Tuesday, July 31, 2012

El Niño weather and climate change threaten survival of baby leatherback sea turtles

El Niño weather and climate change threaten survival of baby leatherback sea turtles

ScienceDaily (May 23, 2012) — When leatherback turtle hatchlings dig out of their nests buried in the sandy Playa Grande beach in northwest Costa Rica, they enter a world filled with dangers. This critically endangered species faces threats that include egg poaching and human fishing practices. Now, Drexel University researchers have found that the climate conditions at the nesting beach affect the early survival of turtle eggs and hatchlings. They predict, based on projections from multiple models, that egg and hatchling survival will drop by half in the next 100 years as a result of global climate change.

"Temperature and humidity inside the nest are significant factors affecting egg and hatchling survival," said Dr. James Spotila, the Betz Chair Professor of Environmental Science in Drexel's College of Arts and Sciences, and senior author of the study reported May 23 in the journal PLoS ONE. Spotila and colleagues, including lead author Dr. Pilar Santidrian Tomillo of Drexel, therefore examined the relationship between regional climate patterns with leatherback turtles' nesting success over six consecutive nesting seasons at Playa Grande. This beach is the major nesting site for leatherback turtles in the eastern Pacific Ocean, containing more than 40 percent of nests.

"We have discovered a clear link between climate and survival of this endangered sea turtle population," said Spotila.

The turtles' hatching success and success emerging from the nest was significantly correlated with weather patterns associated with the El Niño Southern Oscillation (ENSO). ENSO is an irregular pattern of periodic climate variation, shifting between "El Niño" periods with warmer sea surface temperature conditions in the eastern tropical Pacific, and "La Niña" conditions with cooler sea surface temperatures, with ENSO neutral conditions in between. The El Niño cycle is known to influence many ecological processes that vary from location to location.

The researchers found that warmer, dryer El Niño conditions were associated with significantly higher mortality for eggs and hatchlings. Using projections of global climate change due to global warming over the next 100 years, they predicted that El Niño conditions will become more frequent and hatchling success will decline throughout the 21st century at Playa Grande and other nesting beaches that experience similar effects.

As climate conditions change, leatherbacks nesting at Playa Grande cannot move to other beaches. Spotila noted that the beach characteristics and off-shore ocean currents move hatchlings to feeding grounds on a kind of "hatchling highway" that makes Playa Grande an optimal nesting location for leatherbacks that other beaches cannot replace. Spotila was senior author of a modeling study demonstrating this pattern, led by Dr. George Shillinger of Stanford University and published in the June 2012 issue of Proceedings of the Royal Society B.

Spotila has conducted research with nesting leatherback turtles at Las Baulas Park in Costa Rica, where Playa Grande is located, for 22 years. He recently joined the faculty of Drexel's new Department of Biodiversity, Earth and Environmental Science (BEES), formed as a result of the University's unique affiliation with the Academy of Natural Sciences, the oldest natural history museum in the U.S. and a world leader in biodiversity and environmental research.

"The focus on field research and experiential learning in the BEES department will enable more research in environmental science in more places around the world," Spotila said. "As in our long-term leatherback studies, more research by Drexel and Academy students and scientists will contribute to a better understanding of what actions are needed to protect species and environments in critical danger."

Leatherback turtles, Spotila says, are in critical need of human help to survive. "Warming climate is killing eggs and hatchlings," Spotila said. "Action is needed, both to mitigate this effect and, ultimately, to reverse it to avoid extinction. We need to change fishing practices that kill turtles at sea, intervene to cool the beach to save the developing eggs and find a way to stop global warming. Otherwise, the leatherback and many other species will be lost."

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It took Earth ten million years to recover from greatest mass extinction

It took Earth ten million years to recover from greatest mass extinction

ScienceDaily (May 27, 2012) — It took some 10 million years for Earth to recover from the greatest mass extinction of all time, latest research has revealed.

Life was nearly wiped out 250 million years ago, with only 10 per cent of plants and animals surviving. It is currently much debated how life recovered from this cataclysm, whether quickly or slowly.

Recent evidence for a rapid bounce-back is evaluated in a new review article by Dr Zhong-Qiang Chen, from the China University of Geosciences in Wuhan, and Professor Michael Benton from the University of Bristol. They find that recovery from the crisis lasted some 10 million years, as explained May 27 in Nature Geoscience.

There were apparently two reasons for the delay, the sheer intensity of the crisis, and continuing grim conditions on Earth after the first wave of extinction.

The end-Permian crisis, by far the most dramatic biological crisis to affect life on Earth, was triggered by a number of physical environmental shocks -- global warming, acid rain, ocean acidification and ocean anoxia. These were enough to kill off 90 per cent of living things on land and in the sea.

Dr Chen said: "It is hard to imagine how so much of life could have been killed, but there is no doubt from some of the fantastic rock sections in China and elsewhere round the world that this was the biggest crisis ever faced by life."

