On August 13th, 2017 we learned about

Cow pie biogases now provide fuel for farm’s giant feed truck

The average dairy cow produces around 40,000 pounds of manure a year, most of which doesn’t just disappear into thin air. As a cow pie decomposes, some of that solid waste does become a gas, the most notorious of which is methane. Even though you can’t see all that CH4, it makes a big difference to the world since it traps 23 times more heat in the atmosphere than carbon dioxide. Fortunately, methane doesn’t need to simply waft away, and farms are now using their cow poop to power everything from buildings to the very feed trucks that carry food to cows in the first place.

Prepping poop for generating power

Unfortunately, you can’t just scoop some poop into a gas tank and be on your way. Cow poop is made of a variety of materials which need to be separated so they can be used more efficiently, not totally unlike the refinement processes for crude oil. To make the most of their manure, farms have to invest in a huge container called a digester. The digester helps maintain an optimal temperature for poop to break down, and conveniently contains the unpleasant “barnyard aromas” at the same time. The products of digestion are fibrous materials that can be used as cow bedding or other products, potent liquid fertilizer, and assorted “biogases,” including methane.

Methane burns easily, which is why it’s the primary component of natural gas. Burned in combustion generator, plenty of electricity can be harvested to power farms, trucks, and even surrounding communities. Again, the methane doesn’t simply vanish into thin air though, and burning methane does create carbon dioxide as one of it’s by-products. Still, since carbon dioxide isn’t as potent a greenhouse gas as methane, most people consider this a win. It doesn’t hurt if farms can be more self-sustaining either.

Dung-fueled driving

The amount of power than can be generated from reused cow poop is significant enough that many farms are looking to expand their capacity. Farmers that have made the investment to set up one digester are often interested in setting up a second. The Straus Family Creamery in California took a different approach, and invested in a lengthy retrofitting project with their International Harvester feed truck. After eight years of work, they converted the diesel truck into a zero-emissions electric vehicle so that it could be powered by their poop-fueled generator. Apparently the creamery feels their cows’ poop can provide even more, and they plan to power a delivery truck with methane-produced electricity in the near future.

Source: Poop-Powered Electric Feed Truck Debuts at Northern California Creamery by Tiffany Camhi, The California Report

On July 19th, 2017 we learned about

Ice cream isn’t gelato because of additional air, fat and cold

My third-grader said she has a preference for ice cream over gelato, which is interesting since they’re nearly the same mix of sugar, fat, ice and air. Gelato actually means ice cream in Italy, but the rise of what some people call “American ice cream” has prompted some examination of the differences between the two desserts, even beyond third-graders. The same flavoring may seem to taste a bit different, despite similar ingredients. The key is how the frozen treats are prepared, and the specific balance of fat, temperature and ice you’ll find in each.

Ice fixed with fat

At their core, ice cream and gelato both share the same basic formula. By volume, each sugary scoop is mostly ice, but that ice has been prepared to keep it from behaving like a hard, solid block in your mouth. Through a process known as emulsification, the ice crystals are kept as small and separated as possible so that no single piece of ice stands out. They’re suspended between milk fat, sugar and in the case of custard-based ice creams, egg yolk proteins which makes for a cold but smooth and creamy texture, rather than something as hard and crunchy as a snow cone.

Getting the fat and ice balance right is a big part of what makes ice cream delicious. Richer ice creams tend to have more fat, and products labeled “ice cream” in the United States are even required to be at least ten percent fat. Gelato, on the other hand, is made with more milk than cream, and so it has less fat per serving.

Inflated with air

To further soften the fat and ice, air is also whipped into both ice cream and gelato. Ice cream has air whipped in more vigorously, leaving more air bubbles trapped inside the fat, ice and sugar and increasing the volume of the finished product. That change in volume due to air is called overrun, and it can vary a lot depending on the recipe being used. Premium ice creams tend to avoid adding more than 25 percent overrun since it means less fat, sugar and flavor per scoop, but cheaper ice creams really fluffs things up. At the far end of the spectrum, soft-serve ice cream can have 100 percent overrun, making for a very spongy dessert that can melt pretty quickly.

Again, gelato follows the same formula, but in different amounts. Gelato overrun amounts are generally much lower, as it’s churned more slowly than other ice creams. The result is a denser scoop that can pack a lot of flavorings (versus air) into each bite. With less cream and less air, it seems like gelato should be getting closer to just freezing into a single block of ice, but that’s where temperature comes into play.

