Substream - sub_gw_impact_biodiversity

  1. back to all global warming and energy subjects

  2. 20-06-2003 eco nws - global warming - impact - extinction - projected rise could wipe out 95% of species - Researchers at Bristol University have discovered that a mere six degrees of global warming was enough to wipe out up to 95 per cent of the species which were alive on Earth at the end of the Permian period, 250 million years ago. Up to six degrees of warming is now predicted for the next 100 years by United Nations scientists from the Intergovernmental Panel on Climate Change, if nothing is done about emissions of greenhouse gases, principally carbon dioxide. (canberra) - biodiversity

  3. 20-06-2003 eco nws - global warming - impact - extinction - projected rise could wipe out 95% of species - Researchers at Bristol University have discovered that a mere six degrees of global warming was enough to wipe out up to 95 per cent of the species which were alive on Earth at the end of the Permian period, 250 million years ago. Up to six degrees of warming is now predicted for the next 100 years by United Nations scientists from the Intergovernmental Panel on Climate Change, if nothing is done about emissions of greenhouse gases, principally carbon dioxide. (canberra) - biodiversity

  4. 29-08-2003 eco nws - global warming - impact - extinction - species no place to go - 'Some people will tell you that the planet has warmed in the past and that species always managed to adapt, so there's no cause for alarm. Unfortunately that's not the case,' said Johannes Foufopoulos, assistant professor at the University of Michigan School of Natural Resources and Environment. Foufopoulos says new research illustrates major differences between global warming today and past natural climate fluctuations as they relate to species extinctions. Generally, each species requires specific habitat and climate conditions to survive. In the past when climate changed, populations of a species would die out on one edge of their habitat range and expand into newly available habitat at the other edge. This colonization process was crucial for the survival of species during the unstable climate of the last ice ages. However this broad movement of species, which has prevented large-scale extinctions in the past, is not likely to operate effectively in the modern world, he said. (science daily) - biodiversity

  5. 29-08-2003 eco nws - global warming - impact - extinction - species no place to go - 'Some people will tell you that the planet has warmed in the past and that species always managed to adapt, so there's no cause for alarm. Unfortunately that's not the case,' said Johannes Foufopoulos, assistant professor at the University of Michigan School of Natural Resources and Environment. Foufopoulos says new research illustrates major differences between global warming today and past natural climate fluctuations as they relate to species extinctions. Generally, each species requires specific habitat and climate conditions to survive. In the past when climate changed, populations of a species would die out on one edge of their habitat range and expand into newly available habitat at the other edge. This colonization process was crucial for the survival of species during the unstable climate of the last ice ages. However this broad movement of species, which has prevented large-scale extinctions in the past, is not likely to operate effectively in the modern world, he said. (science daily) - biodiversity

  6. 07-09-2004 eco nws - global warming - impact - extinction - australian species vulnerable - Marking Australia's National Threatened Species Day today, WWF-Australia warns that climate change may pose one of the biggest threats to species loss, including some of the country's most iconic inhabitants. Australia is at risk by even small changes in temperature, said Dr Nicola Markus, WWF-Australia's Species and Community Programme manager. 0.7 Celsius temperature rise has had a big impact on the severity of our worst drought on record. - biodiversity

  7. 10-11-2004 eco nws - global warming - impact - extinction - water - ice - arctic ice - arctic and species already affected - Global warming has disrupted the lives of dozens of types of animals, birds and insects in the United States and will soon make the Arctic nearly unrecognizable, according to two reports released this week. The reports document sweeping 'you-can-see-them-with-your-own-eyes' ecological changes underway and offer dire predictions of massive species extinctions, an elevation of sea level by 3 feet and widespread disruptions to Earth's life-support systems. These dramatic changes should be a wake-up call to reduce greenhouse gas emissions and bolster efforts to conserve American wildlife and natural habitat, said Eileen Claussen, president of the Pew Center on Global Climate Change, an independent, nonprofit and nonpartisan organization that commissioned the Observed Impacts of Global Climate Change in the U.S. report. 'Continued climate change could drastically alter the U.S. natural landscape,' said Claussen. Half of the approximately 150 wild plants, animals and insects scientists examined have been affected by global warming. 'This is a surprisingly high number,' said report co-author Camille Parmesan of the University of Texas at Austin. (wired) - biodiversity

  8. 22-11-2004 eco nws - global warming - impact - extinction - 80% decline in ocean krill - There has been a big decline in Antarctic krill, Euphausia superba, the shrimp-like creatures that are dredged by whales and pecked up by seabirds. Fishermen also harvest the krill, a creature just 6cm-long. The research, published in the British science journal Nature, looked at estimates of the krill stock taken between 1926 and last year. Lead researcher Steve Nicol said krill stocks in the waters off the Antarctic Peninsula had declined by 80 percent since the 1970s. The decline has obvious implications for the whales, seals and seabirds that live off krill. (independent online) - biodiversity

  9. 06-12-2004 eco nws - global warming - impact - extinction - ocean reefs - ocean reefs already damaged or at risk - More than two thirds of the world's reefs are severely damaged or under risk of further degradation, and climate change remains the greatest long-term threat to corals, according to the 2004 edition of Status of Coral Reefs of the World. The report comes as delegates gather in Buenos Aires for the 10th Conference of the Parties (CoP 10) to the Convention on Climate Change. (wwf) - biodiversity

  10. 15-12-2004 eco nws - global warming - impact - biodiversity - animal life - animals already affected - In Richmond, the golden orange prothonotary warbler has been coming back from its Caribbean and South American wintering grounds a day earlier each year for nearly two decades as local temperatures have risen. During the same period, Alaska's porcupine caribou herd has declined as climate changes have made it more difficult for the reindeer to feed and migrate during the spring. And warmer spring temperatures could dry up critical breeding habitat for waterfowl in the prairie pothole region, a stretch of land between northern Iowa and central Alberta. These subtle shifts, documented in the first comprehensive assessment of climate change's impact on North American wildlife, indicate that warming has already altered migration routes, blooming cycles and breeding habits of animals and plants across the continent. The Wildlife Society's three-year study, being released today, adds a significant new dimension to the accumulating evidence that altered weather patterns, rising sea levels and hotter temperatures are already transforming regional ecosystems and having other observable effects. (washingtonpost)

  11. 18-01-2005 eco nws - global warming - impact - biodiversity - animal life - heat wakes estonian bears - Estonia's warmest winter for two centuries has woken some of its 600 bears several months early from hibernation, wildlife experts say. The bears' early reappearance has raised concerns for the survival of this year's cubs. 'It has been very warm and wet and many flooded rivers have forced bears out of their dens and out of hibernation,' said Kalev Manniste, a senior official at the Baltic country's State Forest Service. 'Just a few days ago a hunter was telling me that he saw a she-bear with a very small cub walking across the field,' he told Reuters. 'The cub the hunter saw looked too small to survive the winter.' (reuters)

  12. 01-04-2005 eco nws - global warming - impact - seasons - biodiversity - animal life - extinction - effects on seasons and species report - phenology network - Climate change is playing havoc with the timing of the seasons and could drastically alter the landscape, according to one of the most comprehensive studies of its kind. Frogs have begun spawning in Britain as early as October, oaks are coming into leaf three weeks earlier than they were 50 years ago and there were an unprecedented 4,000 sightings of bumblebees by the end of January this year. Scientists, who also noted that people were mowing their lawns earlier, have concluded that spring now arrives ahead of schedule. The findings were submitted to scientists at the UK Phenology Network by hundreds of paid observers across the country and have been combined with environmental data over three centuries. The study is bound to intensify calls for tighter controls on environmental pollution linked to climate change. The report, published yesterday in the BBC Wildlife Magazine, provides startling evidence of how nature is reacting to rising temperatures and changing rainfall patterns. Authors of the report have calculated that spring starts around six days earlier for every 1C temperature rise but not all species are affected in the same way. For example for every 1C temperature rise, oak trees come into leaf 10 days earlier compared to four days earlier for the ash, its main competitor for space. In an example of the ecological balance being upset, these changes also affect caterpillars, which are developing earlier to meet the need to feed on the trees' young leaves. This may also have an effect on the migratory patterns of birds that feed on the insects, which can more readily adapt to climate change. 'The findings suggest that there won't be a smooth progression towards a warmer climate, with all species advancing in unison, but rather that different responses may disrupt the complex linkages in nature,' said Tim Sparks, one of the report's authors. (earth hope) - biodiversity

  13. 14-07-2005 eco nws - global warming - impact - extinction - Dead Birds Do Tell Tales - With a record number of dead seabirds washing up on West Coast beaches from Central California to British Columbia, marine biologists are raising the alarm about rising ocean temperatures and dwindling plankton populations. 'Something big is going on out there,' said Julia Parrish, an associate professor in the School of Aquatic Fisheries and Sciences at the University of Washington. 'I'm left with no obvious smoking gun, but birds are a good signal because they feed high up on the food chain.' Coastal ocean temperatures are 2 to 5 degrees above normal, which may be related to a lack of updwelling, in which cold, nutrient-rich water is brought to the surface. Updwelling is fueled by northerly winds that sweep out near-shore waters and bring cold water to the surface. The process starts the marine food chain, fueling algae and shrimplike krill populations that feed small fish, which then provide a source of food for a variety of sea life from salmon to sea birds and marine mammals. On Washington beaches, bird surveyors in May typically find an average of one dead Brandt's cormorant every 34 miles of beach. This year, cormorant deaths averaged one every eight-tenths of a mile, according to data gathered by volunteers with the Coastal Observation and Seabird Survey Team, which Parrish has directed since 2000. 'This is somewhere between five and 10 times the highest number of bird deaths we've seen before,' she said, adding that she expected June figures to show a similar trend. (wired) - biodiversity

