Science Briefs
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)
Saharan dust effect on Amazon basin rain
Aerosol particles, known as ice nuclei, can cause clouds to form and thereby influence precipitation as well as affect the amount of incoming and outgoing solar radiation. When biomass burning in the Amazon basin is absent, aerosol particles are low. However, when there is biomass burning in central Africa and dust is blown from North African deserts, aerosol particles from Africa reach the Amazon basin in South America, often during the wet season. This is reported by Anthony Prenni and associates at Colorado State University, Harvard University, Universidade de São Paulo (Brazil), and Max Planck Institute (Germany). The ice nuclei consisted primarily of carbonaceous material and dust. It is significant that what goes on in the atmosphere of central and north Africa can affect the weather in the central Amazon basin of South America. (Nature Geoscience 2009; 2:402-405)
Fossil skeleton found in Germany
A 47 million-year-old skeleton of a creature named Darwinius masillae was found in Germany and represents the most complete fossil primate ever found. It included skeleton, soft body outline, and contents of the digestive tract. The discovery was reported by Jens Franzen and associates at Forschungsinstitut Senckenberg, Germany; Naturhistorisches Museum Basel, Switzerland; University of Michigan; University of Oslo, Norway; and Universität Bonn, Germany. Investigation suggests that the individual was an independent-feeding female that died in her first year of life and was an agile, nail-bearing, arboreal quadruped living in the Messel rain forest. It was not just a fossil lemur but part of a larger group of primates. Its discovery will aid in the study of the early evolution of monkeys, apes, and humans. (PLoS One 2009; 4(5): e5723)
Lower insect populations at Chernobyl
Twenty years after the Chernobyl radiation accident in Ukraine, populations of bumble bees, butterflies, grasshoppers, dragonflies, and spiders were substantially reduced in forests around Chernobyl report Anders Møller at the Université Paris and CNRS, France, and Timothy Mousseau, University of South Carolina. As the radiation increased, the number of invertebrates decreased. The authors conclude that the ecological effects of radiation on animals are greater than previously assumed. (Biology Letters 2009;5(3): 356-359)
Flower shape and hummingbird bills
Female hummingbirds of the purple-throated Carib (a hummingbird) in the eastern Caribbean have long, curved bills while the males have short straight bills. Females with their long, curved bills visit flowers that have long, curved flowers, while the males hover over short, straight flowers. This is reported by Ethan Temeles and associates at Amherst College, MA, and the Smithsonian Institution, Washington, DC. It took longer for males than females to feed on long, curved flowers. They conclude that there appears to be a co-adaptation of flower types with bird bill shapes and in feeding specialization. (Ecology 2009;90(5): 1147-1161)
Houseplants reduce ozone indoors
Three common indoor houseplants, snake plant (Sansevieria trifasciata - photo), spider plant (Chlorophytum comosum), and golden pothos (Epipremnum aureum) were tested for their effectiveness in reducing the concentration of the air pollutant ozone in a simulated indoor environment. Reduction of ozone concentration was greater where the plants were present than when plants were absent report Heather Papinchak and associates at Pennsylvania State University; moreover, all three plants were equally effective in reduction of ozone. (HortTechnology 2009; 19: 286-290)
Mocking birds can tell people apart
Mocking birds (Mimus polyglottos) quickly learn to recognize people who are threatening. After only two thirty-second exposures to the nest by humans of one to four successive days, birds would express calls of alarm and retreat further each of the four days when that human approached the nest again, report Douglas Levey and associates at the University of Florida. On a large university campus, the mocking bird could recognize a specific threatening human and ignore other humans who passed by the nest. (Proceedings National Academy of Sciences USA 2009; 106: doi:10.1073/pnas 0811422106)
Ant, plant, and fungus cooperation
Some 2,000 plant species have been identified that produce domatia, which are cavities on the undersides of leaves. Not all plants produce domatia. Typically mites and ants inhabit the domatia and they benefit plants. For example, cotton plants had increased yields of 30% when domatia were present. Also, mites in domatia consumed the mildew on grape resulting in less disease. A three-way symbiosis is rare. Ants and a fungus inhabit the domatia of the African ant-plant Leonardoxa africana. The ants fostered the propagation, removal, and maintenance of a non-pathogenic fungus report Emmanuel Defossez and associates at CNRS and University of Montpellier, France; University of Toreno, Italy; and Laboratory of Zoology, Yaounde, Cameroon. So, a three-way partnership is demonstrated in which ants maintain a fungus garden for their food, the fungus benefits by being provided nutrients from the plant for their growth, and the plants benefit presumably by the ant's feeding on parasitic fungi that can cause disease. (New Phytologist 2009; 182(4): 942-949)
Tracking ash dispersal from volcano
The major explosive eruption of Chaitén volcano in Chile that started May 2, 2008, provided an opportunity to track the dispersal and deposition of fine volcanic ash. This was the first eruption of this volcano since about 7420 BC and was the largest explosive eruption globally since Hudson, Chile, in 1991. The plume was nearly twenty miles high on May 6. Field examination of distal ashfall indicates that about 176,369 tons of ash was deposited over about 77.2 square miles of Argentina during the first week of eruption, report Sebastian Watt and associates at the University of Oxford, UK. Deposition of ash over a continental region allowed the tracking of eruption development and demonstrated the potential complexity of rock fragment and particle dispersal from a single eruption, which in this situation comprised several phases over a week-long period of intense activity. (Journal Geophysical Research 2009; 114, B04207)
Temperature affects bird reproduction
Many bird species are known to reproduce early in years when spring temperatures are high. Is this temperature effect direct or because of food availability? To answer this question, the authors studied the great tit (Parus major) for six years (photo). With a temperature difference of 4 °C, the birds started lying eggs three weeks earlier at the upper temperature than at the lower one. Thus temperature had a direct effect on timing of breeding conclude Marcel Visser and associates at the Netherlands Institute of Ecology, Heteren. (Proceedings Royal Society B 2009; 276: 2323-2331)
Blue straggler stars have triple origin
Blue straggler stars are stars observed to be hotter and bluer than other stars but produce the same amount of light. Because of these characteristics, they have been thought to be younger than other stars in the population of stars. So far two explanations have been given to explain their existence: they are the product of collisions of stars in clusters or they result from transfer or merging of components in primordial materials (a kind of cannibalism). A third scenario is that the progenitors of blue stragglers are formed in primordial hierarchical triple stars that can induce the formation of very close inner binary stars (two stars in a group). These binaries then merge according to Hagai Perets at the Weizmann Institute of Science, Israel, and Daniel Fabrycky at the Harvard Center for Astrophysics. Astronomers sometimes use the term "triple star" to mean multiple stars (three or more) that are close to each other in some hierarchical system and function as one star. (The Astrophysical Journal 2009; 697:1048-1056).