Robust refrigeration

Ice cream is produced and stored at lower temperatures than gelato. Commercial ice cream is sometimes churned in drums cooled with ammonia to -22° Fahrenheit, which helps keep the emulsified ice from moving around too much. It’s generally served at around 10° Fahrenheit so that it’s cold enough be structurally stable while starting to soften enough to let the tasty fats and sugars interact with your tongue.

Gelato avoids freezing up by being churned and served at higher temperatures. Even though there’s less fat, no egg yolks and less air to keep the ice from congealing, the warmer temperatures help maintain the pleasant, creamy texture. It can get soupy pretty quickly, although both gelato and ice cream recipes often include various gums or gelatin to help keep the structure stabilized.

Sugar and salts are of course two more important ingredients for these frozen treats, but they vary so much by recipe that they’re not useful to differentiate ice cream from gelato. Both help keep ice crystals separated while lowering the water’s initial freezing point, but the amount of sweet or salty is usually more about the desired taste rather than the defining the exact amount of creaminess. Perhaps the sweetness does play another role though, which is to add to one’s motivation to finish dessert before finding out when their ice cream or gelato is going to fall apart.

Source: What's the Difference Between Gelato and Ice Cream? by Max Falkowitz, Serious Eats

On July 16th, 2017 we learned about

High-speed ions make Comet 67P a surprising source of molecular oxygen

There’s a lot of oxygen in space, but not in a form you can breath. Thanks to the respiration of plants on Earth, our bodies have evolved to use O2, known as molecular oxygen, to pull off our own metabolic processes. Outside of our delightful atmosphere, the most likely place to find oxygen in the cosmos is bonded to other elements like hydrogen and carbon. O2 isn’t distributed equally around the universe, and scientists were starting to look at it as a marker of an Earth-like, habitual planet. However, newly released data from the Comet 67P/Churyumov-Gerasimenko is making us reconsider this most precious molecule yet again.

When the Rosetta spacecraft first reported molecular oxygen near Comet 67P, the assumption was that it was being released from deep within the comet’s core. As the comet got closer to the Sun, it warmed up, melting ice and loosening up, releasing gases that were normally frozen solid, including O2. This O2 would have then been some of our solar system’s original supply of oxygen, created 4.6 billion years ago alongside our Sun. However, unrelated research serendipitously suggested that O2 might not created as infrequently as previously assumed.

Synthesizing O2 with solar wind

Konstantinos Giapis looked at the data from the Rosetta spacecraft not from a geologists perspective, but from his experience as a chemical engineer developing microprocessors. His work involved studying the interactions between high-powered ions and semiconductor surfaces, usually for the purpose of improving memory components in computers. Giapis happened to be curious about this data from space, and recognized that the oxygen on Comet 67P was emerging in similar conditions to those he usually created in his lab.

The emerging hypothesis is that the molecular oxygen seen wafting off of Comet 67P isn’t from the birth of the solar system, and is instead being created as the comet orbits the Sun. Water molecules from ice inside the comet are indeed being released, but ions from the Sun, collectively known as solar wind, are actually breaking those water molecules apart. More oxygen is also being freed from rust and sand on the outside of the comet, and these loose atoms can then bond into new O2.

If this is confirmed, it’s good to know but certainly complicates our model of the universe. There had been hope that O2 could be an indicator of life on distant exoplanets, but knowing that it these molecules can be made with debris and the ions means that it’s not always going to be a sign of respiration. O2 is still rather unusual, but we now know there are more ways to get a hold of some if you don’t have any plants around.

Source: Comet 67P Found to Be Producing Its Own Oxygen in Deep Space by Nancy Atkinson, Seeker

On July 6th, 2017 we learned about

Testing tar-based water bottles for the transmission of dangerous toxins

Keeping potable water portable has been one of humanity’s big challenges. The different flavors and smells of water are thanks to all the different materials water can pick up and carry from its containers, from stream beds to lead pipes. Some containers are more concerning than others, including some of our favorite plastics of today. As those bottles break down, small amounts of molecules like BPAs can end up in your water. As much as people are trying to avoid these contaminants today, they’re rather benign compared to the first “plastic” water bottles, which were made of something regarded as “nature’s asphalt.”

