Science Briefs
Genome sequence of the horse
The genome of the domestic horse (Equus caballus) has been decoded by a team of fifty-seven investigators from thirty institutions (including the University of Minnesota) in ten countries working over ten years and led by Claire Wade at Broad Institute, MA. The DNA from a female Thoroughbred horse named Twilight (photo) revealed a genome of about 2.7 billion letters (nucleotides); this is slightly larger than the genome of a domestic dog and smaller than the genomes of the human or cow. More than ninety hereditary diseases that affect horses also affect humans. Moreover, 53% of the horse chromosome pairs consist of material like that in a single human chromosome whereas only 29% of dog chromosomes have this similarity. This means that there are fewer chromosome rearrangements that separate humans from horses than separate humans from dogs. The authors think that studies with DNA of horses will aid in study of human diseases. (Science 2009: 326(5954): 865-867)
Swiss Alps growth offset by erosion
The Alps originated from a collision in tectonic plates of Africa and Europe about 55 million years ago. The Alps have been growing taller over that time. According to Swiss geologists, the Alps have grown at about one millimeter (0.04 inches) a year which, over millions of years, would be substantial and even rival the height of the Himalaya Mountains. Actually, the height has not been increasing despite the growth. The answer is that erosion has kept pace with growth, report Jean-Daniel Champagnac and associates at Universität Hannover and GFZ, Germany, and University of Bern, Switzerland. As the mountains are eroded, they rise to about the same amount. (Tectonophysics 2009; 474(1-2): 236-249)
Migratory birds may breed twice a season
Migratory songbirds typically breed in temperate regions and then fly long distances to spend most of the annual cycle in tropical wintering areas. However, in a study of five neotropical migratory species, some birds in each group breed in the summer areas in United States and Canada, then in midsummer migrate to their wintering regions in Mexico and Baja California Sur and breed a second time in the same summer, report Sievert Rohmer and associates at the University of Washington, Seattle, and Environment Canada, Saskatoon. After the second breeding, birds migrate still further south to their final wintering homes. The authors also conclude that conservation plans must consider dual breeding for some birds. (Proceedings National Academy of Sciences USA 2009; 106(45): 19050-19055)
Starfish store water to keep cool
As water temperatures in oceans change with changing tides, sea creatures adapt by moving to other locations; a few adapt their bodies to the changed temperature. The intertidal sea star (Pisaster ochraceous) has a unique technique for controlling its body temperature report Sylvain Pincebourde and associates at the University of South Carolina and the University of California, Davis. At high tide, the sea star stays submerged and fills its body cavity between the intestinal wall and the body wall (coelom) with the cold water. When low tide appears with its warm water, the sea star (or starfish) is able to keep its body temperature cooler from the cold water stored in its coelom. This enables the sea star to survive periods of elevated water temperatures especially after prolonged periods of high temperatures of the atmosphere. (The American Naturalist 2009; 174(6): 890-897)
Carbon atmosphere found on neutron star
A neutron star with a carbon atmosphere in the supernova remnant Cassiopeia A (photo) has an ultra-thin coating calculated to be only about four inches thick because the surface gravity has compressed it—its gravity is 100 billion times stronger than on Earth—and its density is close to that of a diamond. This is reported by Wynn Ho at the University of South Hampton (UK), and Craig Heinke at the University of Alberta (Canada). The diameter of neutron stars is typically about fourteen miles. The authors estimate the age of this neutron star to be only several hundred years. This discovery was made using NASA's Chandra X-ray Observatory. (Nature 2009; 462: 71-73
Brain cell number is controlled by gene
As brains grow and develop there are two processes at work: one in which cells multiply to provide starting material (proliferation), and one in which cells become specialized for specific uses (differentiation). A single gene GSK-3 (glycogen synthase kinase 3) controls the signals that determine how many nerve cells (photo) actually make up the brain report Woo-Yang Kim and associates at the University of North Carolina, McMaster University (Canada), and University of Toronto (Canada). This finding helps in research on neuropsychiatric illness such as schizophrenia, depression, and bipolar disorder. (Nature Neuroscience 2008; 12: 1390-1397)
Spiders provide homes for lizards
The pygmy bluetongue lizard Tiliqua adelaidensis (photo) lives in burrows in the soil that are constructed by trapdoor and wolf spiders report H L. Fellows and associates at Flinders University, South Australia. The lizard does not build burrows or deepen existing burrows. Spiders dig shallow and deep burrows; the spiders prefer the shallow ones and the lizards prefer the deep ones. The lizards do not replace the spiders in the burrow; instead, the lizards occupy deep burrows left by spiders, so that lizards do not have a negative effect on spider populations. On the other hand, long-term conservation for the lizards must include maintaining spider populations to provide a supply of suitable burrow refuges, conclude the authors. (Journal of Zoology 2009; 279(2): 156-16)
Warm Antarctica 15.7 million years ago
During the middle Miocene, about 15.7 million years ago, land temperatures in Antarctica reached 10 °C (50 °F)—the January mean—and the estimated annual sea-surface temperatures ranged from 0 to 11.5 °C (32 to 52.7 °F). This was reported by Sophie Warny at Louisiana State University, and associates at the University of Nebraska; Victoria University of Wellington and CNS Science, New Zealand; Museum of Natural History, Germany; and Istituto Nazionale di Geofisica e Vulcanologia, Italy. With this temperature change there was also an input of fresh water that lowered the saltiness of sea water for a short period of sea-ice reduction. Their evidence is from the collection of fossils of marine algae and pollen from woody plants that revealed the higher temperatures needed for their growth. The algae and pollen were found in sedimentary rock cores drilled in spring of 2007 from the sea floor of McMurdo Sound (photo). (Geology 2009; 37(10): 955-958)
Plants may provide housing for ants
Many plant species in the tropics provide housing for ant colonies in special chambers called domatia (photo). Early on these domatia were considered to be galls, but not today. Most of these structures were thought to be created by interaction between the host and the ant (mutualism) and not as parasitism. However, new research may change that conclusion for some ants as they may, in fact, be parasites on their hosts. The ant Myrmelachista schumanni creates clearings in the Amazon rain forest as evidenced by swollen scars on trunks of trees and within these swellings are networks of cavities inhabited by these ants report David Edwards from the University of Leeds, UK. He worked with a team from the University of East Anglia, UK; Harvard University; University of Toronto, Canada; University of Sao Paulo, Brazil; and the Chinese Academy of Sciences. The authors think that their results support the conclusion that the ants are parasites and elicit galls to increase the amount of nesting space available for ant colonies. They also report that these galls weaken the trees and lead to breakage either from their own weight or from strong winds. (The American Naturalist 2009; 174: 734-740)
Chytrids a cause of frog decline
Chytrids are fungi that are widespread in soils and wet habitats, and have been found in rainforests and at high elevations. Some chytrids cause diseases of crop plants such as the potato. Now they have been found to cause death of frogs in mountainous rain forests of Queensland, Australia, and in Panama. This is reported by Lee Berger of James Cook University and CSIRO in Australia and a team of fourteen scientists representing more than a dozen institutions in Australia, Canada, UK, and USA. This is the first report that a skin infection by a chytrid is fatal to frogs and the authors think that this disease may account for the recent decline in amphibian populations. They studied both wild and captive frogs from additional locations in Australia and Central America. (Proceedings National Academy Sciences USA 2009; 95(15): 9031-9036) This chytrid has been identified as Batrachochytrium dendrobatidis in Science 2009; 326(5952): 582-585.
