by Jonathan O'Callaghan Photo credit: Stock image via Mopic/Shutterstock.
Researchers say they have developed an artificial "leaf” that can produce fuels such as methane and gasoline from carbon dioxide. The team claimed it is a major step towards using fuels made renewably from sunlight for everything from heating our homes to running cars, without emitting any greenhouse gases.
The breakthrough, published in the Proceedings of the National Academy of Sciences, was led by Peidong Yang and his team at the Kavli Energy NanoSciences Institute at the University of California, Berkeley. It builds on the natural process of photosynthesis, where water and carbon dioxide are turned into sugar – organic fuel – by plants. By tweaking the process, via synthetic photosynthesis, it could be possible to create a whole host of different products.
To demonstrate this is possible, the team were able to make their system produce methane, rather than sugar, from carbon dioxide. Their equipment used a combination of semiconducting nanowires and bacteria to work. Using inorganic catalysts, water was split into hydrogen, which was then used by living cells to convert carbon dioxide into chemical products – in this case, methane.
"We're good at generating electrons from light efficiently, but chemical synthesis always limited our systems in the past,” said Yang in a discussion on the breakthrough. “One purpose of this experiment was to show we could integrate bacterial catalysts with semiconductor technology. This lets us understand and optimize a truly synthetic photosynthesis system.”
A similar system devised by Yang and his team earlier this year produced butanol, a component of gasoline, and various biochemical building blocks. Next, they will attempt to make an entirely synthetic system, without the need for bacteria, that builds on designs in nature to replicate the process of photosynthesis, and ultimately produce liquid fuels that can last months or years.
"This is not about mimicking nature directly or literally," said Ted Sargent, the vice-dean of research for the Faculty of Applied Science and Engineering at the University of Toronto, in the discussion. "Instead, it is about learning nature's guidelines, its rules on how to make a compellingly efficient and selective catalyst, and then using these insights to create better-engineered solutions."
So, you won’t be using artificial leaves to power your home or car just yet. But this could be a significant step in that direction.
by Caroline Reid Photo credit: Green leaves. jajaladdawan/Shutterstock.
Humans have been struggling for years to create clean, renewable energy that doesn't decimate the planet. What's even more infuriating is that plants, waving gently in the breeze all the while, have been creating 'green' energy before mankind even existed.
During plant photosynthesis, water and carbon dioxide is turned into glucose and oxygen. Recently, mankind has been trying to learn from plants to produce our own clean, green machines – in this case, artificial leaves.
The latest advancement in the artificial leaf comes from Monash University in Melbourne and brings us another step closer to a commercially viable method of turning water into fuel. Instead of creating glucose, the artificial leaf uses water and sunlight to produce hydrogen and oxygen. This process of "electrochemical splitting" is achieved by running an electric current through the water. The hydrogen can then be used for fuel production.
The make or break for any energy production technology is the all-important level of efficiency. If the energy output is too low, then artificial leaves will never stand a chance at replacing our current sources of energy, including things such as fossil fuels and nuclear power. In the past, the highest efficiency achieved in an artificial leaf was 18%. However, the scientists from Melbourne have increased this to an impressive 22%, the highest efficiency ever seen in artificial leaves. You can read about the details of this new device in Energy and Environmental Science.
While this level of efficiency is the best yet, it is still not quite good enough to make the process financially viable. However, the researchers note that they are aware of the parameters that need fine-tuning and which components need tweaking for the next generation of tests.
“Electrochemical splitting of water could provide a cheap, clean and renewable source of hydrogen as the ultimately sustainable fuel. This latest breakthrough is significant in that it takes us one step further towards this becoming a reality,” Professor Leone Spiccia, the lead researcher, said in a statement. Creating energy without waste is one of the biggest issues the world is facing in the 21st century. Just recently, President Obama set an ambitious goal of reducing emissions by more than 80% by 2050, relative to 2005 levels. This target could be much more easily achieved with the assistance of something like the artificial leaf.
