Science Briefs
Dust may stifle hurricanes
The hurricane seasons of 2005 and 2007 were compared with respect to dust in the air and temperatures over the Atlantic Ocean. Aerosol dust from the Sahara Desert was drier and more abundant in the atmosphere in 2007 than in 2005 report Donglian Sun and associates at George Mason University, Virginia, and the NASA Goddard Space Flight Center, Maryland. They also report that the temperature in the dusty region was higher in the low to middle troposphere but lower in the main development region in the eastern North Atlantic. The researchers suggest that the westward movement of Saharan dry air and dust layer, associated with temperature changes, is important in explaining the difference between the relatively quiet hurricane season in 2007 and the very active season in 2005. (Geophysical Research Letters 2008; 35: L15405)
Preventing lake eutrophication
Excessive nutrient riuchness in a lake can cause dense growth of plants and death of animal life due to lack of oxygen, a process known as eutrophication. Nitrogen and phosphorus are two nutrients considered responsible for eutrophication – so an experiment was designed to test this. A small lake had been fertilized for thirty-seven years with constant annual inputs of phosphorus but with decreasing inputs of nitrogen to test the theory that controlling nitrogen could control eutrophication. For the final sixteen years (1990-2005), the lake was fertilized with phosphorus alone. Despite the fact that the lake showed indications of extreme nitrogen limitation, the lake remained highly eutrophic report David Schindler and associates at the University of Alberta and the Canadian Department of Fisheries and Oceans, Canada; and the University of Minnesota, Duluth. Reducing nitrogen favored nitrogen-fixing bacteria which was enough to enable biomass production in proportion to the phosphorus available to keep the lake highly eutrophic. This emphasized the importance to decreasing inputs of phosphorus into lakes to prevent eutrophication. (Proceedings National Academy Sciences USA 2008; 105(32): 11254-11258)
Fungi mimic cold in wood for violins
Violins made by Antonio Stradivari in the late 17th and early 18th century have superior tone qualities. Stradivari used Norway spruce grown mostly during a period of reduced solar activity when temperature was low. Such trees produced wood with narrow annual rings resulting in considerable elasticity and low density. To test if wood decay fungi could substitute for a cold climate in their effects on wood of Norway spruce (Picea abies) and sycamore (Acer pseudoplatanus), trees were inoculated with wood decay fungi. These fungi reduce wood density without degrading the middle membranes of wood cells to make the wood acoustically similar to that grown in a cold climate report Francis Schwarze and associates at EMPA in Switzerland, and Albert-Ludwigs-Universität Freburg, Germany. The wood decay fungi reduced wood density with relatively little change in speed of sound, and the wood had a radiation ratio on a par with superior resonance wood grown in a cold climate. (New Phytologist 2008; 179(4): 1095-1104)
Chickens not native to Americas
The Spanish introduced chickens into the American continents after their arrival in the 15th century. This is generally accepted as fact except by some who argued that Amerindians in South America had chickens before Columbus discovered the Americas. They maintained that the Araucana and Passion Fowl breeds pre-existed Columbus. By analyzing mitochondrial DNA from chickens from Chile and comparing that to about 1,000 domestic chickens from around the world, the claim for pre-Columbian chickens could not be proven. This is reported by Jaime Gongora and associates from the University of Sydney, Australian National University, University of Queensland, University of Adelaide in Australia; International Livestock Research Institute (Kenya); Chinese Academy of Agricultural Sciences (China); Pontificia Universidad Catolica (Chile); Durham University (UK); and Uppsala University (Sweden). (Proceedings National Academy of Sciences USA 2008; 105(30): 10308-10313)
Globular star clusters in Virgo galaxies
Thousands of globular star clusters that are more than five billion years old have been identified in the Virgo cluster of galaxies by means of the Hubble Space Telescope. These dense bunches of stars comprise some of the oldest stars surviving in the universe. The Virgo cluster is a large galaxy cluster nearest to Earth, but beyond the Milky Way. A giant galaxy is at the cluster center, known as Messier 87, but there are no globular clusters near Messier 87 report Eric Peng and associates at Herzberg Institute of Astrophysics, Canada; Harvard-Smithsonian Center of Astrophysics, Massachusetts; University of Hawaii; European Southern Observatory, Chile; National Central University Taiwan; GEPI, France; and University of California, Berkeley. This group concludes that the giant galaxy captured the star clusters of the smaller galaxies and thereby added to the buildup of Messier 87. Such information helps them explain star formation in the development of galaxies.(The Astrophysical Journal 2008; 681(1): 197-224)
Eiger flank in Alps collapses
Landslides are a hazard in mountains and can be triggered by earthquakes, rainfall, melting permafrost, or retreating glaciers. A large landslide occurred in the Swiss Alps on July 13, 2006, when parts of a huge rock spur on the east face of the Eiger peak collapsed. An infrared system was installed to measure the size of the disintegrating slab, about the volume of two Empire State buildings, and the findings were reported by Thierry Oppikofer and associates at the University of Lausanne and Geotest AG, Switzerland. Blocks of rock that formed the spur moved relative to one another at up to tens of meters along fractures related to previous planes of weakness. The spur was unstable because a single block in the spur acted as a wedge and then disintegrated over time owing to lack of support on the sides. Glaciers that supported the cliff have melted and it appears that the rock has become loose and is now breaking away. The Eiger is 13,025 feet above sea level. (Nature Geoscience 2008; 1: 531-535)
Predator-specific camouflage
Animals that have to respond to different predators are in trouble if they have to respond to many different kinds of predators. Animals that change color can react quickly to a predator except if they encounter several predators: what colors should they change to? The dwarf chameleon (Bradypodion taeniabronchum) changes color to match the background in response to predators that have different visual capabilities report Devi Stuart-Fox and associates at the University of Witwatersrand and the University of KwaZulu Natal, South Africa, and the University of Melbourne and Museum Victoria, Australia. If this chameleon encounters bird and snake predators, it will more closely color match the background to hide from birds rather than for snakes because snakes have poorer color discrimination, according to the authors. The chameleon appears to be more camouflaged to the snake visual system. (Biology Letters 2008; 4(4): 326-329)
Climate change led to diversity
About 460 million years ago, during the Ordovician Period, there was an explosion in diversity among marine life. This period has been associated with a "supergreenhouse effect" in which one of the greatest evolutions of new life forms took place. During this time ocean temperatures cooled from about 45 °C (113 °F) to about that of the current ocean temperature (86 °F) in equatorial waters which allowed an explosion in marine biomass and diversity. This is reported by Julie Trotter and associates at the Australian National University and CSIRO Petroleum Resources, in Australia; the University of Victoria, Canada; and CNRS UMR Villeurbanne, France. Their findings show that the Ordovician seawater is similar to that of today and that a global change in climate occurred. Moreover, the climate played a major role in promoting the unprecedented increase in biodiversity characteristic of this period and opened the modern era of diversity and complexity. (Science 2008; 321(5888): 550-554)
Malaria in ancient Egypt
Malaria is a disease caused by the parasite in the genus Plasmodium. Female flies (Anopheles species) transmit the parasite to humans. There are four species of Plasmodium and each species has different clinical symptoms. Malaria dates back to early Greek times but conclusive data are lacking regarding disease incidence before Hippocrates. Now, ancient DNA for Plasmodium falciparum was found in ancient Egyptian mummy tissues from about 4,000 years ago report Andreas Nerlich and associates at the Academic Teaching Hospital München-Bogenhausen and the Institute of Tropical Medicine, Germany, and the University of Manchester, UK. The occurrence of malaria in ancient Egypt may explain the low life expectancy of ancient Egyptian populations. (Emerging and Infectious Diseases 2008; 14(8): view article)
