Climate Change Increases Risk of Crop Slowdown in Next 20 Years

The world faces a small but substantially increased risk over the next two decades of a major slowdown in the growth of global crop yields because of climate change, new research finds.The authors, from Stanford University and the National Center for Atmospheric Research (NCAR), say the odds of a major production slowdown of wheat and corn even with a warming climate are not very high. But the risk is about 20 times more significant than it would be without global warming, and it may require planning by organizations that are affected by international food availability and price.”Climate change has substantially increased the prospect that crop production will fail to keep up with rising demand in the next 20 years,” said NCAR scientist Claudia Tebaldi, a co-author of the study.Stanford professor David Lobell said he wanted to study the potential impact of climate change on agriculture in the next two decades because of questions he has received from stakeholders and decision makers in governments and the private sector.”I’m often asked whether climate change will threaten food supply, as if it’s a simple yes or no answer,” Lobell said. “The truth is that over a 10- or 20-year period, it depends largely on how fast Earth warms, and we can’t predict the pace of warming very precisely. So the best we can do is try to determine the odds.”Lobell and Tebaldi used computer models of global climate, as well as data about weather and crops, to calculate the chances that climatic trends would have a negative effect of 10 percent on yields of corn and wheat in the next 20 years. This would have a major impact on food supply. Yields would continue to increase but the slowdown would effectively cut the projected rate of increase by about half at the same time that demand is projected to grow sharply.They found that the likelihood of natural climate shifts causing such a slowdown over the next 20 years is only 1 in 200. But when the authors accounted for human-induced global warming, they found that the odds jumped to 1 in 10 for corn and 1 in 20 for wheat.The study appears in this month’s issue of Environmental Research Letters. It was funded by the National Science Foundation (NSF), which is NCAR’s sponsor, and by the U.S. Department of Energy (DOE).More crops needed worldwideGlobal yields of crops such as corn and wheat have typically increased by about 1-2 percent per year in recent decades, and the U.N. Food and Agriculture Organization projects that global production of major crops will increase by 13 percent per decade through 2030 — likely the fastest rate of increase during the coming century. …

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Breakthrough harnesses light for controlled chemical reaction

When chemist Tehshik Yoon looks out his office window, he sees a source of energy to drive chemical reactions. Plants “learned” to synthesize chemicals with sunlight eons ago; Yoon came to the field a bit more recently.But this week, in the journal Science, he and three collaborators detail a way to use sunlight and two catalysts to create molecules that are difficult to make with conventional techniques.In chemistry, heat and ultraviolet (UV) light are commonly used to drive reactions. Although light can power reactions that heat cannot, UV has disadvantages, says Yoon, a chemistry professor at University of Wisconsin-Madison. The UV often used in industry carries so much energy that “it’s dangerous to use, unselective, and prone to making unwanted by-products.”Many chemicals exist in two forms that are mirror images of each other, and Yoon is interested in reactions that make only one of those images.”It’s like your hands,” Yoon says. “They are similar, but not identical; a left-hand glove does not fit the right hand. It’s the same way with molecules in biology; many fail unless they have the correct ‘handedness,’ or ‘chirality.'”The pharmaceutical industry, in particular, is concerned about controlling chirality in drugs, but making those shapes is a hit-or-miss proposition with UV light, Yoon says.He says the new technique answers a question posed by a French chemist in 1874, who suggested using light to make products with controlled chirality. “Chemists could never do that efficiently, and so the prejudice was that it was too difficult to do.”When a graduate student asked for a challenging project seven years ago, Yoon asked him to explore powering reactions compounds with metals that are used to capture the sun’s energy in solar cells. In a solar cell, these metals release electrons to make electricity.”We are taking the electrons that these metals spin out and using their energy to promote a chemical reaction,” Yoon says.Plants do the same thing during photosynthesis, he says: absorb light, release high-energy electrons, and use those electrons to bond water and carbon dioxide into sugars. That reaction is the basis of essentially all of agriculture and all food chains.Once the solar-cell metal supplied electrons, Yoon thought about using a second catalyst to control chirality. He passed the project to Juana Du, another graduate student.”She must have synthesized 70 different catalysts,” says Yoon. …

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First peanut genome sequenced