Mites clean bee nests
Some bee mites perform cleaning services for their hosts in exchange for suitable environments and dispersal. In the field, where mites were present there were no fungi inside the brood cells of bees and more bees died when mites were absent report Natalia Biani and associates at the University of Texas and the Smithsonian Tropical Research Institute, Panama. When fungi were introduced into natural nests of bees (Megalopta genalis and M. ecuadoria), the authors found that mites cleaned out the fungi that had accounted for the death of the bees. The authors concluded that this bee-mite association is one of few examples of cleaning mutualisms on land.(photo of bee head) (The Amerian Naturalist 2009; 173(6): 841-847)
Much of Mercury's crust is of volcanic origin
Mercury is the planet closest to the Sun and it has no atmosphere. The Messenger spacecraft flew by the planet Mercury twice in 2008 and together with observations by Mariner 10 provided high-resolution images of 90% of the surface of Mercury. Analyses of these images indicated that large expanses of the smooth plains of the planet's crust originated volcanically report Brett Denevi and 10 associates at Arizona State University, Carnegie Institute of Washington, Johns Hopkins University, Smithsonian Institution, and Brown University. Three types of terrain were seen: smooth plains, intermediate terrain, and low reflectance material. Smooth plains are widespread and cover about 40% of the surface and are globally distributed. (photo Mercury surface) (Science 2009; 324(5927): 613-618)
White blood cells crawl in vessels
White blood cells (lymphocytes) are a part of the natural immune system and play a major role in defending the host from both tumors and infected cells. (Lymphocytes are one of five types of white blood cells). For white blood cells to be effective in reaching the site of infection or injury, they must cope with the blood stream. The cells can move against the current by producing tiny "legs" and crawl along the lining of the blood vessels. They function like a millipede and cling to the tissues as they crawl to the damaged cells report Ziv Shulman and associates at The Weizmann Institute of Science, Israel; University of Verona, Italy; and Harvard Medical School, Boston. These tiny legs are less than a micrometer long and were seen by means of electron and tranmission microscopes. (A human hair, for comparison, is about 100 micrometers wide). The authors think that the tiny legs have three functions: grip the vessel lining, move, and sense the distress signals that come from damaged tissue. (Immunity 2009; 30(3): 384-396).
Coiling and twining in plants
Why vines twine and tendrils twist has been investigated since Darwin's time. By using microscopic and immunocytochemical techniques, tendrils (threadlike spiral tips of climbing plants) and twining vines were examined for tissues that could account for the coiling and twining. Tendrils that coiled in many different directions had within their tissues a cylinder of gelatinous fibers; however tendrils that coiled in only one direction had gelatinous fibers only along the inner surface of the coil report Andrew Bowling and Kevin Vaughn at the US Department of Agriculture, Stoneville, Mississippi. In tendrils with adhesive tips, the gelatinous fibers were in the core of the tendril. The gelatinous fibers were not present when the stems were still winding around a support, but once the position of the twining stem was fixed, gelatinous fibers appeared near the tips. The number and extent of the fiber development depended on the amount of twist (torsion) needed for the vine to climb a support structure. Their conclusion is that coiling and twining is facilitated by the presence of gelatinous fibers. (American Journal of Botany 2009; 96: 719-727)
Oxytoxin is a bone hormone
Oxytoxin has generally been regarded as a primitive nerve hormone that solely controlled lactation and social bonding. New research shows oxytoxin to be a direct regulator of bone mass report Roberto Tamma at the University of Bari, Italy, and a team of twenty-five investigators from Mount Sinai School of Medicine (NY), Hebrew University of Jerusalem (Israel), Tohoku University (Japan), and Emory University (Georgia). Osteoporosis resulting from reduced bone formation occurred in mice when oxytoxin was absent. Oxytoxin stimulates formation of bone cells. The authors conclude that oxytoxin is a novel, anabolic regulator of bone mass and it has potential for use in treatment of osteoporosis. (Proceedings National Academy of Sciences USA 2009; 106(17):7149-7154)
Romanization of rural town in Gaul
The discussion of Romanization of Gaul at the end of the first century BC and the start of the first century AD has been focused by archaeologists on the elite culture of Gaul. Recent excavations of a largely rural lower class Roman town in what is now central France documents that people changed their building techniques, ceramic preferences, and social habits through the first and second centuries. This is reported by Jane DeRose Evans and associates at Temple University (Philadelphia) and University of François-Rabelais, France. By the end of the second century the town was depopulated, which was thought to be due to an overambitious urbanization project by the Romans. The authors think these excavations enable better understanding of the political, social, and economic life of central France from the Augustan period to the Early Middle Ages. (Photo - bones of young women in bowl) (American Journal of Archaeology 2009; 113(2): 255-272)
Solar winds cause asteroids coloring
Some asteroids are redder than others and the reddening has been attributed to collisions between asteroids that have created fresh surfaces. Space weathering then rapidly changes the surface color to red. "Rapid" in this instance means less than a million years as this is a short time when considering the age of the solar system. The solar wind is the main mechanism of space weathering, and accounts for the red-colored surface of the asteroid report Pierre Vernazza and associates at the European Space Agency, Netherlands; Massachusetts Institute of Technology; ISTI-CNR, Pisa, Italy; and Observatoire de Paris, France. They also report that fresh surfaces on asteroids near a planet may be the result of tidal shaking by the planet that rejuvenated the asteroid surfaces. (Nature 2009; 458:993-995)