Bottled in bitumen

Bitumen is a form of petroleum that can be functionally solid at room temperature, but usually oozes like a very viscous liquid over long amounts of time. It’s composed of a variety of compounds, and can be found in a variety of natural settings, such as sandstone, bubbling up under lakes, or for the paleontologists, the La Brea Tar Pits in Los Angeles. Native American tribes living on islands of the coast of Southern California, collectively known as the Chumash, also found bitumen washing up on their beaches. The little balls of tar seep out of fissures under the ocean, and with a little work, the Chumash peoples realized that bitumen could also seal water into a container better than ceramics or skins.

The recipe for a Chumash water bottles required plant-fiber nets, pitch from trees, an abalone shell and of course a lot of bitumen. The netting was a framework to make the overall shape, which was generally bulbous with a narrow spout on the top. The shell helped provide some initial structure at the bottom, and the rest was made by slathering melted bitumen and pitch along the netting. It’s a sticky, smokey process, but researchers recently recreated it so that they could test exactly how many toxins these bitumen bottles may have been.

Safe to sip and sup?

The carefully recreated bottles were left to hold water for two months to simulate the passage of time, then tested. Mass spectrometry found that the water had picked up naphthalene, phenanthrene, and acenaphthalene, all of which can be toxic if ingested. Tests were also conducted with olive oil instead of water in order to simulate contact with other foods, since there is evidence that Chumash people ate meats and fish off bitumen-based bowls or plates. The olive oil picked up more toxins, but it may not be a perfect proxy for what the Chumash were actually eating. In the end, the most dangerous component in all these products was the smoke made during their production. That wouldn’t have harmed as many people, but anyone regularly making bitumen water bottles likely paid a price to do so.

These investigations weren’t just interested in water bottle technology. Skeletons of Chumash people from around 5,000 years ago turn up with an unusual number of health problems, including poor bone quality, smaller skulls, and bad teeth. The data from the recreated bitumen water bottles don’t fully explain these health problems, although it’s a tough connection to prove at this point. Most studies of toxicity are based around people that still have enough flesh to damage, and so there’s not a lot of information if you want to know how naphthalene might affect bones over a lifetime. Still, the amount of toxins leached into the water, oil and of course, smoke, do suggest that these water bottles contributed to health problems at a minimum.

Source: Plastic Water Bottles Might Have Poisoned Ancient Californians by Nick Stockton, Wired

On July 2nd, 2017 we learned about

Protecting artwork for posterity when it’s made from materials prone to dilapidation and putrefaction

In the last week, I’ve had the pleasure of going to an art museum with eight- and four-year-olds, once at the four-year-old’s request. They especially enjoyed the modern and contemporary pieces that felt more open-ended in how they could be interpreted (protip: kids like Nick Cave.) The biggest concern for our visits was reminding everyone that these objects, even the stuffed animals sewn into a suit composed largely of fishing bobs, weren’t there for us to touch. In order for people two thousand years in the future to be able to see these new pieces the way we were able to see an Egyptian sarcophagus, we all needed to do our part to keep things as pristine as possible. This challenge extends beyond kids’ fingers though, as non-traditional materials used in contemporary art are posing huge challenges for art curators.

Replace and repair

Synthetic items like fishing bobs and stuffed animals seem like the should be easy to preserve. Plastics famously take ages to break down, but manufactured goods don’t always hold up the way you expect. A plastic bob might get cracked during transport, or lost as some of the knitted yarn that holds it breaks down. The question then becomes how to repair the piece— if the original item can no longer be purchased, do you find a substitute? How much change can a piece of art accommodate before it’s no longer the same creation? This has been an issue in some art purposely built from manufactured goods, like florescent tube lights in installations by Dan Flavin. In that case, Flavin knew the lights couldn’t be replaced forever, forcing the piece to change over time.

Responding to rot

Some materials turn sculptures or paintings into what amount to performances. Food has been incorporated into art for thousands of years, but when that food isn’t just presented as an image, things can get messy. Dieter Roth embraced this in his biodegradable art, covering photos in cheese to see how they’d change over time. Jim Victor and Marie Pelton sculpt butter in refrigerated cases, knowing that each piece has a short lifespan from the start. When the eventual decomposition isn’t intentional though, art conservationists have a bigger problem. Janine Antoni has made a few copies of a piece called Lick and Lather, each consisting of self-portrait busts made of chocolate and soap. Over time, chocolate pushes some fatty lipids to the surface, adding white, chalky texture to the otherwise brown surface. The soap versions actually prove to be more difficult to preserve, and curators have worked with Antoni reformulate the exact soap formula so that future replacements can hopefully survive the test of time a bit longer.