The International Peanut Genome Initiative — a group of multinational crop geneticists who have been working in tandem for the last several years — has successfully sequenced the peanut’s genome.Scott Jackson, director of the University of Georgia Center for Applied Genetic Technologies in the College of Agricultural and Environmental Sciences, serves as chair of the International Peanut Genome Initiative, or IPGI.The new peanut genome sequence will be available to researchers and plant breeders across the globe to aid in the breeding of more productive and more resilient peanut varieties.Peanut, known scientifically as Arachis hypogaea and also called groundnut, is important both commercially and nutritionally. While the oil- and protein-rich legume is seen as a cash crop in the developed world, it remains a valuable sustenance crop in developing nations.”The peanut crop is important in the United States, but it’s very important for developing nations as well,” Jackson said. “In many areas, it is a primary calorie source for families and a cash crop for farmers.”Globally, farmers tend about 24 million hectares of peanuts each year and produce about 40 million metric tons.”Improving peanut varieties to be more drought-, insect- and disease-resistant can help farmers in developed nations produce more peanuts with fewer pesticides and other chemicals and help farmers in developing nations feed their families and build more secure livelihoods,” said plant geneticist Rajeev Varshney of the International Crops Research Institute for Semi-Arid Tropics in India, who serves on the IPGI.The effort to sequence the peanut genome has been underway for several years. While peanuts were successfully bred for intensive cultivation for thousands of years, relatively little was known about the legume’s genetic structure because of its complexity, according to Peggy Ozias-Akins, a plant geneticist on the UGA Tifton campus who also works with the IPGI and is director of the UGA Institute of Plant Breeding, Genetics and Genomics.”Until now, we’ve bred peanuts relatively blindly, as compared to other crops,” said IPGI plant geneticist David Bertioli of the Universidade de Braslia. “We’ve had less information to work with than we do with many crops, which have been more thoroughly researched and understood.”The peanut in fields today is the result of a natural cross between two wild species, Arachis duranensis and Arachis ipaensis, which occurred in north Argentina between 4,000 and 6,000 years ago. Because its ancestors were two different species, today’s peanut is a polyploid, meaning the species can carry two separate genomes, designated A and B subgenomes.To map the peanut’s structure, researchers sequenced the genomes of the two ancestral parents because together they represent the cultivated peanut. The sequences provide researchers access to 96 percent of all peanut genes in their genomic context, providing the molecular map needed to more quickly breed drought- and disease-resistant, lower-input and higher-yielding varieties of peanuts.The two ancestor wild species had been collected in nature, conserved in germplasm banks and then used by the IPGI to better understand the peanut genome. The genomes of the two ancestor species provide excellent models for the genome of the cultivated peanut. A. duranenis serves as a model for the A subgenome of the cultivated peanut while A. …

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Natural variation: Warm North Atlantic Ocean promotes extreme winters in US and Europe

The extreme cold weather observed across Europe and the east coast of the US in recent winters could be partly down to natural, long-term variations in sea surface temperatures, according to a new study published today.Researchers from the University of California Irvine have shown that a phenomenon known as the Atlantic Multidecadal Oscillation (AMO) — a natural pattern of variation in North Atlantic sea surface temperatures that switches between a positive and negative phase every 60-70 years — can affect an atmospheric circulation pattern, known as the North Atlantic Oscillation (NAO), that influences the temperature and precipitation over the Northern Hemisphere in winter.When the AMO is in its positive phase and the sea surface temperatures are warmer, the study has shown that the main effect in winter is to promote the negative phase of the NAO which leads to “blocking” episodes over the North Atlantic sector, allowing cold weather systems to exist over the eastern US and Europe.The results have been published today, Wednesday 2 April, in IOP Publishing’s journal Environmental Research Letters.To arrive at their results, the researchers combined observations from the past century with climate simulations of the atmospheric response to the AMO.According to their observations, sea surface temperatures in the Atlantic can be up to 1.5 C warmer in the Gulf Stream region during the positive phase of the AMO compared to the negative, colder phase. The climate simulations suggest that these specific anomalies in sea surface temperatures can play a predominant role in promoting the change in the NAO.Lead authors of the study Yannick Peings and Gudrun Magnusdottir said: “Our results indicate that the main effect of the positive AMO in winter is to promote the occurrence of the negative phase of the NAO. A negative NAO in winter usually goes hand-in-hand with cold weather in the eastern US and north-western Europe.”The observations also suggest that it takes around 10-15 years before the positive phase of AMO has any significant effect on the NAO. The reason for this lag is unknown; however, an explanation might be that AMO phases take time to develop fully.As the AMO has been in a positive phase since the early 1990s, it may have contributed to the extreme winters that both the US and Europe have experienced in recent years.The researchers warn, however, that the future evolution of the AMO remains uncertain, with many factors potentially affecting how it interacts with atmospheric circulation patterns, such as Arctic sea ice loss, changes in solar radiation, volcanic eruptions and concentrations of greenhouse gases in the atmosphere.The AMO also shows strong variability from one year to the next in addition to the changes seen every 60 – 70 years, which makes it difficult to attribute specific extreme winters to the AMO’s effects.Responding to the extreme weather that gripped the eastern coast of the US this winter, Yannick Peings continued: “Unlike the 2012/2013 winter, this winter had rather low values of the AMO index and the pattern of sea surface temperature anomalies was not consistent with the typical positive AMO pattern. Moreover, the NAO was mostly positive with a relatively mild winter over Europe.””Therefore it is unlikely that the positive AMO played a defining role on the east coast of the US, although further work is necessary to answer this question. Such an event is consistent with the large internal variability of the atmosphere, and other external forcings may have played a role.”Our future studies will look to compare the role of the AMO compared to Arctic sea ice anomalies, which have also been shown to affect atmospheric circulation patterns and promote colder, more extreme winters.”Story Source:The above story is based on materials provided by Institute of Physics. Note: Materials may be edited for content and length.

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MRI reveals genetic activity: Deciphering genes’ roles in learning and memory