Fish choose mates by electricity
Mormyrid fish in the Congo rapids of Africa have a special electric organ that enables them to locate and communicate with other fish of the same species. Electric signals also enable female fish to distinguish, and be attracted to, male fish for mating report Philline Feulner and associates at the University of Potsdam, University of Bonn, Humboldt University and the Leibnitz Institute (Berlin), in Germany; the University of Sheffield, UK; and University of Oklahoma. Female fish can recognize electric signals as coming from male fish of the same species (Campylomormyrus species). (Biology Letters 2009; 5(2): 225-228)
Calcification decrease in ocean plankton
Sea water has become more acid attributable to the accumulation of carbon dioxide which lowers both the concentration of carbonate ions and the pH. The decrease in carbonate ion concentration causes calcareous marine organisms to decrease the rate of calcification, as shown in laboratory experiments. Some single-celled, calcite-secreting organisms of planktonic foraminifera represent 25-50% of the total in the open ocean and they influence the transport of organic carbon to the interior of the ocean. Shell weights of modern foraminifer Globigerina bulloides (photo) collected from the Southern Ocean were 30-35% lower than foraminifers collected from Holocene-aged sediments. This is reported by Andrew Moy and associates from the Antarctic Climate and Ecosystems Cooperative Research Center, Australian Antarctic Division, University of Tasmania, and CSIRO Marine and Atmosphere Research, in Tasmania, Australia. They also reported a link between high carbon dioxide concentrations and low shell weights in a 50,000-year-long record from a Southern Ocean marine sediment core. (Nature Geoscience 2009; 2: 276-280)
Wild bees pollinate plants effectively
Colony Collapse Disorder has affected honey bees essential to pollination of many crops in the United States. In growing a crop of high-bush blueberry (Vaccinium corymbosum), which depends on pollen transfer by bees for a good fruitset and large berries, the role of wild bees compared to honey bees was investigated by Julianna Tuell and associates at Michigan State University and the American Museum of Natural History. Unlike honey bees, which live together in hives, most of the wild bees investigated were solitary bees that nest in soil or in wood cavities. These wild bees also visit cherry, apple, and cranberry plants. The authors reported finding at least 166 bee species among the blueberry bushes, 112 of which were active when blueberry was in bloom. They added that many of the wild bee species visit more flowers per minute and deposit more pollen per minute than honey bees (Apis mellifera) and they represent potential blueberry pollinators. Although Andrena carolina was the most abundant of the wild bees counted, the authors stated that several species of wild bees (Osmia spp.-photo) were potential targets for management. They suggested managing wild bee populations by setting out foam blocks with holes drilled into them, or wood with holes of different sizes drilled into them. (Annals Entomological Society of America 2009; 102(2): 275-287)
Music perception in different cultures
Which aspects of music perception are universal and which are developed only after exposure to specific music cultures? In order to study this question, two human populations were selected for comparison: a Western group and a native African population (Mafa). Both groups were considered naive in music. The first experiment was to ascertain if both cultures could recognize three basic emotions in their own and in each other's music: happy, sad, and scared/fearful. The second experiment was to see if the reaction to dissonance was the same for each group when exposed to their own and to the other group's music. Both groups recognized the same emotions whether they were listening to their own music or music of the other culture, and both groups preferred the original to the dissonant variations of the music of both cultures. This study was reported by Thomas Fritz and associates at the Max Planck Institute, Germany; the UCL Institute of Child Health and the University of Sussex, UK; and the University of Montreal, Canada. (Current Biology 2009; 19(7): 573-576)
Centaurs contain amorphous ice
Centaurs in space are an unstable class of minor planets that behave as half asteroid and half comet. They are recent escapees from the Kuiper Belt and are reported by David Jewitt of the University of Hawaii as "destined to meet a fiery oblivion in the hot inner regions of the solar system, or be ejected to the interstellar medium...from the giant planets." Jewitt states that some centaurs are captured by Jupiter and are labeled as "short-period comets" and show comet-like activity beyond Jupiter's orbit. Mass loss in centaurs has been attributed to sublimation of water ice but Jewitt maintains that most centaurs are too cold for activity to originate by sublimation of crystalline water ice, and he has a different explanation. He thinks the activity by centaurs is due to the conversion of amorphous ice into the crystalline form accompanied by the release of trapped gases, such as carbon monoxide. Amorphous ice is water that has cooled so quickly that the molecules haven't had time to form a crystal lattice; instead molecules are arranged randomly. So, his conclusion is that the centaurs contain amorphous, not crystalline, ice. (The Astronomical Journal 2009; 137: 4296-4313)
Agricultural origins in northern China
Apparently there were two periods representing the origins of agriculture in northern China. The first was brief and non-intensive and took place between 7900 and 7200 years ago. During this period people harvested and stored broomcorn millet (Panicum miliaceum—see photo) to provision themselves and their hunting dogs (Canis sp.) throughout the year. The second phase was more intensive and occurred by 5900 years ago during which both broomcorn millet and foxtail millet (Setaria viridis) were cultivated and were part of the diets of people, dogs, and pigs. These determinations were made by using techniques of stable isotope biochemistry and radiocarbon dating of ancient human and animal bones. The research was reported by Loukas Barton and associates at the University of California, Davis; Katmai National Park and Preserve, AK; Lanzhou University, China; Carnegie Institution of Washington, DC; Gansu Province Institute of Cultural Relics and Archaeological Research, China; and Lawrence Livermore National Laboratory, CA. (Proceedings National Academy of Sciences USA 2009; 106: 5523-5528)
