June 12, 2013
Visit a sunny pond in a meadow, park or zoo and you’ll likely see turtles basking on logs and small lizards hanging out on warm rocks. If you’re in the south, you may even spot an alligator lazing on a bright patch of shore.
Ectotherms (better known as cold-blooded animals) such as these reptiles have to shuttle back and forth between shade and sun in order to manually regulate their body temperature. Insects, fish, amphibians and reptiles all do it. Now, new research suggests that these animals begin their temperature-regulating tasks much earlier than previously thought–while they are embryos encased in their eggs.
Previously, researchers thought of developing embryos as cut off from the outside world. But back in 2011, researchers found that Chinese soft-shelled turtle embryos could move between warmer or cooler patches in their eggs, though they lacked any feet at such an early stage of development. Some of the same Chinese and Australian researchers who published that original finding decided to investigate further to see just how deliberate these movements are.
“Do reptile embryos move away from dangerously high temperatures as well as towards warm temperatures?” the team, writing in the journal Biology Letters, wondered. “And is such embryonic movement due to active thermoregulation, or (more simply) to passive embryonic repositioning caused by local heat-induced changes in viscosity of fluids within the egg?”
In other words, are unborn reptiles purposefully moving from one spot to another within their eggs, much like an adult animal does? The team decided to investigate these questions by experimenting on turtle embryos. They incubated 125 eggs from Chinese three-keeled pond turtles. They randomly assigned each of the eggs to one of five temperature groups: constant temperature, hot on top/cool on the bottom, or at a range of heats directed towards one end of the egg.
When they began the experiment, most embryos sat in the middle of their eggs. A week after exposing them to the different temperature groups, the team again measured the baby turtles’ positioning within the eggs. At the 10-day mark, the researchers again measured the turtles’ positions, and then injected half of the eggs with a poison that euthanized those developing embryos. Finally, after another week, they took one last measurement of the developing turtles and euthanized turtles.
The turtles within the eggs held at constant temperature or those that were in the “warm on the top/cool on the bottom” group tended not to shift around in their eggs, the researchers found. Those belonging to the groups that experienced warm temperatures only on one end of their egg, however, did move around. They gravitated towards warm conditions (84-86°F), but if things heated up too extremely (91°F), they edged towards the cooler side of their egg. Crucially, the embryos that the researchers euthanized stopped moving after receiving the dose of poison. This shows that the embryos themselves, not some passive physical process, are doing the shifting.
The turtle embryos, the researchers note, behave much like adult reptiles do when thermoregulating their bodies. They warm up and cool down by moving toward or away from heat sources. For species like turtles, temperature during development plays an important part of determining the embryo’s sex. Turtle nests, which are buried in the sand, often experience a range of different temperatures, so embryos could be playing a role in determining their own gender, edging towards the cooler side of the egg if they feel like becoming a male, or the warmer side if they’re more female-inclined, the authors write.
June 11, 2013
Science is generally considered a rather serious business, full of big questions, dense calculations and incomprehensible jargon.
Then there is the Annals of Improbable Research, a venerable journal that has published data on the effects of peanut butter on the rotation of the Earth and how access to television can be an effective method of birth control. The publication’s stated goal is to publish “research that makes people laugh and then think.” Its articles—which are mostly satire, but with some occasional real research into offbeat issues—probably accomplish the former goal more often than the latter, but they do often contain a grain of scientific truth at their core. And, of course, the organization’s Luxuriant Flowing Hair Club for Scientists™ is an indispensable institution on the international scientific landscape.
For your reading pleasure, we bring you an (admittedly unscientific) list of the 5 most improbable research projects from the Annals:
How did Fiorella Gambale, a scientist at the (nonexistent) Institute for Feline Research in Milano, Italy, answer this age-old question? Simple: she dropped the cat Esther 100 times each from a variety of heights and charted the results. Improbably, the cat landed on its feet all 100 times when dropped from 2, 3, 4, 5 or 6 feet, but failed to do so even once when dropped from 1 foot.
Although these results were never vetted by other scientists—so there’s no way of knowing whether Gambale actually performed the tests—the finding that cats really do land on their feet when dropped from more than 12 inches from the ground actually does jibe with established scientific beliefs. The explanation is that they need a few seconds of free fall to trigger their righting reflex, which allows them to bend their back and twist their torso to orient their feet towards the ground.
“The field of culinary evolution faces one great dilemma,” wrote Joseph Staton, of Harvard’s Museum of Comparative Zoology. “Why do most cooked, exotic meats taste like cooked Gallus gallus, the domestic chicken?” Staton tasted a wide variety of meats (including kangaroo, rabbit, goose, pigeon, and iguana) in exploring the question, and ultimately determined that the quality of “chicken taste” is a conserved trait, something that came about once in the evolutionary history of invertebrates and was passed on to many species.