Low sunspot activity favors tree growth
Cosmic rays reaching Earth vary with the Sun's activity and follow an eleven year cycle. Growth of Sitka spruce (Picea sitchensis) in northern Britain was greatest during periods of low sunspot activity, when most cosmic rays reach Earth, and growth was slower during periods of cosmic ray-blocking sunspot activity. This is reported by Sigrid Dengel and associates at the University of Edinburgh, UK. The period studied was 1961 to 2005 and the period of time when cosmic rays blocked sunspot activity was from 1965 to 2005, when tree growth was less (tree ring measurements). The cosmic ray effect was greater than that from temperature and precipitation, which they considered. The authors are puzzled by the effect and discuss possible explanations and recommend further, larger studies. They speculate, however, that increasing radiation ionizes gases in the atmosphere to account for increasing cloud cover that in turn could boost plant growth by increasing photosynthesis. (New Phytologist 2009; 184(3): 545-551)
Honey bees and other pollinators
The honey bee population is declining worldwide because of the effects of Colony Collapse Disorder and the mite Varroa destructor. As a result, scientists are searching for alternative pollinators, especially for crop and garden plants. In New Zealand, investigators evaluated the effectiveness of thirty-one species of insects that visited flowers of Chinese cabbage (Brassica rapa). Of these, the honey bee and seven other insect species visited the flowers frequently. However, two bee species (Bombus terrestris and Leioproctus sp.) and one fly (Eristalis tenax) proved to be as efficient as the honey bee (Apis mellifera) in pollinating flowers. This is reported by Romina Rader and associates at The New Zealand Institute for Plant & Food Research Ltd., and Landcare Research New Zealand Ltd.; and James Cook University and CSIRO in Australia. On the other hand, the relative abundance of the honey bee made it the most effective pollinator overall. The authors point out that if pollination is to be dependent on other bees, then land has to be managed so that those bees survive and are abundant enough to replace the honey bee as pollinators. (Journal Applied Ecology 2009; 46(5): 1080-1087)
Ardi precedes Lucy among early hominids
"Lucy" is Australopithecus afarensis, found as a fossil in South Africa in 1924 and estimated to have lived 1-4 million years ago. She represents an ancestral group from which Homo apparently evolved. Recently "Ardi" (Ardipithecus ramidus) was found in the Afar rift area of northeastern Ethiopia, and this hominid dates back to 4.4 million years ago. From a study of Ardi, scientists concluded that humans did not descend from chimpanzee-like ancestors but instead evolved through a different pathway than from apes and chimpanzees. Tim White from the University of California, Berkeley, and associates at Rift Valley Research Service, Ethiopia; Cleveland Museum of Natural History and Kent State University, Ohio; University of Tokyo; and Los Alamos National Laboratory, NM, summarized the information. (Science 2009; 326(5949): 64). However, the October 2, 2009, issue of Science (October 2, 2009) has reports of eleven detailed papers and more general summaries of the research on Ardi in a special section comprising pages 60 to 106.
Isolated dwarf galaxy not producing stars
A galaxy such as the Milky Way contains many stars. However, a galaxy was discovered that is as big as the Milky Way but has few stars. It has a small solid mass at its center surrounded by a disc of gas way out of proportion to its star mass, that is, it has only 2% of the star mass of the Milky Way. This is reported by John Cannon of Macalester College (St. Paul, MN), and associates at Wesleyan University (CT), Indiana University, and George Mason University (VA). They named this galaxy ADBS 1138 after the Arecibo Dual Beam Survey. It is called a dwarf galaxy because of its tiny star mass. Even though it includes considerable hydrogen, the galaxy is not creating new stars. Compared to similar "giant disc" dwarf galaxies, this galaxy has the largest hydrogen gas-to-visible-star ratio. They conclude that this system is "exceedingly inefficient" in converting gas into stars. (The Astrophysical Journal 2009; 696: 2194-2114)
A vegetarian spider identified
Spiders are thought to be strict predators. However, an exception has been found—a spider that feeds on acacia shrubs—report Christopher Meehan of Villanova University (PA), and associates at Brandeis University (MA), and Trent University and Queen's University (Canada). They state that this jumping spider (Bagheera kiplingi) from Central America is the first report of a spider that feeds primarily and deliberately on plants. (Current Biology 2009; 19(19): R892-R893)
Green roofs trap carbon dioxide
Green roofs are roofs covered with growing plants. Green roofs can lower air conditioning costs in summer by absorbing and reflecting heat, and can lower heating costs in winter by providing insulation. Such roofs in cities soak up rainwater and prevent increasing costs of sewer water treatment. They also reduce the "heat island" effect in cities and reduce air and noise pollution. Green roofs provide habitat for birds and butterflies. Kristen Getter and associates at Michigan State University examined eight roofs in Michigan and four in Maryland. Sedum species were grown on all twelve roofs. They reported that the entire extensive green roof system sequestered (formed compounds no longer reactive) 375 grams of carbon per square meter (about 3485 pounds per acre). However, results varied with the species of Sedum planted. It was estimated that if the city of Detroit had green roofs, more than 55,000 tons of carbon could be sequestered each year. In Stuttgart, Germany, 25% of the buildings have green roofs. (Environmental Science & Technology 2009; 43(19): 7564-7570)
Earth's geomagnetic fields
The Earth's magnetic fields that circle the Earth protect life from harmful cosmic rays. These magnetic fields were more stable in the past than has generally been thought report Nicholas Swanson-Hysell and associates at Princeton University, Yale University, and the Massachusetts Institute of Technology. The investigators examined 1.1 billion-year-old volcanic rock on the north shore of Lake Superior and learned that the ancient Earth's magnetic field was a pair of equal and oppositely charged or magnetized poles (like a bar magnet) separated by a distance at the center of the Earth. The authors studied the tiny magnetic minerals imbedded within the volcanic rock to determine the orientation of the magnetic field at the time when the rocks emerged at the Earth's surface. By analyzing this information the investigators will be better able to understand movements of continents in the past. (Nature Geoscience 2009; 2:713-717)
Woodland-to-forest transition in the "Big Woods"
The "Big Woods" is an area of dense forest in central Minnesota—characterized as a maple-basswood forest—which represented the peak of deciduous forest development. This woodland was shaped by both climate and fire. After the severity of regional fire regimes declined after about AD 1300, the Big Woods forest replaced the woodlands and savannas (grassland areas with widely spaced trees) report Bryan Shuman and associates at the University of Minnesota. A trend toward wet conditions has long been assumed to explain forest expansion; however, the authors report that water levels of two lakes in the region (Wolsfeld Lake and Bufflehead Pond) were low when open woodlands were transformed into the Big Woods. Moreover, they report that tree ring data show a peak in recruitment of Big Woods tree species during the AD 1930s drought, and that low regional moisture balance need not have been a limiting factor for forest expansion. (Ecology 2009; 90(10): 2792-2807)
Four-winged, feathered dinosaur fossil found