Site for human settlement on the Moon
The Shackleton Crater near the south pole of the Moon is older than the Apollo 15 landing site but younger than the Apollo 14 landing site. The older Shackleton site may have collected volatile elements from outside the Moon for at least two billion years and would be an attractive site for human presence on the Moon. This is reported by Paul Spudis and associates at the Lunar and Planetary Institute, Texas; Applied Physics Laboratory, Maryland; Space Exploration Institute and the Micro-cameras and Space Exploration, in Switzerland. The sun shines in this location a substantial part of each day and there are large deposits of hydrogen, perhaps in the form of water ice. The Shackleton Crater has a diameter of 2,600 kilometers (1616 miles). US astronauts plan to return to the Moon in 2015 or shortly thereafter (Geophysical Research Letters 2008; 35: L14201)
Sleepless gene needed for sleep
Sleep is essential for animals from flies to humans. A gene was identified, called sleepless, in fruit flies (Drosophila spp.) which encodes a certain protein report Kyunghee Koh and associates at the University of Pennsylvania. Without this gene (sleepless), there is greater than 80% loss of sleep in the fruit fly. Sleep is thought to have some restorative function, but much is still unknown about the purpose of sleep. Sleep patterns vary among animals. Flies sleep nine to fifteen hours a day, worms take a two hour nap every 7-12 hours, and giraffes sleep only a few hours each day. Although some of the research will translate to humans, researchers are uncertain just how much will be applicable. (Science 2008; 321(5887): 372-376; read also p. 334-337)
Black holes stifle star formation
Some galaxies over the last eight to ten billion years of cosmic history have formed without stars. To explain such behavior, some astronomers have thought there must be a large supermassive black hole with a prominent bulge component to suppress star formation in galaxies. Using the Sloan Digital Sky Survey, Eric Bell at the Max Planck Institute in Germany reports that more than 99.5% of the red-sequence galaxies with stellar masses about ten billion times the mass of the sun have a prominent bulge component; this implies the presence of a supermassive black hole. This finding agrees with the prediction made by other astronomers of the requirement for preventing stars from forming. (The Astrophysical Journal 2008; 682(1): 355-360)
Genes protect frogs from extinction
Amphibians have been declining worldwide and pathogens may be responsible for some declines. A bacterium (Aeromonas hydrophila) is one of these pathogens, but a fungus and a virus also attack frogs. Certain genes in the African clawed frog (Xenopus laevis) were identified for their ability to recognize pathogens, report Seth Barribeau and associates at the University of Canterbury, New Zealand. They tested the major histocompatibility complex (MHC) genes for their reaction to bacterial infection and found tadpoles with gene types that resisted infection whereas other tadpoles lacked those genes. Since frogs are variable enough to comprise genetically diverse genes the authors think that in an epidemic there will be some frogs that will survive to maintain the species. The MHC genes will confer immunity and protect the species from extinction even though some frogs will not survive. Frogs and toads have the same immune system. The authors encourage management practices that preserve those genes. (PLoS One 2008; 3(7): e2692)
Nitrogen fixation greater in tropics
Plants, especially legumes, produce root nodules that capture nitrogen from air and fix nitrogen for use by growing plants of the next generation. Certain bacteria fix the nitrogen on roots and the process is much more extensive in vast areas of the tropics than in many of the mature forests in temperate and boreal regions. A clear advantage was found for these nitrogen-fixing bacteria in tropical savannas and lowland tropical forests (where phosphorus is deficient) than in mature forests at higher latitudes. This is reported by Benjamin Houlton and associates at Stanford University (CA), Carnegie Institute of Washington (CA), and CSIRO (Australia). Modern-day temperatures seem to hamper rate of nitrogen fixation as well as growth of the nitrogen-fixing bacteria at the higher latitudes. The authors also discuss the effect of climate change on the possible geographical change in nitrogen-fixing abilities, especially where nutrients are limiting and where carbon dioxide is increasing. (Nature 2008; 454: 327-330)
Sand-dust storms in northeast Asia
An abnormally high pressure developed in northern China in the spring of 2006 making for a stronger cold air source across the desert areas. This resulted in the most frequent sand-dust storms in the past ten years in Northeast Asia report Y. Q. Yang and associates at the China Academy of Meteorological Sciences, Beijing. The amount of dust that fell in the city of Beijing on April 17, 2006 was estimated to be 330,000 tons or 20 kilograms (44 pounds) per capita. Frequent occurrences of dust storms is one of the characteristics of global climate change. This Asian sand-dust is transported by the jet stream to the North Pacific and North America. This, in turn, affects rainfall and temperature on land and ocean. (Atmospheric Chemistry and Physics 2008; 8: 25-33)
Water present on the Moon
A single or series of catastrophic heating events have been thought to explain the formation and evolution of the Moon. During the event, highly volatile elements were thought to have been lost, especially hydrogen because it was the lightest element. Now, by using new technologies with secondary ion mass spectrometry, it has become possible to analyze some of the lunar volcanic glasses enabling scientists to show that water is present with an estimate of 745 parts per million. This is reported by Alberto Saal and associates at Brown University (RI), Carnegie Institute of Washington (DC), and Case Western Reserve University (OH). They further note that the Moon may not be entirely depleted of highly volatile elements, including water. (Nature 2008; 454: 192-195)
Orchid sexually provokes wasps
The flower of the Australian tongue orchid (Cryptostylis species) lures wasps (Lissopimpia excelsa) to pollinate blossoms by mimicking female wasps report A. C. Gaskett and associates at Macquarie University and the University of Sydney, Australia. The male wasps are tricked into clasping and copulating with the flower and in doing so release copious amounts of sperm; in the process wasps transfer pollen from one orchid to another. Orchids that provoke such behavior enjoy the greatest pollination by wasps compared to other orchids, so the deception is an obvious advantage. The authors wonder what advantage there is to the wasps which essentially are wasting their sperm on flowers instead of using it to fertilize female wasps. However, they report that female wasps can produce extra naïve males without mating, but not females. (The American Naturalist 2000; 171(6): E206-E212)
Greenland ice melt critical over time
Because of concerns about climate change and the rise of sea level attributable to melting of Greenland ice, the long-term response of Greenland to warming is important. How much carbon dioxide has to be released into the atmosphere before Greenland ice will totally melt? To answer that question a climate-ice sheet model designed to calculate ice loss over millennia was developed by S. Charbit and associates at the Laboratoire des Sciences du Climat et de l'Environnement, France. They report that if more than 3,000 gigatons of carbon is present in the atmosphere total melting of Greenland ice is inevitable. But if less than 2,500 gigatons of carbon is present, partial melting will occur followed by a re-growth phase. The amount of carbon dioxide emission into the atmosphere currently is slightly above 350 gigatons of carbon. The authors conclude that the rate of carbon dioxide emissions over the next century could determine how much ice is lost and how that affects sea-level. The goal would be to keep carbon dioxide emissions to below 2,150 gigatons of carbon to avoid the worst scenario. (Geophysical Research Letters 2008; 35: L12503).