Resiliency of tropical rain forests
In Costa Rica, where rain forests have lost some of their acreage, secondary rain forests are making a comeback by reassembling composition of canopy tree and palm species report Natalie Norden and associates at the University of Connecticut; National Tsing Hua University, Taiwan; and Instituto Tecnolólogico del Costa Rica. The secondary rain forest resembles that of the mature forest community composition. The authors attribute this resiliency of the rain forest to three factors: seed dispersal is high, there is abundant generational material in the regional flora, and old-growth forest remnants are still present locally. (Ecology Letters 2009; 12(5): 385-394)
Earlier timing of Moon's crust
The Moon is thought to have been formed by consolidation of debris coming from the collision of a Mars-sized body with the Earth more than 4,500 million years ago. The primitive Moon was covered with a thick layer of melted material known as the lunar magma ocean. This ocean of melted material crystallized to form the surface of the Moon as seen today. There is a debate regarding when this crystallization occurred. A mineral zircon (zirconium silicate) from the Moon (see photo) was dated as having crystallized 4,417 million years ago report Alexander Nemchin and associates at Curtin University of Technology, Australia; Westfallische Wilhelms-Universtät, Germany; and NASA Johnson Space Center, Texas. From this the authors conclude that the formation of the Moon's crust followed the solidification of 80-85% of the original melted material within about 100 million years after the collision. They further indicate that there was a continued solidification of a low percentage of melted material for an extra 200-400 million years. (Nature Geoscience 2009; 2: 133-136)
Largest wind ripples on in Argentina
The largest wind ripples on Earth, comparable to those found on Mars, were found in Argentina Puna Plateau at an altitude of 4000 meters (13,123 feet) report Juan Pablo Milana at the National University of San Juan, Argentina. The wind ripples are 2.3 meters tall with a wave length of 43 meters. The winds carry a high proportion of pumice particles with a grain size of 19 millimeters (0.75 inch).The large ripple size is related to the strong winds, dense saltation layers, and a long period of evolution. Part of the reason for study is to understand the effects of very strong winds on surfaces with movable materials. (Geology 2009; 37(4): 343-346)
Earliest corn found in Mexico
Starch grains and particles of fossilized plant tissue found in a shelter in the tropical Balsas River Valley of southwest Mexico were identified to be from corn, indicating that this is the earliest date for the origin of corn, nearly 9,000 years ago. This was reported by Dolores Piperno and associates at the Smithsonian National Museum of Natural History, DC; Smithsonian Tropical Research Institute, Panama; Temple University, PA; and University of Exeter, UK. These results confirm early reports that corn originated in the tropical forest rather than in the arid highlands (teosinte, photo). At the site, fossils of a domesticated species of squash (Cucurbita argyrosperma) were also found. (Proceedings National Academy of Sciences USA 2009; 106(13): 5019-5024)
Massive galaxies assembled early after Big Bang
A new picture of galaxy formation is shown in which the most massive galaxies grew rapidly early in the formation of the universe report Chris Collins at the Liverpool John Moores University, UK, and seventeen associates from twelve institutions in five nations. They note further that the brightest cluster galaxies were almost fully assembled four to five billion years after the Big Bang, having grown to more than 90% of their final stellar mass by this time. This conclusion differs from the current consensus which states that galaxies had started as small density changes in the universe but had developed gradually and merged to form building blocks called haloes. These haloes were thought then to have eventually become assembled into galaxies, which meant galaxies were formed much later. (Nature 2009; 458: 603-606)
Rising springs along Silk Road
Rising springs along the ancient Silk Road in northwestern China have repeatedly caused flooding forcing more than a thousand families to abandon their homes. These springs are near the Quilian Mountains in the Hexi Corridor and in an area of extreme aridity. The rising springs appear to be caused by melting glaciers due to global warming and by recent earthquakes that raised the local water table to recharge the groundwater report Jian Sheng Chen at Hohai University, China, and Chi-yuen Wang at the University of California, Berkeley. They report further that this event has implications for the effect of climate change on water resources and management of arid regions. (Geology 2009; 37(3):243-246)
Female finches adjust gender of their eggs
When female Gouldian finches (Erythrura gouldiae) are mated with an incompatible (different color markings) male, they overproduce sons report Sarah Pryke and Simon Griffith of Macquarie University, Sydney, Australia. Moreover, incompatible pairings result in smaller clutch sizes, smaller eggs, and less care of offspring. The authors surmise that because incompatible pairings result in daughters that do not survive or at least do not develop normally, it is a poor investment to produce daughters; hence the greater number of sons. The female can control the gender of the egg. Photo of male and female birds. (Science 2009; 323 (5921): 1605-1607)
Asteroid fragments found in desert
An asteroid headed for Earth was discovered October 6, 2008, by the Catalina Sky Survey. About 19 hours later, the asteroid entered the Earth's atmosphere where it disintegrated at an altitude of 37 kilometers (23 miles). A team of 35 scientists from 7 countries, led by P. Jennniskens at the SETI Institute in California, traced the trajectory of the asteroid and located 47 meteorites in a desert in northern Sudan (see photo). These fragments were identified as being part of a single body, named Almahata Sitta. Subsequent analysis indicated it was a class F asteroid, and the material found was not previously represented in the meteorite collections. (Nature 2009; 458: 485-488)