Doctors commonly use magnetic resonance imaging (MRI) to diagnose tumors, damage from stroke, and many other medical conditions. Neuroscientists also rely on it as a research tool for identifying parts of the brain that carry out different cognitive functions.Now, a team of biological engineers at MIT is trying to adapt MRI to a much smaller scale, allowing researchers to visualize gene activity inside the brains of living animals. Tracking these genes with MRI would enable scientists to learn more about how the genes control processes such as forming memories and learning new skills, says Alan Jasanoff, an MIT associate professor of biological engineering and leader of the research team.”The dream of molecular imaging is to provide information about the biology of intact organisms, at the molecule level,” says Jasanoff, who is also an associate member of MIT’s McGovern Institute for Brain Research. “The goal is to not have to chop up the brain, but instead to actually see things that are happening inside.”To help reach that goal, Jasanoff and colleagues have developed a new way to image a “reporter gene” — an artificial gene that turns on or off to signal events in the body, much like an indicator light on a car’s dashboard. In the new study, the reporter gene encodes an enzyme that interacts with a magnetic contrast agent injected into the brain, making the agent visible with MRI. This approach, described in a recent issue of the journal Chemical Biology, allows researchers to determine when and where that reporter gene is turned on.An on/off switchMRI uses magnetic fields and radio waves that interact with protons in the body to produce detailed images of the body’s interior. In brain studies, neuroscientists commonly use functional MRI to measure blood flow, which reveals which parts of the brain are active during a particular task. When scanning other organs, doctors sometimes use magnetic “contrast agents” to boost the visibility of certain tissues.The new MIT approach includes a contrast agent called a manganese porphyrin and the new reporter gene, which codes for a genetically engineered enzyme that alters the electric charge on the contrast agent. Jasanoff and colleagues designed the contrast agent so that it is soluble in water and readily eliminated from the body, making it difficult to detect by MRI. However, when the engineered enzyme, known as SEAP, slices phosphate molecules from the manganese porphyrin, the contrast agent becomes insoluble and starts to accumulate in brain tissues, allowing it to be seen.The natural version of SEAP is found in the placenta, but not in other tissues. …

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Deep ocean current may slow due to climate change

Far beneath the surface of the ocean, deep currents act as conveyer belts, channeling heat, carbon, oxygen and nutrients around the globe.A new study by the University of Pennsylvania’s Irina Marinov and Raffaele Bernardello and colleagues from McGill University has found that recent climate change may be acting to slow down one of these conveyer belts, with potentially serious consequences for the future of the planet’s climate.”Our observations are showing us that there is less formation of these deep waters near Antarctica,” Marinov said. “This is worrisome because, if this is the case, we’re likely going to see less uptake of human produced, or anthropogenic, heat and carbon dioxide by the ocean, making this a positive feedback loop for climate change.”Marinov is an assistant professor in Penn’s School of Arts and Sciences’ Department of Earth and Environmental Science, while Bernardello was a postdoctoral investigator in the same department and has just moved to the National Oceanography Centre in the United Kingdom. They collaborated with Casimir de Lavergne, Jaime B. Palter and Eric D. Galbraith of McGill University on the study, which was published in Nature Climate Change.Oceanographers have noticed that Antarctic Bottom Waters, a massive current of cold, salty and dense water that flows 2,000 meters under the ocean’s surface from near the Antarctic coast toward the equator has been shrinking in recent decades. This is cause for concern, as the current is believed to “hide” heat and carbon from the atmosphere. The Southern Ocean takes up approximately 60 percent of the anthropogenic heat produced on Earth and 40 to 50 percent of the anthropogenic carbon dioxide.”The Southern Ocean is emerging as being very, very important for regulating climate,” Marinov said.Along with colleagues, Marinov used models to discern whether the shrinking of the Antarctic Bottom Waters could be attributed to anthropogenic climate change.They looked to an unusual phenomenon that had been observed from satellite images taken between 1974 and 1976. The images revealed a large ice-free area within the Weddell Sea. Called a polynya, this opening in the sea ice forms when warm water of North Atlantic origin is pushed up toward the Southern Ocean’s surface. In a separate process, brine released during the sea-ice formation process produces a reservoir of cold, salty waters at the surface of the Weddell Sea. …

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Improved pavement markings can save lives

As spring finally emerges after a ferocious winter, our battered roads will soon be re-exposed. While potholes and cracks might make news, a larger concern should be the deterioration to pavement markings, from yellow to white lines, which are a major factor in preventing traffic accidents.A study from Concordia University, funded by Infrastructure Canada and published in Structure and Infrastructure Engineering, found that snowplows are the biggest culprit in erasing roadway markings.The research team also examined the impact of salt and sand on the visibility of pavement markings. The conclusion: a simple switch in paint can save cars — and lives.Using data from the Ontario and Quebec ministries of transportation and the municipalities of Montreal and Ottawa, Professor Tarek Zayed of Concordia’s Department of Building, Civil and Environmental Engineering measured the relationship between materials used in pavement markings, and their age and durability.He also compared highways with city roads, examined traffic levels and took note of the types of vehicles involved. Finally, Zayed and his research team examined marking types such as highway centre lines, pedestrian crosswalks and traffic intersections.They found snowploughs to be the worst on roads because they literally scrape paint off the streets. “Snow removal is the major contributing factor to wear and tear on pavement markings, because when snow is pushed off the road, part of the markings is taken off too,” says Zayed.What can improve the chances of pavement markings surviving the winter? Zayed suggests that an upgrade to more expensive and durable epoxy paint might be more cost effective in the long run. Other options include paint tape and thermoplastic, although these are quite expensive.He also suggests wider use of a technical device called a retroreflectometer to help assess the paint’s reflectivity and resulting effectiveness. “In the U.S., this standard has been in place for almost a decade,” he says, adding that minimum standards for reflectivity are used to signal when a road must be repainted.Zayed also says Canadian roads are in desperate need of more studies. For example, while epoxy is known to be a more durable paint, since it is not yet widely used in Ontario and Quebec, more research is needed to show exactly how it holds up to stressors like salt and snow removal.While several studies have been conducted in the central and southern United States to compare and evaluate the durability of pavement markings, Zayed points out that the findings don’t translate very well given the strikingly different weather conditions between warm versus seasonal climates.Story Source:The above story is based on materials provided by Concordia University. The original article was written by Suzanne Bowness. …