Sadly, Staton’s attempt to sample dinosaurs was thwarted: He apparently made several calls to Chicago’s Field museum to “borrow merely a single bone” from their T. rex but his request was “entangled in red tape.”
A team of geologists from Texas State and Arizona State Universities addressed this very serious question with the cutting-edge tools of their field: digital elevation analysis software, complex mathematical equations, and a standard-size flapjack from the local IHOP. They found that Kansas is, in fact, considerably flatter than an average pancake, which is actually more rugged than the Grand Canyon when viewed up close. They write that Kansas, on the other hand, “might be described, mathematically, as ‘damn flat.’”
Comparing these two fruits is not quite so difficult, it turns out, when you have access to a Nicolet 740 FTIR spectrometer, which can precisely measure the frequencies of light emitted from any substance. Scott Sandford, a NASA researcher, put this device to use on dried samples of a Granny Smith apply and Sunkist orange that had been pulverized and compressed into pellets. He found that the spectrums of light emissions from the fruits were remarkably similar, a rather stunning revelation given how frequently people employ the what he calls the “apples and oranges defense”: that we should avoid comparing two different things because of how different the fruits are.
“It would appear that the comparing apples and oranges defense should no longer be considered valid,” Sandford wrote. “It can be anticipated to have a dramatic effect on the strategies used in arguments and discussions in the future.”
Alice Shirrell Kaswell, a staff member at the Annals of Improbable Research, definitively answered this question once and for all in 2003: The chicken, it turns out, came approximately 11 hours before the egg. Kaswell came to this finding by separately mailing a dozen eggs and one (1) live chicken via the U.S. Postal Service from Cambridge, Massachusetts to New York City. Both items, sent out on a Monday, arrived on Wednesday, but the chicken was delivered at 10:31 a.m., while the eggs didn’t arrive until 9:37 p.m. Problem = solved.
June 10, 2013
The smell of pungent urine may make humans wrinkle their noses, but white-tailed deer don’t mind it. In winter months, they crowd together in northern Michigan–sometimes 100 animals per square mile–and pee all over everything. All of that urine, it turns out, does more than just create an excess of yellow snow. It directly impacts the ability of plants the deer depend on for survival to grow, meaning the animals may be peeing themselves out of their own winter havens.
Researchers typically think of deer’s impact on the environment in terms of the plants they eat. Usually, the animals “simplify” those plant communities with their munching–in other words they eat up all the plants, so only the heartiest species can survive. But it seems the story may be a bit more complicated than that. Though their nitrogen-rich urine–and, to some extent, their feces–they are increasing the complexity of plant communities by helping a multitude of species flourish–perhaps to their own detriment.
For wildlife managers whose job it is to ensure the forest can support deer well into the future, this is a significant consideration. “It’s important to keep ecological context in mind when discussing deer habitat sustainability,” said Bryan Murray, a doctoral candidate in environmental science at Michigan Technical University, in an email.
Murray and colleagues arrived at these findings after performing experiments with deer living in Michigan’s upper peninsula. Long, bitter winters can dump around 250 inches of snow in the region, so deer survival depends upon finding enough to eat and keeping warm in the frozen landscape. Areas of the forest that contain a mix of trees such as eastern hemlock, northern white cedar and balsam fir provide shelter from the wind and some snowfall with their broad, strong branches and bushy needles. Researchers refer to these deer hot-spots as “deeryards.”
The researchers decided to investigate how deer may be impacting the environment during those times of winter crowding. They fenced off three patches of forest to prevent deer from visiting those areas, then compared those deer-free sections with three other patches where that animals continued to congregate. Over the course of the year, they found that the deer significantly influenced the types of plants that grew in those patches, thanks to the nitrogen they excreted in their urine and feces.
Or, in sciencey-speak: “Our results suggest that browsing ungulates affect spatial patterns of herb-layer cover and diversity through the excretion of nitrogenous wastes in small, discrete patches,” lead author Murray and his colleagues report in the journal Ecology.
How, exactly, do the deer influence what grows in their vicinity? During the winter, the high concentration of deer in specific areas mean that the soil underfoot becomes saturated with pee. Nitrogen from the deer’s wastes builds up in the soil, and when spring arrives, the chemical acts like fertilizer, encouraging the growth of some nitrogen-loving plants, including hardwood seedlings. If this pattern repeats itself over a number of years, the conifer-filled deeryards may disappear, replaced by different types of trees that may not do as good of a job blocking wind or catching snow.
In the past, fewer deer congregated in this area of the upper peninsula, but logging and development are forcing more deer to crowd into smaller and less favorable spaces with smaller numbers of viable deeryards. This creates a potentially vicious cycle of crowding “where deer fertilize the soil, plant productivity increases, more deer are attracted to the habitat, fertilizing the soil, and so on,” Murray says.