Plants in hospitals promote healing
The therapeutic value of plants in a hospital environment is an effective complementary medicine for patients recovering from surgery report Seong Park and Richard Mattson at Kansas State University. They found that patients in hospital rooms with plants and flowers had shorter hospital stays, fewer intake of analgesics, lower rating of pain anxiety and fatigue, and more positive feelings and greater satisfaction with their rooms when compared with patients without plants. (HortScience 2009; 44(6): 102-105)
Nitrous oxide emission from peat
The concentration of greenhouse gas nitrous oxide has been increasing in the atmosphere. Its greatest emission into the air has been reported to come from agricultural and tropical soils. Emission of nitrous oxide from northern uncultivated (natural) soils has been considered to be negligible. Now, it is reported that nitrous oxide emitted by the permafrost zone in subarctic East European tundras from June to October is about equal to that from tropical and agricultural soils, according to Maija Repo and associates from the University of Kuopio and the University of Helsinki, Finland; and the Institute of Biology, Russia. The authors conclude that nitrogen stored in permafrost soils, in addition to carbon, has to be considered when evaluating the climatic influence of tundra. (Nature Geoscience 2009; 2: 189-192)
White dwarfs harbor minor planets
Between 1% and 3% of all single white dwarfs with cooling ages less than around a half billion years old have circumstellar dust. This means that there is an underlying population of minor planets orbiting the white dwarfs report J. Farihu and associates at the University of Leicester, UK; University of California at Los Angeles; and Gemini Observatory, Hawaii. The dust was thought to have originated from a tidally destroyed minor planet. (The Astrophysical Journal 2009; 694: 805-819)
Merging galaxies and black holes
Most large galaxies harbor black holes in their nuclei and it has been observed that galaxies merge fairly frequently. This should create a galaxy with two black holes. After making a large survey of galaxies such a situation was found by Todd Boroson and Tod Lauer at the National Optical Astronomy Observatory in Tucson, Arizona. They reported finding a binary system with two black holes in as tight a pairing as thought to exist within a galaxy. (Nature 2009; 458: 53-55)
Live plants not a major source of methane
Methane emission has been reported from whole plants and from detached leaves; it was estimated that plants could account for 10-45% of the global methane source. However, no known biochemical pathway was found in plants to synthesize methane report R. E. R. Nisbet and associates at the University of Cambridge, University of London, and University of Oxford in UK, and in Stockholm University, Sweden. But under high ultraviolet stress conditions, there can be a spontaneous breakdown of plant material that releases methane. Moreover, plants can take up from soil and transpire water containing dissolved methane. Such findings may have inspired the earlier conclusions. Thus the authors conclude that living plants are not a major source of global methane production. (Proceedings Royal Society B 2009; 276: 1347-1354)
Earthquake mudslides emit carbon dioxide
Carbon dioxide released by the Wenchuan earthquake in China in 2008 was equal to about 2% of the current annual emission from global fossil fuel combustion. This is reported by Jiahu Wang of the University of Texas, Austin, and associates located at Hohai University and the Chinese Academy of Sciences, China; University of Oklahoma; and the University of Melbourne, Australia. Plants and topsoil are removed from the earth surface by the mudslides, depriving new plants nutrients for growth as well as burying vegetation. Decomposing vegetation releases carbon dioxide into the air in an amount comparable to that caused by hurricane Katrina in 2005. Moreover, the loss of nitrogen is twice as much as that released by the 2007 fire in California. A significant part of the nitrogen loss (14%) is in the form of nitrous oxide, which can affect the atmospheric ozone layer. (Geophysical Research Letters 2009; 36: L05401)
Aerosol removal hastens warming in Europe
Temperatures on mainland Europe increased about 1 °C (1.8 °F) since the 1980s which was unexpected based on calculations of human-induced greenhouse warming report Rolf Philipons and associates at the Aerological Station and the Institute for Atmosphere and Climate Science, in Switzerland, and at the Meteorologisches Observatorium Lindenberg, in Germany. However, there has been a 60% decline in aerosols recently so that human-induced aerosols are near low and stable values in Europe. This aerosol decline causes greenhouse gases to increase thereby forcing rapid warming. (Geophysical Research Letters 2009; 36: L02806)
Monkey can use tools
Capuchin monkeys shared a common ancestor with humans 35 million years ago. A study fourn that when confronted with a variety of stones of different shapes, sizes, and weights, the monkeys selected stones suitable for cracking nuts. This is reported by Elisabetta Visalberghi and associates located at the Institute of Cognitive Sciences and Technologies, University of Padua, Sapienza Universitá di Roma, Italy; University of São Paulo, Brazil; and University of Georgia, USA. The monkeys showed that by trial-and-error they learned what stones worked best in cracking nuts and then planned to use those stones in future situations. (Current Biology 2009; 19(3): 213-217)
Fire frequency effect on Alp pines
Global climate change has been predicted to increase drought in the Alps during the twenty-first century. This would also increase the risk of fire and possibly eliminate some tree species. To look into the past for possible effects of fire in the Alps, a subalpine pond in the western French Alps that existed during the early-Holocene expansion (7200 years ago) was examined. A cembra pine (Pinus cembra) forest had been subjected at that time to fire at moderate intervals. After the fires, the abundance of cembra pine decreased significantly, but did not become extinct report A. Genries and associates at the Université Montpellier, Institut de Botanique, CNRS, and Université Paul Cézanne-CNRS, in France, and, Université Laval, Canada. Moreover, they report that these fires were surface fires not stand-depleting fires, and that primarily non-reproductive trees had burned. Their conclusion is that in the future increased drought could reduce the cembra pine populations in the Alps but not make them extinct if the fire frequency intervals were less than 80 years. (Ecology 2009; 90(2): 476-486)