An exceptionally well-preserved, small theropod specimen (Anchiornis huxleyi) was collected from a geological formation (early Late Jurassic) of western Liaoning, China, of 150 million years ago. This is reported by Dongyu Hu and associates from Shenyang Normal University, Chinese Academy of Sciences, and Shenyang Institute of Geology and Mineral Resources, China. Moreover, this dinosaur is in the group of theropods most closely related to birds. The authors think that this extensive feathering sheds new light on the early evolution of feathers and demonstrates the complex distribution of skeletal and integumentary features close to the dinosaur-bird transition. This specimen dates before the true bird appeared. The authors write that feathers may have evolved as a kind of protection and insulation for dinosaurs. (Nature 2009; 461:640-643)
Water ice reported on Mars
Impact craters that form frequently on Mars expose materials that lie below the martian surface. The Mars Reconnaissance Orbiter detected craters at mid-latitude that had formed over the past few years and it revealed the presence of water ice. This is reported by Shane Byrne and associates at the University of Arizona, Malin Space Science Systems (San Diego, CA), University of Colorado, Washington University (St, Louis), Johns Hopkins University, and Universität Bern (Switzerland). After several months the exposed ice sublimated away. The authors suggest that water ice should be stable from decimeters to about a meter below the martian surface, and that Mars weather in the recent past was wetter than it is currently. (Science 2009; 325(5948): 1674-1676)
Birds freshen nests to protect chicks
Several bird species have been reported to add fresh fragments of aromatic plants such as lavender, mint, or yarrow, to their nests. Why do they do this? On Corsica, blue tits (Cyanistes caeruleus-photo) were also found to add fresh fragments of aromatic plants to their nests report Adéle Mennerat and associates at CNRS, Montpelier, and Université de Toulouse, France. Such additions improved the growth and condition of chicks at fledgling stages. The investigators learned that aromatic plants affect the bacterial communities and reduce the bacterial density on nestlings. Heavy bacterial growth can lead to disease. However, the fresh plants had no effect on bacteria living on adult blue tits. Also, the plants did not affect the number of blow-fly larvae infesting the nests. (Oecologia 2009; 161(4): 849-855)
Magnetism used to deliver drugs in body
An "on demand" drug delivery system has been designed by application of an oscillating magnetic field report F. Goya and associates at McMaster University, Canada; CIBER-BBN, Zaragoza, Spain; Massachusetts Institute of Technology and Harvard Medical School, MA. To do this, magnetism has been combined with nanotechnology. A small implantable device less than a half-inch in diameter contains the drug within a special membrane embedded with particles approximately one ten-thousandth the diameter of a human hair. These nanoparticles consist of the mineral magnetite that has natural magnetic properties. By switching on the magnetic field outside the body, but near the device, the tiny particles heat up and cause the membrane to warm up and collapse momentarily. The pores then open up to enable the drug to pass through and into the body. When the magnetic force is turned off, the membrane cools and the gels expand to close the pores and end the drug delivery. This device is not yet ready for clinical use. (Nano Letters 2009, DOI 10.1021/nl9018935, Sept. 8)
Potato famine fungus sequenced
As the agent of the Irish potato famine in the mid-nineteenth century, the fungus Phytophthora infestans had a tremendous effect on human history. This fungus is the most destructive pathogen of potato and causes late blight; it has genetic links to organisms such as the brown algae and diatoms. Potato is the fourth largest food crop and a critical alternative to the major cereal crops. Losses due to late blight are estimated at $6.7 billion worldwide. Now this fungus has been sequenced and found to consist of about 240 megabases which is the largest and most complex genome in its classification, report Brian Haas of Broad Institute of MIT and Harvard with a team of 96 scientists at 34 institutions in seven countries. They report further that this fungus comprises many genes that are induced during infection and which can alter host physiology. This explains why the fungus adapts so rapidly to the potato and other hosts and has such evolutionary potential, according to the authors. (Nature 2009; 461: 393-398)
Deltas sinking from human activities
Many of the world's largest river deltas are densely populated and heavily cultivated. This makes inhabitants vulnerable to flooding due to compaction of sediment from the removal of oil, gas, and water from the underlying sediments of the delta. This was reported by James Syvitski and associates at the University of Colorado, Dartmouth College (NH), Louisiana State University, City University of New York, Geological Survey of Japan, Woods Hole Oceanographic Institution (MA), and University of Southhampton (UK). Thirty-three deltas around the world were examined and the authors found that 85% experienced severe flooding so that 260,000 km2 (100,387 square miles) of land has become submerged. They further estimate that the delta surface area now vulnerable to flooding could increase by 50% based on projected sea level rise, and could get worse unless steps are taken to prevent growth and buffering of deltas. (Nature Geoscience 2009; DOI: 10.1038/ngeo629, Sept.20)
Rooks use stones to get worm
Rooks, members of the crow family, were able to solve a complex problem by using tools. Four captive rooks (Corvus frugilegus) raised the level of water in a tall glass beaker so that a floating worm was within reach of the bird's beak report Christopher Bird at the University of Cambridge and Nathan Emery at Queen Mary University of London, UK. The Birds did this by dropping stones into the glass of water to raise the water level to make the worm reachable. The rooks also learned to use large stones rather than small ones. This experiment is reminiscent of the Aesop's fable "The Crow and the Pitcher" in which a thirsty crow uses stones to raise the level of water in a pitcher to quench its thirst. (Current Biology 2009; 19(16): 1410-1414)
Rock varnish in Tibet and Mars
Rocks exposed to harsh conditions in desert and arid landscapes often develop a hard, usually dark brown to almost black coating, called "rock varnish." Rock varnish can also occur at high-altitudes. Rock varnish comprises a complex combination of iron oxides, clays, and manganese oxides. Manganese-oxidizing bacteria are cited as being associated with rock varnish. Samples from eolian-abraded lava flows at 4700-4800 meters (15,420-15,748 feet) high in the Ashikule Basin in Tibet were collected because this represented an environment similar to that expected on early Mars. This is reported by David Krinsley and associates at the University of Oregon, Arizona State University and Cardiff University (UK). Manganese-enhancing bacteria were not abundant in Tibet yet were three times more abundant than in the Mojave and Sonoran Desert varnishes. The authors think that rock varnishes found on Mars may contain fossil bacteria since bacterial forms were found in the varnish in Tibet; this may offer clues in the quest for evidence of life on Mars now or in the past. (Astrobiology 2009; 9(6): 551-562)
Ripe banana spots with blue halos
