Daily serving of beans, peas, chickpeas or lentils can significantly reduce bad cholesterol

Date:

April 7, 2014 - SCIENCE DAILY

Source:

St. Michael's Hospital

Summary:

Eating one serving a day of beans, peas, chickpeas or lentils can significantly reduce 'bad cholesterol' and therefore the risk of cardiovascular disease, a new study has found. North Americans on average currently eat less than half a serving a day.

Eating one serving a day of beans, peas, chickpeas or lentils can significantly reduce "bad cholesterol" and therefore the risk of cardiovascular disease, a new study has found.

However, most people in North America would have to more than double their consumption of these foods known as pulses to reach that target, said the researchers at St. Michael's Hospital.

The study, led by Dr. John Sievenpiper of the hospital's Clinical Nutrition and Risk Factor Modification Centre, was published today in the Canadian Medical Association Journal.

Dr. Sievenpiper said that by eating one serving a day of pulses, people could lower their LDL ("bad") cholesterol by five per cent. He said that would translate into a five to six per cent reduction in the risk of cardiovascular disease, the leading cause of death in the United States.

One serving of pulses is 130 grams or ¾ cup, yet North Americans on average eat less than half a serving a day. Pulses have a low glycemic index (meaning that they are foods that break down slowly) and tend to reduce or displace animal protein as well as "bad" fats such as trans fat in a dish or meal.

"We have a lot of room in our diets for increasing our pulse intake to derive the cardiovascular benefits," Dr. Sievenpiper said. "Pulses already play a role in many traditional cuisines, including Mediterranean and South Asian. As an added bonus, they're inexpensive. Since many pulses are grown in North America, it's also an opportunity to buy and eat locally and support our farmers."

Dr. Sievenpiper's meta-analysis reviewed 26 randomized controlled trials that included 1,037 people. Men had greater reduction in LDL cholesterol compared with women, perhaps because their diets are poorer and cholesterol levels are higher and benefit more markedly from a healthier diet. Some study participants reported stomach upset such as bloating, gas, diarrhea or constipation but these symptoms subsided over the course of the study.

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Story Source:

The above story is based on materials provided by St. Michael's Hospital. Note: Materials may be edited for content and length.

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Journal Reference:

1. Vanessa Ha, John L. Sievenpiper, Russell J. de Souza, Viranda H. Jayalath, Arash Mirrahimi, Arnav Agarwal, Laura Chiavaroli, Sonia Blanco Mejia, Frank M. Sacks, Marco Di Buono, Adam M. Bernstein, Lawrence A. Leiter, Penny M. Kris-Etherton, Vladimir Vuksan, Richard P. Bazinet, Robert G. Josse, Joseph Beyene, Cyril W.C. Kendall, David J.A. Jenkins. Effect of dietary pulse intake on established therapeutic lipid targets for cardiovascular risk reduction: a systematic review and meta-analysis of randomized controlled trials. CMAJ, 2014 DOI:10.1503/cmaj.131727

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Large-scale fences can cause ecological meltdown, study shows

Date:

April 3, 2014 - SCIENCE DAILY

Source:

Wildlife Conservation Society

Summary:

Scientists have reviewed the ‘pros and cons’ of large scale fencing and argue that fencing should only be used as a last resort. Wildlife fences are constructed for a variety of reasons including to prevent the spread of diseases, protect wildlife from poachers, and to help manage small populations of threatened species. Human-wildlife conflict is another common reason for building fences: Wildlife can damage valuable livestock, crops, or infrastructure, some species carry diseases of agricultural concern, and a few threaten human lives. At the same time, people kill wild animals for food, trade, or to defend lives or property, and human activities degrade wildlife habitat. Separating people and wildlife by fencing can appear to be a mutually bene cial way to avoid such detrimental effects.

Wildlife fences are constructed for a variety of reasons including to prevent the spread of diseases, protect wildlife from poachers, and to help manage small populations of threatened species. Human-wildlife conflict is another common reason for building fences: Wildlife can damage valuable livestock, crops, or infrastructure, some species carry diseases of agricultural concern, and a few threaten human lives. At the same time, people kill wild animals for food, trade, or to defend lives or property, and human activities degrade wildlife habitat. Separating people and wildlife by fencing can appear to be a mutually beneficial way to avoid such detrimental effects. But in a paper in the journal Science, published today, April 4th, 2014, WCS and ZSL scientists review the 'pros and cons' of large scale fencing and argue that fencing should only be used as a last resort.