If the artificial leaf can be improved to a marketable level, then we could be seeing forests of them powering our houses, cars and maybe even entire cities.
“Hydrogen can be used to generate electricity directly in fuel cells. Cars driven by fuel cell electric engines are becoming available from a number of car manufacturers. Hydrogen could even be used as an inexpensive energy storage technology at the household level to store energy from roof-top solar cells,” Professor Doug MacFarlane, co-author of the study, summarized.
A heartening homage to a courageous woman who fought superstition with science and love.
While putting together the annual
omnibus of the year’s best children’s books,
I was reminded of how woefully rare inspired children’s books about
science are in our culture — as rare, perhaps, as are homages to
pioneering female scientists and celebrations of the intersection of art
and science. The confluence of these three rarities is what makes Summer Birds: The Butterflies of Maria Merian (public library | IndieBound) so wonderful.
Writer Margarita Engle and artist Julie Paschkis — the talent behind the gorgeous illustrated tale of Pablo Neruda’s life — tell the story of 17th-century German naturalist and illustrator Maria Merian,
whose studies of butterfly metamorphosis are among the most important
contributions to the field of entomology in the history of science and
forever transformed natural history illustration.
There are many ennobling and empowering threads to the story of
Merian’s life — how she began studying insects as a young girl, two
centuries before the dawn of science education for women;
how she trained tirelessly in art, then brought those skills to
illuminating science, all while raising her daughters; how she traveled
to South Africa with her young daughter in an era when women had
practically no agency of mobility; how she continued to work even after a
stroke left her paralyzed.
But perhaps most pause-giving of all is the reminder of just how much
superstition early scientists had to overcome in the service of simple
truth: In Merian’s time, people considered insects evil and found the
“supernatural” process of metamorphosis particularly ominous, believing
it was witchcraft that transformed the insect from one state to another.
By meticulous and attentive observation, Merian proved that the
process was very much a natural one, and beautifully so. She was only
thirteen. Her groundbreaking work was a prescient testament to Richard
Feynman’s famous assertion that science only adds to the mystery and the awe of the natural world.
When people understand the life cycles of creatures that
change forms, they will stop calling small animals evil. They will
learn, as I have, by seeing a wingless caterpillar turn into a flying
summer bird.
Photo credit:
United Soybean Board, "Potatoes," via Flickr. CC BY 2.0
The US Department of Agriculture (USDA) has just given the go ahead
for farmers to start commercially growing several different genetically
modified potatoes, the New York Timesreports.
The potatoes, which come in Russet Burbank, Ranger Russet and Atlantic
Varieties, have been engineered to produce less of an ingredient that
can turn into a cancer-causing agent when fried. The potatoes also
resist bruising, a common occurrence in harvesting and transport which
can reduce their value or even render them unsellable.
The new varieties, which have been dubbed “Innate” potatoes, were
developed by Idaho-based biotech company JR Simplot. The potatoes are
joining a new generation of GM foods that are designed to benefit both
the farmers and the consumers, rather than just the growers as, for
example, herbicide or pesticide resistant varieties would. Several GM
apple varieties, for instance, were recently created which take longer
to brown when sliced, although these “Arctic apples” have yet to receive approval.
To achieve the improved qualities, Simplot scientists added desirable
genes to the tubers that are naturally found in other cultivated and
wild potatoes. The genes encode a system that results in decreased
production of an amino acid (the building block of proteins) called asparagine.
Although asparagine is found in many foods, it’s produced in high
concentrations in some varieties of potatoes. When heated to
high-temperatures, for example during frying or baking, it can form a
chemical called acrylamide if the right sugar molecules are present.
French fries and potato chips have been found to contain particularly
high levels of acrylamide when compared with other foods.
Lab investigations found that the Innate potatoes produced between 50 to 75%
less acrylamide when fried than non-engineered varieties, but overall
the levels of other nutrients were unaffected. Although it’s known that
acrylamide is a toxic chemical, the benefits of these potatoes to
consumers are hazy at this stage.