Current research shows that the grim conditions continued in bursts for some five to six million years after the initial crisis, with repeated carbon and oxygen crises, warming and other ill effects.
Some groups of animals on the sea and land did recover quickly and began to rebuild their ecosystems, but they suffered further setbacks. Life had not really recovered in these early phases because permanent ecosystems were not established.

Professor Benton, Professor of Vertebrate Palaeontology at the University of Bristol, said: "Life seemed to be getting back to normal when another crisis hit and set it back again. The carbon crises were repeated many times, and then finally conditions became normal again after five million years or so."

Finally, after the environmental crises ceased to be so severe, more complex ecosystems emerged. In the sea, new groups, such as ancestral crabs and lobsters, as well as the first marine reptiles, came on the scene, and they formed the basis of future modern-style ecosystems.

Professor Benton added: "We often see mass extinctions as entirely negative but in this most devastating case, life did recover, after many millions of years, and new groups emerged. The event had re-set evolution. However, the causes of the killing -- global warming, acid rain, ocean acidification -- sound eerily familiar to us today. Perhaps we can learn something from these ancient events."

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Generation X is surprisingly unconcerned about climate change

Generation X is surprisingly unconcerned about climate change

ScienceDaily (July 19, 2012) — As the nation suffers through a summer of record-shattering heat, a University of Michigan report finds that Generation X is lukewarm about climate change -- uninformed about the causes and unconcerned about the potential dangers.

"Most Generation Xers are surprisingly disengaged, dismissive or doubtful about whether global climate change is happening and they don't spend much time worrying about it," said Jon D. Miller, author of "The Generation X Report."

The new report, the fourth in a continuing series, compares Gen X attitudes about climate change in 2009 and 2011, and describes the levels of concern Gen Xers have about different aspects of climate change, as well as their sources of information on the subject.

"We found a small but statistically significant decline between 2009 and 2011 in the level of attention and concern Generation X adults expressed about climate change," Miller said. "In 2009, about 22 percent said they followed the issue of climate change very or moderately closely. In 2011, only 16 percent said they did so."

Miller directs the Longitudinal Study of American Youth at the U-M Institute for Social Research. The study, funded by the National Science Foundation since 1986, now includes responses from approximately 4,000 Gen Xers -- those born between 1961 and 1981, and now between 32 and 52 years of age.
Only about 5 percent of those surveyed in 2011 were alarmed about climate change, and another 18 percent said they were concerned about it. But 66 percent said they aren't sure that global warming is happening, and about 10 percent said they don't believe global warming is actually happening.
"This is an interesting and unexpected profile," Miller said. "Few issues engage a solid majority of adults in our busy and pluralistic society, but the climate issue appears to attract fewer committed activists -- on either side -- than I would have expected."
Because climate change is such a complex issue, education and scientific knowledge are important factors in explaining levels of concern, Miller said. Adults with more education are more likely to be alarmed and concerned about climate change, he found. And those who scored 90 or above on a 100-point Index of Civic Scientific Literacy also were significantly more likely to be alarmed or concerned than less knowledgeable adults. Still, 12 percent of those who were highly literate scientifically were either dismissive or doubtful about climate change, Miller found. He also found that partisan affiliations predicted attitudes, with nearly half of liberal Democrats alarmed or concerned compared with zero percent of conservative Republicans.

"There are clearly overlapping levels of concern among partisans of both political parties," Miller said. "But for some individuals, partisan loyalties may be helpful in making sense of an otherwise complicated issue."

Given the greater anticipated impact of climate change on future generations, Miller expected that the parents of minor children would be more concerned about the issue than young adults without minor children.

"Not so," he said. "Generation X adults without minor children were slightly more alarmed about climate change than were parents. The difference is small, but it is in the opposite direction than we expected."

Miller found that Gen X adults used a combination of information sources to obtain information on the complex issue of climate change, with talking to friends, co-workers and family members among the most common sources of information.

"Climate change is an extremely complex issue, and many Generation X adults do not see it as an immediate problem that they need to address," Miller said.

"The results of this report suggest that better educated young adults are more likely to recognize the importance of the problem, but that there is a broad awareness of the issue even though many adults prefer to focus on more immediate issues -- jobs and schools for their children -- than the needs of the next generation. These results will not give great comfort to either those deeply concerned about climate issues or those who are dismissive of the issue."

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Scientists develop new carbon accounting method to reduce farmers' use of nitrogen fertilizer

Scientists develop new carbon accounting method to reduce farmers' use of nitrogen fertilizer

ScienceDaily (July 18, 2012) — It's summer. For many of us, summer is a time synonymous with fresh corn, one of the major field crops produced in the United States. In 2011, corn was planted on more than 92 million acres in the U.S., helping the nation continue its trend as the world's largest exporter of the crop.

Corn is a nitrogen-loving plant. To achieve desired production levels, most U.S. farmers apply synthetic nitrogen fertilizer to their fields every year.
Once nitrogen fertilizer hits the ground, however, it's hard to contain and is easily lost to groundwater, rivers, oceans and the atmosphere.