  14. 02-07-2006 eco nws - global warming - impact - biodiversity - animal life - Long-haul birds 'returning early' - Birds that migrate long distances have adapted to the world's changing climate in unexpected ways, a study shows. As the planet warms, and spring arrives earlier in Europe, birds are being forced to change their migration patterns. It had been thought that birds travelling long distances from Africa to Europe would be unable to adapt. But a study in Science suggests they have evolved in response to climate change and are returning earlier. The need for migratory birds to time their arrival at breeding grounds with plentiful food supplies is a known evolutionary pressure. Scientists had assumed that birds travelling short distances would be better able to adapt - and arrive earlier for spring - because of similar climate conditions in their nearby winter grounds. / 'Long-migrating birds arrive at least as early as short-migrating birds' - Nils Christian Stenseth, University of Oslo / But researchers in Europe decided to test this theory, using long-term banding and observational data from Scandinavia and Italy dating back to 1980. The study revealed that long-distance fliers have adjusted their migration habits to arrive earlier in northern Europe in time for the start of spring. This suggests a more permanent change in migratory behaviour due to climate change than previously thought. (bbc)

  15. 01-09-2006 eco nws - global warming - impact - biodiversity - animal life - Gene-altered flies testify to global warming - Populations of fruit flies on three separate continents have independently evolved identical gene changes within just two decades, apparently to cope with global warming. �What we�re showing is that global warming is leaving its imprint on genes,� says Raymond Huey at the University of Washington in Seattle, US, who made the discovery with colleagues. �For this to happen in such a short time-frame in so many parts of the world is rather disturbing,� he says. The researchers analysed DNA from Drosophila subobscura, a species of fruit fly originating in Europe, but which spread to the west coasts of South and North America in the late 1970s. They took samples in 26 locations in Europe, South America and North America where the fly species had been analysed before for chromosomal changes. These changes, called inversions � constituting a flip of the order of DNA sections � tally with latitude and, by implication, with ambient temperatures. Warm-adapted inversions Comparisons of contemporary and historical profiles of inversions proved that inversions once found only at warmer latitudes had spread as average temperatures had increased further away from the equator, say the researchers. �At the rates found, the 'warm-adapted inversions' are migrating north at 100 kilometres per 25 years, or 400 kilometres per century,� says Huey. �That�s a lot of gene change.� Huey points out that the flies typically produce four to six generations per year, �so there is huge scope' for such genetic change. It means that flies can adapt to global warming, but species such as sequoia trees � which have hundreds of years between generations � would not have time to adapt, he says. It was not possible to establish definitively whether flies had invaded from warmer latitudes, or whether the �warm� adaptation became dominant through selection. (new scientist)

  16. 06-12-2006 eco nws - global warming - system - atmosphere - co2 - impact - oceans - biodiversity - animal life - co2 uptake & life - SeaWIFS data - Global warming is reducing ocean life, increasing atmospheric C02 - Alarming new satellite data show that the warming of the world�s oceans is reducing ocean life while contributing to increased global warming. The ocean�s food chain is based upon the growth of billions upon billions of microscopic plants. New satellite data show that ocean warming is reducing these plants �� thus imperiling ocean fisheries and marine life, according to an article in the Nov. 7 issue of the scientific journal Nature. �We show on a global scale that the growth of these plants, called phytoplankton, is strongly tied to changes in the warming of the ocean,� said David Siegel, co-author and professor of marine science in the Department of Geography at the University of California, Santa Barbara. Siegel is also director of the Institute for Computational Earth System Science (ICESS). �Phytoplankton grow faster in a cool ocean and slower in a warm one,� said Siegel. �The scary part is that the oceans are warming now �� probably caused by our emissions of greenhouse gases like carbon dioxide.� These microscopic plants are predicted to grow even slower in the warmer oceans of the future. This in turn will reduce the food available to fish and other organisms, including marine birds and mammals, which are supported by the ocean�s food chain. Phytoplankton are responsible for about the same amount of photosynthesis each year as all the plants on land combined. Another disturbing result of reduced phytoplankton is that our atmosphere depends on the consumption of atmospheric carbon dioxide by these plants. Reduced phytoplankton means less carbon dioxide is taken up by the ocean, which could speed global warming, contributing to a vicious cycle of increased warming. �Rising levels of carbon dioxide in the atmosphere play a big part in global warming,� said lead author Michael Behrenfeld of Oregon State University. �This study shows that as the climate warms, phytoplankton growth rates go down and along with them the amount of carbon dioxide these ocean plants consume. That allows carbon dioxide to accumulate more rapidly in the atmosphere, which would produce more warming.� The findings are from a NASA-funded analysis of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument on the OrbView-2 spacecraft, launched in 1997. The uninterrupted nine-year record shows in great detail the ups and downs of marine biological activity or productivity from month to month and year to year. Captured at the start of this data record was a major, rapid rebound in ocean biological activity after a major El Ni�o event. El Ni�o and La Ni�a are major warming or cooling events, respectively, that occur approximately every three to seven years in the eastern Pacific Ocean and are known to change weather patterns around the world. Scientists made their discovery by comparing the SeaWiFS record of the rise and fall of global ocean plant life to different measures of recent global climate change. The climate records included several factors that directly affect ocean conditions, such as changes in sea surface temperature and surface winds. The results support computer model predictions of what could happen to the world's oceans as the result of prolonged future climate warming. 'When we compared changes in phytoplankton activity with simultaneous changes in climate conditions, the agreement between the two records was simply astonishing,' Behrenfeld said. (science blog)

  17. 02-02-2007 eco nws - global warming - system - impact - oceans - biodiversity - animal life - fish - atmosphere - other stressors - report - ipcc - Climate Change Only One Symptom of a Stressed Planet Earth - In releasing its latest comprehensive report, the Intergovernmental Panel on Climate Change (IPCC) focuses an important spotlight on the current state of the Earth�s climate. Climate change is just one of the many symptoms exhibited by a planet under pressure from human activities. 'Global environmental change, which includes climate change, threatens to irreversibly alter our planet,' says Kevin Noone, Executive Director of the International Geosphere-Biosphere Programme (IGBP). Global studies by IGBP show that human-driven environmental changes are affecting many parts of the Earth�s system, in addition to its climate. For example: - Half of Earth�s land surface is now domesticated for direct human use. / - 75 percent of the world�s fisheries are fully or over-exploited. / - The composition of today�s atmosphere is well outside the range of natural variability the Earth has maintained over the last 650,000 years. / - The Earth is now in the midst of its sixth great extinction event. / (science blog)

  18. 08-03-2007 eco nws - global warming - impact - oceans - acidification - biodiversity - animal life - Global warming or not, CO2 levels threaten marine life - Like a piece of chalk dissolving in vinegar, marine life with hard shells is in danger of being dissolved by increasing acidity in the oceans. Ocean acidity is rising as sea water absorbs more carbon dioxide released into the atmosphere from power plants and automobiles. The higher acidity threatens marine life, including corals and shellfish, which may become extinct later this century from the chemical effects of carbon dioxide, even if the planet warms less than expected. A new study by University of Illinois atmospheric scientist Atul Jain, graduate student Long Cao and Carnegie Institution scientist Ken Caldeira suggests that future changes in ocean acidification are largely independent of climate change. The researchers report their findings in a paper accepted for publication in the journal Geophysical Research Letters, and posted on its Web site. 'Before our study, there was speculation in the academic community that climate change would have a big impact on ocean acidity,' Jain said. 'We found no such impact.' In previous studies, increasing levels of carbon dioxide in the atmosphere led to a reduction in ocean pH and carbonate ions, both of which damage marine ecosystems. What had not been studied before was how climate change, in concert with higher concentrations of carbon dioxide, would affect ocean chemistry and biology. To investigate changes in ocean chemistry that could result from higher temperatures and carbon-dioxide concentrations, the researchers used an Earth-system model called the Integrated Science Assessment Model. Developed by Jain and his graduate students, the model includes complex physical and chemical interactions among carbon-dioxide emissions, climate change, and carbon-dioxide uptake by oceans and terrestrial ecosystems. The ocean-surface pH has been reduced by about 0.1 during the past two centuries. Using ISAM, the researchers found ocean pH would decline a total of 0.31 by the end of this century, if carbon-dioxide emissions continue on a trajectory to ultimately stabilize at 1,000 parts per million. During the last 200 years, the concentration of atmospheric carbon dioxide increased from about 275 parts per million to about 380 parts per million. Unchecked, it could surpass 550 parts per million by mid-century. 'As the concentration of carbon dioxide increases, ocean water will become more acidic; which is bad news for marine life,' Cao said. 'Fortunately, the effects of climate change will not further increase this acidity.' There are a number of effects and feedback mechanisms built into the ocean-climate system, Jain said. 'Warmer water, for example, directly reduces the ocean pH due to temperature effect on the reaction rate in the carbonate system. At the same time, warmer water also absorbs less carbon dioxide, which makes the ocean less acidic. These two climate effects balance each other, which results in negligible net climate effect on ocean pH.' The addition of carbon dioxide into the oceans also affects the carbonate mineral system by decreasing the availability of carbonate ions. Calcium carbonate is used in forming shells. With less carbonate ions available, the growth of corals and shellfish could be significantly reduced. (science blog)