An eclipse described in the Odyssey
In the 20th book of the Odyssey there is a poetic description of a total solar eclipse. Later, in a report by Schoch and Neugebauer in the 1920s, a solar eclipse was calculated to have occurred on April 16, 1178 BCE, over the Ionian Islands. Because of skepticism about whether this was a reference to an actual eclipse, the event was reinvestigated by Constantino Baikouzis and Marcelo Magnasco at Rockefeller University (NY) and at Observatorio Astronómico de La Plata, Argentina. The researchers did an exhaustive search of all possible dates from 1250 to 1115 BC of astronomical events that match dates within the text of the Odyssey, and came up with a single date that matched all text references, namely April 16, 1178 BCE. They think that the disputed reference to an eclipse is confirmed by their studies, and that a total solar eclipse was actually reported in the Odyssey. (Proceeding National Academy Sciences USA 2008; 105: 8823-8828)
Adult body mass depends on childhood
Does the body mass index of a child affect that of an adult? That question was posed by Hilkka Ylihärsilä and associates at the National Public Health Institute and the University of Helsinki, Finland, and, the University of Southhampton, UK. They wanted to know if a change in body mass during childhood was related to adult lean and fat mass. They report that a rapid gain in body mass index before two years of age increased adult lean body mass without excess fat accumulation. However, a rapid gain in body mass index in later childhood (two to eleven years of age) resulted in not only a rise in lean mass but a relatively larger increase in fat mass in adult men and women 56-70 years old. (American Journal Clinical Nutrition 2008; 87(6): 1769-1775)
Velocity of ice depends on thickness and slope
It has been reported that interaction between meltwater production and ice velocity leads to more rapid and stronger response of the Greenland ice sheet to climate warming than assumed earlier. Results by R.S.W. Van de Wal and associates at Utrecht University, Netherlands, do not fully support this view. They report that the yearly loss of water was not correlated with the yearly speed of ice movement in the Greenland ice sheet. They found that melting of surface ice that led to draining of water to the interior of the ice sheet was attributable to climate warming, which is noticeable in short time spans. However, in the last seventeen years the ice velocities actually decreased slightly and the authors conclude that thickness of the ice sheet and the slope of the land surface have more to do with velocity than melting of the ice sheet. Moreover, they say that melt rate and ice velocity may have only a limited effect on the response of the Greenland ice sheet to climate warming over the next decades. (Science 2008;321(5885): 111-113)
Green beads signal dawn of agriculture
One trait of modern human behavior is the use of beads as personal ornaments. Early beads (Middle and Upper Paleolithic periods) were made from bone, ivory, shells, and sometimes minerals. These beads were mostly white, yellow, red, brown, or black. In the Near East, during the start of agriculture, green stone was used for the first time to make beads and pendants report Daniella Bar-Yosef Mayer at the University of Haifa, Israel, and Harvard University, and Naomi Porat at the Geological Survey of Israel, Jerusalem. In fact, they report use of a variety of minerals that were green such as apatite, certain copper-bearing minerals, amazonite, and serpentinite. The authors suggest that the appearance of green beads was related to the onset of agriculture because green beads were thought to serve as fertility charms and to ward off the evil eye. (Proceedings National Academy of Sciences USA 2008; 105 (25): 8548-8551)
Asteroid hit America long ago
A large asteroid struck what is now the Delmarva Peninsula, east of Chesapeake Bay (an estuary surrounded by Maryland and Virginia), 35.4 million years ago, creating a crater nearly 90 kilometers (56 miles) wide. This crater was subsequently buried under rock debris and seawater, and now studied only by drilling cores into the crater. Salty water is still trapped in sedimentary rock following the asteroid impact and was never flushed out after the impact. This is reported by G. S. Gohn and associates at the US Geological Survey (Virginia), University of Vienna (Austria), Rutgers University (New Jersey), Humboldt-University (Germany), and Open University (UK). They also report that in the deepest part of the crater the trapped water contains abundant microbes, and this water poses a potential threat to the regional groundwater resource. (Science 2000; 320(5884): 1740-1745)
Explosive vulcanism in Arctic Ocean
About 60% of the Earth's outer surface consists of oceanic crust formed by vulcanic processes at mid-ocean ridges. While explosive vulcanism on land is not unusual, explosive vulcanism in oceans was not thought to occur below 3 kilometers (9842 feet) because of the great water pressure. However, evidence of explosive vulcanism was found for the first time in the ice-covered Arctic Ocean at 4 kilometers (13,123 feet) below sea level. This find is reported by Robert Sohn of the Woods Hole Oceanographic Institution (Massachusetts) and a team of twenty other investigators at eight institutions in Germany, Japan, Sweden, and the USA. The location is the Gakkel Ridge (see line center of photo) in the Arctic Basin at 85 E. This investigation was part of the International Polar Year expedition to Gakkel Ridge. (Nature 2008; 453: 1236-1238)
A new family of geckos found
Geckos have been found on nearly every continent and are of interest because of their sticky toe pads (medicine and industrial applications) and because they are key biodiversity indicators in nature. By sequencing the DNA from forty-four known species of gecko, a new family tree was constructed by Tony Gamble at the University of Minnesota and associates at Villanova University, Pennsylvania. In their reclassification, they discovered a new family or clade Phyllodactylidae, which comprises 103 species found in semiarid and tropical regions of North Africa, the Middle East, North and South America, and the Caribbean. (Zoologica Scripta 2008; 37(4): 355-366)
Fortifying lettuce with iodine
Iodine is reported to be a trace element essential for mammals. A deficiency of iodine can account for certain conditions such as goiter, reproductive failure, mental retardation, and brain damage. About 30% of the world's population is affected by iodine deficiency. One way to remedy this situation is to add iodine to substrates of growing plants. Iodine was shown to accumulate in lettuce leaves when iodine was added to hydroponic solutions in which lettuce was grown report B. Blasco and associates at the University of Granada, Spain. Another benefit reported from the application of iodine was an increase in antioxidant compounds in the lettuce. (Annals of Applied Biology 2008; 152(3): 289-299)
Migration of insects using sun, wind, or magnetism
Migration among insects takes them from one location to a more favorable location. During migration, reproduction and feeding are temporarily suppressed. What guides insects in migration has been an intriguing question. For the monarch butterfly (Danaus plexippus), for example, the only orientation mechanism verified so far is a sun compass. Earlier evidence of monarchs using magnetic cues or polarized light for navigation has been discounted. Small insects such as aphids are subject to the vagaries of wind. The silver Y moth (Autographa gamma - photo) has a sophisticated system of compass navigation that is magnetically based and the moth will not migrate if the wind direction is not consistent with magnetic forces. Evidence for a magnetic sense has been reported also for flies, beetles, ants, bees, and termites. These conclusions were reached in a report by Ring Cardé at the University of California, Riverside. (Current Biology 2008; 18: R472-R474)