While acrylamide is listed as a “probable human carcinogen,” at the moment it is unclear
whether eating foods with a higher acrylamide content can actually
increase the risk of developing cancer. The World Health Organization
and Food and Agriculture Organization have also stated
that the levels of acrylamide in foods pose a major health concern, but
they call for further investigation as the risk of dietary exposure to
the chemical has yet to be determined. So if we don’t know how much, or
how little, acrylamide we have to eat for it to be bad for our health,
we can’t be sure that reducing it in foods is going to have any positive
effects. That being said, reducing the likelihood of bruising will
definitely benefit growers.
Because the Innate varieties were created by adding in genes from other potatoes, rather than different organisms, Simplot
are hopeful that consumers will be more welcoming of the crops.
However, realistically it’s unlikely that this will sway anti-GMO
advocates, and some have already complained that the technology has not
been adequately regulated and thus approval should not have been granted
this early. One group has also pressed McDonald’s to not use the
potatoes, despite the fact that Simplot have been a major supplier of
frozen French fries to the chain since the 1960s.
Photo credit: Paul Bica, "Autumn falls," via Flickr. CC BY 2.0
Every year, fall tickles our visual senses by presenting us with a dazzling array of colors to gaze upon. Fiery reds, golden yellows and deep ambers twinkle from the trees and litter the pavement, ready to be scuffed by our boots. But why do leaves undergo this dramatic color transition that delights leaf peepers annually? Let’s find out.
Throughout the growing season, leaves appear green because of a pigment called chlorophyll. Chlorophyll is found in little disc-like structures called chloroplasts which are dotted throughout plant cells. Chlorophyll molecules absorb red and blue wavelengths of light from the sun but hardly any green, meaning that green wavelengths are reflected back to our eyes and hence the leaves appear this color.
Johann Gulln, "Tre" via Flickr. CC BY 2.0
Chlorophyll is essential for photosynthesis, which is the process of converting light energy into chemical energy. During this process, chlorophyll captures light from the sun which is used to supply the energy for the conversion of carbon dioxide and water into oxygen and carbohydrates, the latter of which serves as food for the plant. Chlorophyll is relatively unstable and consequently is continually being broken down inside cells. In order to maintain a sufficient amount of this pigment inside leaves it’s therefore also continually synthesized, a process that requires sunlight and warm temperatures.
Leaves actually contain several other pigments but chlorophyll is the most abundant during the growing season, hence they are green in spring and summer. During the growing season, a hormone called auxin prevents the growth of a special layer of corky cells called the abscission layer. In late summer or early fall, days start to shorten and nights become longer. Plants are sensitive to the length of darkness each day and when nights reach a particular threshold value, an end to auxin production is triggered. This decline in auxin allows the abscission layer to form at the base of each leaf stem which cuts off the supply of water and nutrients to the leaves. It also prevents the transport of carbohydrates from the leaves to the rest of the plant. When this happens, leaves stop replenishing chlorophyll as it is degraded and it disappears from the leaves relatively quickly.
This is when we start to see color transitions in leaves. Chlorophyll usually masks the other pigments present in the leaves which reflect the characteristic autumnal colors. These are the carotenoids which reflect yellow-orange light and the xanthophylls which reflect yellow light.
Alex, "Fall Colors" via Flickr. CC BY 2.0.
So we’ve covered the golds and oranges, but what about purples and reds? These colors come from a different group of pigments called anthocyanins. These pigments are responsible for the color of certain fruits such as blueberries and raspberries, among others. In contrast to carotenoids and xanthophylls, these pigments are not always present in the leaves but are produced in fall. They’re formed by a reaction between sugars that become trapped in the leaf by the abscission layer and certain molecules present in sap. The color produced by anthocyanins is dependent on the pH of the cell sap; if the sap is quite acidic, the pigments produce a bright red color; if the sap is less acidic, purplish hues are produced.