  19. 27-03-2007 eco nws - global warming - models - impact - extinction - Climates to come and go in decades ahead - A new climate modeling study forecasts the complete disappearance of several existing climates in tropical highlands and regions near the poles, while large swaths of the tropics and subtropics may develop new climates unlike any seen today. In general, the models show that existing climate zones will shift toward higher latitudes and higher elevations, squeezing out the climates at the extremes--tropical mountaintops and the poles--and leaving room for unfamiliar climes and new ecological niches around the equator. The work, by researchers at the University of Wisconsin-Madison and the University of Wyoming, appears online in the journal Proceedings of the National Academy of Sciences (PNAS) during the week of March 26. The National Science Foundation (NSF) funded the research. The most severely affected parts of the world span both heavily populated regions, including the southeastern United States, southeastern Asia, and parts of Africa, and known hotspots of biodiversity, such as the Amazonian rainforest and African and South American mountain ranges. The patterns of change foreshadow significant impacts on ecosystems and conservation. 'There is a close correspondence between disappearing climates and areas of biodiversity,' says University of Wisconsin at Madison geographer Jack Williams, primary author of the paper, which could increase risk of extinction in the affected areas. For example, the Andes, Central America, South Africa and the Indonesian Archipelago are all hotspots of biological diversity. The projected disappearance of the climates unique to these regions places some species at risk of extinction. 'As this research shows, studies integrating paleoclimate data, mathematical modeling and ecological principles provide insights into climate cause-and-effect that are of great practical consequence,' says David Verardo, program director for paleoclimate at NSF, Williams and his colleagues foresee the appearance of novel climate zones on up to 39 percent of the world's land surface area by 2100, if current rates of carbon dioxide and other greenhouse gas emissions continue, and the global disappearance of up to 48 percent of current land climates. (science blog) - biodiversity

  20. 20-04-2007 eco nws - global warming - impact - extinction - Will lemmings fall off climate change cliff? - Contrary to popular belief, lemmings do not commit mass suicide by leaping off of cliffs into the sea. In fact, they are quite fond of staying alive. A bigger threat to the rodents is climate change, which could deprive them of the snow they need for homes and lock up their food in ice, according to the Wildlife Conservation Society, which is launching a study to examine how these tiny but important players in the ecological health of the far North will fare in the age of global warming. (science blog) - biodiversity

  21. 03-12-2009 eco nws - global warming - impact - oceans - ocean acidification - nitrogen - interplay - Elevated Carbon Dioxide Levels May Mitigate Losses of Biodiversity from Nitrogen Pollution - ScienceDaily (Dec. 3, 2009) � Rising levels of carbon dioxide may overheat the planet and cause other environmental problems, but fears that rising CO2 levels could directly reduce plant biodiversity can be allayed, according to a new study by a University of Minnesota scientist Peter Reich. In fact, rising CO2 may actually help counteract losses of diversity from another environmental villain: the global rain of nitrogen from fertilizers and exhaust fumes. The study, published in December 4 in the journal Science, involved a 10-year open-air outdoor experiment in which 48 plots planted with 16 different species of plants were tested using ambient and elevated levels of nitrogen and carbon dioxide. Researchers measured the number of species observed in each plot, the plant biomass both above and below ground, as well as factors related to soil, water and light that might affect plant growth. Over time, the diversity of plants growing in the research plots changed significantly, depending on the combinations of plants and the way added CO2 and nitrogen affected the health of different species. One of the study's key findings is that while the combination of ambient carbon dioxide and nitrogen pollution reduces species richness by 16 percent, adding more CO2 to the mix reduces that change by half. "From a biodiversity perspective, there was no evidence to support the worst-case scenario, in which impacts of rising CO2 and nitrogen deposition combine to suppress diversity by 30 percent, 40 percent or even 50 percent or more," Reich said. "Instead, their interaction ameliorated the diversity loss due to nitrogen enrichment that occurs under ambient CO2. Given the importance of biodiversity to the effective health and function of our ecosystems this is good news, or perhaps better labeled as "not quite as bad" news." Reich, a Regents professor in the department of forest resources, notes that "while it is a relief to find out that rising CO2 and nitrogen may not directly cause enormous losses of diversity, this finding does not detract from the urgent need for us to curb CO2 emissions given the other critical CO2 effects, such as overheating the planet and threatening marine life through ocean acidification."

  22. 18-05-2010 eco nws - global warming - impact - biodiversity - Climate Change Played Major Role in Mass Extinction of Mammals 50,000 Years Ago, Study Finds - ScienceDaily (May 18, 2010) � An international team of scientists has discovered that climate change played a major role in causing mass extinction of mammals in the late quaternary era, 50,000 years ago. Their study, published in Evolution, takes a new approach to this hotly debated topic by using global data modelling to build continental 'climate footprints.' "Between 50,000 and 3,000 years before present (BP) 65% of mammal species weighing over 44kg went extinct, together with a lower proportion of small mammals," said lead author Dr David Nogues-Bravo from the Center for Macroecology, Evolution and Climate in University of Copenhagen. "Why these species became extinct in such large numbers has been hotly debated for over a century." During the last 50,000 years the global climate became colder and drier, reaching full glacial conditions 21,000 years before present time. Since then the climate has become warmer, and this changing climate created new opportunities for colonization of new regions by humans. While both of these global change actors played significant roles in species extinction this study reveals that changing climate was a significant force driving this mass extinction. "Until now global evidence to support the climate change argument has been lacking, a large part of existing evidence was based on local or regional estimates between numbers of extinctions, dates of human arrivals and dates of climate change," said Dr Nogues-Bravo. "Our approach is completely different. By dealing with the issue at a global scale we add a new dimension to the debate by showing that the impact of climate change was not equal across all regions, and we quantify this to reveal each continent's "footprint of climate change." The study shows that climate change had a global influence over extinctions throughout the late quaternary, but the level of extinction seems to be related to each continent's footprint of climate change. When comparing continents it can then be seen that in Africa, where the climate changed to a relatively lesser extent there were fewer extinctions. However, in North America, more species suffered extinction, as reflected by a greater degree of climate change. A key piece of evidence in the humans versus climate debate is the size of the extinct mammals. It has always been assumed that humans mainly impacted on populations of large mammals, while if climate change played the key role there should be evidence of large impacts on small mammals as well as the larger animals. The team's results show that continents which suffered larger climate change impacts suffered larger extinctions of small mammals and viceversa, further strengthening the idea that climate change was a key factor in controlling past extinctions on a global scale. This research has important implications for the current study of climate change, not only in revealing the role of the climate in causing extinction in mammals, but also by demonstrating how the effect will be different across regions and continents. "Our results show that continents with the highest 'climate footprints' witnessed more extinctions then continents with lower 'climate footprints'. These results are consistent across species with different body masses, reinforcing the view that past climate changes contributed to global extinctions." "While climate change is not the only factor behind extinction, past, present or future, we cannot neglect in any way that climate change, directly or indirectly, is a crucial actor to understand past and future species extinctions.," said Miguel Ara�jo, a co-author of the paper from the National Museum of Natural Sciences in Spain.

  23. 24-05-2010 eco nws - global warming - impact - biodiversity - extinction - Small Mammals -- And Rest of Food Chain -- At Greater Risk from Global Warming Than Thought, Research Finds - ScienceDaily (May 24, 2010) � The balance of biodiversity within North American small-mammal communities is so out of whack from the last episode of global warming about 12,000 years ago that the current climate change could push them past a tipping point, with repercussions up and down the food chain, say Stanford biologists. The evidence lies in fossils spanning the last 20,000 years that the researchers excavated from a cave in Northern California. What they found is that although the small mammals in the area suffered no extinctions as a result of the warming that occurred at the end of the Pleistocene epoch, populations of most species nonetheless experienced a significant loss of numbers while one highly adaptable species -- the deer mouse -- thrived on the disruptions to the environment triggered by the changing climate. "If we only focus on extinction, we are not getting the whole story," said Jessica Blois, lead author of a paper detailing the study to be published online by Nature on May 23. "There was a 30 percent decline in biodiversity due to other types of changes in the small-mammal community." The double whammy of late Pleistocene warming, coupled with the coinciding arrival of humans on the North American continent, took a well-documented heavy toll on the large animals. Almost a third of the big, so-called "charismatic" animals -- the ones with the most popular appeal for humans, such as mammoths and mastodons, dire wolves and short-faced bears -- went extinct. But until now, little had been done to explore the effects of that climate shift on smaller fauna. "We were interested in the small animals because we wanted to know about the response of the survivors, the communities of animals that are still on the landscape with us today," said Elizabeth Hadly, professor of biology and a coauthor of the paper. "We focused not only on the Pleistocene transition, but also the last 10,000 or so years since then." Blois and Hadly excavated deposits in Samwell Cave, in the southern Cascades foothills. They also sampled the modern small-mammal community by doing some live trapping in the area of the cave. Blois was a graduate student in biology when they did the work and Hadly her adviser. Radiocarbon dating of the samples was done by Jenny McGuire, a graduate student at the University of California-Berkeley. The biggest change they saw in the fossil deposits was the manner in which different small-animal species were spread across the landscape. "In the Pleistocene, there were about as many gophers as there were voles as there were deer mice," Hadly said. "But as you move into the warming event, there is a really rapid reduction in how evenly these animals are distributed." Some species became extremely rare, others quite common. And the species that became king of the landscape -- by virtue of its very commonness -- was the deer mouse. "That is a pretty big, somewhat startling result," she said, noting that deer mice are so common in western landscapes that most people assume they have virtually always been so. "What these data tell us is that in the Pleistocene they were not dominant at all." Prior to this study, Hadly said most researchers would not have expected species that survived the warming to show any effects. After all, they survived. "What we are saying is there was a big effect," she said. And as some species such as deer mice flourished, many other species declined. "Local declines of species are the precursor of local extinction," said Rodolfo Dirzo, a biology professor at Stanford who was not involved in the study. Local population declines also imply disruption of the local ecosystem even without extinctions, he said. "Small mammals are so common, we often take them for granted," Blois said. "But they play important roles within ecosystems, in soil aeration and seed dispersal, for example, and as prey for larger animals." And different small mammals play those roles differently. "Deer mice just kind of eat everything, they live everywhere and they don't operate with the same complexity in an ecosystem that these other animals take as their roles," said Hadly. She said deer mice are considered a "weedy" species and, like the plants, don't have a strong habitat preference -- they are generalists that will move in wherever there is an opening. When they replace other small-mammal species, the effects ripple through the ecosystem. Deer mice don't dig the elaborate deep burrows that gophers do, so the mice don't aerate soils as effectively. They also don't disperse seeds the same way as tree squirrels, the consummate hoarders -- and forgetters -- of seeds; each forgotten cache is another colonization opportunity for the trees. Nor do the nocturnal mice feed predators the same way as ground squirrels or chipmunks, which are active in the daytime. If those species are supplanted by deer mice, the change can affect the food supply of hawks and other creatures that feed in the daytime. "Even though all of the species survived, small-mammal communities as a whole lost a substantial amount of diversity, which may make them less resilient to future change," Blois said. And according to Hadly, an extraordinarily rapid change is looming. "The temperature change over the next hundred years is expected to be greater than the temperature that most of the mammals that are on the landscape have yet witnessed as a species," she said. "The small-mammal community that we have is really resilient, but it is headed toward a perturbation that is bigger than anything it has seen in the last million years."