Breakdown of chlorophyll is a major contributor to the color changes in fall leaves, and in ripening apples and pears where it provides colorless nonfluorescent tetrapyroles. However, in banana (Musa acuminata) the chlorophyll fades to show a unique fluorescent breakdown product (catabolite) causing the yellow bananas to glow blue when observed under ultra-violet light. This is reported by Simone Moser and associates at the University of Innsbruck, Austria, and Columbia University, NY. These bright blue rings on the peels of very ripe bananas occur near stomates, which are pores to enable gas exchange in the plant skin. These rings accumulate as the fruit ripens and consist of intermediate compounds that precede transition to dead tissue. Such studies help in understanding the critical stages that precede cell death. (Proceedings National Academy Sciences USA 2009; 106(37): 15538-15543)
Antioxidants in plant food products
Proanthocyanidins were found in a large number of commercial food products of plant origin available in Finland. Proanthocyanidins are in a class of flavonoids that have antioxidant activity. Consumption of antioxidants is thought to provide protection against oxidative damage and contribute positive health benefits leading to greater reduction in risk of chronic disease, specifically for cancer and heart disease. Proanthocyanidins were detected in 49 of 99 selected food items report Jarkho Helliström and associates at MTT Agrifood Research Finland and University of Kuopio, Finland. The greatest contents were found in chokecherry, rose hips, and cocoa products. Berries and fruits were generally the best sources of proanthocyanidins, whereas most of the vegetables, roots, and cereals lacked them completely. (Journal of Agricultural and Food Chemistry 2009; 57(17): 7899-7906)
Galaxies collided 2-3 billion years ago
Galaxies generally grow in mass by gravitational attraction of smaller galaxies. Clues to galaxy formation history yield information on number, luminosity, and shape of the relics of this process but it is not always easy to analyze. A panoramic survey of the Andromeda galaxy revealed stars and other structures that are remnants of dwarf galaxies destroyed by the tidal field of Andromeda. This is reported by a team of twenty-nine researchers led by Alan McConnachie at the NRC Herzberg Institute of Astrophysics, in Canada, and associates of sixteen institutions in Australia, Canada, France, Germany, United Kingdom, and United States. They report further that Andromeda collided with Triangulum 2-3 billion years ago as evident by the brightness of the latter galaxy as well as the stellar structure surrounding it. They continue that Triangulum will eventually be totally destroyed by Andromeda. These two galaxies are closest to our own galaxy, the Milky Way. (Nature 2009; 461:66-69)
Much of panda habitat destroyed by earthquake
A major earthquake struck Sichuan Province in southwestern China in May 2008. Besides the catastrophic loss of human life (nearly 70,000 people) and destruction of towns and villages, the earthquake severely damaged ecosystems that support some of the last remaining giant panda (Ailuropoda melanoleuca) populations in the wild, report Weihua Xu and associates at the Chinese Academy of Sciences, Beijing. About 354 km (137 square miles) of panda habitat in this region were destroyed, which represents about 23% of the area. In addition, landslides and mudflows destroyed additional habitats in the area. The steep slopes that remain are not good sites for pandas, and this could affect their survival. (Frontiers in Ecology and the Environment 2009; 7(7): 353-358)
Lungless salamander discovered
A new species of lungless salamander has been found in the Appalachian foothills of northern Georgia (USA) report Carlos Camp and associates from Piedmont College (GA) and University of Georgia, University of Missouri, East Carolina University (SC), and University of California, Berkeley. The salamander is only 25-26 millimeters (about an inch) long and it is so different from other salamanders that a new genus and species was erected to classify it (Urspelerpes brucei). It is the only lungless salamander in the United States whose males have a different color and pattern than females, a trait more characteristic of birds. It has five toes, in contrast to other small species which have only four toes. This new species appears to be rare and therefore merits conservation concern, according to the authors. (Journal of Zoology 2009; 279(1): 86-94)
Mutation rate in humans determined
The first direct measurement of the general rate of mutation at individual DNA letters in humans has been reported by a team of sixteen Chinese and British scientists. The team was led by Yali Xue at the Wellcome Trust Sanger Institute (UK). Others were from the Chinese People's Liberation Army General Hospital and Beijing Genomics Institute (Shenzhen), China. In the past, scientists have been trying to get a reliable estimate of the mutation rate in humans. By using new sequencing technology to measure directly one mutation rate, these scientists report that all humans carry approximately 200 new mutations in their DNA. They sequenced the Y chromosomes of two persons separated by thirteen generations and counted the number of differences. Most of the mutations are harmless and do not affect health or appearance. The Y chromosome was studied because it passes unchanged from father to son and mutations accumulate slowly over the generations. (Current Biology; 27 August 2009, doi:10.1016/j.cub.2009.07.032)
Oldest stone axes in Europe found
Stone tools can tell us about activities, skills, and customs of early humans and can reveal technological skills developed at a given stage in history. Such information has been collected and documented to show that stone tools were about a million and a half years old in Africa, but about a half million years old in Europe. Two hand-axe sites have been discovered that are nearly twice the age of the supposedly earliest find in western Europe report Gary Scott and Luis Gibert at the Berkeley Geochronology Center, California. Two sites in southeastern Spain were found in which magnetic minerals had a polarity opposite to what is now found. The last reversal of the Earth's magnetic field took place 780,000 years ago. Because these magnetic changes are global and well documented, geologists can date ancient artifacts by using a method called paleomagnetism. According to the authors, this means that the first hand axes used by humans in Europe are 400,000 years older than was previously thought, making this occurrence closer to the dates reported in Africa. (Nature 2009; 461: 82-85)
Bats sing while mating
Birds are widely known for singing behavior, but in mammals, examples of vocal syntax are exceedingly rare; one exception is the whale. The way the syllables and phrases are ordered and combined (syntax) by the Brazilian free-tailed bat Tadarida brasiliensis (which also lives in the southwest United States) were studied. A team led by Kirsten Bohn at Texas A&M University, the University of Texas, and Bat Conservation International, in Texas, studied this bat. Three types of phrases were detected: a chirp, a buzz, and a trill; these were heard in different combinations during mating. By decoding the sounds, the researchers determined that male bats emit distinguishable syllables and phrases that they use as love songs to attract females, and sometimes to warn other males to stay away. Because the sounds are difficult to hear by humans, sounds were recorded for analysis. They also reported that the sounds made showed individual differences among bats. (PLoS ONE 2009; 4(8): e6746)
Ocean tides heat Saturn moon
Enceladus is a tiny moon of the planet Saturn. The Cassini spacecraft that passed by Saturn reported vast plumes of vapor erupting from geysers near the south pole to show that considerable heat was being generated there. What is the source of that heat? The ocean is covered with ice, yet tidal flow was considered great enough to generate heat to produce the geyser plumes reports R. H. Tyler at the University of Washington. The moon's axis is tilted about 0.05 degrees to bring about a strong tidal flow and thereby generate heat, he explains. (Geophysical Research Letters 2009; 36: L15205)
Rice adapts to flooding