Although fencing can have conservation benefits, it also has costs. When areas of contiguous wildlife habitat are converted into islands, the resulting small and isolated populations are prone to extinction, and the resulting loss of predators and other larger-bodied species can affect interactions between species in ways that cause further local extinctions, a process which has been termed "ecological meltdown."

"In some parts of the world, fencing is part of the culture of wildlife conservation -- it's assumed that all wildlife areas have to be fenced. But fencing profoundly alters ecosystems, and can cause some species to disappear. We're asking that conservationists as well as other sectoral interests carefully weigh up the biodiversity costs and benefits of new and existing fences," said ZSL's Rosie Woodroffe, lead author of the study.

In addition to their ecosystem-wide impact, fences do not always achieve their specific aims. Construction of fences to reduce human-wildlife conflict has been successful in some places but the challenges of appropriate fence design, location, construction, and maintenance mean that fences often fail to deliver the anticipated benefits. Ironically, in some places, fences also provide poachers with a ready supply of wire for making snares.

Co-author Simon Hedges of WCS said: "A variety of alternative approaches -- including better animal husbandry, community-based crop-guarding, insurance schemes, and wildlife-sensitive land-use planning -- can be used to mitigate conflicts between people and wildlife without the need for fencing. WCS projects working with local people and government agencies have shown that human-elephant conflict can be dramatically reduced without using fences in countries as different as Indonesia and Tanzania."

Co-author Sarah Durant of ZSL's said, "An increased awareness of the damage caused by fencing is leading to movements to remove fences instead of building more. Increasingly, fencing is seen as backwards step in conservation."

The desire to separate livestock from wildlife in order to create zones free from diseases such as foot and mouth has resulted in extensive fencing systems, particularly in southern Africa. Some of these fences have had devastating environmental effects. Fortunately, it is increasingly recognized that a combination of improved testing, vaccination, and standardized approaches to meat preparation can prevent spread of diseases without the need to separate cattle from wildlife by fencing.

The authors conclude that as climate change increases the importance of facilitating wildlife mobility and maintaining landscape connectivity, fence removal may become an important form of climate change preparedness, and so fencing of wildlife should be avoided whenever possible.

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Story Source:

The above story is based on materials provided by Wildlife Conservation Society.Note: Materials may be edited for content and length.

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Journal Reference:

1. R. Woodroffe, S. Hedges, S. M. Durant. To Fence or Not to Fence. Science, 2014; 344 (6179): 46 DOI: 10.1126/science.1246251

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Amazon studied to predict impact of climate change

Date:

April 1, 2014 - SCIENCE DAILY

Source:

Virginia Tech (Virginia Polytechnic Institute and State University)

Three extreme weather events in the Amazon Basin in the last decade are giving scientists an opportunity to make observations that will allow them to predict the impacts of climate change and deforestation on some of the most important ecological processes and ecosystem services of the Amazon River wetlands.

Scientists from Virginia Tech, the Woods Hole Research Center, and the University of California, Santa Barbara, funded by NASA, are collaborating with Brazilian scientists to explore the ecosystem consequences of the extreme droughts of 2005 and 2010 and the extreme flood of 2009.

"The research fills an important gap in our understanding of the vulnerability of tropical river-forest systems to changes in climate and land cover," said the project's leader, Leandro Castello, assistant professor of fish and wildlife conservation in Virginia Tech's College of Natural Resources and Environment.

The huge study area encompasses 1.7 million square miles, the equivalent of half of the continental United States.

In addition to historical records and ground observations, the researchers will use newly available Earth System Data Records from NASA -- satellite images of the Amazon and its tributaries over the complete high- and low-water cycles.

NASA is funding the study with a $1.53 million grant shared among the three institutions.

"Amazon floodplains and river channels -- maintained by seasonal floods -- promote nutrient cycling and high biological production, and support diverse biological communities as well as human populations with one of the highest per capita rates of fish consumption," said Castello.

