More Confusion Over Salt.
An article in the New York Times raises significant doubt about the advice of government and health agencies concerning the optimal amount of salt in our diet. In some respects, it seems that the established wisdom “the less salt the better” has been passed down without the benefit of rigorous scientific scrutiny. The author points out the questionable status of the government’s own advice on low salt intake and looks at some studies that have raised the possibility that too little salt also can be dangerous to our health. If you think all this is confusing, you are not alone.
The Tundra Is Growing Up.
The cold, harsh Eurasian tundra, vast tracts of land stretching from Northern Europe across Asiatic Russia, is changing before our eyes. Typically, only shrub-like plants inhabit the southern portion of the tundra. Today, those shrubs are growing into trees and short, but growing forests, are covering huge areas of tundra. The driving force behind this trend is warm summers, especially warm Julys. The trend is self-accelerating. As more of the winter snowpack is covered by trees, less solar energy will be reflected into space (the albedo effect) and more will be absorbed by the forests, further increasing temperatures and the greening of the tundra.
More at Live Science.
Attack of the Giant Spiders.
No, it’s not a summer horror movie release but a dangerous development in Tinsukia district in India. A new species of spiders, the size of a human thumb and similar in appearance to a tarantula, have been biting villagers in this remote area of India. Apparently never before seen, the hairy spiders live in colonies and are aggressive toward humans. Several bitten victims have tried to lance their wounds with razor blades and this has exacerbated the health threat.
More at Christian Post.
New Slimmer Look for Dinosaurs.
Artistic depictions of dinosaurs, based upon their well-understood skeletal remains, have come under recent scrutiny. Comparing dinosaur skeletons to those of other large land animals that exist today, such as bears and elephants, scientists have constructed a mathematical formula to better approximate the dinosaurs’ most likely body volume. They now believe that at least the sauropods, the largest plant eaters that fascinate most every child, were probably 20% less bulky than some of the previous artistic renderings would suggest.
More at Live Science.
What David Blaine Can Learn From the Octopus.
In an incredible display of camouflage, Scientific American blogs reports a video recording of an octopus making itself virtually invisible.
Monkey Lip Smacking Precursor to Human Speech?
Although bound to be controversial, a new study suggests that the lip smacking behavior of monkeys might contain clues about the origins of human speech. Monkey mothers are known to make repetitive smacking sounds to their infants, although the sounds do not originate in the mother’s larynx. Scientists analyzed the sounds and the body components that are involved in producing them and determined that rhythmic lip smacking requires a high degree of coordination between the lips, mouth, tongue and jaw. It turns out that the smacks monkeys make is at the same frequency as human speech — about 5 cycles per second. The researchers theorize that the lip and tongue smacks persisted in hominids and when they were later combined with vocalizations, the earliest precursor to human speech appeared.
More at Discovery.
Even Rain Can’t Stop a Hungry Mosquito
Considering how a fast falling raindrop has some 50 times the mass of an ordinary mosquito, you might think mosquitoes would avoid the rain so as not to be crushed. It turns out, however, that their light weight allows them to easily survive a collision with a raindrop. An experiment using high speed video demonstrated that the mosquito usually avoids harm by going with the flow — it simply attaches itself to the raindrop, hitches a ride, and then separates itself before the raindrop smashes into the ground. Still, there’s no harm in rooting for the raindrops.
More at Science News.
Smaller Insects A Result of Bird Evolution.
Today, we don’t have to deal with dragonflies with 3-foot wingspans. An increase in oxygen leads to an increase in insect size, and vice versa. So, around 300 million years ago, when the oxygen content of the air was at 30% rather than the 21% it is today, giant insects were the norm. However, it was not a decline in oxygen that decreased insect size. Rather, about 150 million years ago, the ancestors to modern birds appeared and apparently decimated the large insects. The result was that insect size reduced itself over time, even though oxygen levels remained high during that period.
More at Science News.
New England Jellyfish Invade the Black and Caspian Seas.
North America is not always the victim of invasive species importation. In the case of
the New England light-reflecting jellyfish, Mnemiopsis leidyi, the problem was exported to
the Black Sea, probably by a ship returning there from the New England area and dumping its
ballast. The reflecting jellyfish are kept in check in New England by at least two predators, one
itself a jellyfish called Beroes, but these predators did not exist in the Black Sea. Unchecked,
the reflecting jellies did significant damage to Black Sea fisheries by voraciously devouring
zooplankton, which normally feeds the native fish. As luck would have it, Beroes jellyfish
finally arrived in the Black Sea, probably also hidden in ship ballast. However, the extensive
damage done to the local fisheries will take awhile to repair. And, recently, the reflecting
jellyfish have appeared in the Mediterranean and North Seas.
More at Scientific American.
Melting Arctic Means Colder Winters.
It may seem counter-intuitive, but as the ice melts in the Arctic it sets up conditions that
include much colder winters for those in the Northern Hemisphere, including the United States.
As explained by Charles H. Greene, professor of earth and atmospheric sciences, and Bruce C.
Monger, both of Cornell University, warming temperatures cause the relatively cold Arctic air to
wander further south than is usual, causing much more severe winters in the temperate zones of
the Northern Hemisphere. The bottom line is that along with record setting spring and summer
high temperatures, Arctic melting may cause record-setting cold temperatures and snowfall in
More at Red Orbit.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.