To adapt to changing and hostile environments, living organisms must acquire new biological functions. Deep water rice has evolved and adapted to flooding by acquiring the ability to lengthen its internodes, the stem portion between joints in the stem. The internodes are hollow and act as snorkels to allow gas exchange with the atmosphere and prevent drowning. This is reported by Yoko Hattori at Nagoya University, and associates at Kyushi University, RIKEN in Yokohama, and the National Institute of Agrobiological Resources, Tsukuba, Japan. This team identified two genes to account for this adaptation and named them SNORKEL1 and SNORKEL2. These genes trigger the response to deep water by encoding ethylene response factors. Under deep water conditions, ethylene accumulates in the plant and induces expression of the two genes. The products of the two genes lead to formation of gibberellin which, in turn, triggers the elongation of the internodes. These genes can also be introduced into non-deep water rice to enable these varieties to grow in lowland areas that are frequently flooded during the rainy season. (Nature 2009; 460: 1026-1030)
Small woodlots as migratory stopovers
Migrant birds select stopover sites based on local habitat characteristics such as food resources, regardless of the landscape report Diane Packett and John Dunning at Purdue University. Small, isolated woodlots composed largely of forest edge with high fruit and insect abundance may, therefore, be important conservation targets in highly fragmented landscapes where forest cover is limited. The authors made 384 surveys in twelve woodlots that involved 3,695 migrants comprising 76 bird species. The study suggested to the authors that conservation efforts should extend to smaller forested lands to help stabilize declining migratory bird populations. The value of small woodlots was emphasized to enable migrant birds to rest and find food along the thousands of miles of migration. (The Auk 2009; 126(3): 579-589)
Water detection below Earth's mantle
A small amount of water affects the physical properties of the mantle materials in the Earth's crust by lowering residue on the surface, reducing consistency, and by increasing quake activity. Electrical conductivity is high in cold, seismically active areas. Now research shows that some of the water in the transition zone (zone between upper and lower mantle) is carried into that region by cold, subducting slabs (tectonic slabs that slide under others) report Anna Kelbert and associates at Oregon State University. Enhanced electrical activity in parts of the Earth's crust can signal the presence of water far below the Earth's surface. These areas of high electrical conductivity coincide with the presence of subduction zones where the tectonic plates are being subducted beneath the Earth's crust. (Nature 2009; 460(1003-1006)
Diamond serves as an optical lens
Diamonds are hard, stable, and not considered a flexible material. However, by preparing a thin diamond slice of nanometer dimensions and overlaying this on a special substrate, the diamond can serve as a flexible lens report A. Kriele and associates at Fraunhofer Institut Angewandte Festkörperphysik, Germany. By exerting pressure, the focal length can be changed from infinity to 3.5 millimeters. This lens has promise for use in remote or harsh environments. (Applied Physics Letters 2009; 9531905)
Fungus directs where ants to die
Some specialized parasites have the knack of controlling their hosts. A unique way of manipulating the host was observed with the fungus Ophiocordyceps unilateralis which is a parasite on a carpenter ant Camponotus leonardi. The fungus manipulates the ant to die at just the right spot for the fungus report Sandra Andersen and associates at the University of Copenhagen and University of Aarhus, Denmark; University of Groningen, Netherlands; University of Cambridge and University of Exeter, UK; University of Leuven, Belgium; and National Centre for Engineering and Biotechnology, Thailand. They found dead ants under leaves attached by their mandibles on the north side of saplings about 25 cm (about 10 inches) above the soil where temperature and humidity were just right for fungus growth and reproduction. The fungus infects the ant and the ant nests high in the canopy of Thailand forests. The fungus does not kill the ant right away but coerces the ant to leave the high places and climb down to the undersides of leaves in understory plants and saplings. Here the ant clamps its mandibles just before it dies. The fungus continues to grow on the dead ant and then drops spores to the forest floor to infect other crawling ants crawling. The fungus grows inside the dead ant body and converts the contents to sugar needed for fungus growth, but it avoids the muscles that control the mandibles so that the ant remains attached to the leaf. The fungus also does not attack the outer shell of the ant and thereby the shell can serve as a protective cover for the fungus. The only protection the ant has to avoid the fungus is to climb to the high canopy of trees. (The American Naturalist 2009; 174(3): 424-433)
Hurricane activity affects climate
In a study of hurricane and climate activity over the past 1,500 years, a peak in Atlantic tropical cyclone activity occurred during medieval times (around 1,000 AD) followed by a subsequent lull in activity. This is reported by Michael Mann and associates at Pennsylvania State University, University of Massachusetts, and Woods Hole Oceanographic Institution. According to the authors, this peak of activity rivals and even exceeds recent hurricane activity, and results from the reinforcing effects of La Niña-like climate conditions and relative tropical Atlantic warmth. (Nature 2009; 460: 880-883)
Migratory geese cause airplane crash
More than 7,400 bird-aircraft collisions (birdstrikes) were reported in 2007. Most occurred during plane take-off or landing. Using feather remains and other tissue samples collected from the engines of US Airways Flight 1549 which crash landed in the Hudson River in New York City on January 15, 2009, molecular tools and stable hydrogen isotopes were used to demonstrate that migratory Canada geese were responsible for the crash. These findings were reported by Peter Marra and associates at Smithsonian Migratory Bird Center, Smithsonian Institution, and US Department of Agriculture, Wildlife Service, in Ohio. (Frontiers in Ecology and the Environment 2009; 7(6): 297-304)
Pigeons disperse seeds long distances
Grain-eating pigeons can disperse large amounts of live seeds when they die, some with seeds in their crops a long distance from the parent plant. This is reported by Enrique Bucher and Pablo Bocco at Universidad Nacional de Córdoba, Argentina. They worked with the eared dove (Zenaida auriculata) breeding colonies in central Argentina where breeding populations may reach more than 8,000 doves per hectare (3200 per acre). When doves died, seeds were removed from their crops and tested for germination; the germination rate was over 50%. When the corpse lay on the ground for thirty days, germination still varied between 35% and 65%. The greatest daily flight distance from breeding colonies was 117 kilometers (73 miles). Thus they conclude that weed seeds can be transported from lands to islands and overland to account for the introduction of invasive plants in a location. (Ecology 2009; 90(8): 2321-2327)
Water once flowed on Mars
Once, more than two million years ago, surface liquid water on Mars was released by ground-ice thaw and persisted for many seasonal cycles. This is reported by Mathew Balme of the Planetary Science Institute, Tucson, AZ, and C. Gallagher of University College Dublin, Ireland. The observations of water-like channels cross-cutting pre-existing surface features are consistent with a surface that had evolved over time, they say. They state that ice melted near the equator sometime in the past million years and then refroze. They conclude that this argues against the landscape being volcanic as some have claimed. (Earth and Planetary Science Letters 2009; 265(1-2): 1-15)
