April 22, 2013
Over the past few decades, researchers have developed biofuels derived from an remarkable variety of organisms—soybeans, corn, algae, rice and even fungi. Whether synthesized into ethanol or biodiesel, though, all of these fuels suffer from the same limitation: They have to be refined and blended with heavy amounts of conventional, petroleum-based fuels to run in existing engines.
Though this is far from the only current problem with biofuels, a new approach by researchers from the University of Exeter in the UK appears to solve at least this particular issue with one fell swoop. As they write today in an article in Proceedings of the National Academy of Sciences, the team has genetically engineered E. coli bacteria to produce molecules that are interchangeable to the ones in diesel fuels already sold commercially. The products of this bacteria, if generated on a large-scale, could theoretically go directly into the millions of car and truck engines currently running on diesel worldwide—without the need to be blended with petroleum-based diesel.
The group, led by John Love, accomplished the feat by mixing and matching genes from several different bacteria species and inserting them into the E. coli used in the experiment. These genes each code for particular enzymes, so when the genes are inserted into the E. coli, the bacteria gains the ability to synthesize these enzymes. As a result, it also gains the ability to perform the same metabolic reactions that those enzymes perform in each of the donor bacteria species.
By carefully selecting and combining metabolic reactions, the researchers built an artificial chemical pathway piece-by-piece. Through this pathway, the genetically modified E. coli growing and reproducing in a petri dish filled with a high-fat broth were able to absorb fat molecules, convert them into hydrocarbons and excrete them as a waste product.
Hydrocarbons are the basis for all petroleum-based fuels, and the particular molecules they engineered the E. coli to produce are the same ones present in commercial diesel fuels. So far, they’ve only produced tiny quantities of this bacterial biodiesel, but if they were able to grow these bacteria on a massive scale and extract their hydrocarbon products, they’d have a ready-made diesel fuel. Of course, it remains to be seen whether fuel produced in this way will be able to compete in terms of cost with conventional diesel.
Additionally, energy never comes from thin air—and the energy contained within this bacterial fuel mostly originates in the broth of fatty acids that the bacteria are grown on. As a result, depending on the source of these fatty acids, this new fuel could be subject to some of the same criticisms leveled at biofuels currently in production.
For one, there’s the argument that converting food (whether corn, soybeans or other crops) into fuel causes ripple effects in global food market, increasing the volatility of food prices, as a UN study from last year found. Additionally, if the goal of developing new fuels is to fight climate change, many biofuels fall dramatically short, despite their environmentally-friendly image. Using ethanol made from corn (the most widely used biofuel in the U.S.), for example, is likely no better than burning conventional gasoline in terms of carbon emissions, and maybe actually be worse, due to all the energy that goes into growing the crop and processing it info fuel.
Whether this new bacteria-derived diesel suffers from these same problems largely depends upon what sort of fatty acid source is eventually used to grow the bacteria on a commercial scale—whether it would by synthesized from a potential food crop (say, corn or soy oil), or whether it could come from a presently-overlooked energy source. But the new approach already has one major advantage: Just the steps needed to refine other biofuels so they can be used in engines use energy and generate carbon emissions. By skipping these steps, the new bacterial biodiesel could be an energy efficient fuel choice from the start.
April 19, 2013
Last year, to celebrate the 42nd Earth Day, we took a look at 10 of the most surprising, disheartening, and exciting things we’d learned about our home planet in the previous year—a list that included discoveries about the role pesticides play in bee colony collapses, the various environmental stresses faced by the world’s oceans and the millions of unknown species are still out in the environment, waiting to be found.
This year, in time for Earth Day on Monday, we’ve done it again, putting together another list of 10 notable discoveries made by scientists since Earth Day 2012—a list that ranges from specific topics (a species of plant, a group of catfish) to broad (the core of planet Earth), and from the alarming (the consequences of climate change) to the awe-inspiring (Earth’s place in the universe).
1. Trash is accumulating everywhere, even in Antarctica. As we’ve explored the most remote stretches of the planet, we’ve consistently left behind a trail of one supply in particular: garbage. Even in Antarctica, a February study found (PDF), abandoned field huts and piles of trash are mounting. Meanwhile, in the fall, a new research expedition went to study the Great Pacific Garbage Patch, counting nearly 70,000 pieces of garbage over the course of a month at sea.
2. Climate change could erode the ozone layer. Until recently, atmospheric scientists viewed climate change and the disintegration of the ozone layer as entirely distinct problems. Then, in July, Harvard researcher Jim Anderson (who won a Smithsonian Ingenuity Award for his work) led a team that published the troubling finding that the two might be linked. Some warm summer storms, they discovered, can pull moisture up into the stratosphere, an atmospheric layer 6 miles up. Through a chain of chemical reactions, this moisture can lead to the disintegration of ozone, which is crucial for protecting us from ultraviolet (UV) radiation. Climate change, unfortunately, is projected to cause more of these sorts of storms.