Oxygen loss in oceans
Carbon dioxide produced by burning fossil fuels can prolong global warming for a long time because it takes decades to hundreds of thousands of years for natural processes to remove carbon dioxide from the atmosphere. By means of a model projecting over 100,000 years, a team of scientists predict that global warming will increase in strength and duration, and that oceans will get warmer and lose oxygen report Gary Shaffer and associates at the University of Copenhagen, the Danish Center for Earth System Science, the Danish Meteorologial Institute, and the University of Denmark, in Denmark; and the University of Concepcion, Chile. Oxygen in the top 500 meters (1640 feet) of the ocean becomes less soluble as the water warms up and that accounts for most of the loss of oxygen from oceans. The authors conclude that fossil-fuel use must be reduced substantially over the next few generations to avoid extensive depletion of oxygen for thousands of years. (Nature Geoscience 2009; 2(1): 105-109)
Beat in music detected by newborn infants
The question to be investigated was whether perception of beat in music is innate or learned after birth. Beat detection, that is, detection of a regular pulse in a sound signal, has been considered to be a fundamental human trait and important in determining the origin of music. Newborn infants developed expectation for the downbeat (onset of rhythmic cycles) even when it is not marked by stress or other defining features report Iatván Winkler an associates at the Hungarian School of Science, Budapest University, and Semmelweis University, in Hungary; and Universiteit van Amsterdam. Sensory expectation elicits brain activity when the downbeat is omitted. The authors conclude that humans are born with the character of beat perception. (Proceedings National Academy Sciences USA 2009; 106(7): 2468-2471)
Vibrations cause earthworm emergence
In southeastern United States, earthworms are harvested from soil by pounding wooden states into the ground and then scraping the stake surface with a flat, metal object. This produces vibrations that bring earthworms (Diplocardia spp.) to the soil surface within minutes and the emergence is less frequent with increasing distance from the stake. The earthworm response seems to be to avoid vibrations, or, the earthworms perceive the vibrations to be due to falling rain report O. Mitra and associates at Carleton University, Ottawa, Canada, and USDA Forest Service, Athens, Georgia. Rain produces anaerobic conditions (lack of free oxygen) that stimulate earthworms to seek refuge to air containing oxygen above soil surfaces. (Biology Letters 2009; 5(1): 16-19)
Nerve stem cells function as embryo cells
Four factors that can transfer genetic information (transcription) were used to induce nerve cells in mice to be able to form many other kinds of cells (pluripotentcy) report Jeong Beom Kim at Max Planck Institute in Germany and seventeen associates at four institutions in Germany and the United States. They report that these pluripotent stem cells are similar to embryonic stem cells and can be efficiently differentiated to make other kinds of cells, thereby providing an alternative to using embryo cells in cell transfers. (Cell 2009; 136(3): 411-419)
Columnar jointing discovered on Mars
Columnar jointing, which indicates the presence of cooling lava and liquid water, was found in Marte Valles, Mars, on the near-surface rocks. This is reported by M. P. Milazzo and associates at the US Geological Survey, Flagstaff, Arizona; the University of Arizona; SETI Institute, California; and NASA's Ames Research Center, California. These columnar lavas are located on the wall of an impact crater with features of terrestrial coumnar basalts, and covered an area at least 200square kilometers (77 square miles). Photos were taken from the Mars Reconnaisance Orbiter. (Geology 2009; 37(2): 171-174)
Tracking songbird migration time
Tracking songbird migration to the tropical wintering grounds has been difficult. Songbirds are too small for satellite tracking and tracking devices were too big to attach to their bodies. Geolocators were developed that were small enough to be attached to wood thrushes and purple martins that had been breeding in northern Pennsylvania. Rapid long-distance movements were found in both species. The purple martins flew south 2500 kilometers (1553 miles) to Yucatan Peninsula in five days at 500 kilometers (311 miles) per day. They stopped over in this region for three to four weeks report Bridget Stutchbury and associates at York University, Canada; Tom Ridge Environmental Center, PA; and British Antarctic Survey, Cambridge, UK. Four of the wood thrushes spent one to two weeks in southeastern United States before crossing the Gulf of Mexico, and two stopped on the Yucatan Peninsula for two to four weeks before continuing migration. Wood thrushes overwinter in Honduras or Nicaragua. Overall migration rate was two to six times more rapid in spring than in fall. Authors conclude that tracking individuals to wintering sites is needed to predict effects of tropical habitat loss and climate change. (Science 2009; 323(5916): 896)
Silicates around white dwarfs
Silicates are the most abundant compounds on the surface of the Earth and are common in meteorites and comets. Silicates have now been found in six dust-orbiting, externally polluted white dwarfs (circled in photo) report Michael Jura and associates at the University of California, Los Angeles, and the University of Leicester, UK. They further report that these dust particles are likely produced by "tidal disruption of asteroids" and the white dwarf is then said to be a "polluted" white dwarf. This happens when an asteroid (leftover scraps of planetary material) gets too close to a star and is pulled apart by the star's gravity. Observations such as these, made by using NASA's Spitzer Space Telescope, help astronomers better understand the make-up of the rocky planets around other stars. (The Astronomical Journal 2009; 137:3191-3197)