The researchers will look at how the natural seasonality of river levels influences aquatic and terrestrial grasses, fisheries, and forest productivity in the floodplains, and how extreme events such as floods and droughts may disturb this cycle.

"We are confident that deforestation and climate change will, in the future, lead to more frequent and severe floods and droughts," said Michael Coe, a senior scientist at the Woods Hole Research Center. "It is important that we understand how the Amazon River and ecosystem services such as fisheries are affected so that we can devise mitigation strategies."

Amazonian grasses, sometimes called macrophytes, convert atmospheric carbon to plant biomass, which is then processed by aquatic microorganisms upon decomposition.

"Terrestrial grasses grow during the short window when water levels are low, sequestering some carbon, and then die when the floods arrive, releasing the carbon into the aquatic system," said Thiago Silva, an assistant professor of geography at São Paulo State University in Rio Claro, Brazil. "They are followed by aquatic grasses that need to grow extremely fast to surpass the rising floods and then die off during the receding-water period."

"Although most of the macrophyte carbon is released back to the atmosphere in the same form that it is assimilated, carbon dioxide, some of it is actually exported to the ocean as dissolved carbon or released to the atmosphere as methane, a gas that has a warming potential 20 times larger than carbon dioxide," said John Melack, a professor at the University of California, Santa Barbara.

Researchers will measure plant growth and gas exchange, and use photographs from the field and satellites.

Two other Amazon resources -- fisheries and forests -- are important to the livelihood of the people of the region.

"We will combine water level, fishing effort, and fish life-history traits to understand the impact of droughts and floods on fishery yields," said Castello, whose specialty is Amazon fisheries. "Floods in the Amazon are almost a blessing because in some years they can almost double the amount of fish in the river that is available for fishermen and society."

The fishery data include approximately 90,000 annual interview records of fisheries activities on the number of fishers, time spent fishing, characteristics of fishing boats and gear used, and weight of the catch for 40 species. The hydrological data include daily water level measurements recorded in the Madeira, Purus, and Amazonas-Solimões rivers.

The researchers will examine the potential impact of future climate scenarios on the extent and productivity of floodplain forests -- those enriched by rising waters, called whitewater river forests, and nutrient-poor blackwater river forests.

For example, extreme droughts may reduce productivity due to water stress and increases in the frequency and severity of forest fires. Prolonged periods of inundation, on the other hand, may decrease productivity or increase mortality due to water-logging stress.

"We will evaluate these responses for the first time at a regional scale using remotely sensed indicators of vegetation condition and fire-induced tree mortality to measure the response of floodplain forests to inter-annual flood variability and extreme climate events," said Marcia Macedo, a research associate at the Woods Hole Research Center.

Researchers will measure tree litter dry weight, depth of flooding, tree height and diameter, and stand density. They will also use photographs and satellite images.

Previous research has focused on Amazon upland forests and the potential impacts of deforestation, fire, and drought. The research team will compare new greenhouse gas simulations to previous simulations.

"Our research informs large river ecology globally because natural flowing rivers like the Amazon are rare these days, and most research to date, being done in North America and Europe, has focused on degraded systems," Castello said.

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Story Source:

The above story is based on materials provided by Virginia Tech (Virginia Polytechnic Institute and State University). Note: Materials may be edited for content and length.

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Corals don’t lie: Centuries of rising sea levels and temperature data revealed

Date:

April 1, 2014- SCIENCE DAILY

Source:

Australian Institute of Marine Science

AIMS scientists together with a team from The University of Western Australia, CSIRO and the University of San Diego have analysed coral cores from the eastern Indian Ocean to understand how the unique coral reefs of Western Australia are affected by changing ocean currents and water temperatures. The research was published today in the international journal Nature Communications. The findings give new insights into how La Niña, a climate swing in the tropical Pacific, affects the Leeuwin current and how our oceans are changing.