Why introduced plants succeed
Why some plants introduced into a new area succeed in becoming established and dispersed while other do not has been investigated many times. The answer for most introduced plants is that they succeed because they are self-pollinated report Alexandra Harmon-Threatt and associates at Washington University, St. Louis, MO. Moreover, the pollinator visitation rates are similar to those of their native relatives. They conclude that by ascertaining the pollination habits of introduced plants, a better understanding and prediction of biological invasions is possible. (American Journal of Botany 2009; 96: 1544-1550)
Bald songbird species found in Laos
A new species of bulbul (Pyconotus hualon) has been found in the rugged central limestone belt of Laos, report Iain Woxvold at the University of Melbourne, Australia, and associates at the Wildlife Conservation Society Lao Program, Lao PDR. This is the first time in more than 100 years in the finding of a new Asian species from the bulbul family—a bare-faced songbird and apparently the only bald songbird in mainland Asia. It is about the size of a thrush and lives in the sparse forests of the stony outcrops of Laos. It probably escaped detection because the area is seldom visited. (Forktail 2009; 25(7): 1-12)
Comet responsible for impact
In 1908, an object from space struck a forest near Tunguska, Russia, and leveled everything for miles (photo). The impacting object must have contained considerable ice and therefore was very likely a comet, report Michael Kelley and associates from Cornell University (NY) and Clemson University (SC). The water and ice, instead of dispersing, remained in the atmosphere to form thin clouds visible at night ("noctilucent clouds") according to the authors. These clouds were observed in Great Britain as extremely bright night skies in days after the impact. They present this as an explanation of the 1908 Great Siberian Impact Event, because they reported others had observed that water vapor plumes from the space shuttle's main engine rapidly expanded and moved quickly to the summer pole. Once there the water vapor plume condensed into large noctilucent cloud displays. (Geophysical Research Letters 2009; 36: L14103)
Earthworms oust native plants
Earthworm invasion, rather than non-native plant invasion, is the driving force behind changes in forest plant communities in northeastern North America, including declines of native plant species. Earthworm invasions appear to aid plant invasions in these forests, report Victoria Nuzzo, Natural Area Consultant in NY, and associates at Cornell University (NY). Earthworms also reduce plant litter on the soil surface. They studied fifteen forests in northeastern North America, and concluded that to protect forest understory plant species, forest managers should consider more than just invasive plants. (Conservation Biology 2009; 23(4): 966-974). In a following article by John Maerz and others at the same institution, the presence of earthworms also accounts for loss of salamanders in the forest because of the loss of leaf litter that harbors small arthropods on which salamanders depend. (Conservation Biology 2009; 23(4): 975-981)
Tiger moths jam bat sonar
The tiger moth Bertholdia trigona (photo) defends itself against the attacking big brown bats (Eptesicus fuscus) by using ultrasonic clicks that jam bat sonar report Aaron Corcoran and associates at Wake Forest University (NC) and Colorado State University. They used high-speed cameras and an ultrasonic microphone to record the action over nine consecutive nights. Bats like eating these moths and emit sounds to locate them. As bats get closer they emit sounds at increasing frequencies. Moths turn on their sound system which reverses the pattern of bat sounds and the bat sonar decreases indicating that the bat has lost its target. Bats sends out signals, and by listening for return echoes they know how close they are to the moth, a process known as echolocation. This is an effective defense mechanism of moths against bats. (Science 2009; 325(5938): 325-327)
Northern and Southern lights vary
It has generally been assumed that the aurora borealis (Northern Lights) and the aurora australis (Southern Lights) are mirror images of each other because the charged particles causing the auroras follow the symmetric magnetic field lines connecting the two hemispheres. Charged particles from the solar wind strike atoms and molecules in the atmosphere and produce spectacular light displays in the Earth's upper atmosphere known as the auroras. Now, Karl Magnus Laundal and Nikolai Østgaard at the University of Bergen, Norway, report differences in the two lights. They report that some intense spots are visible at dawn in the Northern Hemipshere in summer but at dusk in the Southern Hemisphere in winter. Moreover, they say that there are currents within each hemisphere that are related to seasons that have not been noted before and that accounts for the difference. (Nature 2009; 460:491-493)
Nitric oxide improves spinach
Nitric oxide has been recognized as a plant hormone and is being tested in greenhouses to improve production of vegetable crops. Nitric oxide as a gas significantly increased plant growth of spinach, increased the rate of photosynthesis in leaves, increased the concentrations of soluble sugar, protein, antioxidants (vitamin C, glutathione, and flavonoids), and increased the iron reducing-antioxidant power in stems and leaves. This shows that nitric oxide treatment increases production and improves the quality of spinach grown in greenhouses report C. W. Jin and associates at Zhejiang University, China, and at LaTrobe University, Australia.(Annals of Applied Biology 2009; 155(1): 113-120)
Roots growing upward into snow
Plants have a variety of ways of adapting to acquire mineral nutrients. Some of these adaptions involve the structure and positioning of root systems. A unique adaption is the discovery of specialized snow roots as a plant strategy to cope with a very short season for nutrient uptake and growth in alpine snow-beds. The snow-beds are patches in the landscape that remain covered with snow well into the summer. This was reported by Vladimir Onipchenko and associates at Moscow State University, Timiryyazev Institute, Teberda State Reserve, and Karachaevo-Cherkessian University, in Russia; and VU University, Netherlands. They report that the Caucasian snow-bed plant Corydalis conorhiza forms an extensive network of specialized above-ground roots that grow upward against gravity into the snow to acquire nitrogen directly from within snow packs (photo shows matted roots after snow melt). These roots capture nitrogen that would otherwise run off down-slope over a frozen surface. They also produce normal roots that grow into the soil. Global warming could affect survival of this unusual alpine plant, they say. (Ecology Letters 2009; 12(8): 758-764)
Radiation from Martian dust storm
A non-thermal microwave radiation from a deep Martian dust storm was reported by Christopher Ruf and associates from the University of Michigan, California Institute of Technology, and Malin Space Science Systems, Inc. (California). The radiation was detected only for a few hours when a 35 kilometer deep dust storm (photo) was viewed by a radio telescope on June 8, 2006. The radiation appeared to be induced by an electric discharge during the storm. (Geophysical Research Letters 2009; 36: L13202)
Hadrosaur was a grazer not a browser