Anguskirk, "Maple Leaves at Westonbirt Arboretum in Gloucestershire," via Flickr. CC BY-NC-ND 2.0
Since photosynthesis begins to diminish in fall, why are plants investing valuable sugar supplies in the production of pigments in leaves that are going to fall off and die anyway? Several lines of evidence suggest that anthocyanins act as a sunscreen to protect chlorophyll from the bright fall sunlight. While sunlight is generally brighter in the summer months, the plants are more susceptible to damage in fall because leaf systems begin to break down. This sun protection therefore likely helps to keep leaves on the trees for longer so that more nutrients can be harvested from them. Some also believe that trees invest resources in anthocyanin production because it may act as an insect repellant. For example, some insects may associate red with toxicity or poor palatability, meaning they are less inclined to lay their eggs on these leaves.
The range of colors that we experience in fall is greatly influenced by the weather and soil moisture. Cool temperatures and lots of sunlight boost the production of anthocyanins, but freezing temperatures break down the equipment used to produce these pigments, meaning that early frost will trigger an early end to colorful foliage. Dry weather also increases the sugar concentration in sap which therefore also boosts anthocyanin production.
Stanley Zimny, "Red and Green autumn," via Flickr. CC BY-NC 2.0
As fall progresses, the cells in the abscission layer dry out even more. Eventually, the connections between cells are weakened and the leaves will drop. While many trees become bald relatively quickly, some manage to keep hold of a lot of their leaves, even in winter, but the bright colors gradually fade. This is because sunlight and freezing temperatures cause the remaining pigments to break down, leaving only tannins which are brown. Happy leaf peeping!
James Marvin Phelps, "Fall Color," via Flickr. CC BY-NC 2.0
Photo credit:
This tobacco plant depends on a cyanobacterial enzyme for carbon
fixation that works faster than the plant counterpart. Incorporation of
this enzyme could lead to increases in the rate of photosynthesis and
agricultural yield / Rothamsted Research
Scientists working with plant enzymes have figured out a way to
enhance photosynthesis, creating turbocharged crops that could one day
lead to crazy high agricultural yields. The work was published in Nature this week.
The world’s population is projected to pass nine billion by 2050. And
across the planet, crop yield is limited by the efficiency of
photosynthesis -- capturing sunlight to produce sugar and oxygen from
carbon dioxide and water. The conversion of CO2 to sugar is
mediated by an enzyme called Rubisco. And in plants, it’s a somewhat
inefficient, slow-working enzyme. To compensate, plants have to produce a
lot of it: Rubisco is possibly the most abundant protein on Earth, Nature reports, accounting for up to half of all the leaf's soluble protein.
But there might be another way. Photosynthetic microbes called
cyanobacteria have a faster form of Rubisco that’s coupled with CO2-concentrating mechanisms. However, attempts at replacing the CO2-converting machinery in plants with that of cyanobacteria have been unsuccessful.
Now, a team led by Maureen Hanson from Cornell University has announced a successful generation of tobacco plants (Nicotiana tabacum, a common model for genetic studies) with Rubisco from a blue-green algae, Synechococcus elongatus. By
replacing the gene for the carbon-fixing enzyme in tobacco plants with
two genes for the cyanobacterial version, their engineered plants
(pictured above and below) perform photosynthesis and have higher rates
of CO2 turnover than plants with the native version of the enzyme -- when grown in an elevated CO2 environment.
“This
is the first time that a plant has been created through genetic
engineering to fix all of its carbon by a cyanobacterial enzyme,” Hanson
says in a news release.
“It is an important first step in creating plants with more efficient
photosynthesis.” So how’d they succeed where others have failed? A
broad-stroke approach, Hanson tells Popular Mechanics:
Not only did they swap in the cyanobacterial genes, they also made
several other genetic substitutions to include proteins for
manufacturing the enzyme. One key trick was to discourage wasteful reactions: Sometimes Rubisco
wants to react with oxygen instead of CO2, which is a waste of energy.
Rubisco in plants is less reactive with oxygen and the tradeoff is that
it slows down carbon fixing and photosynthesis. Fast-fixing Rubisco in
cyanobacteria is way more reactive with oxygen. To cope with that,
cyanobacteria protect the enzyme in special micro-compartments, called
carboxysomes, that keep oxygen out and concentrate CO2 for efficient
photosynthesis.