So it seems that the deer themselves could wind up playing a part in their own undoing by wetting their winter beds.
In the 1960s and early 70s, researchers such as Harvard’s Timothy Leary enthusiastically promoted the study of so-called “magic” mushrooms (formally known as psilocybin mushrooms) and championed their potential benefits for psychiatry. For a brief moment, it seemed that controlled experiments with mushrooms and other psychedelics would enter the scientific mainstream.
Then, everything changed. A backlash against the 1960s’ drug culture—along with Leary himself, who was arrested for drug possession—made research nearly impossible. The federal government criminalized mushrooms, and research ground to a halt for over 30 years.
But recently, over the past few years, the pendulum has swung back in the other direction. And now, new research into the mind-altering chemical psilocybin in particular—the hallucinogenic ingredient in “magic” mushrooms—has indicated that carefully controlled, low doses of it might be an effective way of treating people with clinical depression and anxiety.
The latest study, published last week in Experimental Brain Research, showed that dosing mice with a purified form of psilocybin reduced their outward signs of fear. The rodents in the study had been conditioned to associate a particular noise with the feeling of being electrically shocked, and all the mice in the experiment kept freezing in fear when the sound was played even after the shocking apparatus was turned off. Mice who were given low doses of the drug, though, stopped freezing much earlier on, indicating that they were able to disassociate the stimuli and the negative experience of pain more easily.
It’s difficult to ask a tortured mouse why exactly it feels less fearful (and presumably even more difficult when that mouse is in the midst of a mushroom trip). But a handful of other recent studies have demonstrated promising effects of psilocybin on a more communicative group of subjects: humans.
In 2011, a study published in the Archives of General Psychiatry by researchers from UCLA and elsewhere found that low doses of psilocybin improved the moods and reduced the anxiety of 12 late-stage terminal cancer patients over a long period. These were patients aged 36 to 58 who suffered from depression and had failed to respond to conventional medications.
Each patient was given either a pure dose of psilocybin or a placebo, and asked to report their levels of depression and anxiety several times over the next few months. Those who’d been dosed with psilocybin had lower anxiety levels at one and three months, and reduced levels of depression starting two weeks after treatment and continuing for a full six months, the entire period covered by the study. Additionally, carefully administering low doses and controlling the environment prevented any participants from having a negative experience while under the influence (colloquially, a “bad trip.”)
A research group from Johns Hopkins has conducted the longest-running controlled study of the effects of psilocybin, and their findings might be the most promising of all. In 2006, they gave 36 healthy volunteers (who’d never before tried hallucinogens) a dose of the drug, and 60 percent reported having a “full mystical experience.” 14 months later, the majority reported higher levels of overall well-being than before and ranked taking psilocybin as one of the five most personally significant experiences of their lives. In 2011, the team conducted a study with a separate group, and when members of that group were questioned a full year later, the researchers found that according to personality tests, the participants’ openness to new ideas and feelings had increased significantly—a change seldom seen in adults had increased.
As with many questions involving the functioning of the mind, scientists are still in the beginning stages of figuring out whether and how psilocybin triggers these effects. We do know that soon after psilocybin is ingested (whether in mushrooms or in a purified form), it’s broken down into psilocin, which stimulates the brain’s receptors for serotonin, a neurotransmitter believed to promote positive feelings (and also stimulated by conventional anti-depressant drugs).
Imaging of the brain on psilocybin is in its infancy. A 2012 study in which volunteers were dosed while in an fMRI (functional magnetic resonance imaging) machine, which measures blood flow to various parts of the brain, indicated that the drug decreased activity in a pair of “hub” areas (the medial prefrontal cortex and posterior cingulate cortex), which have dense concentrations of connections with other areas in the brain. “These hubs constrain our experience of the world and keep it orderly,” David Nutt, a neurobiologist at the Imperial College London and lead author, said at the time. “We now know that deactivating these regions leads to a state in which the world is experienced as strange.” It’s unclear how this could help with depression and anxiety—or whether it’s simply an unrelated consequences of the drug that has nothing to do with its beneficial effects.
Regardless, the push for more research into the potential applications of psilocybin and other hallucinogens is clearly underway. Wired recently profiled the roughly 1,600 scientists who attended the 3rd annual Psychedelic Science meeting, many of which are studying psilocybin—along with other drugs like LSD (a.k.a. “acid”) and MDMA (a.k.a. “ecstasy”).
Of course, there’s an obvious problem with using psilocybin mushrooms as medicine—or even researching its effects in a lab setting. Currently, in the U.S., they’re listed as a “Schedule I controlled substance,” meaning that they’re illegal to buy, possess, use or sell, and can’t be prescribed by a doctor, because they have no accepted medical use. The research that has occurred went on under strict government supervision, and getting approval for new studies is notoriously difficult.