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Child ADHD stimulant medication use leads to BMI rebound in late adolescence

A new study from researchers at Johns Hopkins Bloomberg School of Public Health found that children treated with stimulants for attention deficit hyperactivity disorder (ADHD) experienced slower body mass index (BMI) growth than their undiagnosed or untreated peers, followed by a rapid rebound of BMI that exceeded that of children with no history of ADHD or stimulant use and that could continue to obesity.The study, thought to be the most comprehensive analysis of ADHD and stimulant use in children to date, found that the earlier the medication began, and the longer the medication was taken, the slower the BMI growth in earlier childhood but the more rapid the BMI rebound in late adolescence, typically after discontinuation of medication. Researchers concluded that stimulant use, and not a diagnosis of ADHD, was associated with higher BMI and obesity. The study was published in Pediatrics.”Our findings should motivate greater attention to the possibility that longer-term stimulant use plays a role in the development of obesity in children,” said Brian S. Schwartz, MD, MS, Professor of Environmental Health Sciences, Epidemiology, and Medicine at the Bloomberg School of Public Health and lead author of the study. “Given the dramatic rise in ADHD diagnosis and stimulant treatment for it in recent decades, this is an interesting avenue of research regarding the childhood obesity epidemic, because the rises in each of these roughly parallel one another.”Previous research has found substantial evidence that stimulant use to treat ADHD is associated with growth deficits, and some evidence of growth delays. However, the reported associations of ADHD with obesity in both childhood and adulthood was paradoxical and somewhat unexplained. The results of this study suggest it is likely due to the strong influence that stimulants have on BMI growth, with delays in early childhood and a strong rebound in late adolescence. The study also found longitudinal evidence that unmedicated ADHD is associated with higher BMIs, but these effects were small.ADHD is one of the most common pediatric disorders, with a 9% prevalence among children in the U.S., and ADHD medication is the second most prescribed treatment among children. Over the past 30 years, treatment for ADHD with stimulants has increased rapidly. From 2007 to 2010, 4.2.% of children under age 18 had been prescribed stimulants in the past 30 days, more than five times the amount prescribed to the same-aged children between 1988 and 1984.The study analyzed the electronic health records of 163,820 children, ages 3 to 18, in the Geisinger Health System, a Pennsylvania-based integrated health services organization. …

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Land cover change over five years across North America revealed

A new set of maps featured in the CEC’s North American Environmental Atlas depicts land cover changes in North America’s forests, prairies, deserts and cities, using satellite images from 2005 and 2010. These changes can be attributed to forest fires, insect infestation, urban sprawl and other natural or human-caused events. Produced by the North American Land Change Monitoring System (NALCMS), a trinational collaborative effort facilitated by the CEC, these maps and accompanying data can be used to address issues such as climate change, carbon sequestration, biodiversity loss, and changes in ecosystem structure and function.This project, which seeks to address land cover change at a North American scale, was initiated at the 2006 Land Cover Summit, in Washington, DC. Since then, specialists from government agencies in Canada, Mexico and the United States have worked together to harmonize their land cover classification systems into 19 classes that provide a uniform view of the continent at a consistent 250-meter scale.To view examples of significant land cover changes in British Colombia, California, and Cancun, slide the green bars on the maps, found at: www.cec.org/nalcms.To view the full 2005-2010 land cover change map, visit www.cec.org/atlas and click on “Terrestrial Ecosystems” on the left. Under “Land Cover,” click on the plus sign next to “2005-2010 land cover change” to add the map layer to North America. Then zoom in and take a look at all the purple patches — these are the areas of North America where land cover has changed over the five-year period.North American Land Change Monitoring SystemNALCMS is a joint project between Natural Resources Canada/Canada Centre for Mapping and Earth Observation (NRCan/CCMEO), the United States Geological Survey (USGS), and three Mexican organizations: the National Institute of Statistics and Geography (Instituto Nacional de Estadstica y Geografa — Inegi), the National Commission for the Knowledge and Use of Biodiversity (Comisin Nacional para el Conocimiento y Uso de la Biodiversidad — Conabio), and the National Forestry Commission of Mexico (Comisin Nacional Forestal — Conafor), supported by the Commission for Environmental Cooperation (CEC).The North American Environmental AtlasThe North American Environmental Atlas brings together maps, data and interactive map layers that can be used to identify priority areas to conserve biodiversity, track cross-border transfers of pollutants, monitor CO2 emissions across major transportation routes and predict the spread of invasive species. Land Cover 2010 and Land Cover Change 2005-2010 are the latest in a series of maps that harmonize geographic information across North America’s political boundaries to depict significant environmental issues at a continental scale.Story Source:The above story is based on materials provided by Commission for Environmental Cooperation. Note: Materials may be edited for content and length.