"That's not good for the crops, the farmers or the environment," says Phil Robertson, a scientist at Michigan State University and principal investigator at the National Science Foundation's (NSF) Kellogg Biological Station (KBS) Long-Term Ecological Research (LTER) site.
KBS is one of 26 such NSF LTER sites across the United States and around the globe in ecosystems from forests to coral reefs.

Nitrogen lost to the environment from agricultural fields is nitrogen not used by crops, Robertson says. "This costs farmers money and degrades water and air quality, with significant health, biodiversity and downstream economic effects."

Farmers already manage fertilizer to avoid large losses. But, to reduce losses further, it currently costs more money than the fertilizer saves.

Robertson and colleagues are working on a way to help make the time and expense of efforts to mitigate fertilizer loss worthwhile. They're putting the finishing touches on a program that would pay farmers to apply less nitrogen fertilizer in a way that doesn't jeopardize yields. The program, called the nitrous oxide greenhouse gas reduction methodology, is being conducted in partnership with the Electric Power Research Institute.

"This project is a great example of how long-term, fundamental research can contribute practical solutions to important environmental problems of concern in the U.S.--and ultimately around the world," says Matt Kane, an NSF program director for LTER.

In the United States, agriculture accounts for almost 70 percent of all nitrous oxide emissions linked with human activity. Nitrous oxide is one of the major gases contributing to human-induced climate change; it has a lifetime in the atmosphere of more than 100 years. In addition, a molecule of nitrous oxide has more than 300 times the heat-trapping effect in the atmosphere as a molecule of carbon dioxide.

In soils, the production of nitrous oxide through microbial activity is a natural process. By applying large amounts of fertilizer, however, humans have greatly increased the amount of nitrous oxide in soils. This is particularly true when nitrogen fertilizer is added in larger amounts than the crop needs, and when it is applied at times or in ways that make it difficult for the crop to get the full benefit.
"Improving the efficiency of nitrogen use for field crop agriculture holds great promise for helping mitigate climate change," Robertson says.

The nitrous oxide greenhouse gas reduction methodology, which is a way for farmers to participate in existing and emerging carbon markets, recently was approved by the American Carbon Registry and is in its final stages of validation by the Verified Carbon Standard--two carbon market standards that operate worldwide.
When farmers reduce their nitrogen fertilizer use, they can use the methodology as a means of generating carbon credits. These credits can be traded in carbon markets for financial payments.
The scientific underpinning for the methodology rests on decades of research Robertson and colleagues have conducted at the KBS LTER site.

"By closely following nitrous oxide, crop yields and other ecosystem responses to fertilizers," Robertson says, "we discovered that nitrous oxide emissions increase exponentially and consistently with increasing nitrogen fertilizer use."

The idea of the methodology is to offer ways of using less fertilizer to produce crops. But if farmers apply less fertilizer, will their crop production take a hit?

"Carbon credits provide an incentive to apply fertilizer more precisely, not to reduce yields," says Robertson. "If yields were reduced significantly, the climate effect would be nil because a farmer somewhere else would have to use more nitrogen to make up the yield loss, thereby generating more nitrous oxide."

The new methodology developed at NSF's KBS LTER site was successfully used by a Michigan farmer in Tuscola County as part of a proof-of-concept project.

"A major value of the approach is that it is straightforward to understand and implement," says KBS LTER scientist Neville Millar, who co-led development of the methodology.
In addition to providing an economic incentive, the methodology is a tool farmers can apply to enhance their land stewardship.

"The same strategies that farmers can use to minimize nitrous oxide loss will act to reduce the loss of nitrate to groundwater and loss of other forms of nitrogen to the atmosphere," says Millar.
Adam Diamant, technical executive at the Electric Power Research Institute and a co-developer of the methodology, says the new approach resulted in a "quadruple win: for farmers, for industrial organizations that may be required to reduce their greenhouse gas emissions, for the atmosphere and for water quality from the upper Midwest all the way to the Gulf of Mexico."

Adds Robertson: "We're in uncharted territory with a growing global human population and unprecedented environmental change.

Performing the research that links environmental benefits to environmental markets, without compromising crop yields, is crucial for feeding more people while sustaining Earth's ecosystems."

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Pollution can make citizens, both rich and poor, go green

Pollution can make citizens, both rich and poor, go green

ScienceDaily (July 30, 2012) — Nothing inspires environmentalism quite like a smog-filled sky or a contaminated river, according to a new study that also indicates that environmentalism isn't just for the prosperous.

People living in China's cities who say they've been exposed to environmental harm are more likely to be green: re-using their plastic grocery bags or recycling. Moreover, the study, published this week in the international journal AMBIO, indicates that the poor would sacrifice economic gain to protect their environment.

"The human and natural worlds are tightly coupled and we cannot protect the environment without empirical studies on how rich and poor people are understanding and reacting to the natural world around them." said Jianguo "Jack" Liu, a co-author of the AMBIO paper and director of the Center for Systems Integration and Sustainability (CSIS) at Michigan State University.
The paper, "How Perceived Exposure to Environmental Harm Influences Environmental Behavior in Urban China," flies in the face of the conventional wisdom that the poor cannot afford to protect the environment.