Previously, the team inserted blue-green algae genes in tobacco to
create carboxysomes in plant cells, and they’re now working on combining
genes for cyanobacterial Rubisco with genes for carboxysomes in the
tobacco’s chloroplast -- the organelle where photosynthesis actually
takes place.
Plant engineered for more efficient photosynthesis
This
image shows a tobacco plant that has been genetically engineered for
the first time so that all its organic material comes from carbon
fixation by a cyanobacterial (blue-green algae) enzyme. It is an
important first step in creating plants with more efficient
photosynthesis.
A genetically
engineered tobacco plant, developed with two genes from blue-green algae
(cyanobacteria), holds promise for improving the yields of many food
crops.
Plants photosynthesize – convert carbon
dioxide, water and light into oxygen and sucrose, a sugar used for
energy and for building new plant tissue – but cyanobacteria can
perform photosynthesis significantly more quickly than many crops can.
“This
is the first time that a plant has been created through genetic
engineering to fix all of its carbon by a cyanobacterial enzyme,” said
Maureen Hanson, a co-author of the study and Liberty Hyde Bailey
Professor of Plant Molecular Biology at Cornell.
“It is an important first step in creating plants with more efficient photosynthesis,” Hanson said.
The
study is published Sept. 17 in the journal Nature. Myat Lin, a
postdoctoral fellow in Hanson’s lab, and Alessandro Occhialini, a
scientist at the U.K.’s Rothamsted Research, are co-lead authors of the
study.
Crops with cyanobacteria’s faster carbon
fixation would produce more, according to a computer modeling study by
Justin McGrath and Stephen Long at the University of Illinois. Producing
more crops on finite arable land is a necessity as the world’s
population is projected to pass nine billion by 2050.
Though
others have tried and failed, the Cornell and Rothamsted researchers
have successfully replaced the gene for a carbon-fixing enzyme called
Rubisco in a tobacco plant with two genes for a cyanobacterial version
of Rubisco, which works faster than the plant’s original enzyme.
All
plants require Rubisco to fix carbon during photosynthesis. Rubisco
reacts with both carbon dioxide and oxygen in the air, but when it
reacts with oxygen, a plant’s rate of photosynthesis slows down, leading
to lower yields.
In many crop plants, including
tobacco, Rubisco is less reactive with oxygen, but a trade-off leads to
slower carbon fixing and photosynthesis, and thus, smaller yields. The
Rubisco in cyanobacteria fixes carbon faster, but it is more reactive
with oxygen. As a result, in cyanobacteria, Rubisco is protected in
special micro-compartments (called carboxysomes) that keep oxygen out
and concentrate carbon dioxide for efficient photosynthesis.
In
previous research, Lin, Hanson and colleagues inserted blue-green algae
genes in tobacco to create carboxysomes in the plant cells. In future
work, the researchers will need to combine genes for cyanobacterial
Rubisco with genes for carboxysomes in the tobacco’s chloroplasts, the
site in the cell where photosynthesis takes place.
Co-authors
include Martin Parry, a professor of plant biology, and researcher John
Andralojc, both at Rothamsted Research. The study was funded by the
National Science Foundation, the Biotechnology and Biological Sciences
Research Council, the National Institutes of Health and the 20:20 Wheat
Institute Strategic Program.
In a small corner of western Poland, near the town of Gryfino, a strange and eerie woodland exists. This bizarre collection of curved trees, named the “Crooked Forest,” is shrouded in mystery and despite the numerous different theories that have been proposed over the years, no one truly knows what caused the trees to adopt this conformation.
The Crooked Forest consists of around 400 pine trees that grow with a 90-degree bend at their base, the vast majority of which are bent northward. Curiously, the Crooked Forest is enveloped by a larger forest of straight growing pine trees. It is estimated that the trees were planted in the 1930s and that they were around 7-10 years old when they experienced whatever force/damage that resulted in trunk curvature.