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Dingo poisoning should be stopped to protect native Australian mammals

Poisoning of dingoes — the top predators in the Australian bush — has a deleterious effect on small native mammals such as marsupial mice, bandicoots and native rodents, a UNSW-led study shows.The research, in forested National Parks in NSW, found that loss of dingoes after baiting is associated with greater activity by foxes, which prey on small marsupials and native rodents.As well, the number of kangaroos and wallabies increases when dingoes, also known as wild dogs, disappear. Grazing by these herbivores reduces the density of the understorey vegetation in which the small ground-dwelling mammals live.”Dingoes should not be poisoned if we want to halt the loss of mammal biodiversity in Australia. We need to develop strategies to maintain the balance of nature by keeping dingoes in the bush, while minimising their impacts on livestock,” says the senior author, UNSW’s Dr Mike Letnic.The study is published in the journal Proceedings of the Royal Society B.The researchers surveyed seven pairs of forested sites within conservation reserves managed by the NSW National Parks and Wildlife Service.Baiting of dingoes with 1080 poison had been carried out at one location in each pair, but not the other. Apart from the resulting difference in the number of dingoes present, the pairs of locations had similar eucalypt coverage, geology and landforms, and were less than 50 kilometres apart.”This provided an extraordinary natural experiment to compare the impact of the loss of dingoes on a forested ecosystem,” says Dr Letnic, an ARC Future Fellow in the Centre for Ecosystem Science in the UNSW School of Biological, Earth and Environmental Sciences.It is the first study to show how removing large carnivores can result in simultaneous population outbreaks of herbivores and smaller predators. And that these population outbreaks, in turn, can have deleterious effects on smaller mammals.The activity of dingoes, foxes, feral cats and bandicoots was assessed from their tracks. Kangaroos and wallabies and possums were counted from the back of a four wheel drive. Traps were used to catch marsupials and native rodents, and surveys of vegetation were carried out.”We found foxes and large herbivores benefit from dingo control, while small-bodied terrestrial mammal species decline in abundance,” says Dr Letnic.”Predation by foxes is one of the most important threats to small native mammals, and grazing by herbivores can reduce their preferred habitats for shelter, leaving them exposed to predators.”The study’s findings in the forested areas are consistent with the effects of dingo removal in desert areas of Australia.”Actively maintaining dingo populations, or restoring them in areas where they have been exterminated, is controversial but could mitigate the impacts of foxes and herbivores,” says Dr Letnic.”Poisoning of dingoes is counter-productive for biodiversity conservation, because it results in increases in fox activity and declines of small ground-dwelling native mammals.”Story Source:The above story is based on materials provided by University of New South Wales. Note: Materials may be edited for content and length.

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Agroforestry can ensure food security, mitigate effects of climate change in Africa

Agroforestry can help to achieve climate change mitigation and adaptation while at the same time providing livelihoods for poor smallholder farmers in Africa.Scientists at the World Agroforestry Centre (ICRAF) say agroforestry — which is an integrated land use management technique that incorporates trees and shrubs with crops and livestock on farms — could be a win-win solution to the seemingly difficult choice between reforestation and agricultural land use, because it increases the storage of carbon and may also enhance agricultural productivity.In a special issue of Current Opinion in Environmental Sustainability, scientists say that in most parts of Africa, climate change mitigation focuses on reforestation and forest protection however, such efforts to reduce deforestation conflict with the need to expand agricultural production in Africa to feed the continent’s growing population.Agriculture in Africa is dominated by smallholder farmers. Their priority is to produce enough food. Under such circumstances, any measures that will be put in place to mitigate the effects of climate change should also improve food production.”This mixture shows the role that agroforestry can play in addressing both climate mitigation and adaptation in primarily food-focused production systems of Africa” says Dr. Cheikh Mbow, Senior Scientist, Climate Change and Development at the World Agroforestry Centre (ICRAF) and lead author of the article.”It has been demonstrated by science that if you develop agroforestry it has the potential to buffer the impact of climate change. For example, a farm with trees will suffer less to the impacts of climate change because it will absorb some of these impacts so agroforestry is a good response to develop resilience of agrosystems to the challenges brought about by climate change” he says.The report however notes that for farmers to incorporate trees in their farms there is need to revise the cultivation methods and provide them with some support to ensure swift adoption.Agroforestry is one of the most common land use systems across landscapes and agroecological zones in Africa but need much more adoption in order to increase the impact on food security. With food shortages and increased threats of climate change, interest in agroforestry is gathering for its potential to address various on-farm adaptation needs. “The failure of extension services in poor African countries limits the possibility to scale up innovations in agroforestry for improved land use systems .”The scientists conclude that agroforestry should therefore attract more attention in global agendas on climate change mitigation because of its positive social and environmental impacts.Story Source:The above story is based on materials provided by World Agroforestry Centre (ICRAF). Note: Materials may be edited for content and length.

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Exotic plant species alter ecosystem productivity

In their joint publication in the journal Ecology Letters German and American biologists have reported an increase in biomass production in ecosystems colonised by non-native plant species. In the face of climate change, these and other changes to ecosystems are predicted to become more frequent, according to the researchers.All over the world, plant and animal species are increasingly encroaching upon ecosystems where they don’t belong as a result of human influence. This phenomenon is known as a biological invasion. Observational studies on biological invasions show that the invasion of non-native plant species can alter ecosystems. One important aspect of this is biomass production: compared to intact ecosystems, the productivity of ecosystems with non-native species is considerably higher. “In such purely observational studies however, it is not possible to differentiate between cause and effect,” says Dr. Harald Auge from the Helmholtz Center for Environmental Research (UFZ). “The question is whether exotic plant species prefer to colonise more productive ecosystems, or whether increased productivity is a result of the invasion.”To get to the bottom of this question, UFZ researchers joined forces with colleagues from the Martin-Luther University Halle-Wittenberg, the University of Montana, the University of California and the US Forest Service and staged invasions by setting up experimental sites in three disparate grassland regions -in Central Germany, Montana and California, on which 20 native plant species (from the respective region) and 20 exotic plant species were sown. Researchers investigated whether and to which extent herbivorous small mammals such as mice, voles or ground squirrels as well as mechanical disturbance to the soil would influence exotic plant species colonizing ability.”The experimental design was exactly the same for all three regions to ensure comparability. We wanted to find out whether superordinate relationships were playing a role, irrespective of land use, species compositions and climate differences,” explains Dr Auge. …