Improving antioxidant properties of pizza
In a study of baking conditions for preparing whole-wheat pizza crusts, longer dough fermentation time and increased baking time or temperature can increase antioxidant availability report Jeffrey Moore and associates at the University of Maryland. Increasing baking temperature from 204 to 288 °C (399 to 550 °F) with a seven minute bake time increased the antioxidant properties by as much as 82%. Bran particle size had no effect on antioxidant properties. (Journal of Agricultural and Food Chemistry 2009; 57(3): 832-839)
Natural oil slicks in Gulf of Mexico
At least one hundred sixty-four surface oil slicks that were the result of natural seepage of oil from Earth were detected in the northwest Gulf of Mexico by glint reflectance from the Sun. This is reported by Chuanmin Hu and associates at the University of South Florida, University of Massachusetts Dartmouth, and at IMSG/NESDIS and NESDIS NOAA in Maryland. These natural seepages were detected by using MODIS imagery (Moderate Resolution Imaging Spectroradiometer) located on the satellites Terra and Aqua. Terra travels north to south over the equator in mornings and Aqua travels from south to north in afternoons. By using MODIS imagery, natural seepage rates in the world's oceans can be determined, according to the authors. (Geophysical Research Letters 2009; 36: L01604)
Gourd family came from Asia
To improve economically important plants genetically and to conserve them, it is important to know where they came from geographically. Plant scientists can determine origin by examination of plants in herbaria and by DNA analyses. When plants were examined from thirty herbaria worldwide, the origin of the gourd family Cucurbitaceae—that includes cucumber, squash, and muskmelon—was found to be in Asia during the late Cretaceous. This was reported by Hanno Schaefer and associates at the University of Munich, Germany. There was repeated spread of varieties into Africa, Americas, and Australia. Madagascar was colonized thirteen times from Africa, and Australia was colonized twelve times from southeast Asia. The authors estimate that there were at least forty-three successful long-distance dispersal events every 10 million years. Authors emphasize how important museum or university herbaria have been in getting information useful in modern plant genetics. (Proceedings of The Royal Society B 2009; 276(1658) 843-851)
Bacteria used to track human migration
The Pacific area has been reported to be peopled by two prehistoric migrations. One population reached New Guinea and Australia and a second reached the Polynesian islands by way of Melanesia. Accompanying these migrations was a bacterium Helicobacter pylori (causes ulcers) that comprises two distinct populations according to Yoshan Moodley at the Max Planck Institute in Germany and nine associates at institutions in Australia, France, Germany, Ireland, New Caledonia, New Guinea, Russia, Taiwan, and USA (TX). This split in populations of bacteria occurred 31,000 to 37,000 years ago according to archaeological history. The divergence was enough to show that bacterial populations were isolated for the past 32,000 years. By study of bacterial populations and their dispersion, the authors conclude that there is support for two distinct human migrations into the Pacific. The first and early migration to New Guinea and Australia was followed by a much later migration from Taiwan into the Paciific. (Science 2009; 323(5913): 527-530)
Evening primrose dispersal
Evening primroses (Oenothera species) growing in western USA diversified due to past climate changes according to Margaret Evans and associates at Yale University. They studied nineteen closely related species of Oenothera by comparing DNA sequence data. Their analyses revealed that evening primrose species shared a common ancestor about a million years ago when there were striking fluctuations in climate such as glaciers and interglacial cycles. These events could have changed the distribution of species north and south repeatedly to bring about diversity through interbreeding. They focused on Oenothera deltoids, whereas the common species in the east and midwest is O. biennis (photo) (The American Naturalist 2009; 173(2): 225-240)
Deep convection returns to the ocean
Surface water in the subpolar North Atlantic Ocean usually sinks deeply as a distinct water mass. As water sinks, carbon is removed from the air and chemically bound. In recent years, this convection has been shallow or absent, construed to be a result of a warmer climate. However, in the winter of 2007-2008, there was a surprising return of deep water convection in the Labrador and Irminger seas of the subpolar North Atlantic Ocean report Kjetil Våge at Woods Hole Oceanographic Institution (MA) as part of a team. His associates were at IFREMER , France; Laboratoire d'Océanographie Dynamique et de Climatologie, France; Bedford Institute of Oceanography, Canada; University of Washington; Meteorological Service of Canada; and the Danish Meteorological Institute. In addition, the convective state took place abruptly without a phase of preconditioning as normally expected. This enhanced flow of heat from the sea to the atmosphere made the surface water cold and dense enough to sink and start the deep convection in the ocean. Other factors such as change in hemispheric air temperature, storm tracks, and the flow of fresh water to the Labrador Sea complicate the situation to make it difficult to predict when deep mixing can again occur. (Nature Geoscience 2009; 2:67-72)
Home landscapes affect wildlife
Managed home landscapes in which non-native ornamental plants are favored over native plants dominate home properties in the United States. The question arises as to how this affects bird and butterfly populations on home grounds. This question was investigated by Karin Burghardt and associates at the University of Delaware. They reported that properties with native plants supported many more caterpillars and caterpillar species and greater abundance of birds with greater diversity and more species, and more breeding pairs, than properties landscaped with more conventional plants and shrubs. Moreover, when bird species that were of special conservation concern were considered, they were eight times more abundant and more diverse on the native-plant properties. (Conservation Biology 2009; 23(1): 219-224).