"We feel it's a major contribution to provide empirical evidence that environmental harm is one of the most important predictors of environmental behavior," said Xiaodong Chen, who conducted the study while working on his doctorate at CSIS.

"Environmental harm could be more important than economic status in predicting environmental behavior. If people are affected by degraded environmental conditions, then even people with low economic status still may sacrifice some economic benefit in order to protect the environment."
Indeed, the growing environmental consciousness in China has been accompanied by increased involvement by the public in environmental protection. For instance, the paper notes that in 2005 there were some 1,000 protests per week related to environmental pollution in China, a number projected to increase rapidly.

Scientists have studied environmental attitudes for years, but the paper notes that it's behavior that ultimately counts. There is a growing body of literature on environmental attitudes and behavior in China, yet little is known about how people perceive and respond to personal exposure to environmental harm.

Chen and co-authors Liu; Nils Peterson of North Carolina State University and a CSIS alumnus; Vanessa Hull, doctoral candidate in CSIS; Chuntian Lu, MSU sociology doctoral student; and Dayong Hong of Renmin University in China used China's General Social Survey of 2003, which was the first nationwide survey to address this issue.

Some 5,000 urban respondents were asked specifically about their environmental behavior -- if they sorted their garbage to separate recyclables, re-used plastic bags, talked about environmental issues with family or friends, participated in environmental education programs, volunteered in environmental organizations or took part in environmental litigation.

The people taking the survey were allowed to define environmental harm for themselves.
The authors found that actions that resulted in direct results such as environmental litigation were the ones that people most likely turned to after being exposed to environmental harm. Other actions, such as trash recycling programs, may produce indirect results. However, people's views about the environment are most likely to inspire them to participate in environmental behaviors if those behaviors are ones that they can control, such as re-using plastic bags and talking about environmental issues.

"Basically, it means that if people are affected by environmental harm, they feel they should do something positive, and something they themselves can control," Chen said.

The findings, Chen said, can help instruct policy to transform recognition of environmental harm into environmental action.

The survey was administered jointly by the Survey Research Center of the Hong Kong University of Science and Technology and the Department of Sociology at Renmin University of China.
The research was funded by the National Science Foundation, MSU AgBioResearch, and the Giorgio Ruffolo Fellowship in Sustainability Science at Harvard University. Chen now is an assistant professor of geography at University of North Carolina-Chapel Hill.

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250 years of global warming: Berkeley Earth releases new analysis

250 years of global warming: Berkeley Earth releases new analysis

ScienceDaily (July 30, 2012) — According to a new Berkeley Earth study released July 29, 2012, the average temperature of Earth's land has risen by 1.5 °C over the past 250 years. The good match between the new temperature record and historical carbon dioxide records suggests that the most straightforward explanation for this warming is human greenhouse gas emissions.

Together with their most recent results and papers, Berkeley Earth also released their raw data and analysis programs. They will be available online at BerkeleyEarth.org on July 30.

The new analysis from Berkeley Earth goes all the way back to 1753, about 100 years earlier than previous groups' analyses. The limited land coverage prior to 1850 results in larger uncertainties in the behavior of the record; despite these, the behavior is significant.

Robert Rohde, Lead Scientist for Berkeley Earth and the person who carried out most of the analysis, noted that "Sudden drops in the early temperature record (1753 to 1850) correspond to known volcanic events." Volcanoes spew particles into the air, which then reflect sunlight and cool the earth for a few years. In the Berkeley Earth temperature plot, sudden dips in temperature caused by large volcanic explosions are evident back to the late 1700s.

Berkeley Earth compared the shape of the gradual rise over 250 years to simple math functions (exponentials, polynomials) and to solar activity (known through historical records of sunspot numbers), and even to rising functions such as world population.

Richard Muller, Founder and Scientific Director of Berkeley Earth, notes "Much to my surprise, by far the best match was to the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice." He emphasizes that the match between the data and the theory doesn't prove that carbon dioxide is responsible for the warming, but the good fit makes it the strongest contender. "To be considered seriously, any alternative explanation must match the data at least as well as does carbon dioxide."

In its 2007 report the IPCC concluded only that "most" of the warming of the past 50 years could be attributed to humans. It was possible, according to the IPCC, that increased solar activity could have contributed to warming prior to 1956. Berkeley Earth analyzed about 5 times more station records than were used in previous analyses, and this expanded data base along with its new statistical approach allowed Berkeley Earth to go about 100 years farther back in time than previous studies. By doing so, the Berkeley Earth team was able to conclude that over 250 years, the contribution of solar activity to global warming is negligible.

Some of the scientists on the Berkeley Earth team admit surprise that the new analysis has shown such clear agreement between global land-­‐temperature rise and human-­‐caused greenhouse gases. "I was not expecting this," says Richard Muller, "but as a scientist, I feel it is my duty to let the evidence change my mind."