Frog uses ultrasonic calls to mate
Usually male frogs vocalize while the females are typically silent, or in a few species females emit feeble calls or rapping sounds during courtship. However, the female, concave-eared torrent frog (Odorrana tormota) attracts males with ultrasonic calls report Jun-Xian Shen and associates at the Chinese Academy of Sciences (Beijing and Shanghai), University of Illinois, and University of California (Los Angeles). These frogs live along streams in central China (Huangshan Hot Springs) and the noise of waterfalls and rushing water may have led to evolution of ear structure with well-developed ultrasonic communication capacity, according to the authors. The accuracy of the sound is remarkable in that the male can jump towards the sound with accuracy greater than 99%. The authors note that this degree of accuracy rivals that of vertebrates noted for the greatest location accuracy such as barn owls, dolphins, elephants, and humans. (Nature 2008; 453:914-916)
Rapid uplift of the Andes
The surface uplift of mountain belts is generally described as a gradual rise in elevation. Studies of the Andes mountains show that their elevation was stable for tens of millions of years. However, about eight million years ago the central Andean plateau sprang upwards by 1.5 kilometers (4,921 feet) or more in one to four million years, which is fast by geological time. This is reported by Carmala Garzione and associates at the University of Rochester (NY), Michigan State University, University of Florida, California Institute of Technology, Indian Institute of Science (India), and Universität Hannover (Gemany). Their explanation is that the mantle lithosphere suddenly fell away to lessen the mantle weight and gave rise to a lighter crust to bring about the uplift. They used data on isotopes to arrive at these conclusions. (Science 2008; 320(5881): 1304-1307)
St. John's wort ineffective for ADHD
Attention-deficit/hyperactivity disorder (ADHD) affects 3% - 12% of children in the United States. Up to 30% of these children do not respond to pharmaceutical medication so other treatments have been sought. Extracts of St. John's wort (Hypericum perforatum) have been reported to be effective for treatment of depression with mixed results. Moreover, this plant was thought to act as a norepinephrine reuptake inhibitor (present in atomoxetine). Due to these reasons, St. John's wort was tried as a treatment of ADHD. In an eight-week study with 54 children (6-17 years old), there proved to be no benefit from St. John's wort for treatment of ADHD report Wendy Weber and associates at Bastyr University, Kenmore, Washington. (Journal American Medical Association 2008; 299(22): 2633-2641)
Resveratrol retards aging in mice
High doses of resveratrol, a natural constituent of red grapes, red wine, pomegranates, and other foods, have been shown to extend the life span in some invertebrates and prevent early mortality in mice fed a high-fat diet. New studies were aimed at finding the effects of low doses of resveratrol and it was found that resveratrol, at doses readily achievable for humans, can partially mimic calorie restriction and retard aging factors in mice. This is reported by Jamie Barger and associates at LifeGen Technologies (Wisconsin), University of Wisconsin, University of Michigan, University of Alabama, DSM Nutritional Products Ltd. (Switzerland), Vanderbilt University, and University of Florida. The dosages achieved to be effective fulfill the definition of a dietary compound that mimics some aspects of calorie-restricted diets according to the authors. They also conclude that these new findings are associated with the prevention of decline in heart function associated with aging. (PLoS One 2008; 3(6): e2264)
Large earthquakes trigger others
At least twelve of fifteen major earthquakes stronger than magnitude 7.0 that occurred since 1990 have triggered small earthquakes hundreds and thousands of miles away, even on opposite sides of Earth. This is reported by Aaron Velasco and associates at the University of Texas, US Geological Survey (California), and University of Utah Seismograph Stations. The earthquake in Sumatra in 2006, for example, triggered a quake in Ecuador. Some of these small earthquakes triggered by the major one were in locations not normally prone to earthquakes. Data were collected from more than 500 seismograph (photo) stations around the world. Both Love waves, involved in shearing, and Rayleigh waves, involved in volumetric movement of particles, were detected in this long range effect. (Nature Geoscience 2008: 1: 375-379).
Fish scales reveal fate of Atlantic salmon
Atlantic salmon typically spend one to five years in freshwater rivers before swimming into the ocean. After they enter the ocean they undergo a period of rapid growth called smolting. To study fish growth, scales (photo) are collected and analyzed in the same way as analyzing growth rings in trees. Fish scales from 2,854 fish were examined for monthly growth rates after smolting and recorded by Jennifer McCarthy and associates at the University of Massachusettts, National Marine Fisheries Service (RI), and the Norwegian Institute for Nature Research (Oslo). They studied three maturity groups of salmon (Salmo salar) from the Drammen River in Norway. They reported a significant decline in growth during the fourth and fifth months, typically months of maximum growth. The fish grew well while in the river but grew poorly when at sea and only a few of these fish returned to the river to spawn. The authors believe this indicates that ocean conditions had changed to become unfavorable for growth and development of young salmon. This ocean change that affect young salmon, they say, could account for the decline in salmon populations in the North Atlantic. (Journal of Fish Biology 2008; 72(7): 1572-1588)
Habitat disturbance affects turtle growth
Habitat disturbances can affect both growth and reproduction in animals. Catastrophic storms and removal of non-native vegetation were examined for their effects on the long-lived turtle Terrepene carolina bauri. The disturbances affected the sexes differently. Adult male growth rates increased by 19% after the disturbances whereas female growth rates decreased by a similar amount report. This is reported by C. Kenneth Dodd of the University of Florida and Michael Dreslik at the Illinois Natural History Survey. The authors think that after a disturbance the females divert resources from growth to reproduction while the males allocate available resources to growth. The timing of maturation is thereby affected and helps to explain why turtle populations recover slowly following catastrophic disturbances even though adult survivability is high. (Journal of Zoology 2008; 275(1): 18-25)
Fungi transform uranium to phosphate
The testing of depleted uranium ammunition and its use in Iraq and the Balkans has lead to dispersion of unstable depleted uranium metal into the environment. Although the depleted uranium is less radioactive it is still toxic and poses a threat to human populations. Fungi are reported to be one of the most active components of microorganisms in soil in interacting with chemical or geological compounds there, especially fungi that grow in the plant-root zone. Free-living and plant symbiotic fungi can colonize depleted uranium surfaces and transform metallic depleted uranium to uranyl phosphate minerals. This is reported by Marina Fomina and associates at University of Dundee, Synchrotron Radiation Source Daresbury Laboratory, Macaulay Institute, and University of Manchester, all in the UK. The fungi have the ability to retain these phosphates for a long time and thereby tie up the uranium compounds. Uranyl phosphate minerals are still mildly radioactive and human exposure should be limited. (Current Biology 2008; 18:R375-R377)