That said, the fact that research is occurring at all is an obvious sign that things are slowly changing. The idea that medicinal use of marijuana would one day be permitted in dozens of states would have once seemed far-fetched—so perhaps it’s not entirely absurd to suggest that medicinal mushrooms could be next.
June 7, 2013
Ocean plants produce some 50% of the planet’s oxygen. Seawater absorbs a quarter of the carbon dioxide we pump into the atmosphere. Ocean currents distribute heat around the globe, regulating weather patterns and climate. And, for those who take pleasure in life’s simple rewards, a seaweed extract keeps your peanut butter and ice cream at the right consistency!
Nonetheless, those of us who can’t see the ocean from our window still feel a disconnect—because the ocean feels far away, it’s easy to forget the critical role the ocean plays in human life and to think that problems concerning the ocean will only harm those people that fish or make their living directly from the sea. But this isn’t true: the sea is far more important than that.
Every year, scientists learn more about the top threats to the ocean and what we can do to counter them. So for tomorrow’s World Oceans Day, here’s a run-down of what we’ve learned just in the past 12 months.
This year, we got the news that the apparent “slow down” in global warming may just be the ocean shouldering the load by absorbing more heat than usual. But this is no cause to celebrate: the extra heat may be out of sight, but it shouldn’t be out of mind. Ocean surface temperatures have been rising incrementally since the early 20th century, and the past three decades have been warmer than we’ve ever observed before. In fact, waters off the U.S. East Coast were hotter in 2012 than the past 150 years. This increase is already affecting wildlife. For example, fish are shifting their ranges globally to stay in the cooler water they prefer, altering ecosystems and fisheries’ harvests.
Coral reefs are highly susceptible to warming: warm water (and other environmental changes) drives away the symbiotic algae that live inside coral animals and provide them food. This process, called bleaching, can kill corals outright by causing them to starve to death, or make it more likely that they will succumb to disease. A study out this year found that even if we reduce our emissions and stop warming the planet beyond 2°C, the number considered to be safe for most ecosystems, around 70% of corals will degrade and die by 2030.
Although coral reefs can be quite resilient and can survive unimaginable disturbances, we need to get moving on reducing carbon dioxide emissions and creating protected areas where other stressors such as environmental pollutants are reduced.
More than a hit of acid
The ocean doesn’t just absorb heat from the atmosphere: it also absorbs carbon dioxide directly, which breaks down into carbonic acid and makes seawater more acidic. Since preindustrial times, the ocean has become 30% more acidic and scientists are just starting to unravel the diverse responses ecosystems and organisms have to acidification.
And it really is a variety: some organisms (the “winners”) may not be harmed by acidification at all. Sea urchin larvae, for instance, develop just fine, despite having calcium carbonate skeletons that are susceptible to dissolving. Sponges that drill into shells and corals show an ability to drill faster in acidic seawater, but to the detriment of the organisms they’re boring into.
Nonetheless, there will be plenty of losers. This year saw the first physical evidence of acidification in the wild: the shells of swimming snails called pteropods showed signs of dissolution in Antarctica. Researchers previously found that oyster larvae fail under acidic conditions, potentially explaining recent oyster hatchery collapses and smaller oysters. Acidification may also harm other fisheries.
Plastic, plastic, everywhere
Americans produced 31 million tons of plastic trash in 2010, and only eight percent of that was recycled. Where does the remaining plastic go? A lot of it ends up in the ocean.
Since last World Oceans Day, trash has reached the deep-sea and the remote Southern Ocean, two of the most pristine areas on Earth. Most of the plastic trash in the ocean is small—a few centimeters or less—and can easily be consumed by animals, with damaging consequences. Some animals get hit on two fronts: when already dangerous plastic degrades in their stomachs it leaches toxic chemicals into their systems. Laysan albatross chicks are fed the bits of plastic by their parents in lieu of their typical diet and one-third of fish in the English Channel have nibbled on plastic.
Where have all the fish gone?
A perennial problem for the ocean, overfishing has only gotten worse with the advent of highly advanced gear. Despite fishing fleets going farther and deeper, the fishing gains are not keeping up with the increased effort.
Our brains can’t keep up either: even as we catch fewer fish, we acclimate to the new normal, adjust to the shifting baseline, and forget the boon that used to be, despite the fact that our memories are long enough to realize that most of the world’s fisheries (especially the small ones that aren’t regulated) are in decline.
Thankfully, those responsible for managing our fisheries are aware of what’s at stake. New knowledge about fish populations and their role in ecosystems can lead to recovery. A report from March 2013 shows that two-thirds of U.S. fish species that are closely managed due to their earlier declines are now considered rebuilt, or on their way.
Learn more about the ocean from the Smithsonian’s Ocean Portal. This post was co-authored by Emily Frost and Hannah Waters.