Elizabeth Muller, co-­‐Founder and Executive Director of Berkeley Earth, says that "One of our goals at Berkeley Earth is complete transparency -- we believe that everyone should be able to access raw climate data and do their own analysis. Scientists have a duty to be 'properly skeptical', and we are trying to lower the barriers to entry into the field."

Robert Rohde created an online feature that allows look up temperature records by location. "If you want to know what the temperature change has been in your city, your state, or even your country, you can now find this online at BerkeleyEarth.org" says Rohde. He adds, "We hope people will have a lot of fun interacting with the data." This feature should be available to the public by Monday, July 30.

A previous Berkeley Earth study, released in October 2011, found that the land-­‐surface temperature had risen by about 0.9 °C over the past 50 years (which was consistent with previous analyses) and directly addressed scientific concerns raised by skeptics, including the urban heat island effect, poor station quality, and the risk of data selection bias.

The Berkeley Earth team values the simplicity of its analysis, which does not depend on the large complex global climate models that have been criticized by climate skeptics for their hidden assumptions and adjustable parameters. The conclusion that the warming is due to humans is based simply on the close agreement between the shape of the observed temperature rise and the known greenhouse gas increase.

Elizabeth adds, "The current data does not include ocean temperatures; these will be added in the next phase of the Berkeley Earth studies. Another next step for our team is to think about the implications of our findings."

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Rise in temperatures and COsub2/sub follow each other closely in climate change

Rise in temperatures and COsub2/sub follow each other closely in climate change

ScienceDaily (July 23, 2012) — The greatest climate change the world has seen in the last 100,000 years was the transition from the ice age to the warm interglacial period. New research from the Niels Bohr Institute at the University of Copenhagen indicates that, contrary to previous opinion, the rise in temperature and the rise in the atmospheric CO2 follow each other closely in terms of time. The results have been published in the scientific journal, Climate of the Past.

In the warmer climate the atmospheric content of CO2 is naturally higher. The gas CO2 (carbon dioxide) is a green-house gas that absorbs heat radiation from Earth and thus keeps Earth warm. In the shift between ice ages and interglacial periods the atmospheric content of CO2 helps to intensify the natural climate variations.

It had previously been thought that as the temperature began to rise at the end of the ice age approximately 19,000 years ago, an increase in the amount of CO2 in the atmosphere followed with a delay of up to 1,000 years.

"Our analyses of ice cores from the ice sheet in Antarctica shows that the concentration of CO2 in the atmosphere follows the rise in Antarctic temperatures very closely and is staggered by a few hundred years at most," explains Sune Olander Rasmussen, Associate Professor and centre coordinator at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

Deep-sea's important role
The research, which was carried out in collaboration with researchers from the University of Tasmania in Australia, is based on measurements of ice cores from five boreholes through the ice sheet in Antarctica. The ice sheet is formed by snow that doesn't melt, but remains year after year and is gradually compressed into kilometers thick ice. During the compression, air is trapped between the snowflakes and as a result the ice contains tiny samples of ancient atmospheres. The composition of the ice also shows what the temperature was when the snow fell, so the ice is an archive of past climate and atmospheric composition.

"The ice cores show a nearly synchronous relationship between the temperature in Antarctica and the atmospheric content of CO2, and this suggests that it is the processes in the deep-sea around Antarctica that play an important role in the CO2 increase," explains Sune Olander Rasmussen.

He explains that one of the theories is that when Antarctica warms up, there will be stronger winds over the Southern Ocean and the winds pump more water up from the deep bottom layers in the ocean where there is a high content of CO2 from all of the small organisms that die and fall down to the sea floor and rot. When strong winds blow over the Southern Ocean, the ocean circulation brings more of the CO2-rich bottom water up to the surface and a portion of this CO2 is released into the atmosphere. This process links temperature and CO2 together and the new results suggest that the linking is closer and happens faster than previously believed.

Climatic impact
The global temperature changed naturally because of the changing solar radiation caused by variations in Earth's orbit around the Sun, Earth's tilt and the orientation of Earth's axis. These are called the Milankowitch cycles and occur in periods of approximately 100,000, 42,000, and 22,000 years. These are the cycles that cause Earth's climate to shift between long ice ages of approximately 100,000 years and warm interglacial periods, typically 10,000 -- 15,000 years. The natural warming of the climate was intensified by the increased amount of CO2 in the atmosphere.

"What we are observing in the present day is the mankind has caused the CO2 content in the atmosphere to rise as much in just 150 years as it rose over 8,000 years during the transition from the last ice age to the current interglacial period and that can bring the Earth's climate out of balance," explains Sune Olander Rasmussen, adding: "That is why it is even more important that we have a good grip on which processes caused the climate of the past to change, because the same processes may operate in addition to the anthropogenic changes we see today. In this way the climate of the past helps us to understand how the various parts of the climate systems interact and what we can expect in the future."