3. This flower lives on exactly two cliffs in Spain. In September, Spanish scientists told us about one of the most astounding survival stories in the plant kingdom: Borderea chouardii, an extremely rare flowering plant that is found on only two adjacent cliffs in the Pyrenees. The species is believed to be a relic of the Tertiary Period, which ended more than 2 million years ago, and relies on several different local ant species to spread pollen between its two local populations.
4. Some catfish have learned to kill pigeons. In December, a group of French scientists revealed a phenomenon they’d carefully been observing over the previous year: a group of catfish in Southwestern France had learned how to leap onto shore, briefly strand themselves, and swim back into the water to consume their prey. With more than 2,000,000 Youtube views so far, this is clearly one of the year’s most widely enjoyed scientific discoveries.
5. Fracking for natural gas can trigger moderate earthquakes. Scientists have known for a while that whenever oil and gas are extracted from the ground at a large scale, seismic activity can be induced. Over the past few years, evidence has mounted that injecting water, sand and chemicals into bedrock to cause gas and oil to flow upward—a practice commonly known as fracking—can cause earthquakes by lubricating pre-existing faults in the ground. Initially, scientists found correlations between fracking sites and the number of small earthquakes in particular areas. Then, in March, other researchers found evidence that a medium-sized 2011 earthquake in Oklahoma(which registered a 5.7 on the moment magnitude scale) was likely caused by injecting wastewater into wells to extract oil.
6. Our planet’s inner core is more complicated than we thought. Despite decades of research, new data on the iron and nickel ball 3,100 miles beneath our feet continue to upset our assumptions about just how the earth’s core operates. A paper published last May showed that iron in the outer parts of the inner core is losing heat much more quickly than previously estimated
, suggesting that it might hold more radioactive energy than we’d assumed, or that novel and unknown chemical interactions are occurring. Ideas for directly probing the core are widely regarded as pipe dreams, so our only options remains studying it from afar, largely by monitoring seismic waves.
7. The world’s most intense natural color comes from an African fruit. When a team of researchers looked closely at the blue berries of Pollia condensata, a wild plant that grows in East Africa, they found something unexpected: it uses an uncommon structural coloration method to produce the most intense natural color ever measured. Instead of pigments, the fruit’s brilliant blue results from nanoscale-size cellulose strands layered in twisting shapes, which which interact with each other to scatter light in all directions.
8. Climate change will let ships cruise across the North Pole. Climate change is sure to create countless problems for many people around the world, but one specific group is likely to see a significant benefit from it: international shipping companies. A study published last month found that rising temperatures make it probable that during summertime, reinforced ice-breaking ships will be able to sail directly across the North Pole—an area currently covered by up to 65 feet of ice—by the year 2040. This dramatic shift will shorten shipping routes from North America and Europe to Asia.
9. One bacteria species conducts electricity. In October, a group of Danish researchers revealed that the seafloor mud of Aarhus’ harbor was coursing with electricity due to an unlikely source: mutlicellular bacteria that behave like tiny electrical cables. The organisms, the team found, built structures that traveled several centimeters down into the sediment and conduct measurable levels of electricity. The researchers speculate that this seemingly strange behavior is a byproduct of the way of the bacteria harvests energy from the nutrients buried in the soil.
10. Our Earth isn’t alone. Okay, this one might not technically be a discovery about Earth, but over the past year we have learned a tremendous amount about what our Earth isn’t: the only habitable planet in the visible universe. The pace of exoplanet detection has accelerated rapidly, with a total of 866 planets in other solar systems discovered so far. As our methods have become more refined, we’ve been able to detect smaller and smaller planets, and just yesterday, scientists finally discovered a pair of distant planets in the habitable zone of their stars that are relatively close in size to Earth, making it more likely than ever that we might have spied an alien planet that actually supports life.
April 5, 2013
In the aftermath of Superstorm Sandy last fall, New York Governor Andrew Cuomo joked to President Barack Obama that New York “has a 100-year flood every two years now.” On the heels of flooding from 2011′s Hurricane Irene and Tropical Storm Lee, it certainly seemed that way. Given that climate change has sparked multiple major storms and raised sea levels, and that urban and agricultural development have impeded our natural flood-management systems, chronic flooding could be here to stay.