Megaflood as the cause of Box Canyon
Seepage erosion over centuries was said to have created canyons that had an amphitheater as a head. Some of these types of canyons seen in western United States have also been observed on Mars. Box Canyon, Idaho, meets the requirements in shape and form for sapping by groundwater because it is cut into a basaltic plain with no drainage network upstream report Michael Lamb and associates at the University of California, Berkeley. They also report that about ten cubic meters (353 cubic feet) per second of water seeps from the vertical headwall; however, by analyzing the sediments and the scoured rock, the authors calculated that a megaflood greater than 220 cubic meters (7769 cubic feet) of water per second carved that canyon 45,000 years ago. They conclude that these results add to the growing recognition of catastrophic flooding in the American northwest in the formation of canyons rather than the result of seepage erosion, and that this may apply also to the formation of canyons observed on Mars. (Science 2008; 320(5879): 1067-1070)
Bats used in reforestation
In neotropical regions where forests had been cleared for agriculture and then abandoned for agricultural uses, reforestation sometimes fails to occur naturally. In an effort to foster reforestation, fruit-eating bats were induced to roost in the reforested areas. A pasture-forested area was selected in Costa Rica and artificial bat roosts were placed there by Detlev Kelm and associates at the Leibniz Institute for Zoo and Wildlife Research and the University of Erlangen-Nuremberg, Germany. Within weeks of roost installation, ten species of bats occupied the artificial roosts and five species did so permanently in numbers like those of natural roosts. Moreover, sixty-nine different seed types, mostly of early successional plant species, were transported by bats to the artificial roosts in the disturbed habitats. The authors report that this method of placing artificial roosts attracted bats who in turn reintroduced plant species important to forest regeneration and bat conservation. (Conservation Biology 2008; 25-Apr-2008, doi: 10.1111/j.1523-1739.2008.00925.x)
Bird flu virus transmitted to dogs
In South Korea, avian influenza virus types H3N2, H6N1, H6N1, and H9N2 occur. Moreover, three genetically similar canine flu viruses were isolated from dogs with symptoms of severe respiratory disease. This is reported by Daeaub Song and associates at the Green Cross Veterinary Products, Ltd., Dongwoong Pharmaceutical Co., Ltd., Animal Genetics, Inc., and Seoul National University, South Korea. They showed that there can be direct transmission of avian influenza virus H3N2 directly from poultry to dogs, and that dogs may aid in the transmission among species and further the spread of the influenza virus. (Emerging Infectious Diseases 2008; 14(5): May).
Hunger reduction by salatrim
Salatrim is a modified tricylglycerol that is used as a lower-calorie fat replacement for humans. Traditional fat meals and a mixture of traditional fat with salatrim were fed to twenty-two healthy, normal-weight young men in experiments done by Lone Sorensen and associates at the University of Copenhagen, Denmark. They reported that a salatrim meal increased a sense of fullness and decreased hunger more than the traditional fat meal, and they concluded that salatrim had a modestly suppressive effect on appetite compared to traditional fat. (American Journal of Clinical Nutrition 2008; 87(8): 1163-1169)
Early settlers in South America
The lack of artifacts of early people in southern Chile has raised questions of the origin of early settlers in that area. The remains of nine species of marine algae have been recovered from the hearths and other features of a site of Monte Verde in southern Chile, reports Tom Dillehay and associates at Vanderbilt University (TN), Universidad Austral de Chile and FORECOS (Chile), University of Texas, and Ithaca College (NY). The site was carbon dated to be 14,200 to 13,980 years old. The authors conclude that inhabitants of this area in Chile used seaweed from distant beaches and estuarine environments for food and medicine and that seaweeds were important to the diet and health of early humans in the Americas. (Science 2008; 320(5877): 784-786)
Origin of the Magellanic Stream
The Magellanic Clouds were discovered in the Southern Hemisphere and reported by Magellan in about 1519. Behind the Clouds of Magellan are several galaxies. Two irregular galaxies closest to the Milky Way (the galaxy in which Earth is located) are the Large Magellanic Cloud and the Small Magellanic Cloud. An unusual stream of gas lies behind the Magellanic Clouds and are of interest because they may yield clues to the origin and fate of the satellite galaxies such as the large and small Magellanic Clouds. At least half of the trailing Stream and most of the Leading Arm originates in the Large Magellanic Cloud. This is reported by David Nidever and associates at the University of Virginia; Sterrewacht Leiden, Netherlands; and National Radio Astronomy Observatory, Virginia. In contrast, it was reported previously that both the Magellanic Stream and its Leading Arm originated in the Small Magellanic Cloud or in the Magellanic Bridge. Blowout of gas from the Large Magellanic Cloud probably plays a role in creating the Magellanic Stream and the Leading Arm, according to the authors. (The Astrophysical Journal 2008; 679(1): 432-459)
Climate effect on grasses and butterflies
Browns, satyrs, and wood nymphs are butterflies in the tribe Satyrinae. About 2,200 species of Satyrinae occurr worldwide in this group and rely mainly on grasses as host plants. The diversification in population of these butterflies occurred simultaneously with the rapid expansion of grasses during the marked cooling and drying of Earth in the Oligocene report Carlos Peña at Stockholm University, Sweden, and Niklas Wahlberg at the University of Turku, Finland. The authors think that a change in global climate twenty-five million years ago brought about the widespread expansion of grasses which in turn triggered the great divergence in species of these butterflies dependent on grasses. (Biology Letters 2008; 4(3): 274-278)
Genetic code of the platypus
The platypus (Ornithorhynchus anatinus), native to Australia and New Zealand, is a strange animal that seems to be part bird, part reptile, and part lactating mammal. Males produce venom similar to that produced by reptiles. This animal has a coat of fur adapted for a water lifestyle and the females lactate yet lay eggs. The platypus is classified as a mammal because it produces milk and is covered with fur. The female has no teats but nurse young through the skin on her abdomen. The platypus has about 18,500 genes as reported by a team of scientists from thirty-one institutions in nine countries (Australia, France, Germany, Israel, Japan, New Zealand, Spain, United Kingdom, and United States). Sequencing of this genome is valuable in enabling scientists to learn how mammals evolved and for the biology and conservation of monotremes. (Nature 2008; 453: 175-183)
Hydrogen clouds near our galaxy
Five previously unknown neutral hydrogen clouds were discovered in the M81/M82 group of galaxies report Katie Chynoweth and associates at Vanderbilt University, National Radio Astronomy Observatory (WV), and University of Massachusetts. The M81 group of galaxies is one of the nearest to our "Local Group" of galaxies and is paired with the M82 group. The Local Group of Galaxies comprises more than thirty galaxies, including the Milky Way (our galaxy) and Andromeda galaxy, and is more than 10 million light years in diameter. Observations were made by using the Robert C. Byrd Green Bank Telescope. The authors conclude that the clouds are mostly likely relics of ongoing interactions between galaxies in the group. (The Astronomical Journal 2008; 135: 1983-1992)