One of the most abundant of the dinosaurs in the Late Cretaceous—about 67 million years ago—was the Edmontosaurus—a plant-eating dinosaur classified as a hadrosaur. It has been reported to feed on twigs and leaves. Now, Vincent Williams and associates at the University of Leicester and the Natural History Museum in London, UK, report that Edmontosaurus (photo) was a grazer not a browser. They ascertained this by examining teeth of a specimen from Wyoming and found microscopic scratches on teeth caused by feeding activity. They concluded that the relative motion of the teeth rows to each other during feeding accounted for these scratches and was consistent with grazing, not browsing. This hadrosaur had flexible upper jaws so that as the lower jaws clamped shut they would force the teeth in the upper jaws to spread outward to grind against the teeth in the lower jaws, indicative of grazing. (Proceedings National Academy of Sciences USA 2009; 106(27): 11194-11199)
Fruit flies detect plant toxins
Many plants produce bitter-tasting toxins such as alkaloids, phenolics, and non-protein amino acids that discourage animals such as cows and insects from feeding on them. It has been puzzling how animals know whether a plant contains a toxin or not. The best-known non-protein amino acid is L-canavanine which accumulates in legumes including alfalfa seed. The fruit fly (Drosophila melanogaster) has a receptor in its leg that enables the fly to taste L-canavanine report Christian Mitri and associates at the University of Montpeillier, France. The fruit fly tastes with its legs where there are taste neurons that have receptors for sugar, water, and bitter compounds. When the fruit fly receptor tells the fly the substrate is okay, the fly extends the proboscis and drinks the liquid; however if it is not okay, it blocks the extension of the proboscis. The receptor for L-canavanine is called DmX, and the gene that controls it is DmXR. (PLoS Biology 2009; 7(6): e1000147)
Midsize black holes in another galaxy
The existence of intermediate-mass black holes has been in dispute even though many candidates have been proposed. By using X-ray emission equipment, an intermediate-mass black hole of more than 500 times heavier than the Sun has been found in the ESO 243-49 galaxy report Sean Farrell and associates at the Universität de Toulouse and CSRS, France; and the University of Leicester, UK. Star-sized "supermassive" black holes have been reported in many galaxies which weigh millions to billions times more than the weight of the Sun. Astronomers still don't know how these intermediate black holes gain their mass. (Nature 2009; 460: 73-75)
Skim milk better than fruit drink
After a breakfast with skim milk, overweight men and women consumed considerably less energy at lunch than after a breakfast which included a fruit drink report Emma Dove and associates at the University of Western Australia. The consumption of skim milk compared with a fruit drink leads to increased perception of feeling full and to decreased energy intake at the next meal. They further report that skim milk in their test contained 25 grams of protein whereas the fruit drink contained less than one gram of protein. Thus, skim milk reduces appetite and energy intake at the next meal in overweight men and women. (American Journal of Clinical Nutrition 2009; 90(1): 70-75)
Coronary heart disease not caused by CRP
CRP (C-reactive protein-see photo) is produced by the liver and has become suspect in causing coronary heart disease because high concentrations of CRP were associated with heart attacks. Thus. a team of thirty-six investigators led by Paul Elliott at the Imperial College of London (UK) and associates from eleven institutions in seven countries studied 28,112 cases. They identified the gene that governs the production of CRP in the liver and they reported that there was no agreement between coronary heart disease risk of CRP genotypes and CRP concentrations. They concluded that high CRP levels were not the cause of coronary heart disease and that there is no point in searching for a drug that targets CRP to prevent heart attacks. This was a meta-analysis study. (Journal American Medical Association 2009; 302(1): 37-48)
Glass present in interplanetary dust
Micrometeorites are interplanetary dust particles 25-500 micrometers (µM) in diameter (0.009842252 to 0.019685039 inches)—see dust photo. They carry the main mass of extraterrestrial matter that is captured by Earth. The coarse-grained micrometeorites consist mainly of aggregates of olivine (magnesium iron silicate) and pyroxenes and glass. The glass portion of the micrometeorites is trapped in olivine found in ice at Cap Prudhomme in Antarctica which was studied by M. E Varela at CASLEO in Argentina and G. Kurat at the University of Vienna, Austria. They reported that the micrometeorites entering the Earth's atmosphere were heated to variable degrees which resulted in either very little chemical modification or the total melting of the glass. The melting caused loss of some alkali elements. The glasses of micrometeorites heated to very low degree have a chemical composition indistinguishable from glasses in comet particles, to provide evidence that interplanetary dust may represent samples from comets, according to the authors. (Earth and Planetary Science Letters 2009; 284(1-2): 208-218)
Elevated carbon dioxide enhances fish otolith growth
Much of the carbon dioxide added to the atmosphere from the burning of fossil fuels enters the ocean. This makes the ocean more acidic. Earlier studies had shown that marine life generally undergoes slowing of structural calcification with increased carbon dioxide. In contrast, elevated carbon dioxide enhanced the growth of otoliths in young white sea bass (Atractoscion nobilis)—otoliths are bony structures used by fish to sense orientation and movement (see photo)—report David Checkley and associates at the University of California. They had expected otoliths to grow more slowly with increased carbon dioxide concentrations. The authors state they don't know whether larger otoliths are good or bad, or whether these results apply to other fish in the ocean. (Science 2009; 324(5935): 1683)
Shark migration
The basking shark (Cetorhinus maximus) is the world's second largest fish and inhabits boreal to warm temperate latitudes of the Atlantic and Pacific oceans. Basking sharks travel each season and occasionally live at mesopalagic depths (650-3280 feet deep); they were thought to be restricted to temperate latitudes. Now sharks are shown to be seasonal migrants to mesopalagic tropical waters and migrate from feeding areas off the coast of New England to the Bahamas, Caribbean Sea, and on to the coast of South America and the southern hemisphere. This is reported by Gregory Skomal and associates at the Massachusetts Division of Marine Fisheries, University of New England, Maine Department of Marine Resources, and Woods Hole Oceanographic Institution. These sharks sometimes stay at mesopalagic depths for weeks or months at a time. The authors think that this highlights the need for conservation efforts for sharks throughout their range. (Current Biology 2009; 19(12): 1019-1022)
Caribou hunted on Lake Huron's bottom
A caribou hunting ground was evident at the bottom of Lake Huron sometime between 10,000 and 7,000 years ago report John O'Shea and Guy Meadows at the University of Michigan. They surveyed the Alpena-Amberly ridge, a feature that would have been a dryland corridor crossing the Lake Huron basin, and found a series of stone features that match structures used for caribou hunting. They speculate that there may be intact settlements and ancient landscapes preserved beneath Lake Huron. (Proceedings National Academy of Sciences USA 2009; 106: 10120-10123)
Gray hair due to damaged DNA
Gray hair is a typical sign of aging in mammals and is caused by incomplete maintenance of melanocyte stem cells with age. This is reported by Ken Inomata and associates at Kanazawa University, KOSF Corporation, Hokkaido University, Tokyo Medical and Dental University, and Kyoto University, in Japan. Melanocyte stem cells are pigment-producing cells in the hair follicles. This research team studied mice as they also turn gray with age, and found that stress, such as from chemicals and radiation, damages the DNA so they no longer produce pigment. They call this "genotoxic stress." During the formation of hair cells, some melanocyte stem cells become melanocytes and some stay as stem cells and store pigment for the next generation of hairs; individual hairs last two to three months. Melanocytes give hair its color. It has not yet been proven that emotional stress causes gray hair. Moreover, they think that this process actually protects stem cells and preserves their quality and quantity. These studies have implications for studies on cancer, researchers say. (Cell 2009; 137(6): 1088-1099)