Wetlands, which include swamps, lagoons, marshes and mangroves, help mitigate the problem by trapping floodwaters. “Historically, wetlands in Indiana and other Midwestern states were great at intercepting large runoff events and slowing down the flows,” environmental engineer Meghna Babbar-Sebens of Oregon State University said in a recent statement. ”With increases in runoff, what was once thought to be a 100-year flood event is now happening more often.”
One key problem is that most of our wetlands no longer exist. By the time the North American Wetlands Conservation Act (PDF) was passed in 1989, more than half of the wetlands in the United States had been paved over or filled in. In some states, the losses are much greater: California has lost 91 percent of its wetlands, and Indiana, 85 percent. In recent years, scientists have been honing the art of wetlands restoration, and now a recent study published in the journal Ecological Engineering by scientists at Oregon State University is helping to make new wetlands easier to plan and design.
The research focused on Eagle Creek Watershed, ten miles north of Indianapolis, and identified nearly 3,000 potential sites where wetlands could be restored or created to capture runoff. Through modeling, the scientists discovered that a little wetland goes a long way. “These potential wetlands cover only 1.5% of the entire watershed area, but capture runoff from 29% (almost a third) of the watershed area,” the study authors wrote.
Their next step was to begin developing a web-based design system to allow farmers, agencies and others to identify areas optimal for new or restored wetlands and to collaborate in designing them. The recently launched system, called Wrestore, uses Eagle Creek as a test-piece.
The tool has a variety of functions: It helps identify a region’s rivers and streams, divides watersheds into smaller sub-watersheds and shows where runoff is likely to collect—places conducive to building wetlands. If a city wants to reduce flooding in its watershed, the site’s interactive visualization engine displays various conservation options and allows groups of city planners to collaborate on the design of new wetlands.
“Users can look at various scenarios of implementing practices in their fields or watershed, test their effectiveness via the underlying hydrologic and water quality models, and then give feedback to an ‘interactive optimization’ tool for creating better designs,” Babbar-Sebens, lead author of the study and the lead scientist on the web tool, told Surprising Science.
It provides an easy way for landowners to tackle such environmental challenges. “The reason we used a web-based design system is because it gives people the flexibility to try and solve their problems of flooding or water quality from their homes,” Babbar-Sebens said.
As the spring flood season approaches and environmental degradation continues throughout the nation, a new tool for mitigating wetland loss with targeted, minimal wetland gain is certainly a timely innovation. Babbar-Sebens and her team have been testing it out on Eagle Creek Watershed and will be fine-tuning it throughout the spring. ”There is a lot of interest in the watershed community for something like this,” she said.
March 31, 2013
You probably think of the Arctic as a cold, frozen tundra—home to lichen, polar bears and scattered herds of reindeer. In many places, this view would be accurate, but in a few relatively southern areas in Canada, Alaska and Russia, warming temperatures over the past few decades have allowed new types of plants, such as shrubs, to take root.
And by 2050—if current warming trends continue—we’ll see a dramatically different ecosystem across the Arctic, starting with something that’s largely unknown in the area currently: trees. According to research published today in Nature Climate Change, tree cover in the Arctic could increase by more than 50 percent over the next few decades.
The research team, which included scientists from a number of universities and was led by Richard Pearson of the American Museum of Natural History, made the calculation based off of current projections of how the Arctic’s climate will change by 2050. So far, temperatures in the region have risen about twice as fast as those for the planet as a whole.
They created a model that predicts which class of plants (various grasses, mosses, shrubs or trees) will grow given a particular temperature and precipitation range expected for the future; for each spot on a map of the Arctic, they fed in the 2050 projections. Doing this kind of vegetative modeling for the Arctic, they say, is relatively straightforward compared to doing it for somewhere like the tropics, because there are hard limits on the temperature and growing season length that given plant types can tolerate.
They found that tree cover will expand drastically, covering up to 52 percent more land area than currently, rising far north of the current tree line in Alaska and Canada. This new tree cover will mostly come at the expense of areas currently covered by shrubs, but shrubs will take over places now dominated by tundra plants (lichens and mosses), and some areas presently under ice will convert into tundra.
In effect, the area’s warming climate and lengthening growing season will shift all current vegetation zones to more northerly and colder regions. Already, these vegetation zones have shifted an average of five degrees of latitude over the past 30 years–in other words,
the vegetation in one spot resembles how a location five degrees south looked 30 years ago .
But by 2050, this shift will be even more dramatic—perhaps equaling 20 degrees of latitude—and a projected 48 to 69 percent of the Arctic’s vegetated areas will switch to a different class of plants. Some rare plant species could be at risk of extinction if they’re not able to migrate as quickly as the vegetation zones move.