Nanobacteria or nanoparticles cause disease
Nanobacteria were first reported by Robert Folk at Texas A&M in the 1990s. They were seemingly smaller than DNA and in fact contained no DNA. Hence, they were disregarded as forms of life. On the other hand, some claimed to have grown them in culture, creating a controversy as to whether they are life forms or not. Recently, renal stone formation, cardiovascular disease, and cancer have been attributed to nanobacteria. Some scientists maintain that nanobacteria are alive and are associated with disease development. The controversy continues as Jan Martel and John Ding-E Young at Chang Gung University in Taiwan, and at Rockefeller University in New York reported that precipitates of calcium carbonate in human blood are remarkably similar to the so-called nanobacteria in size, shape, and cellular division-like formations and appearance as colony forms. Moreover, certain techniques show that monoclonal antibodies claimed to be specific for nanobacteria did react with serum albumin. They did not find DNA by any of the usual techniques. Thus it is not clear yet whether these structures are in fact nanobacteria or nanoparticles that can infect humans and still have these unusual properties. (Proceedings National Academy of Sciences USA 2008; 105(14): 5549-5554)
Polarization in the Northern Lights
Unexpectedly, astronomers observed what seems to be a polarization of emission lines in the spectacle of the Northern Lights report Jean Lilensten and associates at CNRS-UJF (Grenoble, France), University of Oslo, ESTEC (Noordwijk, Netherlands), University Centre in Svalbard (Norway), and CNRS-INPG (St Martin, France). They regard the polarization of emission lines in the Northern Lights as a noteworthy observational measurement in astronomy, in that it has never been detected for certainty in planetary upper atmospheres. This was noted first in January 2007 at Svalbard (Spitsbergen), Norway. Because of the many collisions in the atmosphere, scientists thought that the process could not lead to polarization, that is, the electromagnetic waves could not be aligned in the same direction. These observations and measurements, they conclude, enable better understanding of geophysics and planetary science and create new perspectives for future space missions to other planets. (Geophysical Research Letters 2008; 35: L08804)
Sunflower in Mexico before Columbus
Mexico is the origin of many domesticated crops such as beans, corn, cotton, pepper, and squash. Now sunflower can be added to that list based on archaeological, linguistic, ethnographic, and ethnohistoric data report David Lentz and associates at the University of Cincinnati; Florida State University; Instituto de Antropologia e Historia and Universidad Nacional Autónoma de Mexico, Mexico. Sunflower (Helianthus annosus) was domesticated in Mexico by about 2600 BC, was cultivated widely by the first millenium BC, and was well known to the Aztecs. The researchers also note that association of sunflower with the solar religion of indigenous peoples as well as warfare in Mexico may have led to its suppression after the Spanish conquest. (Proceedings National Academy of Sciences USA 2008; 105(17): 6232-6237)
Stratosphere HCl decreased since 2004
The peak in stratospheric hydrochloric acid (HCl) was reached in the late 1960s. Then the amount of HCl remained relatively constant between 1998 and 2004 with some month-to-month fluctuation. But since 2004, there has been a pronounced decrease in HCl report D. J. Lary and O. Aulov at the University of Maryland and the NASA Goddard Space Flight Center, Maryland. HCl is the most abundant form of chlorine in the stratosphere and is produced by reaction of chlorine with methane. Chlorine destroys ozone. Ozone in the stratosphere is beneficial (good ozone) in that it protects life on Earth from harmful ultraviolet rays from the sun, but ozone in the troposphere (lower part of atmosphere) is considered to be a greenhouse gas and a pollutant (bad ozone). Ninety per cent of the ozone in the atmosphere is in the stratosphere. (Journal of Geophysical Research 2008; 113: D15S04)
Glacial lakes cooled ocean
The most abrupt, widespread climate instability of the last 10,000 years took place 8200 years ago. In only a few years the average temperature dropped to a deep freeze that lasted a century or more until the fresh and salt water was back in balance. This instability was attributed to the release of fresh, cold water into the North Atlantic Ocean from the draining of glacial Lakes Agassiz and Ojibway out the Hudson Strait that disrupted ocean circulation. The volume of water released from these lakes is uncertain; a clue to learning that volume could be records of sea level changes before and after that time, if known. The place to look for evidence of changing sea levels is not sites near the exit of glacial waters into the Atlantic but the east coast of South America and the west coast of Africa report Roblyn Kendall and associates at the University of Toronto, Canada; University of Durham, UK; and Tulane University, Louisiana. Large glacial adjustment signals in response to the Late Pleistocene deglaciation were found at these two locations and serve as sites for further research, they report. (Geology 2008; 36(5): 423-426)
Cochlear shape affects low-frequency hearing
The cochlea is a spiral cavity of the inner ear shaped like a snail shell. It has been thought that the coiled cochlea evolved to conserve space inside the skull. Cochlear coiling is absent in reptiles, birds, and monotreme animals. New research shows that curvature of the spiral is a feature that correlates with low frequency hearing report Daphne Manoussaki and associates at Vanderbilt University; Technical University of Crete, Greece; National Institutes of Health, Bethesda, MD; Harvard Medical School; Woods Hole Oceanographic Institution, MA; and Massachusetts Ear and Eye Infirmary, Boston. The cochlear spiral shape redistributes wave energy toward the outer wall, especially along the innermost, tightest spiral turn, and thereby enhances sensitivity to lower frequency sounds. (Proceedings National Academy of Sciences USA 2008; 105(16): 6162-6166)
Mercury travels from water to songbirds
Mercury has contaminated rivers worldwide and affects health of aquatic organisms as well as the humans who eat them. Spiders inhabiting the waters of a river in Virginia were consumed by songbirds; the spiders not only contained mercury but it became more concentrated in the spider's body report Daniel Cristol and associates at the College of William and Mary, Virginia. Thus, they say, contaminated rivers pose a threat to predatory invertebrates that feed on aquatic habitats. (Science 2008; 329(5874): 335)
Cellulose in salt 253 million years old
Cellulose was found in fluid inclusions of halite (NaCl) and in crystalline salt in an underground nuclear dump in New Mexico that dates back 253 million years. This is reported by Jack Griffin and associates at the University of North Carolina, University of Mississippi, US Department of Energy (New Mexico), and Westminster College (Utah). These deposits were found 650 meters (0.4 mile) below the surface originating in the Late Permian Salado Formation in southeastern New Mexico. The cellulose was in the form of five nanometer microfibers as well as in composite ropes and mats. Such cellulose microfibers represent the oldest native macromolecules to have ever been isolated. It points to cellulose as a target in the search for life on other planets. (Astrobiology 2008; 8(2): 215-228).