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National U.S. study reveals how urban lawn care habits vary

What do people living in Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, and Los Angeles have in common? From coast to coast, prairie to desert — residential lawns reign.But, according to a new study in the Proceedings of the National Academy of Sciences, beneath this sea of green lie unexpected differences in fertilization and irrigation practices. Understanding urban lawn care is vital to sustainability planning, more than 80% of Americans live in cities and their suburbs, and these numbers continue to grow.The study was undertaken to test “the homogenization hypothesis.” Peter Groffman, a scientist at the Cary Institute of Ecosystem Studies and one of the paper’s authors explains, “Neighborhoods in very different parts of the country look remarkably alike, from lawns and roads to water features. This study is the first to test if urbanization produces similar land management behaviors, independent of the local environment.”Some 9,500 residents in the six study cities were queried about their lawn care habits. The research team, led by Colin Polsky of Clark University and colleagues at 10 other institutions, took into account differences in climate and neighborhood socioeconomics, both within and between cities. A focus was put on fertilization and irrigation, practices with potentially hefty environmental price tags.Fertilizer is rich in nitrogen and phosphorus. This stimulates lawn growth, but when fertilizer washes into waterways, it causes algal blooms that degrade water quality and rob oxygen from fish and other aquatic life. According to the Environmental Protection Agency, landscape irrigation accounts for nearly one-third of residential water use nationwide.Some 79% of surveyed residents watered their lawns and 64% applied fertilizer. Groffman comments, “These numbers are important when we bear in mind that lawns cover more land in the United States than any other irrigated crop. …

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Livestock can produce food that is better for people, planet

With one in seven humans undernourished, and with the challenges of population growth and climate change, the need for efficient food production has never been greater. Eight strategies to cut the environmental and economic costs of keeping livestock, such as cows, goats and sheep, while boosting the quantity and quality of the food produced have been outlined by an international team of scientists.The strategies to make ruminant — cud-chewing — livestock a more sustainable part of the food supply, led by academics at the University of Bristol’s School of Veterinary Sciences, are outlined in a Comment piece in Nature this week.The eight strategies include:Feed animals less human food. Livestock consume an estimated one-third or more of the world’s cereal grain, which some advocate would be better used to feed people directly. Some of this could indeed be avoided by capitalising on ruminants’ ability to digest food that humans cannot eat, such as hay, silage and high-fibre crop residues. Raise regionally appropriate animals. Working to boost yields from local breeds makes more sense in the long term than importing poorly adapted breeds that are successful elsewhere. European and North American Holstein dairy cows can produce 30 litres of milk a day. Thousands of these animals have been exported to Asia and Africa in an attempt to alleviate malnutrition. But exposed to hot climates, tropical diseases and sub-optimal housing, the cows produce much less milk, and the costs of feed and husbandry far exceed those of native breeds. Farmers, therefore, should be encouraged to keep and improve livestock adapted to local conditions. …

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Predators delay pest resistance to Bt crops

Crops genetically modified with the bacterium Bt (Bacillus thuringiensis) produce proteins that kill pest insects. Steady exposure has prompted concern that pests will develop resistance to these proteins, making Bt plants ineffective.Cornell research shows that the combination of natural enemies, such as ladybeetles, with Bt crops delays a pest’s ability to evolve resistance to these insecticidal proteins.“This is the first demonstrated example of a predator being able to delay the evolution of resistance in an insect pest to a Bt crop,” said Anthony Shelton, a professor of entomology at Cornell University’s New York State Agricultural Experiment Station in Geneva, N.Y., and a co-author of the paper. Xiaoxia Liu, a visiting scientist from China Agricultural University who worked in the Shelton lab, is the lead author on the paper published in the journal PLoS One.Bt is a soil bacterium that produces proteins that are toxic to some species of caterpillars and beetles when they are ingested, but have been proven safe to humans and many natural enemies, including predaceous ladybirds. Bt genes have been engineered into a variety of crops to control insect pests.Since farmers began planting Bt crops in 1996 with 70 million hectares planted in the United States in 2012, there have been only three clear-cut cases in agriculture of resistance in caterpillars, and one in a beetle. “Resistance to Bt crops is surprisingly uncommon,” said Shelton.To delay or prevent insect pests from evolving resistance to Bt crops, the U.S. Environmental Protection Agency promotes the use of multiple Bt genes in plants and the practice of growing refuges of non-Bt plants that serve as a reservoir for insects with Bt susceptible genes.“Our paper argues there is another factor involved: the conservation of natural enemies of the pest species,” said Shelton. These predators can reduce the number of potentially resistant individuals in a pest population and delay evolution of resistance to Bt.In the study, the researchers set up large cages in a greenhouse. Each cage contained Bt broccoli and refuges of non-Bt broccoli. They studied populations of diamondback moth (Plutella xylostella) larvae, a pest of broccoli, and their natural enemies, ladybird beetles (Coleomegilla maculata), for six generations.Cages contained different combinations of treatments with and without predators, and with and without sprayed insecticides on the non-Bt refuge plants. Farmers commonly spray insecticides on refuge plants to prevent loss by pests, but such sprays can kill predators and prey indiscriminately.The results showed that diamondback moth populations were reduced in the treatment containing ladybird beetles and unsprayed non-Bt refuge plants. …

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Importance of nutrients for coral reefs highlighted by scientists