  24. 12-08-2010 eco nws - global warming - impact - biodiversity - extinction - Biodiversity Hot Spots More Vulnerable to Global Warming Than Thought - ScienceDaily (Aug. 12, 2010) � Global warming may present a threat to animal and plant life even in biodiversity hot spots once thought less likely to suffer from climate change, according to a new study from Rice University. Research by Amy Dunham, a Rice assistant professor of ecology and evolutionary biology, detailed for the first time a direct correlation between the frequency of El Ni�o and a threat to life in Madagascar, a tropical island that acts as a refuge for many unique species that exist nowhere else in the world. In this case, the lemur plays the role of the canary in the coal mine. The study in the journal Global Change Biology is currently available online and will be included in an upcoming print issue. Dunham said most studies of global warming focus on temperate zones. "We all know about the polar bears and their melting sea ice," she said. "But tropical regions are often thought of as refuges during past climate events, so they haven't been given as much attention until recently. "We're starting to realize that not only are these hot spots of biodiversity facing habitat degradation and other anthropogenic effects, but they're also being affected by the same changes we feel in the temperate zones." Dunham's interest in lemurs, which began as an undergraduate student at Connecticut College, resulted in a groundbreaking study last year that provided new insight into a long-standing mystery: Why male and female lemurs are the same size. This time, she set out to learn how El Ni�o patterns impact rainfall in southeastern Madagascar and how El Ni�o and cyclones affect the reproductive patterns of the Milne-Edwards' Sifaka lemur. The lemur's mating habits are well-defined, which makes the animal a good candidate for such a study. Female lemurs are sexually responsive to males for only one day a year in the austral summer months of December or January and give birth six months later. Dunham's co-authors -- Elizabeth Erhart and Patricia Wright -- have done behavioral studies of lemurs in Ranomafana, a national park in the southeastern rainforest of Madagascar, for 20 years. Erhart is an associate professor and assistant chair of the Department of Anthropology at Texas State University-San Marcos, and Wright is a professor of anthropology at Stony Brook University and director of the Institute for the Conservation of Tropical Environments. "There aren't many species that have such long-term demographic data that enable us to look at these kinds of questions," Dunham said. "So this was a unique opportunity." The warming of global sea temperatures may "enhance" El Ni�o cycles, according to the National Oceanic and Atmospheric Administration. Dunham found that in Ranomafana, contrary to expectations, El Ni�o makes wet seasons wetter. "When it rains heavily, lemurs are not active. They sit there and wait for the rain to stop, huddling for warmth," Dunham said. Anecdotal evidence suggested heavy rains knock fruit off the trees when lactating lemurs need it most, and may even kill trees outright. Dunham learned from the data that cyclones making landfall have a direct negative effect on the fecundity -- or potential reproductive capacity -- of lemurs. The team also discovered that fecundity "was negatively affected when El Ni�o occurred in the period before conception, perhaps altering ovulation, or during the second six months of life, possibly reducing infant survival during weaning," they wrote. "Madagascar's biodiversity is an ecological treasure," Dunham said. "But its flora and fauna already face extinction from rapid deforestation and exploitation of natural resources. The additional negative effects of climate change make conservation concerns even more urgent."

  25. 18-02-2011 eco nws - global warming - impact - biodiversity - eco systems - lake - largest lake - World's Largest Lake Sheds Light on Ecosystem Responses to Climate Variability - ScienceDaily (Feb. 18, 2011) � Siberia's Lake Baikal, the world's oldest, deepest, and largest freshwater lake, has provided scientists with insight into the ways that climate change affects water temperature, which in turn affects life in the lake. The study is published in the journal PLoS ONE. "Lake Baikal has the greatest biodiversity of any lake in the world," explained co-author Stephanie Hampton, deputy director of UC Santa Barbara's National Center for Ecological Analysis & Synthesis (NCEAS). "And, thanks to the dedication of three generations of a family of Russian scientists, we have remarkable data on climate and lake temperature." Beginning in the 1940's, Russian scientist Mikhail Kozhov took frequent and detailed measurements of the lake's temperature. His descendants continued the practice, including his granddaughter, Lyubov Izmest'eva at Irkutsk State University. She is a co-author of the study and a core member of the NCEAS team now exploring this treasure trove of scientific and historical records. First author Steve Katz, of NOAA's Channel Islands National Marine Sanctuary, explained that the research team discovered many climate variability signals, called teleconnections, in the data. For example, changes in Lake Baikal water temperature correlate with monthly variability in El Ni�o indices, reflecting sea surface temperatures over the Pacific Ocean tens of thousands of kilometers away. At the same time, Lake Baikal's temperatures are influenced by strong interactions with Pacific Ocean pressure fields described by the Pacific Decadal Oscillation. "Teasing these multiple signals apart in this study illuminated both the methods by which we can detect these overlapping sources of climate variability, and the role of jet stream variability in affecting the local ecosystem," said Katz. Hampton added: "This work is important because we need to go beyond detecting past climate variation. We also need to know how those climate variations are actually translated into local ecosystem fluctuations and longer-term local changes. Seeing how physical drivers of local ecology -- like water temperature -- are in turn reflecting global climate systems will allow us to determine what important short-term ecological changes may take place, such as changes in lake productivity. They also help us to forecast consequences of climate variability." The scientists found that seasonality of Lake Baikal's surface water temperatures relate to the fluctuating intensity and path of the jet stream on multiple time scales. Although the lake has warmed over the past century, the changing of seasons was not found to trend in a single direction, such as later winters. The climate indices reflect alterations in jet stream strength and trajectory, and these dynamics collectively appear to forecast seasonal onset in Siberia about three months in advance, according to the study. Lake Baikal's seasonality also tracked decadal-scale variations in Earth's rotational velocity. The speed of Earth's rotation determines the length of a day, which differs by milliseconds from day to day depending on the strength of atmospheric winds, including the jet stream. This scale of variability was also seen to affect the timing variability in seasonal lake warming and cooling, reinforcing the mechanistic role of the jet stream. "Remarkably, the temperature record that reflects all these climate messages was collected by three generations of a single family of Siberian scientists, from 1946 to the present, and the correlation of temperature with atmospheric dynamics is further confirmation that this data set is of exceptionally high quality," said Katz. "This consistent dedication to understanding one of the world's most majestic lakes helps us understand not only the dynamics of Lake Baikal over the past 60 years, but also to recognize future scenarios for Lake Baikal. The statistical approach may be used for similar questions in other ecosystems, although we recognize that the exceptional quality and length of the Baikal data was one of the keys to our success."

  26. 04-03-2011 eco nws - global warming - impact - co2 - biodiversity - animal life - plant life - Predicted Increase in Atmospheric CO2 Will Directly Affect Living Organisms: Carbon Dioxide Exacerbates Oxygen Toxicity - ScienceDaily (Mar. 4, 2011) � A research team at the Laboratoire de Chimie Bact�rienne (Bacterial Chemistry Laboratory, CNRS, Marseille) has demonstrated that carbon dioxide (CO2) plays a role in the formation of oxidative damage in vivo. Under conditions of oxidative stress, certain types of damage (cell death, some DNA lesions, mutation frequency, etc.) affecting the model organism Escherichia coli tend to increase depending on the level of atmospheric CO. The CO2 levels studied range from 40 ppm (1) to the current projections for 2100 (1,000 ppm). The results indicate that the predicted increase in atmospheric CO2 should have a direct effect on living organisms. A paper on this work will be published in the February 25, 2011 issue of EMBO Reports. Air pollution, tobacco smoke, chemical products, food additives, physical stress and even the normal use of oxygen by the body all contribute to the production of Reactive Oxygen Species (ROS) (2). These compounds are involved to varying degrees in the different types of cellular oxidative damage: genetic mutations, cancerization, protein oxidation, etc. The Bacterial Viability and Oxidative Stress team, led by Sam Dukan of the Laboratoire de Chimie Bact�rienne, a CNRS lab at the Institut de Microbiologie de la M�diterran�e (Mediterranean Institute of Microbiology, CNRS / Universit� de la M�diterran�e) has been investigating the involvement of various ROS in the process of cell death. Their latest findings on the model bacteria Escherichia coli reveal the importance of a new factor involved in the formation of oxidative damage in vivo: carbon dioxide (CO2). The researchers asked the Jacomex company to develop a prototype "glove compartment" that would make it possible to control the level of atmospheric CO2 while maintaining a fixed oxygen concentration (20%, as in Earth's atmosphere). Reproducing the atmospheres of yesterday, today and tomorrow (in terms of oxygen, nitrogen and carbon dioxide levels), this tool was used to measure the effects of an oxidative stress (hydrogen peroxide, H2O2) on E. coli at different levels of atmospheric CO2 (from 40 to 1,000 ppm, the current atmospheric concentration being 389 ppm). The results show that an increase in CO2 is accompanied by an increase in various parameters, including cell death, DNA mutation frequency and the number of DNA lesions (3). The authors of the paper suggest that this phenomenon may be due to in vivo reactions between CO2 and various ROS, which could induce the formation of various free radicals, in particular the carbonate radical (CO3�-). In fact, this reaction had already been demonstrated in vitro. Interestingly, this radical is especially target-specific. For example, in relation to DNA it seems to react primarily with guanine, a target that the researchers found to be affected by the CO2 concentration. In addition, the team has shown that the physiological characteristics of E. coli (intracellular pH, metabolic pathways, defenses against ROS, speed of protein degradation, etc.) were not modified by the CO2 level, thus excluding all other possible interpretations of the damage observed. Considering the range of CO2 concentrations examined, this study suggests that the projected increase in atmospheric CO2 (1,000 ppm by 2100) could have direct effects on living organisms such as bacteria (increase in certain DNA lesions, mutation frequency, etc.). The team at the Laboratoire de Chimie Bact�rienne plans to continue its research on E. coli in order to characterize the different mutations associated with DNA lesions. They also intend to examine the possible role of carbonic anhydrase (4) in the defense against oxidative stress, and hope to collaborate with other research teams to study more evolved organisms like mice. Their objective is to investigate the link between the concentration of atmospheric CO2 and the occurrence of pathologies known to be linked to oxidative stress (neurodegenerative diseases, cancers, etc.). (1) ppm: parts per million (2) Hydrogen peroxide (H2O2), superoxide (O2�-) and hydroxyls (HO�). (3) The researchers used the presence of an oxidized guanine base (8-Oxo-G) as the marker. The concentration of this oxidized base indicates the level of DNA lesions. (4) Carbonic anhydrase is an enzyme of the lyase family that catalyzes the hydration of CO2 to form carbonic acid (H2CO3). The reaction is reversible.