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Climate change and deforestation: Pre-human effect on biodiversity in northern Madagascar

Climate change and deforestation: Pre-human effect on biodiversity in northern Madagascar

ScienceDaily (July 20, 2012) — A recent study, by an international research group led by Lounès Chickhi, group leader at the Instituto Gulbenkian de Ciência (Portugal) and CNRS researcher (in Toulouse, France), questions the prevailing account that degradation of tropical ecosystems is essentially a product of human activity. Their findings call for reassessment of the impact of local communities on their environment.

The impact of deforestation on loss of biodiversity is undeniable. Madagascar, a biodiversity hotspot for its richness of endemic species, has been especially hard hit by deforestation and subsequent destruction of natural habitats, caused mainly, it is thought, by human pauperisation, economic activities and population growth. A recent study, by an international research group led by Lounès Chickhi, group leader at the Instituto Gulbenkian de Ciência (Portugal) and CNRS researcher (in Toulouse, France), questions the prevailing account that degradation of tropical ecosystems is essentially a product of human activity. Their findings call for reassessment of the impact of local communities on their environment.

Published in the journal Proceedings of the Natural Academy of Sciences (PNAS), the research shows that the population of golden-crowned sifaka (Propithecus tattersalli), inhabitants of the Daraina region in the north of Madagascar, indeed contracted dramatically, but at a time that precedes human arrival on the island. Furthermore, by examining aerial and satellite photographs of the Daraina region, the researchers concluded that forest cover in this region has remained remarkably stable over the last 60 years, thus excluding any strong effect of humans on the environment.

Taken together, and combined with historical and paleontological records, the findings strongly suggest that the present-day open habitats of Daraina are a result of pre-human climatic changes (such as the Holocene droughts, which happened between 10 000 and 4 000 years before the present time). These may have been the cause of the increase in open landscapes in northern Madagascar, and subsequent reduction in the number of the tree-dwelling Golden crown sifakas.

The team combined genetic data, which holds specific signatures of major population contraction or expansion events, with remote-sensing data (aerial photography and satellite imao ges), to look at a long-lasting and controversial question in conservation biology: to discriminate between the contributions of human and natural factors to changes in ecosystems.

Their findings are highly relevant for the communities of climatologists, ecologists, evolutionary biologists and conservationists, as Lounès Chikhi describes, "There is no doubt that humans have played a major role in driving several Malagasy species to extinction, since their arrival on the island. Although our findings relate to a specific region in Madagascar, they shine the spotlight on how important it is that conservation projects account for regional differences. The presence of humans, we have demonstrated, may not be the only cause for loss of biodiversity. It is risky to alienate local communities by excluding them from their territories, rather that bringing them on as precious allies to help conservationists find local answers for sustainable resource management."

Lounès Chikhi points out that, despite their findings, there are not many reasons to be over-optimistic. The golden-crowned sifaka is amongst the most threatened in Madagascar -- the IUCN recently proposed that it be included in their Red List as critically endangered. Furthermore, the Daraina region may be affected by plans to tar the main road which crosses the habitat of these lemurs, and increased poaching and mining, since the political coup in 2009, mean that conservation efforts needs to be maintained and indeed strengthened.
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The new face of El Niño

The new face of El Niño

ScienceDaily (July 24, 2012) — Emerging once every two to seven years in the equatorial Pacific, El Niño causes disorder across the globe and for the global economy. But in the past ten years, it has changed its face. It is increasingly taking the form of Modoki, 'similar but different' as it was baptised by the Japanese team who first discovered this less tumultuous cousin that provokes droughts in India and Australia. Recent research has described the physical manifestations of this El Niño variant, which is centred in the central pacific, unlike its eastern relative. The impact on marine biology and its probable effects on fishing still need to be examined. To achieve this, IRD researchers and their partners from the Legos(1) and Locean(3) laboratories have studied its effects on the very first links in the food chain.

Less aquatic life in the centre of the Pacific
In the same manner as its physical mechanisms, from a biological point of view, Modoki episodes are also characterised by displacement of phenomenal effects. There is not the same widespread decrease in phytoplankton that is seen in the eastern Pacific during classic El Niño events, rather a more localised version in the central zone of the basin.

Oceanographers have observed the colouring of the Pacific using 'water colouration' satellite images taken between 1997 and 2010. The blue or green colour of the ocean seen from space actually reflects variations in the surface levels of chlorophyll. Scientists have thus observed low levels of chlorophyll in the centre of the Pacific basin (under 0.1mg per m3) during Modoki events that took place between 2002-3, 2004-5, 2006-7 and 2009-10. The concentration is an indicator of the biomass of phytoplankton at the ocean surface. In this way, the levels recorded in the central area of the basin during recent El Niño Modoki events convey the scarcity of aquatic nutrients necessary for plant development and thus for marine life forms.