“Due to the lack of long-term observations of marine climate we used long coral cores, with annual growth bands similar to tree rings, to provide a record of the past. We obtained records of past sea temperatures by measuring the chemical composition of the coral skeleton from year to year. This showed how changing winds and ocean currents in the eastern Indian Ocean are driven by climate variability in the western tropical Pacific Ocean,” said Dr Jens Zinke (Assistant Professor at the UWA Oceans Institute and AIMS-UWA scientist). The long coral records allowed the scientists to look at these patterns of climate variability back to 1795 AD.

La Niña events in the tropical Pacific result in a strengthened Leeuwin Current and unusually warm water temperatures and higher sea levels off southwest Western Australia.

“A prominent example is the 2011 heat wave along WA’s reefs which led to coral bleaching and fish kills,” said Dr Ming Feng CSIRO Principal Research Scientist. 

The international team found that in addition to warming sea surface temperatures, sea-level variability and Leeuwin Current strength have increased since 1980. The coral cores also reveal that the strong winds and extreme weather of 2011 off Western Australia are highly unusual in the context of the past 215 years. The authors conclude that this is clear evidence that global warming and sea-level rise is increasing the severity of these extreme events which impact the highly diverse coral reefs of Western Australia, including the Ningaloo Reef World Heritage site.

“Given ongoing global climate change, It is likely that future La Niña events will result in more extreme warming and high sea-level events with potentially significant consequences for the maintenance of Western Australia's unique marine ecosystems,” said Dr Janice Lough, AIMS Senior Principal Research Scientist.

The researchers used core samples of massive Porites colonies from the Houtman-Abrolhos Islands, the most southerly reefs in the Indian Ocean which are directly in the path of the Leeuwin Current. Using the chemical composition of the annual coral growth bands they were able to reconstruct sea surface temperature and Leeuwin Current for 215 years, from 1795 to 2010.

Story Source:

The above story is based on materials provided by Australian Institute of Marine Science. Note: Materials may be edited for content and length.

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Journal Reference:

1. J. Zinke, A. Rountrey, M. Feng, S.-P. Xie, D. Dissard, K. Rankenburg, J.M. Lough, M.T. McCulloch. Corals record long-term Leeuwin current variability including Ningaloo Niño/Niña since 1795. Nature Communications, 2014; 5 DOI: 10.1038/ncomms4607

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Deforestation of sandy soils a greater climate threat

Date:

April 1, 2014

Source:

Yale School of Forestry & Environmental Studies

Summary:

A new study finds that tree removal has far greater consequences for climate change in some soils than in others, a finding that could provide key insights into which ecosystems should be managed with extra care. In a comprehensive analysis of soil collected from 11 distinct U.S. regions, from Hawaii to northern Alaska, researchers found that the extent to which deforestation disturbs underground microbial communities that regulate the loss of carbon into the atmosphere depends almost exclusively on the texture of the soil.

Deforestation may have far greater consequences for climate change in some soils than in others, according to new research led by Yale University scientists -- a finding that could provide critical insights into which ecosystems must be managed with extra care because they are vulnerable to biodiversity loss and which ecosystems are more resilient to widespread tree removal.

In a comprehensive analysis of soil collected from 11 distinct U.S. regions, from Hawaii to northern Alaska, researchers found that the extent to which deforestation disturbs underground microbial communities that regulate the loss of carbon into the atmosphere depends almost exclusively on the texture of the soil. The results were published in the journalGlobal Change Biology.

"We were astonished that biodiversity changes were so strongly affected by soil texture and that it was such an overriding factor," said Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies and lead author of the study. "Texture overrode the effects of all the other variables that we thought might be important, including temperature, moisture, nutrient concentrations, and soil pH."

The study is a collaboration among Yale researchers and colleagues at the University of Boulder, Colorado and the University of Kentucky.

A serious consequence of deforestation is extensive loss of carbon from the soil, a process regulated by subterranean microbial diversity. Drastic changes to the microbial community are expected to allow more CO₂ to escape into the atmosphere, with the potential to exaggerate global warming.

Specifically, the researchers found that deforestation dramatically alters microbial communities in sandy soils, but has minimal effects in muddy, clay-like soils, even after extensive tree removal.

According to the researchers, particles in fine, clay-like soil seem to have a larger surface area to bind nutrients and water. This capacity might buffer soil microbes against the disturbance of forest removal, they said. In contrast, sandy soils have larger particles with less surface area, retaining fewer nutrients and less organic matter.