  27. 04-03-2011 eco nws - global warming - impact - co2 - biodiversity - plant life - plants - water release - Rising Carbon Dioxide Is Causing Plants to Have Fewer Pores, Releasing Less Water to the Atmosphere - ScienceDaily (Mar. 4, 2011) � As carbon dioxide levels have risen during the last 150 years, the density of pores that allow plants to breathe has dwindled by 34 percent, restricting the amount of water vapor the plants release to the atmosphere, report scientists from Indiana University Bloomington and Utrecht University in the Netherlands in an upcoming issue of the Proceedings of the National Academy of Sciences. In a separate paper, also to be published by PNAS, many of the same scientists describe a model they devised that predicts doubling today's carbon dioxide levels will dramatically reduce the amount of water released by plants. The scientists gathered their data from a diversity of plant species in Florida, including living individuals as well as samples extracted from herbarium collections and peat formations 100 to 150 years old. "The increase in carbon dioxide by about 100 parts per million has had a profound effect on the number of stomata and, to a lesser extent, the size of the stomata," said Research Scientist in Biology and Professor Emeritus in Geology David Dilcher, the two papers' sole American coauthor. "Our analysis of that structural change shows there's been a huge reduction in the release of water to the atmosphere." Most plants use a pore-like structure called stomata (singular: stoma) on the undersides of leaves to absorb carbon dioxide from the air. The carbon dioxide is used to build sugars, which can be used by the plant as energy or for incorporation into the plants' fibrous cell walls. Stomata also allow plants to "transpire" water, or release water to the atmosphere. Transpiration helps drive the absorption of water at the roots, and also cools the plants in the same way sweating cools mammals. If there are fewer stomata, or the stomata are closed more of the day, gas exchange will be limited -- transpiration included. "The carbon cycle is important, but so is the water cycle," Dilcher said. "If transpiration decreases, there may be more moisture in the ground at first, but if there's less rainfall that may mean there's less moisture in ground eventually. This is part of the hyrdrogeologic cycle. Land plants are a crucially important part of it." Dilcher also said less transpiration may mean the shade of an old oak tree may not be as cool of a respite as it used to be. "When plants transpire they cool," he said. "So the air around the plants that are transpirating less could be a bit warmer than they have been. But the hydrogeologic cycle is complex. It's hard to predict how changing one thing will affect other aspects. We would have to see how these things play out." While it is well known that long-lived plants can adjust their number of stomata each season depending on growing conditions, little is known about the long-term structural changes in stomata number or size over periods of decades or centuries. "Our first paper shows connection between temperature, transpiration, and stomata density," Dilcher said. "The second paper really is about applying what we know to the future." That model suggests that a doubling of today's carbon dioxide levels -- from 390 parts per million to 800 ppm -- will halve the amount of water lost to the air, concluding in the second paper that "plant adaptation to rising CO2 is currently altering the hydrological cycle and climate and will continue to do so throughout this century." Dilcher and his Dutch colleagues say that a drier atmosphere could mean less rainfall and therefore less movement of water through Florida's watersheds. The Florida Everglades depend heavily on the slow, steady flow of groundwater from upstate. The siphoning of that water to development has raised questions about the future of the Everglades as a national resource.

  28. 26-03-2011 eco nws - global warming - impact - arctic - icebergs - biodiversity - animal life - Antarctic Icebergs Play a Previously Unknown Role in Global Carbon Cycle, Climate - ScienceDaily (Mar. 26, 2011) � In a finding that has global implications for climate research, scientists have discovered that when icebergs cool and dilute the seas through which they pass for days, they also raise chlorophyll levels in the water that may in turn increase carbon dioxide absorption in the Southern Ocean. An interdisciplinary research team supported by the National Science Foundation (NSF) highlighted the research this month in the journal Nature Geoscience. The research indicates that "iceberg transport and melting have a role in the distribution of phytoplankton in the Weddell Sea," which was previously unsuspected, said John J. Helly, director of the Laboratory for Environmental and Earth Sciences with the San Diego Supercomputer Center at the University of California, San Diego and Scripps Institution of Oceanography. Helly was the lead author of the paper, "Cooling, Dilution and Mixing of Ocean Water by Free-drifting Icebergs in the Weddell Sea," which was first published in the journal Deep-Sea Research Part II. The results indicate that icebergs are especially likely to influence phytoplankton dynamics in an area known as "Iceberg Alley," east of the Antarctic Peninsula, the portion of the continent that extends northwards toward Chile. The latest findings add a new dimension to previous research by the same team that altered the perception of icebergs as large, familiar, but passive, elements of the Antarctic seascape. The team previously showed that icebergs act, in effect, as ocean "oases" of nutrients for aquatic life and sea birds. The teams's research indicates that ordinary icebergs are likely to become more prevalent in the Southern Ocean, particularly as the Antarctic Peninsula continues a well-documented warming trend and ice shelves disintegrate. Research also shows that these ordinary icebergs are important features of not only marine ecosystems, but even of global carbon cycling. "These new findings amplify the team's previous discoveries about icebergs and confirm that icebergs contribute yet another, previously unsuspected, dimension of physical and biological complexity to polar ecosystems," said Roberta L. Marinelli, director of the NSF's Antarctic Organisms and Ecosystems Program. NSF manages the U.S. Antarctic Program, through which it coordinates all U.S. scientific research and related logistics on the southernmost continent and aboard ships in the Southern Ocean. The latest findings document a persistent change in physical and biological characteristics of surface waters after the transit of an iceberg, which has important effects on phytoplankton populations, clearly demonstrating "that icebergs influence oceanic surface waters and mixing to greater extents than previously realized," said Ronald S. Kaufmann, associate professor of marine science and environmental studies at the University of San Diego and one of the authors of the paper. The researchers studied the effects by sampling the area around a large iceberg more than 32 kilometers (20 miles) long; the same area was surveyed again ten days later, after the iceberg had drifted away. After ten days, the scientists observed increased concentrations of chlorophyll a and reduced concentrations of carbon dioxide, as compared to nearby areas without icebergs. These results are consistent with the growth of phytoplankton and the removal of carbon dioxide from the ocean. The new results demonstrate that icebergs provide a connection between the geophysical and biological domains that directly affects the carbon cycle in the Southern Ocean, Marinelli added. In 2007, the same team published findings in the journal Science that icebergs serve as "hotspots" for ocean life with thriving communities of seabirds above and a web of phytoplankton, krill and fish below. At that time, the researchers reported that icebergs hold trapped terrestrial material, which they release far out at sea as they melt, a process that produces a "halo effect" with significantly increased nutrients and krill out to a radius of more than three kilometers (two miles).

  29. 04-04-2011 eco nws - global warming - tree growth - fecundity - impact - Tree Growth and Fecundity Affected More by Climate Change Than Previously Thought - ScienceDaily (Apr. 4, 2011) � An 18-year study of 27,000 individual trees by National Science Foundation (NSF)-funded scientists finds that tree growth and fecundity--the ability to produce viable seeds--are more sensitive to climate change than previously thought. The results, published April 5 in the journal Global Change Biology, identify earlier spring warming as one of several factors that affect tree reproduction and growth. They also show summer drought as an important but overlooked risk factor for tree survival, and that species in four types of trees--pine, elm, beech, and magnolia--are especially vulnerable to climate change. The findings may help scientists and policymakers better predict which species are vulnerable to climate change and why. "In a sense, what we've done is an epidemiological study on trees to better understand how and why certain species, or demographics, are sensitive to variation and in what ways," says James Clark of Duke University, lead author of the paper. To conduct the study, Clark and colleagues measured and recorded the growth, mortality and fecundity of each of the 27,000 trees at least once every three years, ultimately compiling an archive of more than 280,000 tree-years of data. Using a specially designed bioinformatic analysis, they quantified the effects of climate change on tree species over time. "This work demonstrates the limitations of current modeling approaches to predict which species are vulnerable to climate change and illustrates the importance of incorporating ecological factors such as species competition," says Alan Tessier, program director in NSF's Division of Environmental Biology, which funded the research. The approach allowed the scientists to calculate the relative importance of various factors, alone and in combination, including the effects of localized variables such as competition with other trees for light, or the impact of summer drought. "As climate continues to change, we know forests will respond," says Clark. "The problem is, the models scientists have used to predict forest responses focus almost solely on spatial variation in tree species abundance--their distribution and density over geographic range." If all trees of a species grew in the same conditions--the same light, moisture, soil and competition for resources--this generalized, species-wide spatial analysis might suffice, Clark says. Then scientists wouldn't need to worry about demographic variables and risk factors when trying to predict biodiversity losses due to climate change. "But in the real world, we do," Clark says. "That's where the new concept of climate and resource tracking of demographic rates comes in. "Trees are much more sensitive to climate variation than can be interpreted from regional climate averages." The trees studied included 40 species, located in eleven different forest stands in three geographic regions of the Southeast--the southern Appalachians, the Piedmont and the coastal plain. They were subjected to both natural and experimental variations. "By quantifying the effects and relative importance of competition [between species] and climate variables," says Clark, "including impacts on fecundity, over both time and space, the model we've developed addresses this need and can be used to guide planning." Clark's co-authors are Duke University doctoral student David Bell and research associate Lauren Nicholas, and Michelle Hersh, a postdoctoral researcher at Bard College and the Cary Institute of Ecosystem Studies.