A new publication from researchers at the University of Southampton and the National Oceanography Centre, Southampton highlights the importance of nutrients for coral reef survival.Despite the comparably small footprint they take on the ocean floor, tropical coral reefs are home to a substantial part of all marine life forms. Coral reefs also provide numerous benefits for human populations, providing food for millions and protecting coastal areas from erosion. Moreover, they are a treasure chest of potential pharmaceuticals and coral reef tourism provides recreation and income for many.Unfortunately, coral reefs are declining at an alarming rate. To promote management activities that can help coral reef survival, an international group of world renowned scientists have summarized the present knowledge about the challenges that coral reefs are facing now and in the future in a special issue of the journal Current Opinion in Environmental Sustainability. The contribution of scientists from the University of Southampton to this special issue highlights the crucial role of nutrients for the functioning of coral reefs.The University of Southampton researchers who are based at the Coral Reef Laboratory in the National Oceanography Centre, Southampton, explain that “too many” nutrients can be as bad for corals as “not enough.”Dr Jrg Wiedenmann, Professor of Biological Oceanography at the University of Southampton and Head of the Coral Reef Laboratory, says: “The nutrient biology of coral reefs is immensely complex. It is important to distinguish between the different direct and indirect effects that a disturbance of the natural nutrient environment can have on a coral reef ecosystem.”Since corals live in a symbiotic relationship with microscopically small plant cells, they require certain amounts of nutrients as “fertiliser.” In fact, the experimental addition of nutrients can promote coral growth. “One should not conclude from such findings, however, that nutrient enrichment is beneficial for coral reefs — usually the opposite is true,” explains Dr Cecilia D’Angelo, Senior Research Fellow in the Coral Reef Laboratory and co-author on the article.Dr Wiedenmann, whose research on coral reef nutrient biology is supported by one of the Starting Grants from the European Research Commission, adds: “Too many nutrients harm corals in many different ways, easily outweighing the positive effects that they can undoubtedly have for the coral-alga association.Paradoxically, the initial addition of nutrients to the water column might result in nutrient starvation of the corals at a later stage. In this publication, we conceptualise the important role that the competition for nutrients by phytoplankton, the free-living relatives of the corals’ symbiotic algae, may have in this context.””Nutrient pollution will continue to increase in many coral reefs. Therefore, an important prerequisite to develop efficient management strategies is a profound understanding of the different mechanisms by which corals suffer from nutrient stress.”Story Source:The above story is based on materials provided by University of Southampton. Note: Materials may be edited for content and length.

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Bisphenol A (BPA) at very low levels can adversely affect developing organs in primates

Bisphenol A (BPA) is a chemical that is used in a wide variety of consumer products, such as resins used to line metal food and beverage containers, thermal paper store receipts, and dental composites. BPA exhibits hormone-like properties, and exposure of fetuses, infants, children or adults to the chemical has been shown to cause numerous abnormalities, including cancer, as well as reproductive, immune and brain-behavior problems in rodents. Now, researchers at the University of Missouri have determined that daily exposure to very low concentrations of BPA by pregnant females also can cause fetal abnormalities in primates.”BPA is an endocrine disrupting chemical that has been demonstrated to alter signaling mechanisms involving estrogen, androgen and thyroid hormones,” said Frederick vom Saal, Curators Professor of Biological Sciences in the College of Arts and Science at MU. “Previous studies in rodents have demonstrated that maternal exposure to very low doses of BPA can significantly alter fetal development, resulting in a variety of adverse outcomes in the fetus. Our study is one of the first to show this also happens in primates.”Although BPA is considered a toxic chemical in other countries such as Canada, the U.S. has been slow to address the issue, said vom Saal. Until now, most studies involving BPA have been conducted on laboratory mice and rats, leading U.S. regulatory agencies to call for studies in primates. With funding provided by the National Institute of Environmental Health Sciences (NIEHS), a research institute of the National Institutes of Health, vom Saal and his colleagues studied the chemical’s blood levels in pregnant female rhesus monkeys and their fetuses, which are considered to be very similar to human fetuses.After collecting tissue samples, other researchers analyzed the tissues to determine if BPA exposure was harmful to fetal development. Researchers found evidence of significant adverse effects in mammary glands, ovaries, brain, uterus, lung and heart tissues in BPA exposed fetus when compared to fetuses not exposed to BPA. …

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Temperature and ecology: Rival Chilean barnacles keep competition cool

Here are two facts that make the lowly barnacle important: They are popular models for ecology research, and they are very sensitive to temperature. Given that, the authors of a new study about a bellwether community of two barnacle species in Chile figured they might see clear effects on competition between these two species if they experimentally changed temperature. In the context of climate change, such an experiment could yield profound new insights into the biological future of a major coastline that is prized for its ecological, aesthetic, and economic values.But in the study to be printed in the April 2014 issue of the Journal of Experimental Marine Biology and Ecology, the scientists found no significant effect of temperature on competition at all. That surprising non-finding may have its own implications.”The dominant if somewhat dated narrative in marine ecology, and ecology more broadly, is that competition is a major structuring force in natural communities,” said co-author Heather Leslie, assistant professor of environmental studies and biology at Brown University. “We know it’s a more nuanced story, but to find cases where it’s a bit of a draw is really unusual.”Moreover, temperature did not turn out to be the mediating factor.”Temperature wasn’t the beast that we often think of it being, which in itself is surprising,” Leslie said.Plenty of studies of other co-occurring barnacles would have suggested otherwise. In the North Atlantic, there is a well-documented and clear dynamic between two barnacle species, the little gray barnacle (Chthamalus fragilis) and the northern rock barnacle (Semibalanus balanoides). The little gray barnacle can only survive high up on the rocks, where it is hottest and driest, because farther down it gets thoroughly routed by the northern rock barnacle. Temperature, in other words, provides the little gray’s only refuge.The picture in Chile was downright unclear. Previous studies had yielded conflicting hints about how temperature might affect the competition between two southern hemisphere barnacle species, Jehlius cirratus and Notochthalamus scabrosus. Led by Emily Lamb, who began the work as a Brown undergraduate concentrating in environmental science and is now a research assistant at the Estacin Costera de Investigaciones Marinas (ECIM) in Chile, the team devised an experiment to get a more definitive answer.Made in the shadeLike their northern cousins, the Chilean barnacles Jehlius and Notochthalamus live in a clearly stratified society with Jehlius more abundant higher up and Notochthalamus more abundant lower down into the tide. …