So what could have caused these trees to grow in this bizarre “J" shape? The weather? War? Aliens? (Aliens……)
Here are some of the ideas proposed so far.
Some believe that fluctuations in gravitational forces or a unique gravitational pull in the area could be responsible, but there is basically zero evidence to support this bizarre theory. The force of gravity pulls objects down, not sideways.
A slightly more plausible, but still fairly unlikely, theory is that heavy snow could have flattened the trees for an extended period of time whilst they were still saplings. This, combined with a long spring melt, would be capable of permanently shaping the trees if there was still a thick layer of snow on top of the trunk whilst the trees experienced a growth spurt during spring. However, the reason this seems unlikely is that, as mentioned, the Crooked Forest is surrounded by pine trees that are not oddly shaped. It would therefore be very unusual for a snowstorm to only affect one specific area of a forest and not the rest.
Another popular idea is that during the invasion of Poland in World War II, enemy tanks plowed through the young forest, once again flattening the trees to such an extent that they grew back crooked.
Another problem is that once again, why is only this one small patch affected? While the dates may match up for this given that the crooked forest is estimated to be around 80 years old give or take, it seems unlikely that the trauma of being run over by ridiculously heavy tanks would result in this odd yet uniform curvature, if the young trees survived at all.
The final idea that has been thrown around that seems to have gained most acceptance is perhaps the most boring one (Occam’s razor and all that), which proposes that the curves are man-made. This would make sense given the fact that the trees are very consistent. The suggestion is that during the 1930s, local farmers planted and manipulated the trees for ultimate use as a construction material, for example for pieces of furniture or, more likely, ship building. An extract from a piece entitled Wooden Vessel Ship Construction even supports this idea:
“Oaks from the areas of Northern Europe were fine for the development of long straight planking, but the gnarled English “Hedgerow” Oak was the best for the natural curved timbers used to strengthen the ship internally. Trees were even deliberately bent in certain ways so as to ‘grow’ a needed set of curved timbers. These curved timbers were known as ‘compass’ timbers.”
The invasion of Poland during World War II would have likely interrupted this activity, preventing the farmers from being able to finish the job and thus leaving this peculiar forest that we still see today.
The local town was also devastated during the war and was not reestablished until the 1970s when a new power plant was built in the area. This would explain why none of the locals have the foggiest idea why the trees look like this.
Ultimately, no one can be certain of what caused the curvature of these trees since there are no witnesses that can testify one way or another, but the last explanation certainly seems the most plausible.
Mushrooms, the natural recyclers of our forests, are almost as diverse on their own as the entire animal kingdom. Nature photography usually focuses on other larger objects, so we often miss the beauty and diversity that mushrooms have to offer. Photographer Steve Axford, however, is passionate about the world of fungi and shares his visual discoveries with many of his devoted followers.
Axford lives in the Northern Rivers region of New South Wales in Australia, but he travels all around the world, capturing photos of rare animals, plants, and many different diverse people that he meets. What he loves photographing most, however, are fungi, many of which are so rare that they’ve never been photographed before – at least not in such an inspiring and artistic way. Enjoy! [Read more...]
Marasmius haematocephalus
Panus fasciatus
Campanella sp.
Leratiomyces sp. / Found in Booyong Reserve, Booyong, NSW
Mycena interrupta
Schizophyllum commune
Mycena chlorophos
Cyptotrama aspratum or Gold tuft
Marasmius haematocephalus
Marasmius sp.
Campanella sp.
Mycena austrororida
Cyathus novaezelandiae or Birds Nest Fungi, Tara Ridge
While putting together the annual
“This is the first time that a plant has been created through genetic engineering to fix all of its carbon by a cyanobacterial enzyme,” Hanson says in a news release. “It is an important first step in creating plants with more efficient photosynthesis.” So how’d they succeed where others have failed? A broad-stroke approach, Hanson tells Popular Mechanics: Not only did they swap in the cyanobacterial genes, they also made several other genetic substitutions to include proteins for manufacturing the enzyme.