  30. 17-05-2011 eco nws - global warming - impact - biodiversity - fav - Mass Extinction of Marine Life in Oceans During Prehistoric Times Offers Warning for Future - ScienceDaily (May 17, 2011) � The mass extinction of marine life in our oceans during prehistoric times is a warning that the same could happen again due to high levels of greenhouse gases, according to new research. Professor Martin Kennedy from the University of Adelaide (School of Earth & Environmental Sciences) and Professor Thomas Wagner from Newcastle University, UK, (Civil Engineering and Geosciences) have been studying 'greenhouse oceans' -- those that have been depleted of oxygen, suffering increases in carbon dioxide and temperature. Using core samples drilled from the ocean bed off the coast of western Africa, the geologists studied layers of sediment from the Late Cretaceous Period (85 million years ago) across a 400,000-year timespan. They found a significant amount of organic material -- marine life -- buried within deoxygenated layers of the sediment. Professor Wagner says the results of their research, published in the Proceedings of the National Academy of Sciences (PNAS), has relevance for our modern world: "We know that 'dead zones' are rapidly growing in size and number in seas and oceans across the globe," he said. "These are areas of water that are lacking in oxygen and are suffering from increases of CO2, rising temperatures, nutrient run-off from agriculture and other factors." Their research points to a mass mortality in the oceans at a time when Earth was going through a greenhouse effect. High levels of carbon dioxide in the atmosphere and rising temperatures led to a severe lack of oxygen (hypoxia) in the water that marine animals depend upon. "What's alarming to us as scientists is that there were only very slight natural changes that resulted in the onset of hypoxia in the deep ocean," said Professor Kennedy. "This occurred relatively rapidly -- in periods of hundreds of years, or possibly even less -- not gradually over longer, geological time scales, suggesting that Earth's oceans are in a much more delicate balance during greenhouse conditions than originally thought, and may respond in a more abrupt fashion to even subtle changes in temperature and CO2 levels." Professor Kennedy said that the doubling of the amount of carbon dioxide in our atmosphere over the past 50 years is "like hitting our ecosystem with a sledge-hammer" compared to the very small changes in incoming solar energy (radiation) which was capable of triggering these events in the past. "This could have a catastrophic, profound impact on the sustainability of life in our oceans, which in turn is likely to impact on the sustainability of life for many land-based species, including humankind," he added. However, the geological record offers a glimmer of hope thanks to a naturally occurring response to greenhouse conditions. After a hypoxic phase, oxygen concentration in the ocean seems to improve, and marine life returns. This research has shown that natural processes of carbon burial kick in and the land comes to the rescue, with soil-formed minerals collecting and burying excess dissolved organic matter in seawater. Burial of the excess carbon ultimately contributes to CO2 removal from the atmosphere, cooling the planet and the ocean. "This is nature's solution to the greenhouse effect and it could offer a possible solution for us," said Professor Wagner. "If we are able to learn more about this effect and its feedbacks, we may be able to manage it, and reduce the present rate of warming threatening our oceans."

  31. 28-05-2011 eco nws - global warming - impact - biodiversity - Climate Change and Marine Mammals: Winners and Losers - ScienceDaily (May 28, 2011) � Current hotspots of marine mammal diversity are concentrated in the temperate waters of the southern hemisphere, and the number of cetacean and pinniped species will likely remain highest in these areas in the coming 40 years, -- regardless of climate change. However, on the level of individual species the picture may be different: Whereas about half the species of marine mammals will experience some loss in their habitat, distributional ranges of the other half may increase by up to 40 percent. This is the conclusion of a study recently published in the online scientific journal PLoS ONE and conducted by marine biologist Dr. Kristin Kaschner, research affiliate at the Institute of Biology I of the University of Freiburg, in collaboration with researchers from the USA, Canada, and Brazil. The international team of ecologists produced predictions of patterns of global marine mammal biodiversity using a species distribution model which incorporated oceanographic data such as water depth, sea surface temperature, and sea ice concentration as well as information on marine mammal species occurrence. The researchers subsequently modeled and investigated the effects of global warming on individual species' distributions and biodiversity hotspots by the year 2050 based on an intermediate climate change scenario. They found current marine mammal biodiversity to be highest along the Pacific coasts of North America and Japan, north of New Zealand and in waters surrounding several Subantarctic islands. Based on the simulation, overall the expected change in the distribution patterns of marine mammals by 2050 was relatively small, with the exception of Antarctic and Arctic waters where currently only relatively few species occur. In these polar regions, the model predicted local losses in native species of up to 80 percent while at the same time overall biodiversity could increase by more than an order of magnitude due to the invasion of temperate and subpolar species. Tropical waters will also be experience a loss in diversity, albeit one of less severity. However, the researchers stress that the results of the study probably underestimate impacts of climate change, since the model could not account for indirect effects such as changes in prey distribution or breeding habitat of polar species. Cetaceans and pinnipeds play an important role in the marine food webs, and marine mammal biodiversity hotspots can thus be indicative of high levels of overall biodiversity. Prediction models such as the one used in this study may therefore help with the identification marine areas of high conservation concern.. One of the main targets of the international Convention on Biological Diversity (CBD) is to the establishment of a network of marine protected areas covering at least ten percent of the global ocean surface by the year 2020. With currently just over one percent being protected, however, the international community is still far from achieving this goal.

  32. 18-06-2011 eco nws - global warming - impact - dead zones - biodiversity - oceans - Ocean's Harmful Low-Oxygen Zones Growing, Are Sensitive to Small Changes in Climate - ScienceDaily (June 18, 2011) � Fluctuations in climate can drastically affect the habitability of marine ecosystems, according to a new study by UCLA scientists that examined the expansion and contraction of low-oxygen zones in the ocean. The UCLA research team, led by assistant professor of atmospheric and oceanic sciences Curtis Deutsch, used a specialized computer simulation to demonstrate for the first time that the size of low-oxygen zones created by respiring bacteria is extremely sensitive to changes in depth caused by oscillations in climate. These oxygen-depleted regions, which expand or contract depending on their depth, pose a distinct threat to marine life. "The growth of low-oxygen regions is cause for concern because of the detrimental effects on marine populations -- entire ecosystems can die off when marine life cannot escape the low-oxygen water," said Deutsch. "There are widespread areas of the ocean where marine life has had to flee or develop very peculiar adaptations to survive in low-oxygen conditions." The study, which was published June 9 in the online edition the journal Science and will be available in an upcoming print edition, also showed that in addition to consuming oxygen, marine bacteria are causing the depletion of nitrogen, an essential nutrient necessary for the survival of most types of algae. "We found there is a mechanism that connects climate and its effect on oxygen to the removal of nitrogen from the ocean," Deutsch said. "Our climate acts to change the total amount of nutrients in the ocean over the timescale of decades." Low-oxygen zones are created by bacteria living in the deeper layers of the ocean that consume oxygen by feeding on dead algae that settle from the surface. Just as mountain climbers might feel adverse effects at high altitudes from a lack of air, marine animals that require oxygen to breathe find it difficult or impossible to live in these oxygen-depleted environments, Deutsch said. Sea surface temperatures vary over the course of decades through a climate pattern called the Pacific Decadal Oscillation, during which small changes in depth occur for existing low-oxygen regions, Deutsch said. Low-oxygen regions that rise to warmer, shallower waters expand as bacteria become more active; regions that sink to colder, deeper waters shrink as the bacteria become more sluggish, as if placed in a refrigerator. "We have shown for the first time that these low-oxygen regions are intrinsically very sensitive to small changes in climate," Deutsch said. "That is what makes the growth and shrinkage of these low-oxygen regions so dramatic." Molecular oxygen from the atmosphere dissolves in sea water at the surface and is transported to deeper levels by ocean circulation currents, where it is consumed by bacteria, Deutsch said. "The oxygen consumed by bacteria within the deeper layers of the ocean is replaced by water circulating through the ocean," he said. "The water is constantly stirring itself up, allowing the deeper parts to occasionally take a breath from the atmosphere." A lack of oxygen is not the only thing fish and other marine life must contend with, according to Deutsch. When oxygen is very low, the bacteria will begin to consume nitrogen, one of the most important nutrients that sustain marine life. "Almost all algae, the very base of the food chain, use nitrogen to stay alive," Deutsch said. "As these low-oxygen regions expand and contract, the amount of nutrients available to keep the algae alive at the surface of the ocean goes up and down." Understanding the causes of oxygen and nitrogen depletion in the ocean is important for determining the effect on fisheries and fish populations, he said. Deutsch and his team used a computer model of ocean circulation and biological processes that produce or consume oxygen to predict how the ocean's oxygen distribution has changed over the past half century. The researchers tested their predictions using observations made over the last several decades, specifically targeting areas where oxygen concentration is already low, because marine life in these areas will feel the changes most quickly. - How would rising global temperatures affect these low-oxygen environments? - As temperature increases, less oxygen leaves the atmosphere to dissolve in the ocean, Deutsch explained. Additionally, the shallower levels of the ocean heat up and become more buoyant, slowing the oxygen circulation to lower layers. "In the case of a global temperature increase, we expect that low-oxygen regions will grow in size, similar to what happened at the end of the last ice age 30,000 years ago," Deutsch said. "Since these regions change greatly in size from decade to decade due to the Pacific Decadal Oscillation, more data is required before we can recognize an overall trend. "Global warming will almost certainly influence the amount of oxygen in the ocean, but we expect it to be a slow effect that takes place over long periods of time," he added. "There are huge changes in the volume of this low-oxygen water, but the changes oscillate in a natural cycle instead of a persistent growth as many expected. Oxygen comes and goes in the ocean in a way that is not attributable to the long-term warming of the planet. Instead, it is part of the natural rhythm of the ocean."