Plants use color to lure insects
Carnivorous plants such as the pitcher plant use color as a signal to lure insects and thereby enhance their capture rates report H. Martin Schaefer of the University of Freiburg, Germany, and Graeme Ruxton at the University of Glasgow, UK. Pitcher plants were artificially colored red and green; the red pitchers captured more flying insects. It was previously thought that pitcher plants used contrasting green and red stripes to attract insects. This is useful in making insect traps in that the color needs only to be different from the background, and that contrasting colors are not essential. (Biology Letters 2008; 4(2): 153-155)
Jet streams are moving poleward
Jet streams are known to be driving factors for weather in mid-latitudes. In a study of historical trends, the jet streams have risen in altitude and moved poleward in both hemispheres from 1979 to 2001 report Cristina Archer and Ken Caldeira at the Carnegie Institution of Washington (Stanford, California). In the northern hemisphere the jet stream has weakened. In the southern hemisphere, the subtropical jet has weakened but the polar jet has strengthened. It is possible to attribute these trends in the movement of the jet stream to human activities, but the authors caution that more observations are needed to assert this with any confidence. Natural variability alone or in combination with human activity needs study before they would draw such conclusions. (Geophysical Research Letters 2008; 35:L08803)
Migrating moths use compass at night
Migrating insects often use wind at high altitudes when flying at night but can thereby be at the mercy of wind. But nocturnal moths have complex behavioral patterns that guide their migratory flight in favorable directions report Jason Chapman and associates at Rothamsted Research, University of Greenwich, and University of York, UK; and University of Oldenburg, Germany. They worked with the noctuid moth Autographa gamma that fly generally in the direction of wind but they compensate for cross-wind drift to get to their destination by using a compass and an inherited preferred direction to optimize their migratory track. (Current Biology 2008; 18:514-518)
Fate of new lakes in the Sahara
Precipitation in the Ethiopian highlands was unusually high in 1996 and caused an overflow of Lake Nasser. The spilled water formed five new lakes in the Sahara in southern Egypt. The lakes persisted because they were underlain with shale and chalk and the lake levels remained steady from August 2001 to August 2003 mainly because the loss from evaporation was equalized by continuous water from Lake Nasser. However, from August 2003 to April 2007, the water supply from Lake Nasser stopped completely and evaporation started to reduce lake levels. If this trend continues it is projected that these new lakes will disappear by March 2011. This was reported by Mohamed Abdelsalam and associates at the Missouri University of Science and Technology, USA; Sohag University, Egypt; University of Texas, Dallas; and National Authority for Remote Sensing and Space Sciences, Cairo, Egypt. (Geosphere 2008; 4(2): 375-386)
Long-distance carriers for flu virus
Wild ducks have been blamed for increased outbreaks of the avian influenza virus (H5N1) across Asia, the Middle East, and Africa. If so, it would require that wild birds would have had to excrete virus without themselves becoming sick. Of six wild ducks tested, mallards and tufted ducks excreted more virus than did common teals, Eurasian widgeons, and gadwalls report Juthatip Keawcharoen and associates at the Erasmus Medical Center, Rotterdam, Netherlands. The mallard was the prime candidate for long-distance spread for this avian influenza virus HPAIV (H5N1) because it was the only one to excrete abundant amounts of the virus without becoming diseased. (Emerging Infectious Diseases 2008; 14(4): April)
Earliest worked gold in Americas found
Some have thought that hereditary elites and the capacity of a society to create significant agricultural surpluses were required before metal working traditions could emerge. This apparently was disproved by the discovery of a necklace made of gold and turquoise near Lake Titicaca in Peru made almost 4,000 years ago at a time when people were still hunter-gatherers. This was reported by Mark Aldenderfer and associates at the University of Arizona, Pennsylvania State University, University of California (Santa Barbara), and University of Missouri. The researchers note that this supports the hypothesis that the earliest metalworking in the Andes was working with native gold. (Proceedings National Academy of Sciences USA, 2008; 105(13): 5002-5005)
Soil bacteria can subsist on antibiotics
Antibiotics have been used successfully in medicine to control infections caused by bacteria. In nature, microorganisms produce antibiotics and play an ecological role in their survival. For example, the fungus Penicillium notatum produces penicillin that inhibits growth of bacteria. However, hundreds of soil bacteria were isolated that could grow on antibiotics as a sole source of carbon report Gautam Dantas and associates at Harvard University. Of eighteen antibiotics tested, thirteen to seventeen of them supported growth of bacteria from eleven different soils. Many of these bacteria were close relatives of those causing diseases in humans and livestock. The researchers conclude that this illustrates that soil exists as a reservoir of resistant genes to possibly render current antibiotics ineffective. (Science 2008; 320(5872): 100-103)
Acetylene as a fast food in early Earth
Acetylene, formed by the decomposition of methane in light, occurs in the atmospheres of Titan and giant planets like Jupiter. However, acetylene is found in only trace amounts of Earth's atmosphere. Nevertheless, a methane-rich atmosphere has been thought to be characteristic of early Earth, and, if so, it would also have been rich in acetylene. Because acetylene is known to inhibit chemical processes in microorganisms where oxygen is lacking, its role in growth and development of organisms is puzzling. One bacterium (Pelobacter acetylenicus) was reported to grow on acetylene because it produces the enzyme acetylene hydratase, and in that way produces acetaldehyde. Ronald Oremland and Mary Voytek at the US Geological Survey in California and Virginia, think this finding of acetylene may be involved in the development of life in early Earth and perhaps in the outer solar system. (Astrobiology 2008; 8(1): 45-58)
Ants choose seeds by their odor
Of all the invertebrates, only ants have a major role in seed dispersal. Moreover, thousands of plant species produce seeds specialized for dispersal by ants. A specific example is in the Amazonian rain forest where tree ants collect seeds of several epiphyte species and cultivate them in nutrient-rich nests in hanging gardens known as ant gardens. However, the way that ants locate, recognize, and accept only certain seeds while rejecting other seeds is not known. It was learned that workers of the ant-garden ants (Camponotus femoratus) were attracted to seeds of the ant-garden plant Peperomia macrostachya because of seed odor report Elsa Youngsteadt and associates at North Carolina State University and the Technische Universität Braunschweig (Germany). They identified five compounds emitted from the seeds that as a blend attract worker ants. The authors conclude that this illustrates a chemical basis for this ant-plant interaction. (Proceedings National Academy of Sciences USA 2008; 105(12): 4571-4575)
Methane detected in distant planet
The organic gas methane was detected in a planet the size of Jupiter that has an orbit beyond our solar system report Mark Swain and associates at the California Institute of Technology and University College London (UK). The methane was detected by the Hubble Space Telescope. This is the same planet (HD 189733b) where water was reported to be present a year ago. This planet orbits a star that is 63 light years away in the constellation Vulpecula, but it has atmospheric temperatures close to 1800 degrees Fahrenheit, making it uninhabitable for life as we know it. (Nature 2008; 452:329-331)