When El Niño fools with the weather
Under 'normal' conditions above the Pacific, the trade winds blow strongly from east to west. They accumulate, thus confining the vast warm waters with little surface activity known as the 'warm pool' to the western part of the ocean. This enormous warm water reservoir with a temperature of over 28°C feeds the flows of warmth and humidity that affect the vast majority of the Earth's atmosphere, rather like a planetary heat pump. When a classic El Niño episode occurs, the trade winds experience a brutal drop in force, and the upwelling(4) phenomenon that is triggered all around the equator by the Coriolis effect slows down. The huge reservoir spreads out into the Pacific towards the east and the water becomes depleted.

But when Modoki occurs, the trade winds hardly drop in force. The result is a minimal slowing down of equatorial upwelling and a blockage of water from the 'warm pool' in the central basin, which in turn explains the depletion being localised in the centre of the ocean.

Colder, richer waters to the east
Another recent study, carried out in partnership with researchers from Peru(2), has recently demonstrated that Modoki type events might encourage the upwelling phenomenon which occurs in this case along the South-American coastline.

As part of their research, the team examined the surface temperature of the ocean, again observed from space and simulated using a high-resolution oceanic model. To achieve this, researchers analysed satellite images from all across Peru since 1981, and a high-resolution simulation stretching back to 1958. They thus demonstrated a cooling of the sea nearer the Peruvian coastline, corresponding to an increase in upwelling, linked to an increase in the frequency of Modoki events. This cold water rising from the deep is rich in the nutrients that support new life in the region's seas. The new face of El Niño could thus have an effect on halieutic resources around the coasts of South America.

Initially viewed by scientists as a new phenomenon, Modoki has since been proved by research to be a variant of El Niño. Indeed, Modoki is not a recent phenomenon. Researchers have found evidence of it in climate records dating back 120 years(6). However, even though a link to climate change has not yet been firmly established, its frequency may increase five times by 2050(6). Classic major episodes of El Niño from 1982-3 and 1997-8 led to a drop in fish stocks, particularly in Peru. What will happen with Modoki? The extent to which it will influence fishing resources is still to be determined.

Notes :
(1) Laboratoire d'études en géophysique et océanographie spatiales (UMR IRD / CNES / CNRS / UPS Toulouse 3)

(2) from the Discoh LMI (Imarpe, IGP and Senamhi)

(3) Laboratoire d'océanographie et du climat: expérimentations et approches numériques (UMR IRD / CNRS / MNHN / UPMC Paris 6)

(4) An 'upwelling' is a zone of cold and nutrient-rich water rising to the surface. Around the equator as a result of the Coriolis effect, masses of water moved by the trade winds are pushed towards the poles and replaced by deeper water.

(5) Instituto del Mar del Perú

(6) Nature, 2009, 461 (7263), p. 511-514. fdi:010048207

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Mangroves: A filter for heavy metals

Mangroves: A filter for heavy metals

ScienceDaily (July 24, 2012) — A mangrove is a forest consisting of various species of mangrove trees growing with their bases submerged in water, at the interface between land and sea. They cover more than three quarters of tropical coastlines, that is to say almost 200,000km². In New Caledonia, they accounts for almost 80% of the island's western coastline. They act as a buffer zone between the lagoon and the mountain mining areas, rich in metallic elements (iron, manganese, nickel, chrome and cobalt, nearly all toxic pollutants).

New Caledonia is the3rd largest nickel producer worldwide, with over 30% of the planet's resources, and it has been the location of intense mining activity since the end of the 19th century. Around 300 million m3 of spoils rich in heavy metals have been created until now. A significant amount of this mining waste has been transported to coastal areas by the dramatic climate events, (thunderstorms and tropical tempests, cyclones) that often occur in this region. Accentuated by mining activity, this erosion is the most important cause of deterioration of the coastline, the mangroves, the fringing reef and the lagoon.

Polluted mangroves
An IRD team and their partners(1) have recently demonstrated that concentrations of mineral metals such as iron, nickel and chrome are 10 to 100 times higher in mangroves situated downstream from mining sites. Recently, two studies have been published, one concerning the mangrove downstream from a nickel mine that operated in the 20th century at the mouth of the Dumbéa river in the south west of the island, the other being unaffected by mining activity in its catchment area (used as a control) in Conception Bay, near Nouméa.

Core samples of sediment 70cm in length were taken at low tide from the different zones in the mangroves, in order to account for differing coverage in vegetation. The mangrove ecosystem is clearly divided into different zones, each dominated by a separate type of mangrove tree, according to the topography of the land and the duration of tidal immersion. Rhizophora trees are found where the mangrove meets the sea, large in size with their root systems above ground. In the central zone where high tides are intermittent, the medium-sized Avicennia mangrove shrubs are found. Located at the rear is the 'tanne', the area least often submerged by water, consisting salt-saturated soil, bare or sparsely populated with vegetation.

The core samples extracted were examined using a variety of chemical treatments designed to dissolve minerals containing metallic elements. Such analysis has enabled a comparison between the concentrations of metals in the sediment from the two mangroves under study, in addition to their potential toxicity, and revealed the biogeochemical processes that are specific to the various species of mangrove trees.