  33. 21-06-2011 eco nws - global warming - impact - biodiversity - oceans - Multiple Ocean Stresses Threaten 'Globally Significant' Marine Extinction, Experts Warn - ScienceDaily (June 21, 2011) � An international panel of marine experts warns in a new report that the world's ocean is at high risk of entering a phase of extinction of marine species unprecedented in human history. The preliminary report arises from the first ever interdisciplinary international workshop to consider the cumulative impact of all stressors affecting the ocean. Considering the latest research across all areas of marine science, the workshop examined the combined effects of pollution, acidification, ocean warming, overfishing and hypoxia (deoxygenation). The scientific panel concluded that: - The combination of stressors on the ocean is creating the conditions associated with every previous major extinction of species in Earth's history. - The speed and rate of degeneration in the ocean is far faster than anyone has predicted. - Many of the negative impacts previously identified are greater than the worst predictions. - Although difficult to assess because of the unprecedented speed of change, the first steps to globally significant extinction may have begun with a rise in the extinction threat to marine species such as reef-�forming corals. / Dr Alex Rogers, Scientific Director of the International Programme on the State of the Ocean (IPSO) which convened the workshop said: "The findings are shocking. As we considered the cumulative effect of what humankind does to the ocean the implications became far worse than we had individually realized. This is a very serious situation demanding unequivocal action at every level. We are looking at consequences for humankind that will impact in our lifetime, and worse, our children's and generations beyond that." Marine scientists from institutions around the world gathered at Oxford University under the auspices of IPSO and the International Union for Conservation of Nature (IUCN). The group reviewed recent research by world ocean experts and found firm evidence that the effects of climate change, coupled with other human-�-induced impacts such as over-�-fishing and nutrient run-�-off from farming, have already caused a dramatic decline in ocean health. Increasing hypoxia (low oxygen levels) and anoxia (absence of oxygen, known as ocean dead zones) combined with warming of the ocean and acidification are the three factors which have been present in every mass extinction event in Earth's history. There is strong scientific evidence that these three factors are combining in the ocean again, exacerbated by multiple severe stressors. The scientific panel concluded that a new extinction event was inevitable if the current trajectory of damage continues. As examples, the panel point out: - The rate at which carbon is being absorbed by the ocean is already far greater now than at the time of the last globally significant extinction of marine species, some 55 million years ago, when up to 50% of some groups of deep-sea animals were wiped out. - A single mass coral bleaching event in 1998 killed 16% of all the world's tropical coral reefs. - Overfishing has reduced some commercial fish stocks and populations of by-�catch species by more than 90%. - New science also suggests that pollutants including flame retardant chemicals and synthetic musks found in detergents are being traced in the Polar Seas, and that these chemicals can be absorbed by tiny plastic particles in the ocean which are in turn ingested by marine creatures. / The experts agreed that adding these and other threats together means that the ocean and the ecosystems within it are unable to recover, being constantly bombarded with multiple attacks. The report sets out a series of recommendations and calls on states, regional bodies and the United Nations to enact measures to better conserve ocean ecosystems, and in particular demands the urgent adoption of better governance of the largely unprotected high seas which make up the majority of the world's ocean. Dan Laffoley, Marine Chair of IUCN's World Commission on protected Areas and Senior Advisor on Marine Science and Conservation for IUCN, and co-�-author of the report, said: "The world's leading experts on oceans are surprised by the rate and magnitude of changes we are seeing. The challenges for the future of the ocean are vast, but unlike previous generations we know what now needs to happen. The time to protect the blue heart of our planet is now, today and urgent."

  34. 12-07-2011 eco nws - global warming - impact - biodiversity - extinction - One in 10 Species Could Face Extinction: Decline in Species Shows Climate Change Warnings Not Exaggerated, Research Finds - ScienceDaily (July 12, 2011) � One in 10 species could face extinction by the year 2100 if current climate change impacts continue. This is the result of University of Exeter research, examining studies on the effects of recent climate change on plant and animal species and comparing this with predictions of future declines. Published in leading journal Proceedings of the National Academy of Sciences (PNAS), the study uses the well-established IUCN Red List for linking population declines to extinction risk. The research examines nearly 200 predictions of the future effects of climate change from studies conducted around the world, as well as 130 reports of changes which have already occurred. The research shows that on average the declines that have already happened match predictions in terms of the relative risk to different species across the world. Many studies have predicted that future climate change will threaten a range of plants and animals with extinction. Some of these studies have been treated with caution because of uncertainty about how species will respond to climate change. But widely published research showing how animals and plants are already responding to climate change gave the Exeter team the opportunity to check whether the predictions were wide of the mark. By producing the largest review ever of such studies, they show that predictions have, on average, been accurate, or even slightly too cautious. Lead author Dr Ilya Maclean of the University of Exeter said: "Our study is a wake-up call for action. The many species that are already declining could become extinct if things continue as they are. It is time to stop using the uncertainties as an excuse for not acting. Our research shows that the harmful effects of climate change are already happening and, if anything, exceed predictions." The study covered a wide range of species in all types of habitat across the globe. The findings confirm that human-induced climate change is now a threat to global biodiversity. Co-author Dr Robert Wilson, also of the University of Exeter, said: "By looking at such a range of studies from around the world, we found that the impacts of climate change can be felt everywhere, and among all groups of animals and plants. From birds to worms to marine mammals, from high mountain ranges to jungles and to the oceans, scientists seem to have been right that climate change is a real threat to species. "We need to act now to prevent threatened species from becoming extinct. This means cutting carbon emissions and protecting species from the other threats they face, such as habitat loss and pollution." Examples of existing responses to climate change: Decreased ice cover in the Bering Sea reduced the abundance of bivalve molluscs from about 12 to three per square metre over a very short period of time (1999-2001). These shells are the main food source for species higher up the food chain, such as Spectacled Eider. Climatic warming and droughts are causing severe declines in once-common amphibian species native to Yellowstone National Park in the United States of America. Between 1992-1993 and 2006- 2008, the number of blotched tiger salamander populations fell by nearly half, the number of spotted frog populations by 68 per cent, and the number of chorus frog populations by 75 per cent. In Antarctica, few animals exist on land, but one of the most abundant, a nematode worm living in the soil in dry, cold valleys experienced a 65 per cent decline between 1993 and 2005 as a result of climate change. Examples of predicted responses to climate change: On Tenerife, an endemic plant, the Canadas rockrose has a 74 to 83 per cent chance of going extinct in the next 100 years as a result of climate change related droughts. In Madagascar, climate warming is predicted to cause endemic reptiles and amphibians, often found in mountain ranges, to retreat towards the summit of the mounts. With a warming of just two degrees Celsius, well within current projections, three species are predicted to lose all of their habitat. Birds living in northern Boreal Forests in Europe are expected to decline as a result of global warming. Species such as Dotterel are predicted to decline by 97 per cent by 2100 and species such as Two-barred Crossbill and Pine Grosbeak could lose their entire range within Fenno-Scandia.

  35. 24-08-2011 eco nws - global warming - impact - biodiversity - Global Warming May Cause Higher Loss of Biodiversity Than Previously Thought - ScienceDaily (Aug. 24, 2011) � If global warming continues as expected, it is estimated that almost a third of all flora and fauna species worldwide could become extinct. Scientists from the Biodiversity and Climate Research Centre (Biodiversit�t und Klima Forschungszentrum, BiK-F) and the SENCKENBERG Gesellschaft f�r Naturkunde discovered that the proportion of actual biodiversity loss should quite clearly be revised upwards: by 2080, more than 80 % of genetic diversity within species may disappear in certain groups of organisms, according to researchers in the title story of the journal Nature Climate Change. The study is the first world-wide to quantify the loss of biological diversity on the basis of genetic diversity. Most common models on the effects of climate change on flora and fauna concentrate on "classically" described species, in other words groups of organisms that are clearly separate from each other morphologically. Until now, however, so-called cryptic diversity has not been taken into account. It encompasses the diversity of genetic variations and deviations within described species, and can only be researched fully since the development of molecular-genetic methods. As well as the diversity of ecosystems and species, these genetic variations are a central part of global biodiversity. In a pioneering study, scientists from the Biodiversity and Climate Research Centre (BiK-F) and the Senckenberg Gesellschaft f�r Naturkunde have now examined the influence of global warming on genetic diversity within species. - Over 80 percent of genetic variations may become extinct - The distribution of nine European aquatic insect species, which still exist in the headwaters of streams in many high mountain areas in Central and Northern Europe, was modelled. They have already been widely researched, which means that the regional distribution of the inner-species diversity and the existence of morphologically cryptic, evolutionary lines are already known. If global warming does take place in the range that is predicted by the Intergovernmental Panel on Climate Change (IPCC), these creatures will be pushed back to only a few small refugia, e.g. in Scandinavia and the Alps, by 2080, according to model calculations. If Europe's climate warms up by up to two degrees only, eight of the species examined will survive, at least in some areas; with an increase in temperature of 4 degrees, six species will probably survive in some areas by 2080. However, due to the extinction of local populations, genetic diversity will decline to a much more dramatic extent. According to the most pessimistic projections, 84 percent of all genetic variations would die out by 2080; in the "best case," two-thirds of all genetic variations would disappear. The aquatic insects that were examined are representative for many species of mountainous regions of Central Europe. - Slim chances in the long term for the emergence of new species and species survival - Carsten Nowak of the Biodiversity and Climate Research Centre (BiK-F) and the Senckenberg Gesellschaft f�r Naturkunde, explains: "Our models of future distribution show that the "species" as such will usually survive. However, the majority of the genetic variations, which in each case exist only in certain places, will not survive. This means that self-contained evolutionary lineages in other regions such as the Carpathians, Pyrenees or the German Central Uplands will be lost. Many of these lines are currently in the process of developing into separate species, but will become extinct before this is achieved, if our model calculations are accurate." Genetic variation within a species is also important for adaptability to changing habitats and climatic conditions. Their loss therefore also reduces the chances for species survival in the long term. - New approach for conservation - So the extinction of species hides an ever greater loss, in the form of the massive disappearance of genetic diversity. "The loss of biodiversity that can be expected in the course of global warming has probably been greatly underestimated in previous studies, which have only referred to species numbers," says Steffen Pauls, Biodiversity and Climate Research Centre (BiK-F), of the findings. However, there is also an opportunity to use genetic diversity in order to make conservation and environmental protection more efficient. A topic that is subject to much discussion at present is how to deal with conservation areas under the conditions of climate change. The authors of the study urge that conservation areas should also be oriented to places where both a suitable habitat for the species and a high degree of inner-species genetic diversity can be preserved in the future. "It is high time," says Nowak, "that we see biodiversity not only as a static accumulation of species, but rather as a variety of evolutionary lines that are in a constant state of change. The loss of one such line, irrespective of whether it is defined today as a "species" in itself, could potentially mean a massive loss in biodiversity in the future."