"If you disrupt the community in a sandy soil, all of the nutrients the microbes rely on for food are leached away: they're lost into the atmosphere, lost into rivers, lost through rain," Crowther said. "But in clay-like soil, you can cut down the forest and the nutrients remain trapped tightly in the muddy clay."

The researchers also examined how the effects of deforestation on microbial biodiversity change over time. Contrary to their expectations, they found no correlation, even over the course of 200 years.

"The effects are consistent, no matter how long ago deforestation happened," Crowther said. "In a clay soil, you cut down the forest and the nutrients are retained for long periods of time and the community doesn't change. Whereas in a sandy soil, you cut down a forest and the community changes dramatically within only a couple of years."

Using previously documented information about soil distribution, the researchers were able to map potential areas where belowground ecosystems are more likely to be vulnerable to deforestation. This has the potential to inform land management practices concerned with the conservation of biodiversity and the sequestration of carbon in the soil.

Story Source:

The above story is based on materials provided by Yale School of Forestry & Environmental Studies. The original article was written by Kevin Dennehy. Note: Materials may be edited for content and length.

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Journal Reference:

1. Thomas W. Crowther, Daniel S. Maynard, Jonathan W. Leff, Emily E. Oldfield, Rebecca L. McCulley, Noah Fierer, Mark A. Bradford. Predicting the responsiveness of soil biodiversity to deforestation: a cross-biome study.Global Change Biology, 2014; DOI: 10.1111/gcb.12565

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Natural variation: Warm North Atlantic Ocean promotes extreme winters in U.S. and Europe

Date:

April 1, 2014  - SCIENCE DAILY

Source:

Institute of Physics

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."

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Story Source:

The above story is based on materials provided by Institute of Physics. Note: Materials may be edited for content and length.

Journal Reference:

1. Yannick Peings, Gudrun Magnusdottir. Forcing of the wintertime atmospheric circulation by the multidecadal fluctuations of the North Atlantic ocean.Environmental Research Letters, 2014; 9 (3): 034018 DOI: 10.1088/1748-9326/9/3/034018

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Meeting climate targets may require reducing meat, dairy consumption

Date:

March 30, 2014

Source:

Chalmers University of Technology

Greenhouse gas emissions from food production may threaten the UN climate target of limiting global warming to 2 degrees Celsius, according to research at Chalmers University of Technology, Sweden.

On Monday 31 March the Intergovernmental Panel on Climate Change (IPCC) presents their report on the impacts of climate change.

Carbon dioxide emissions from the energy and transportation sectors currently account for the largest share of climate pollution. However, a study from Chalmers now shows that eliminating these emissions would not guarantee staying below the UN limit. Emissions from agriculture threaten to keep increasing as global meat and dairy consumption increases. If agricultural emissions are not addressed, nitrous oxide from fields and methane from livestock may double by 2070. This alone would make meeting the climate target essentially impossible.

"We have shown that reducing meat and dairy consumption is key to bringing agricultural climate pollution down to safe levels," says Fredrik Hedenus, one of the study authors. "Broad dietary change can take a long time. We should already be thinking about how we can make our food more climate friendly."

By 2070, there will be many more of us on this planet. Diets high in meat, milk, cheese, and other food associated with high emissions are expected to become more common. Because agricultural emissions are difficult and expensive to reduce via changes in production methods or technology, these growing numbers of people, eating more meat and dairy, entail increasing amounts of climate pollution from the food sector.

"These emissions can be reduced with efficiency gains in meat and dairy production, as well as with the aid of new technology," says co-author Stefan Wirsenius. "But the potential reductions from these measures are fairly limited and will probably not suffice to keep us within the climate limit, if meat and dairy consumption continue to grow."

Beef and lamb account for the largest agricultural emissions, relative to the energy they provide. By 2050, estimates indicate that beef and lamb will account for half of all agricultural greenhouse gas emissions, while only contributing 3 percent of human calorie intake. Cheese and other dairy products will account for about one quarter of total agricultural climate pollution.

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The above story is based on materials provided by Chalmers University of Technology. Note: Materials may be edited for content and length.

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