Wren incubation longer in tropics
Incubation period of birds of the same species are often longer in tropical than in temperate regions. The reasons for this are not known. House wrens were selected for study because their geographic range includes tropical equatorial and temperate high latitudes and they have incubation periods averaging one to two days longer at tropical latitudes. This is reported by Douglas Robinson and associates at Oregon State University, Auburn University, Illinois Wesleyan University, and Illinois State University. The researchers incubated eggs of house wrens in Illinois and in Panama under identical conditions in mechanical incubators. They found that the tropical house wren still required 1.33 days longer, on average, to hatch. The authors concluded that parental attendance patterns did not account for latitudinal differences but that there is some yet unmeasured factor intrinsic to the egg or embryo, or both, that extends the development time in the tropics. (American Naturalist 2008; 171(4): 532-535)
The age of the Grand Canyon
The age and development of the Grand Canyon has aroused curiosity since its discovery. Victor Polyak and associates at the University of New Mexico used uranium and lead dating evidence in water table-type structures formed by deposition of minerals from water in caves such as a stalactite (speleothems). They report the Grand Canyon evolved by headward erosion from west to east about 3.7 million years ago report. (Science 2008; 319(5868): 1377-1380)
Self-cleaning fabrics developed
Nanocrystals of titanium oxide are bonded to keratin protein in wool and silk fibers which in the presence of sunlight break down dirt molecules, stains, and microorganisms, including odor-causing bacteria. This is reported by Walid Daoud and associates at Monash University, Australia, and Hong Kong Polytechic University. Thus clothing made from wool or silk can be cleaned without washing them and be hung out on clothes lines exposed to sunlight, or they can even be cleaned while being worn—any light will work. Such treatment is valuable for clothing worn by soldiers or campers. It also reduces the demand for water, detergents, and energy used in laundering and dry cleaning. As an example, researchers poured red wine on coated fabric and after twenty hours of exposure to sunlight, the stain was nearly invisible. The coating is not toxic. Keratins are a type of natural protein. It is estimated to be several years before self-cleaning clothes will be on the market. (Chemistry of Materials 2008; 20(4): 1242-1244)
Climate change delays mushroom fruiting
Many species of fungi produce fruiting bodies (mushrooms) in fall. The time of appearance was studied in Norway from 1940 to 2006 from herbarium records. The time of mushroom formation (fruiting) on average was delayed 12.9 days since 1980 report Håvard Kauserud and associates at the University of Oslo, Norway. Moreover, early fruiting species had a stronger delay than late fruiters to compress the season for mushroom harvest. In addition, there was a trend for earlier fruiting in the northern and more continental parts of Norway than in the southern and oceanic parts. This delay in time of fruiting coincided with the increase in temperature and precipitation during fall and winter for the same year and the subsequent year. The extension of the growing season was attributed to global climate change. The authors think that this trend to delayed fruiting will continue as climate become warmer over time. (Proceedings National Academy Sciences USA 2008; 105(10): 3811-3814).
Giant frog fossil found in Madagascar
Fossils of a giant frog found in Madagascar date back to the late Cretaceous, about 70 million years ago among the dinosaurs, report Susan Evans and associates at University College London (UK) and Stony Brook University (NY). This frog has teeth and thick armor, was estimated to weigh ten pounds, and was sixteen inches long. This compares to the largest living frog known (Goliath) of West Africa which weighs seven pounds. This giant frog is unrelated to other frogs in Madagascar or Africa but is related to horned frogs found today in South America. (Proceedings National Academy Sciences USA 2008; 105(8): 2951-2956).
Nanowires a power source in fabrics
When zinc nanowires are wound around kevlar textile fibers, the wires rub against each other to generate an electric charge that can be directed to a cathode output report Yong Qin and associates at the Georgia Institute of Technology, Atlanta. People wearing clothing made with these fibers can produce electrical energy by body movement as wires brush against each other. The authors continue that this is a simple, low-cost approach to convert vibration and friction energy into electricity using piezoelectric zinc oxide nanowires around textile fibers. Mechanical energy is converted to electrical energy. This project was developed for use by the military where other electric sources are impractical, but it has endless applications in civilian life to power small, electrical devices. (Nature 2008; 451:809-813)
Parasite induces fruit mimicry in ant
Nematodes (e.g. eelworms, threadworms) are parasitic on a tropical canopy ant and change ant appearance to resemble ripe fruits in the tropical rain forest canopy. This is reported by Steve Yanowick and associates at the Florida Medical Entomology Laboratory, University of Oklahoma, Smithsonian Tropical Research Institute (Panama), University of California (Berkeley), and Oregon State University. Healthy ants are black, but infected ants have bright red, berry-like parts of the posterior abdomen (gaster) that are full of parasite eggs (see photo). These infected gasters are held in a conspicuous, elevated position as the ants are walking and are easily detached from live ants. Infected ants are attractive to fruit-eating birds who eat the red gasters and pass on the parasitic eggs in their droppings. The droppings are collected by ants and fed to the developing ant brood to thereby complete the life cycle. The authors state that this is the first documentation of parasites causing fruit mimicry in an animal host to complete their life cycle. (The American Naturalist 2008; 171(4): 536-544)
Human hair analysis reveals geographical origin
The geographical region of origin for humans can be determined by the chemical composition of scalp hair report James Ehleringer and associates at Isoforensics, Inc., Utah; University of Utah; Purdue University; and University of California, Berkeley. They do this by determining the ratios of hydrogen and oxygen isotopes in scalp hair, which differs with geography. The drinking water in different regions of the forty-eight states have different isotopic ratios of hydrogen to oxygen. By comparing ratios in hair to the drinking water of the location, forensic scientists can determine the region-of-origin for unidentified human remains. (Proceedings National Academy of Sciences USA 2008; 105(8): 2788-2793)
Carbon dioxide linked to air pollution mortality
Increased water vapor and temperatures from greater carbon dioxide concentrations increase ozone concentrations where ozone is already concentrated. Thus, global warming may exacerbate ozone the most in already-polluted areas according to Mark Jacobson at Stanford University, California. He developed a model to show that carbon dioxide may increase annual air pollution deaths in the United States by about a thousand, and cancers by 20-30 per thousand rise in carbon dioxide-induced temperature. Furthermore, he reported that about 40% of the additional deaths may be due to ozone and the rest to particles that increase because of carbon dioxide-enhanced stability, humidity, and biogenic particle mass. He calculated that worldwide this could add up to 21,600 deaths from increase in carbon dioxide. (Geophysical Research Letters 2008; 35, LO3809, doi:10.1029/2007GL031101)