Recuse from the light

Of course, even traditional materials need special care to hold up over time. While the effects of heat and humidity might be more obvious, even light can damage an oil painting. Ultraviolet light can damage pigments in paint, breaking up specific molecules that end up changing the painting’s colors. Museums therefore do their best to avoid bright light on paintings, but even darkness can cause changes. Linseed oils used to make the oil paint more malleable tend to darken and yellow in darkness, although that particular change is eventually self-correcting after a painting is exposed to light again.

All these changes mean that a lot of planning, thought and even physics and chemistry are needed to keep art objects in good shape over long periods of time. Collectors are now having art appraised not just for their vision and value, but also for how durable the piece may be. In some cases, the solution is to plan ahead and build replacement parts with an original piece, but other times the answer seem to be accepting that change is inevitable. Even if something doesn’t end up looking like the artist originally intended, there’s still a good chance it will be valued and appreciated for generations to come— just ask those Greek sculptors who might barely recognize their own work now that the paint and arms have fallen off.

Source: How Do You Conserve Art Made of Bologna, or Bubble Gum, or Soap? by Jacoba Urist, The Atlantic

On June 27th, 2017 we learned about

Whipped cream’s fantastic fluffiness is built by fat-covered bubbles

Whipped cream might make a lot more sense if we just called it “foamed cream.” Sure, there is a lot of whipping or whisking involved, but that hardly describes what’s happening inside the collection of milk fats and water that can cause it to turn from a thick, yummy liquid into a fluffy, nearly-sculptable foam. The cream isn’t solidifying thanks to crystalization like freezing water— if anything, stiffened cream is something closer to a non-Newtonian fluid like Silly Putty. Unlike those fluids though, whipped cream is sort of a one way road- you have to get it right the first time, as this process can’t be reversed and reattempted.

Whipping up some fat-lined foam

The key to this structural pickiness is the composition of milk fat, as whipped cream is technically an emulsion. Starting with whipping or heavy cream from the store, you have a liquid with some proteins, sugars, water and a lot of tiny globules of fat. Those globules are small enough to flow and feel like liquid in your mouth, but they actually have a bit of structure to them. The inside of each globule are fatty acids, mostly consisting of the hydrophobic triglyceride. To avoid interacting with water molecules in the milk, the triglycerides are contained in an outer shell of phospholipids. This is a stable arrangement, but it’s also too runny to put on your pumpkin pie or strawberry shortcake.

When you start whisking your cream, the whisk introduces little air bubbles into the liquid cream. Normally, these bubbles can escape by floating to the top of the cream, but as you keep whisking something else happens to trap them. The fat globules are big enough that they get hit and broken apart by the whisk, and while the phospholipids hardly care, the triglycerides still want to avoid interacting with water. So to find an attachment point, they glom onto the air bubbles floating through the cream, creating little fatty-acid shells around them. The high fat content of the cream serves up plenty of triglycerides to do this job, and eventually the triglyceride-lined bubbles are numerous enough to provide a structure to the cream. This is the moment when you not only get peaks in your cream, but it starts to grow in volume as well since there’s now air trapped inside.

What happens beyond the bubbles

If you keep whipping though, you can start to break up these precious triglyceride-bubbles too. The air pockets will be destroyed, as the triglycerides are left with nothing to grab onto but each other. You’ll get further separation between your fat and water, eventually leaving you with butter. It’s obviously not a total loss, but possibly not what you meant to put on your dessert.

So why does properly whipped/foamed cream eventually liquefy again? As you might expect, those triglyceride-lined bubbles aren’t that strong, and heat only serves to soften them further. Inversely, if you’re whipping cream, make sure it’s cold so that it will be as strong as possible. If you really need to prolong your cream’s fluff-time, cornstarch or powdered sugar can be added, giving the concoction more structural elements to work with, like a tastier version of many slime recipes.

What does the whipping in cream from a can?

If you’re in a bigger hurry, use the canned stuff, that uses pressured nitrous oxide to inject bubbles into cream. As that cream is forced through a tiny nozzle, the original fat globules are sheared open, recreating the effect of whisking in an instant. Try not to inhale the nitrous oxide though, as it’s not good for your brain, or for the ozone layer either.