Andean uplifts affected plant diversity
The Andean uplift has generally been considered a single, time-limited event; however, geological research now shows that the uplift took place in discrete periods from west to east and that it affected different regions at different times. To illustrate how this affected plants, the coffee plant family (Rubiaceae) was selected for study by Alexandre Antonelli and associates at the University of Gothenburg and Stockholm University in Sweden, and Consejo Superior de Investigaciones Cientificas, Spain. They found that coffee plants originated in the Paleotropics and reached South America by means of the boreotropical connections. For a long time, there was a barrier to further dispersal between northern and central Andes Mountains. Then a later uplift occurred that ended the barrier and enabled further dispersal, also giving rise to a huge wetland system (Lake Pebas) in western Amazonia. This prevented formation and dispersal of new species for at least six million years, providing further evidence of several uplifts at different times. (Proceedings National Academy of Sciences USA 2009; 106(24): 9749-9754)
Butterfies avoid enemy ants in laying eggs
Butterflies carefully select plants on which to lay their eggs to avoid ants that feed on butterfly eggs. They do this by visually identifying the kind of ant that specially feeds on butterfly eggs report Sebastian Sendoya and associates at the Universidade Estadual de Campinas, Brazil. They observed that the butterfly Eunica bechina (photo) oviposit on the plant Caryocar brasiliense that are not hosts to Cepalotes ants. The butterflies are able to use ant size and form as visual clues to avoid laying eggs on plant parts occupied by ants more likely to kill larval offspring. (The American Naturalist 2009; 174(1): 134-140)
Time birds need to grow feathers
The pace of life is generally slower among large organisms. Large flying birds depend on large wing feathers that wear out over time and must be replaced by molting. A large bird requires more time to produce a new feather and this determines the way that such birds molt because partially grown feathers reduce flight efficiency. Small birds replace flight feathers quickly, often growing several feathers at a time in each wing. Large birds either prolong molt over two or more years, or adopt complex patterns of multiple feather replacement. Some birds do not rely on flight for feeding so they replace all their feathers at the same time. These conclusions were reported by Sievert Rohwer and associates at the University of Washington, Seattle, and the University of Missouri, St. Louis. (PLoS Biology 2009; 7(6): e1000132)
Life year-round in Arctic forests
About 53 million years ago during the Eocene, large herbivores were year-round inhabitants on Ellesmere Island (Nunavut), which is about 79° N in the Arctic. This is reported by Jaelyn Eberle and associates at the University of Colorado, Colorado College, and Colorado School of Mines. A hippopotamus-like mammal (Coryphodon-photo), alligators, tortoises and a diverse mammalian fauna endured six months of darkness each year where temperatures were summer-like for plant growth. The researchers predict that if present-day warming continues, there will be year-round occupation of plants and animals in the Arctic. (Geology 2009; 37(6): 499-502)
Growth increased by climate change
Diversity is threatened by human-induced climate change. Variables in marine environments such as temperature and carbon dioxide are changing at the same time. With the sea star Pisaster ochraceus, a keystone predator, growth and feeding rates increased as temperature increased from 5 °C to 21 °C and also when the carbon dioxide concentration in water was doubled. This is reported by Rebecca Gooding and associates at the University of British Columbia, Canada. Actually, the growth rate increased whether the temperature increased or not between 12-21 °C. Studies with other organisms have shown a negative growth effect from increased carbon dioxide concentration, so the authors emphasize that different types of organisms will respond differently to changing climatic variables. (Proceedings National Academy Sciences USA 2009: 106(23): 9316-9321)
Earthquakes promote genetic change
The effect of an earthquake on biofilms located in serpentinite (photo), a metamorphic rock containing the mineral serpentine, was studied to determine whether bacteria in the biofilm would be affected by seismic shaking. Two bacteria were tested: Pseudomonas sp. and Bacillus subtilis. As the vibrations from the shaking continued, the plasmid DNA in one cell was acquired by the cell lacking the specific plasmid DNA, report Naoto Toshida and Nori Fujiura at the University of Miyazaki, Japan. The second (recipient) cell acquired antibiotic resistance from the first cell to demonstrate transformation attributable to the seismic shaking. They conclude that bacterial genetic exchange occurs readily when biofilms that form in crevices of serpentinite are exposed by seismic shaking and that such shaking could be a key factor in bacterial evolution. (Astrobiology 2009; 9(3): 289-295)
Antarctic ice sheet 34 million years old
According to Antarctic Climate History, rapid global climate change about 34 million years ago started ice sheet development in Antarctica. This was accompanied by a carbon dioxide content that was less than three times the concentration of the pre-industrial amount plus the development of the Antarctic Circumpolar Current. These two changes led to cooling and glaciation that were also influenced by changes in the Earth's orbit. The ice sheets appear to have started on the isolated Gamburtsev mountains at Dome A which is at the center of the present ice sheet. Radar was used to ascertain the ice base at Dome A showing the Alpine topography when the mean summer temperature then was around 3 °C (37 °F) and that river valleys were overdeepened by valley glaciers. This is reported by Sun Bo and associates at the Polar Research Institute of China, University of Edinburgh (UK), and the National Institute of Polar Research (Japan). This landscape is likely to have developed during the initial phase of Antarctic glaciation and this landscape probably has been preserved beneath the present ice sheet for around 14 million years, according to the authors. (Nature 2009; 459: 690-693)
Leatherback turtle survey in Gabon
The world's largest population of leatherback sea turtles was found nesting in Gabon (Equatorial West Africa) report Matthew Witt from the University of Exeter (UK) and a team of others. This team comprised members from the Wildlife Conservation Society (NY); the University of Florence (Italy); and IUCN-France, in addition to local organizations in Gabon such as PROTOMAC, IBINGA-ACPE, CNIDO-Gabon, AGENCE Nationale des Parcs Nationaux, Gabon Environment, Aventures Sana Frontiéres, and WWF-Gabon. This team estimated that 15,730 to 41,373 breeding females nest along the Gabon coast. This is more than were previously thought to exist in the world; these turtles have been listed as critically endangered globally. Moreover, they reported that 79% of the turtles were found within national parks and other already protected areas. These populations were detected by aerial surveys. Efforts are underway to coordinate conservation and ensure protection from nest poaching and habitat disturbances. (Biological Conservation 2009; 142(8): 1719-1727)