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Water samples taken from the Upper Ganges River shed light on the spread of potential ‘superbugs’

Experts from Newcastle University, UK, and the Indian Institute of Technology in Delhi (IIT-Delhi), reveal the spread of antibiotic-resistance to one of the most pristine locations in Asia is linked to the annual human pilgrimages to the region. The research team are now calling on governments around the world to recognise the importance of clean drinking water in our fight against antibiotic resistance.The spread of antibiotic-resistance to one of the most pristine locations in Asia is linked to the annual human pilgrimages to the region, new research has shown.Experts from Newcastle University, UK, and the Indian Institute of Technology in Delhi (IIT-Delhi), sampled water and sediments at seven sites along the Upper Ganges River, in the foothills of the Himalayas.They found that in May and June, when hundreds of thousands of visitors travel to Rishikesh and Haridwar to visit sacred sites, levels of resistance genes that lead to “superbugs” were found to be about 60 times greater than other times of the year.Publishing their findings today in the journal Environmental Science and Technology, the team say it is important to protect people visiting and living at these sites while also making sure nothing interferes with these important religious practices.They argue that preventing the spread of resistance genes that promote life-threating bacteria could be achieved by improving waste management at key pilgrimage sites.”This isn’t a local problem — it’s a global one,” explains Professor David Graham, an environmental engineer based at Newcastle University who has spent over ten years studying the environmental transmission of antibiotic resistance around the world.”We studied pilgrimage areas because we suspected such locations would provide new information about resistance transmission via the environment. And it has — temporary visitors from outside the region overload local waste handling systems, which seasonally reduces water quality at the normally pristine sites.”The specific resistance gene we studied, called blaNDM-1, causes extreme multi-resistance in many bacteria, therefore we must understand how this gene spreads in the environment.”If we can stem the spread of such antibiotic resistant genes locally — possibly through improved sanitation and waste treatment — we have a better chance of limiting their spread on larger scales, creating global solutions by solving local problems.”Funded by the Engineering and Physical Sciences Research Council (EPSRC), the aim of the research was to understand how antibiotic resistance was transmitted due to a specific human activity. Local “hot-spots” of antibiotic resistance exist around the world, particularly densely-populated regions with inconsistent sanitation and poor water quality.By comparing water quality of the Upper Ganges in February and again in June, the team showed that levels of blaNDM-1 were 20 times higher per capita during the pilgrimage season than at other times.Monitoring levels of other contaminants in the water, the team showed that overloading of waste treatment facilities was likely to blame and that in many cases, untreated sewage was going straight into the river where the pilgrims bathe.”The bugs and their genes are carried in people’s guts,” explains Professor Graham. “If untreated wastes get into the water supply, resistance potential in the wastes can pass to the next person and spiralling increases in resistance can occur.”Worldwide, concern is growing over the threat from bacteria that are resistant to the so-called “last resort” class of antibiotics known as Carbapenems, especially if resistance is acquired by aggressive pathogens.Of particular concern is NDM-1, which is a protein that confers resistance in a range of bacteria. NDM-1 was first identified in New Delhi and coded by the resistant gene blaNDM-1.Until recently, strains that carry blaNDM-1 were only found in clinical settings, but in 2008, blaNDM-1 positive strains were found in surface waters in Delhi. Since then, blaNDM-1 has been found elsewhere in the world, including new variants.There are currently few antibiotics to combat bacteria that are resistant to Carbapenems and worldwide spread of blaNDM-1 is a growing concern.Professor Graham, who is based in the School of Civil Engineering and Geosciences at Newcastle University, UK, said the team had planned to repeat their experiments last year, but the region was hit by massive floods in June and the experiments were abandoned.The team has since returned to Rishikesh and Haridwar and hope their work will prompt public action to improve local sanitation, protecting these socially important sites. On a global scale, they want policymakers to recognise the importance of clean drinking water in our fight against antibiotic resistance.”What humans have done by excess use of antibiotics is accelerate the rate of evolution, creating a world of resistant strains that never existed before” explains Graham.”Through the overuse of antibiotics, contamination of drinking water and other factors, we have exponentially speeded-up the rate at which superbugs might develop.”For example, when a new drug is developed, natural bacteria can rapidly adapt and become resistant; therefore very few new drugs are in the pipeline because it simply isn’t cost-effective to make them.”The only way we are going to win this fight is to understand all of the pathways that lead to antibiotic resistance. Clearly, improved antibiotic stewardship in medicine and agriculture is crucial, but understanding how resistance transmission occurs through our water supplies is also critical. We contend that improved waste management and water quality on a global scale is a key step.”

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