Source: Cream Science: On Whipping, Butter, and Beyond by Claire Lower, Serious Eats

On June 21st, 2017 we learned about

How Rebecca Huit heaved a Hummer over her head, plus handled her flaming fingers

Sciencing the Sisters Eight!

Rebecca Huit is one of the younger sisters in The Sisters Eight, but she commands an outsized amount of attention from her siblings, even before gaining her powers. When she does start demonstrating unusual abilities, it’s unclear what’s happening at first, because she manifests both inhuman strength and incendiary fingertips. There’s little reason to suspect these abilities are tied to each other, and so we’ll unpack each power on their own.

More massive muscles

The development of Rebecca’s strength may have two distinct causes. At the opening of Rebecca’s Rashness, we find that Rebecca is vigorously training at all hours of the day, and getting eye-popping results. She’s able to easily support the full weight of her sister, Petal, from one arm with no sign of fatigue, indicating that she’s somehow gotten a lot stronger than the average seven-year-old. The book fails to mention any changes to Rebecca’s appearance, but there’s a chance that she’s suddenly been building muscle mass because her body has stopped blocking its growth.

Many mammals, including humans, cats, cows and dogs, naturally create a protein called myostatin. This protein acts as a regulator on our muscle development, keeping us from building excessive amounts of muscle that might cause a drain on our energy levels without much practical gain from an evolutionary standpoint. When genetic mutations, or a decrease of another protein called follistatin, somehow leave an animal without myostatin, muscles develop to unusual sizes, greatly increasing the creature’s strength. Even newborn babies lacking myostatin will show bulk in their leg muscles, and can lift over six pounds in one hand by the time they’re four and a half. If Rebecca has suddenly dropped her myostatin production, developing enough muscle to lift Petal wouldn’t be a big challenge.

Hoisting the Hummer

Shortly thereafter, Rebecca amazes her family by lifting up an entire Hummer, raising it over her head. Hoisting 6400 pounds into the air is a far cry from supporting an older sister, and even new muscle growth might not account for the amount of strength necessary. Since Rebecca was lifting the Hummer to help her friend Pete, there’s a good chance that she was tapping into what’s known as hysterical strength. This is the strength that people tap into in emergencies to do things like… well, rescuing friends trapped under cars. In real life, these people are usually only lifting a quarter of the car’s weight to free someone, and they’re not actually using more strength than their muscles normally offer— it’s just more strength than the body ever wants to use.

Like the myostatin that keeps our muscle production in check to save resources, our brains normally cap our muscle exertion below their physical limits. This provides a buffer for our safety so that we don’t damage muscles, ligaments, tendons or bone. It also helps us save some calories to get home to recuperate after exertion, rather than leave us completely limp on the ground. Hysterical strength isn’t achieved with boosted muscles then, but by removing the feelings of pain and fatigue that normally keep things in check at around 60% of our potential strength. People who have experienced hysterical strength have sometimes paid a price in self-induced injuries, although they usually don’t notice things like eight cracked teeth until they’ve calmed down after the triggering emergency.

Hot hands

For better or for worse, the flames that later shoot from Rebecca’s fingers aren’t tied to emergency responses, as she can set things ablaze at will. Flames are described as blasting from her fingers, indicating that there’s some sort of pressurized fuel source to push the fire away from her hands, like the pressurized nozzles on a flamethrower. Unlike a flamethrower, we see no sign of a pilot flame though, so some other mechanism must be heating things up enough to burn things down than traditional fuels like propane or butane.

A model for spraying flammable fuels is the African bombardier beetle. When threatened, this beetle can spray a mix of hydrogen peroxide and hydroquinones that combine in mid-air to form oxygen, boiling water and benzoquinones. None of these components aren’t literally combusting during this reaction, but the resulting spray can cause chemical burns, clouds of vapor and intense heat, sometimes as high as 200° Fahrenheit. Potential predators hit this cocktail are likely to be burned and incapacitated, allowing the beetle to escape danger. It’s not going to literally set your drapes on fire necessarily, but if Rebecca was spraying anything like this out of her fingers it would still cause plenty of damage.

