known to eat small kittens and anything else that will fit down their throats.
And so another food web has already begun, right under our urban noses.
Who says you have to leave the city to find wildlife?
for the article in NY Times
Scientists at the University of Illinois have developed a polymer skin that heals itself when damaged. Their model for the technique: Mother Nature.
Nancy Sottos tells Nature Materials, 'Healing in biological systems is accomplished by a pervasive vascular network that supplies the necessary biochemical components. A cut in the skin triggers blood flow from the capillary network in the dermal layer to the wound site rapidly forming a clot... minor damage to the same area can be healed repeatedly.'
This sort of self-healing has been seen before in artificial membranes, but what differs with this new technology is that damaged areas can heal more than once. Previous systems healed because they contained unreacted polymer capsules that when broken reacted to form a seal. But this technology takes healing one step further.
'After damage occurs at the coating, healing agent wicks from the microchannels into the crack(s) through capillary action,' the researchers report in Nature Materials. 'Once in the crack plane the healing agent interacts with the catalyst particles in the coating to initiate polymerisation, rebonding the crack faces autonomically. After a sufficient time period the cracks are healed and the structural integrity of the coating restored. As cracks reopen under subsequent loading the healing cycle is repeated.'
This new system will be invaluable to materials science, and its possibilities will be endless.
While the technology of self healing polymers mimics natural systems, one thing it lacks is its ability to break down to be reused in the system. Let's hope in the future we look to nature to figure out how to create polymers that last so long as we need them, and as the flower that has been pollinated returns to the soil to provide future resources, our products will also return to futher the cycle.
for the article in RSC
My friend Robyn at Biomimicry Institute found this video of the polymer healing
Wednesday, June 13, 2007
Nader Khalili is looking to tradition for clues on how to produce ecologically friendly buildings. He is following what many peoples of pre-industrial age used, materials that were readily available, local, and free.
"To me it's obvious to use earth as a building block," says Khalili in an interview with AFP, "I don't consider that I have invented anything at all. All the Mediterranean civilizations used earth or natural materials in their architecture."
Nader Khalili came to th US in 1971, bringing with him ideas about architecture from his homeland of Iran. Traditionally in the Middle East, primitive houses were not only made of the abundant materials of the earth, but they were shaped differently. They used a shape from nature- the sphere. Like an egg that is strong when pressure is applied in equal amounts over its surface, the simple properties of physics in a dome shaped structure increase its strength. In our modern day of steel and braces, timber in mass production we began making our homes like cookie cutter productions. Khalili has shown us that domes lack the inherent flaws of cubes, making them resistant to wind, rains, and even earthquakes.
Its a simple concept, to fill bags with earth, stack them, and cover them with clay. The dome is fired, and the finishing touches put in. Khalili teaches these principles at CalEarth Institute in California. His students are able to build a beautiful home built for less than $4,000, safe to live in and good for the environment. They use natural light, passive heating and cooling, and are easy to build.
I learned about Khalil a few years ago and bought his book to check out how he does it. Ceramic Houses and Earth Architecture turned out to be a wonderfully comprehensive manual on how to build an earth dome, so detailed he even included instructions on how to make clay temperature gages for the firing process.
Khalil's latest project is to build domes on the moon for NASA.
for the original article in Yahoo News