The mangrove -- a highly adapted forest
Mangrove trees use a real arsenal of survival techniques to deal with the extreme conditions of their natural habitat. To counteract the absence of oxygen in the mud, they have developed remarkable root systems, enabling air to penetrate the soil. The Rhizophora located on the waterfront have developed roots that form stilts, emerging from their branches, in order to combat the swell and currents. As a result, there is a major accumulation of litter within the sediment, where anoxic(2) processes take place, leading to the precipitation of 'sulphide' type minerals. In this type of forest, metals can thus merge with decomposing organic matter, or co-precipitate with the sulphides, and are thus trapped by the mangrove.

The Avicennia are characterised by a star-shaped root system that develops a sub-surface level, with vertical growths emerging skywards. These formations are known as 'pneumatophores', and allow the mangrove tree to extract oxygen from the atmosphere. However, these breathing organs are not watertight, and lose a portion of their oxygen to the sediment. As such, beneath the vegetation, metallic elements linked to iron oxides are dissolved and transferred to the mangrove trees.

This research has led to a better global understanding of the processes that control the mangrove ecosystem. It has confirmed that mangroves act as a well for contaminants over the long term.
However, their surface coverage is decreasing by 1 to 2% each year. The cause: demographic growth along the tropical coastlines and urbanisation, as well as prospecting for and exploitation of natural resources, such as nickel in New Caledonia. Without the dense network of vegetation provided by the mangrove trees, sediment that is loaded with pollutants could be returned to the lagoon, a haven for biodiversity and a major source of revenue for the local population through fishing and aquaculture.
  1. This research has been carried out by the University of New Caledonia, Koniambo Nickel SAS and the AEL/LEA laboratory in Nouméa, the University of Orléans and Paris-Sud University.
  2. produced in the absence of oxygen
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Unusual Greenland ice sheet surface melt

Unusual Greenland ice sheet surface melt

ScienceDaily (July 24, 2012) — For several days this month, Greenland's surface ice cover melted over a larger area than at any time in more than 30 years of satellite observations. Nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its two-mile-thick center, experienced some degree of melting at its surface, according to measurements from three independent satellites analyzed by NASA and university scientists.

On average in the summer, about half of the surface of Greenland's ice sheet naturally melts. At high elevations, most of that melt water quickly refreezes in place. Near the coast, some of the melt water is retained by the ice sheet and the rest is lost to the ocean. But this year the extent of ice melting at or near the surface jumped dramatically. According to satellite data, an estimated 97 percent of the ice sheet surface thawed at some point in mid-July.

Researchers have not yet determined whether this extensive melt event will affect the overall volume of ice loss this summer and contribute to sea level rise.

"The Greenland ice sheet is a vast area with a varied history of change. This event, combined with other natural but uncommon phenomena, such as the large calving event last week on Petermann Glacier, are part of a complex story," said Tom Wagner, NASA's cryosphere program manager in Washington. "Satellite observations are helping us understand how events like these may relate to one another as well as to the broader climate system."

Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, Calif., was analyzing radar data from the Indian Space Research Organisation's (ISRO) Oceansat-2 satellite last week when he noticed that most of Greenland appeared to have undergone surface melting on July 12. Nghiem said, "This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?"
Nghiem consulted with Dorothy Hall at NASA's Goddard Space Flight Center in Greenbelt, Md. Hall studies the surface temperature of Greenland using the Moderate-resolution Imaging Spectroradiometer (MODIS) on NASA's Terra and Aqua satellites. She confirmed that MODIS showed unusually high temperatures and that melt was extensive over the ice sheet surface.

Thomas Mote, a climatologist at the University of Georgia, Athens, Ga; and Marco Tedesco of City University of New York also confirmed the melt seen by Oceansat-2 and MODIS with passive-microwave satellite data from the Special Sensor Microwave Imager/Sounder on a U.S. Air Force meteorological satellite.

The melting spread quickly. Melt maps derived from the three satellites showed that on July 8, about 40 percent of the ice sheet's surface had melted. By July 12, 97 percent had melted.

This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland's weather since the end of May. "Each successive ridge has been stronger than the previous one," said Mote. This latest heat dome started to move over Greenland on July 8, and then parked itself over the ice sheet about three days later. By July 16, it had begun to dissipate.

Even the area around Summit Station in central Greenland, which at 2 miles above sea level is near the highest point of the ice sheet, showed signs of melting. Such pronounced melting at Summit and across the ice sheet has not occurred since 1889, according to ice cores analyzed by Kaitlin Keegan at Dartmouth College in Hanover, N.H. A National Oceanic and Atmospheric Administration weather station at Summit confirmed air temperatures hovered above or within a degree of freezing for several hours July 11-12.

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. "But if we continue to observe melting events like this in upcoming years, it will be worrisome."
Nghiem's finding while analyzing Oceansat-2 data was the kind of benefit that NASA and ISRO had hoped to stimulate when they signed an agreement in March 2012 to cooperate on Oceansat-2 by sharing data.

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