Overall, this all leaves Rebecca as a very dangerous, volatile girl, and most people wouldn’t want to risk being near these abilities on the best of days. The combination of extra strength operating at its full capacity, even temporarily, while spraying noxious, burning chemicals is so extreme that Rebecca’s eventual imprisonment really seems like the only rational option for the remaining siblings. As well as the surrounding neighborhood.

Source: The Man of Steel, Myostatin, and Super Strength by E. Paul Zehr, Scientific American

On June 1st, 2017 we learned about

Plants protect themselves from heat waves at our peril (thanks to our pollution)

When it’s hot outside, the human body tries to cope by sweating, resting, and if you’re in the sun directly, creating freckles or moles to try to block damage from ultraviolet light. As much as plants need sunlight for photosynthesis, too much heat can be a problem for them too, but rather than emitting some stinky sweat like us, they end up emitting a group of chemicals called isoprenes (C5H8). This helps plants avoid damage from the sun, but some of those isoprenes can also combine with air pollutants, forming new compounds like ozone (O3). As you’ll see on air quality forecasts, this all combines to dangerous conditions in congested areas, even beyond the heat itself.

Worse than the sum of their parts

Plants evolved heat-beating chemistry long ago, and obviously the world has weathered many heat waves. While we’re just starting to appreciate the role plants can play in ozone creation, the most recent addition to this system is actually pollution from human activity, like burning fossil fuels to power cars and other power plants. One group of gasses, nitrous oxides, can readily react with isoprene, making these pollutants into a health hazard. The combination is great at making ozone at ground level, right where it can be inhaled by humans to do damage to our lungs.

In simulations of various temperature conditions, these effects don’t just scale up as things get hotter. A 77º Fahrenheit day, is likely to push plants to increase their isoprene output a bit, resulting in anywhere from a 6 to 20 percent increase in ozone levels in a city. However, as the plants get further from their comfort zone, their rate of isoprene output increases. A 86º Fahrenheit day can end up with 60 percent higher ozone, posing a significantly higher health risk.

Changing the equation

It’s important to stress that while plants are part of this dynamic, they’re not really the problem. In places without human emissions to provide reagents like nitrous oxide, the extra isoprenes in the air shouldn’t be a big problem. The fact that plants also help capture carbon dioxide, which contributes to overall climate change, also points to their net value in air quality management. Fewer plants mean more loose carbon dioxide, and then more heat being trapped in the atmosphere. Some heat, and heat waves, is of course inevitable, leaving us with… oh right— the cars and other exhaust emissions! If we can reduce those emissions, a day hot enough to stress our trees doesn’t have to become a dangerous day for us.

Source: When it’s hot, plants become a surprisingly large source of air pollution by Ashley Yeager, Science News

On May 16th, 2017 we learned about

To stay efficient, bear diets shift throughout spring and summer

Scientists are using a variety of approaches to confirm that bears are not, in fact, living off of stolen picnic baskets. Using techniques that range from stalking to chemical hair analysis, we’re learning that bears are actually conscientious eaters, shifting their diets with the season to target foods that aren’t too sugary or too fibrous. Instead, they seem to be looking for food that has just the right amount of protein and fat to make sure they’re all set for the next winter’s hibernation.

Stalking bears in springtime

In Japan, researchers followed some Asiatic black bears (Ursus thibetanus) for months at a time, documenting their every move to see what was on the menu. With telephoto lenses, will and endurance, they were able to make a record of what the bears ate at different points of the spring and summer over two years. What they found is that the bears were very good at targeting foods that offered protein to build muscle, while avoiding things that might be too rich in fiber, which is less efficient to digest. For example, in early spring the bears would eat budding leaves, but move onto things like ants once the plants had grown out further. In some cases, maximizing protein even seemed to trump over all calories, possibly just as a way to be as efficient with digestion as possible.

Scanning fur in summer

In British Columbia, grizzly bear (Ursus arctos) diets were examined in a much less direct method, but similar trends were found. Rather than observe the bears directly, researchers looked at trace evidence of the bears diets for signs of what was being digested. This kind of research often utilizes feces for evidence, but with concern that feces may over-represent fibrous items that are hard to digest, scientists from the Canadian Natural Resource Science Section sampled bears’ hair. By looking at the chemical isotopes that turned up in hair found on trees and bushes, the team was able to figure out what foods had been digested and then grown into the animals’ fur (and presumably muscles, bones, etc.)