Because plants are the base of any food chain, this conversion will have wide-ranging effects, both locally and elsewhere. “These impacts would extend far beyond the Arctic region,” Pearson said in a press statement. “For example, some species of birds seasonally migrate from lower latitudes and rely on finding particular polar habitats, such as open space for ground-nesting.” Their migrations patterns would presumably be altered by the growth of forests on what had been open tundra.
Most troubling, the conversion of white, snow-covered land to dark vegetation will further
affect the warming of the planet. Because darker colors absorb more radiation than the white of ice and snow, shifting large masses of land to a darker color is projected to further accelerate warming, creating a positive feedback loop: more warming leads to a greener Arctic, which leads to more warming.
Given all the other problems that the area is rapidly encountering as the climate changes—melting glaciers, increasing oil exploration and hybridizing bear species—it’s clear that the Arctic will be one of the most environmentally fragile regions of the planet over the coming century.
March 29, 2013
On the morning of July 16, 2010, a hunk of ice four times the size of Manhattan cracked away from the tongue of Greenland’s Petermann Glacier and drifted to sea as the largest iceberg since 1962. Just two years later, another massive section of ice calved from the same glacier. Icebergs like these don’t stay put in the Arctic–they get picked up by currents and ushered to warmer climates, melting along the way.
According to a new study published in the journal Geophysical Research Letters, Greenland’s melting glaciers and ice caps sent 50 gigatons of water gushing into the oceans from 2003 to 2008. This comprises about 10 percent of the water flowing from all ice caps and glaciers on Earth. The research comes on the heels of a study last year that showed the ice sheets of Greenland and Antarctica are disappearing three times faster than in the 1990s, and that Greenland’s is melting at an especially accelerated rate. In the new study, scientists were able to put an even finer point to the ice-melt situation by separating out the glaciers and ice caps from the ice sheet, which blankets 80 percent of the island. What they discovered is that Greenland’s glaciers are actually melting more quickly than the ice sheet.
Studies such as these demonstrate the impacts of a warming climate on Greenland’s glaciers. But, as they say, a picture is worth a thousand words. Visual evidence of this liquefaction is captured by NASA satellites, which are able to take snapshots of calving glaciers and document longer-term ice melt. NASA displays photos of the glaciers in its State of Flux photo gallery, along with a rotating collection of satellite images that illustrate other changes to the environment, including wildfires, deforestation and urban development.
The photos, with their “now-you-see-it, now-you-don’t” quality, illustrate how glaciers are fast becoming ephemeral. Here are a few stark examples:
The set of images above shows the edge of Greenland’s Helheim Glacier, located on the fringe of the Greenland Ice Sheet, as captured by a satellite in 2001, 2003 and 2005. The calving front is marked by the curved line through the valley, while bare ground appears brown or tan and vegetation is red.
According to NASA, when warmer temperatures initially cause a glacier to melt, it can spark a chain reaction that accelerates the thinning of the ice. As the edge of the glacier begins to liquefy, it crumbles, creates icebergs and eventually disintegrates. The loss of mass throws the glacier off balance, and further thinning and calving occurs, a process that stretches the glacier through its valley. Total ice volume decreases then shrinks the glacier as calving carries ice away. Helheim’s calving front stayed put from the 1970s until 2001, at which point the glacier began hasty cycles of thin, advance, and dramatic retreat, ultimately moving 4.7 miles toward land by 2005.
The massive calving event at Petermann Glacier in 2010 is pictured in these two images. The glacier is the white ribbon on the right side of each photo, and its tongue extends into the Nares Strait, which appears as a bluish-black stripe across the center of the right image and is heavily flecked with white chunks in the photo on the left. In the first image, the tongue of the glacier is intact; in the second, a huge chunk of ice has broken off and can be seen floating away through the fjord. This iceberg was 97 square miles in size–four times bigger than the island of Manhattan.
In the summer of 2012, a second massive iceberg crumbled away from the Petermann Glacier. In these images, the glacier is the white ribbon snaking up from the bottom right. If you follow the tongue up, you’ll see that it appears intact in the photos at left and center (though the center image has an ominous crack spanning its width), which were taken the day before the calving occurred. The photo on the right shows that it crumbled as the glacier calved.
Given that Greenland experienced an exceptionally warm summer in 2012 and temperatures were higher than average this winter, 2013 is primed for more melting and massive icebergs. Last year’s ice-melt season lasted two months longer than the average since 1979, and this year’s is already off to an inauspicious start. It kicked off on March 13 with the sixth-smallest sea-ice area on record for Greenland, according to the National Snow and Ice Data Center. What will the new summer calving season bring?