Dust important in galaxy formation
The dust found in interstellar space is critical to the formation and development of galaxies and it governs chemistry and physics in space. Dust can be detected in galaxies that date back to 870 million years after the Big Bang; how it became dusty that early has intrigued scientists. In the universe, dust develops mainly from the material that is ejected from stars. Dust is important also because it cools the interstellar medium, attenuates light emitted by galaxies, and dust fragments can collapse molecular clouds into intermediate and low mass stars. By analysis of data gathered from the Spitzer telescope, dust forming around a star in a nearby galaxy has a 25% lower abundance of heavy elements than are found in the sun, report G. C. Sloan and associates at Cornell University, National Optical Astronomical Observatory of Japan, University College of London (UK), University of Manchester (UK), Royal Observatory of Belgium, Australian National University, and Keele University (UK). Because this dust lacks heavy elements, the authors conclude that primordial composition is not an obstacle to dust production. (Science 2009; 323(5912): 353-355)
Origin of blue straglers
Blue straglers are unusually hot and bright stars found in cores of ancient star clusters. Globular clusters are seen in galactic halos in the Milky Way and there may be 180-200 or more of them (see photo). Most are about twelve or more billion years old. Astronomers report that they should have evolved long ago. Two known processes that can create these straglers are collisions of objects in space and binary evolution, but the relative importance of these two processes is unclear, according to Christian Knigge and associates at the University of Southhampton (UK) and at McMaster University (Canada). Now they conclude that most blue straglers, even those in cluster cores, come from binary systems. They arrive at this conclusion because they found a correlation between the number of blue straglers in the cluster core and the total stellar mass contained within the core. The binary theory of origin means that current or former binary stars have merged or are in the process of merging; the merger of two stars would create a single star with a greater mass to make a hotter and brighter star than stars of similar age. If that happened it would support the current stellar evolution theory, in their view. (Nature 2009; 457:288-290)
White-nose syndrome in bats
The cause of death in bats in northeastern USA has been puzzling. In Connecticut, Massachusetts, New York, and Vermont it was estimated that over two years 75% of the bat population declined attributable to the white-nose syndrome. It was called that because the muzzles, ears, and wing membranes in hibernating bats are covered with a white fungal growth. Different species of bats are susceptible including the little brown myotis, northern long-eared bats, tricolored bats, big brown bats, and some unidentified bats. From ten of these bats, a previously undescribed fungus was isolated, named Geomyces sp., which grows at low temperatures in cold climates. This is reported by a team led by David Biehert of the US Geological Survey, Wisconsin, and associates from six other institutions or government agencies. This doesn't prove that Geomyces causes the white-nose syndrome because they did not inoculate bats to reproduce the disease. Bats are important ecologically in control of insects, in pollinating plants, and in seed dissemination. (Science 2009; 323(5911): 227)
Glacier acceleration short-lived?
The recent marked retreat, thinning, and acceleration of glaciers south of 70° N increases concern over Greenland's contribution to rise in sea level. These changes seem to parallel the warming trend in Greenland but this could be a transient response to climatic change and should therefore not be extrapolated into the future. This is reported by Faezeh Nick and associates at Durham University (UK), Ohio State University, and University of Washington. They state that their simulation model shows that the ice acceleration, thinning, and retreat begin at the place where calving takes place and then propagate upstream through "dynamic coupling" along the glacier. Moreover, they say that these changes are unlikely to be caused by basal lubrication through surface melt propagating to the glacier bed. Furthermore, they continue that tidewater outlet glaciers adjust extremely rapidly to changing conditions at the point of calving, to make unreliable any extrapolation into the future. (Nature Geoscience 2009; 11 January 2009; doi:10.1038/ngeo394)
Storms on Mars disturb magnetic field
Space weather related to the effect of high pressure solar wind strongly disturbs or alters the magnetic field and the ion layer on Mars. This is reported by E. Dubinin and associates at the Max Planck Institute, Germany; University of Iowa; CETP-IPSI, France; and the Swedish Institute of Space Physics, Sweden. The magnetic barrier formed by the pileup of the draped interplanetary magnetic field is no longer a shield against the incoming solar wind. Dense masses of ion gas (plasma) are blown from the ionosphere which becomes fragmented. This scavenging effect of the solar winds increases losses of volatile material from Mars by a factor of about 10. (Geophysical Research Letters 2009; 36(1): L01 105, doi:10 1029/2008G:03659)
Global warming correlations
A series of climate model simulations of the twentieth century on published correlations between an index of local economic activity and recent global warming were analyzed by Gavin Schmidt at the NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University. These correlations have been used to support a hypothesis that the observed surface warming record has been contaminated in some way to overestimate true global warming. Schmidt reports that these correlations do not fall outside the simulated distribution and are likely to have arisen by chance alone. He concludes that there is no compelling evidence from these correlations that there is any large-scale contamination of natural global warming. (International Journal of Climatology 2009; 7 January, DOI: 10.1002/JOC.1831)