Similar to the Japanese study, these bears seemed intent to eat very efficiently. Plants were a bigger part of the diet than expected, with a focus again on protein sources. When the bears had apparently eaten enough plant-based protein, they started in on salmon as a source of fat. It’s easier for a body to build fat from another animal’s fat, so the bears selectively ate the fattiest parts of the fish, like the skin, roe and brains. The desire for fat was so specific that the rest of the fish were often discarded along the river, even if they could have offered other forms of nutrition.

Finally, looking at fur also revealed that the grizzly bears started growing their winter coats later in the summer than previously understood. As with the findings on bears’ diets, this information should help people understand and plan around bears’ feeding schedules and movement. Ideally, this would make it easier for the bears to meet their needs without running into too many complications with humans along the way.

Source: Chemical content of bears’ hair reveals surprising eating habits by Jamie Durrani, Chemistry World

On April 13th, 2017 we learned about

Samples from Enceladus show the moon may be a ‘candy shop’ for microbes

When the Cassini spacecraft launched in 1997, scientists weren’t sure what they’d find around Saturn’s orbit, but it they certainly weren’t expecting what’s now being described as a “candy shop” for microbes. With a lot of instruments to study the moon Titan, it was certainly a surprise when the icy moon Enceladus was seen spraying columns of water into space. Liquid water isn’t something to be scoffed at, especially 888.2 million miles from the Sun, and so subsequent flybys of Enceladus were been arranged, with the latest in 2015 taking the probe within 30 miles of the moon’s surface. With these latest samples, researchers have found that the geysers not only contain water, but also significant amount of molecular hydrogen (H2) and carbon dioxide (CO2), both of which indicate that Enceladus’ oceans may indeed be habitable.

(Relatively) heaping helpings of hydrogen

Detecting molecular hydrogen in Enceladus’ geysers matters in a couple of ways. Hydrogen doesn’t usually like to bond to itself, and so to find H2 in quantities even as low as 0.4 percent by volume indicates a significant amount of chemical reactions taking place below Enceladus’ icy shell. These amounts were considered to be out of equilibrium for a more stabilized environment, and so there’s likely a lot of energy being fed into the system to keep churning the hydrogen out. The current best guess for how this system works is that geothermal activity in the rocky core of Enceladus is creating hydrothermal vents at the ocean’s floor which then lead to chemical reactions between rocks and water, not unlike the thermal vents you find on Earth.

This then leads to the second significance of hydrogen, which is that it’s the aforementioned candy in the ‘candy shop.’ Microbes on Earth metabolize H2 and CO2, making methane as a byproduct. This form of harvesting energy may have been the first source of food for early life on our planet, and so people are wondering if it’s taking place on Enceladus as well.

Nobody is declaring the existence of alien life yet though. While Cassini has detected water, hydrogen and carbon, as well as methane as a possible waste-product, we haven’t seen other elements like phosphorus or nitrogen yet, so our usual ingredients list for life isn’t completely filled out. Some researchers also wonder if we’re seeing too much hydrogen, since microbes would theoretically be eating it up instead of allowing it to escape, although perhaps it’s just produced faster than they can eat it. It’s hard to answer some of these questions with Cassini though, as the spacecraft wasn’t designed to look for all these signs of life, and is running out of fuel. To protect what may or may not be on Enceladus, NASA actually plans to crash the spacecraft into Saturn later this year rather than risk losing control of it.

Establishing the presence of geysers on Europa

Those of us wanting more may be in luck though, because more evidence is piling up of similar phenomena on Jupiter’s moon, Europa. The Hubble telescope recently captured new images of what seems to be a similar geyser erupting through that moon’s icy shell. What’s more, the location of that geyser matches up with earlier images, as well a relatively hot patch on the moon, according to heat maps made by the Galileo spacecraft in the 1990s. Scientists suspect that a similar cycle of venting is happening on Europa, and that it might be a better candidate to find microbial life, largely because it’s billions of years older than Enceladus and thus would have more time to have life evolve.

While Cassini may be leaving us with a bit of a cliffhanger here, we might be able to get some definitive answers about Europa. The Europa Clipper mission that is currently being planned will be sent to the moon fully loaded to hunt for microbial life, and the hydrogen candy it loves so much.

Source: NASA Missions Provide New Insights into "Ocean Worlds" in Our Solar System, NASA News & Features