  36. 15-09-2011 eco nws - global warming - impact - fish - biodiversity - food supply - In Rapidly Warming Seas, Some Fish Lose While Others Gain - ScienceDaily (Sep. 15, 2011) � Rising temperatures in the northeast Atlantic Ocean have already led to major shifts in the abundance of commercially important fish stocks. That's according to a report published online on Sept. 15 in Current Biology, a Cell Press publication, that is the first to consider the absolute abundance of species as opposed to their presence or absence alone. "We see many more southerly, warm-water species faring well on the European shelf than more northerly, cold-adapted species," said Stephen Simpson of the University of Bristol. "This means more small-bodied, faster-growing species with shorter generation times, and potentially more diversity." Simpson's team analyzed data coming from 11 independent surveys, covering 28 years, more than a million square kilometers of the European continental shelf, and more than 100 million fish. "Our study is the first to combine a whole suite of European data sets to get the 'big picture' of how warming is affecting fish communities," Simpson said. The northeast Atlantic has been described as the "cauldron of climate change," with warming occurring at a rate four times the global average over the past 30 years, Simpson explained. "While a 1.31� Celsius change in mean annual temperature in the North Sea over the past three decades may sound trivial, temperature has a strong influence on egg maturation rates, growth, and survival of fish larvae, and impacts on the planktonic communities that underpin the food webs that sustain commercial fisheries," he said. Indeed, the data show that fish in European waters have undergone profound community-level changes that are related to dramatic warming trends for the region. The vast majority -- a whopping 72 percent -- of common fish species have already shown a response to the rising sea temperatures. Of those, three out of every four fish species have grown in numbers with warming. Catches of cold-loving species, including haddock and cod, have dropped by half in the past three decades, while landings of warm-loving species, including hake and dab, have more than doubled. The results show that studies focused only on changes to where particular fish species are found (species ranges) will miss the far more ecologically and economically relevant effects of warming, Simpson said. They also suggest that there will be an unavoidable change in what's for dinner. "We may see a further decline in cold-adapted species, many of which were the staple for our grandparents," Simpson said. "The flip side is a likely increase in species that for the UK may seem relatively exotic now -- red mullet and John dory. Over time, with effective management and an appropriate response in consumer demand, European seas have the potential to yield productive and sustainable fisheries into the future."

  37. 27-09-2011 eco nws - global warming - impact - animal life - biodiversity - How Global Warming Could Cause Animals to Shrink - ScienceDaily (Sep. 27, 2011) � The way in which global warming causes many of the world's organisms to shrink has been revealed by new research from Queen Mary, University of London. Almost all cold-blooded organisms are affected by a phenomenon known as the 'temperature-size rule', which describes how individuals of the same species reach a smaller adult size when reared at warmer temperatures. But until now, scientists have not fully understood how these size changes take place. Writing in the journal The American Naturalist, Dr Andrew Hirst and colleagues from Queen Mary's School of Biological and Chemical Sciences explore this unusual shrinking effect in more detail, and show conclusively how it occurs. Funded by the Natural Environment Research Council, the study was carried out using data on marine planktonic copepods. These tiny crustaceans are the main animal plankton in the world's oceans and are important grazers of smaller plankton and a food source for larger fish, birds and marine mammals. By gathering together more than 40 years of research studying the effect of temperature on these organisms, their results show that growth rate (how fast mass is accumulated) and development rate (how fast an individual passes through its life stages) are consistently decoupled in a range of species, with development being more sensitive to temperature than growth. Dr Hirst explains: "We've shown that growth and development increase at different rates as temperatures warm. The consequences are that at warmer temperatures a species grows faster but matures even faster still, resulting in them achieving a smaller adult size. "Decoupling of these rates could have important consequences for individual species and ecosystems," he added. The team's findings suggest that rates fundamental to all organisms (such as mortality, reproduction and feeding), may not change in synch with one another in a warming world. This could have profound implications for understanding how organisms work, and impact on entire food webs and the world's ecosystems. Although the team's findings disagree with earlier assertions of many macro-ecologists, they clearly explain the smaller sizes associated with the 'temperature-size rule'. They hope their work will help those investigating the potential impacts of climate change on the natural world.

  38. 13-10-2011 eco nws - global warming - impact - forests - atmosphere - co2 - ozone - Future Forests May Soak Up More Carbon Dioxide Than Previously Believed - ScienceDaily (Oct. 13, 2011) � North American forests appear to have a greater capacity to soak up heat-trapping carbon dioxide gas than researchers had previously anticipated. As a result, they could help slow the pace of human-caused climate warming more than most scientists had thought, a U-M ecologist and his colleagues have concluded. The results of a 12-year study at an experimental forest in northeastern Wisconsin challenge several long-held assumptions about how future forests will respond to the rising levels of atmospheric carbon dioxide blamed for human-caused climate change, said University of Michigan microbial ecologist Donald Zak, lead author of a paper published online this week in Ecology Letters. "Some of the initial assumptions about ecosystem response are not correct and will have to be revised," said Zak, a professor at the U-M School of Natural Resources and Environment and the Department of Ecology and Evolutionary Biology in the College of Literature, Science, and the Arts. To simulate atmospheric conditions expected in the latter half of this century, Zak and his colleagues continuously pumped extra carbon dioxide into the canopies of trembling aspen, paper birch and sugar maple trees at a 38-acre experimental forest in Rhinelander, Wis., from 1997 to 2008. Some of the trees were also bathed in elevated levels of ground-level ozone, the primary constituent in smog, to simulate the increasingly polluted air of the future. Both parts of the federally funded experiment -- the carbon dioxide and the ozone treatments -- produced unexpected results. In addition to trapping heat, carbon dioxide is known to have a fertilizing effect on trees and other plants, making them grow faster than they normally would. Climate researchers and ecosystem modelers assume that in coming decades, carbon dioxide's fertilizing effect will temporarily boost the growth rate of northern temperate forests. Previous studies have concluded that this growth spurt would be short-lived, grinding to a halt when the trees can no longer extract the essential nutrient nitrogen from the soil. But in the Rhinelander study, the trees bathed in elevated carbon dioxide continued to grow at an accelerated rate throughout the 12-year experiment. In the final three years of the study, the CO2-soaked trees grew 26 percent more than those exposed to normal levels of carbon dioxide. It appears that the extra carbon dioxide allowed trees to grow more small roots and "forage" more successfully for nitrogen in the soil, Zak said. At the same time, the rate at which microorganisms released nitrogen back to the soil, as fallen leaves and branches decayed, increased. "The greater growth has been sustained by an acceleration, rather than a slowing down, of soil nitrogen cycling," Zak said. "Under elevated carbon dioxide, the trees did a better job of getting nitrogen out of the soil, and there was more of it for plants to use." Zak stressed that growth-enhancing effects of CO2 in forests will eventually "hit the wall" and come to a halt. The trees' roots will eventually "fully exploit" the soil's nitrogen resources. No one knows how long it will take to reach that limit, he said. The ozone portion of the 12-year experiment also held surprises. Ground-level ozone is known to damage plant tissues and interfere with photosynthesis. Conventional wisdom has held that in the future, increasing levels of ozone would constrain the degree to which rising levels of carbon dioxide would promote tree growth, canceling out some of a forest's ability to buffer projected climate warming. In the first few years of the Rhinelander experiment, that's exactly what was observed. Trees exposed to elevated levels of ozone did not grow as fast as other trees. But by the end of study, ozone had no effect at all on forest productivity. "What happened is that ozone-tolerant species and genotypes in our experiment more or less took up the slack left behind by those who were negatively affected, and that's called compensatory growth," Zak said. The same thing happened with growth under elevated carbon dioxide, under which some genotypes and species fared better than others. "The interesting take home point with this is that aspects of biological diversity -- like genetic diversity and plant species compositions -- are important components of an ecosystem's response to climate change," he said. "Biodiversity matters, in this regard."

  39. 28-11-2011 eco nws - global warming - impact - oceans - biodiversity - Marine Biodiversity Loss Due to Global Warming and Predation, Study Predicts - ScienceDaily (Nov. 28, 2011) � The biodiversity loss caused by climate change will result from a combination of rising temperatures and predation -- and may be more severe than currently predicted, according to a study by University of British Columbia zoologist Christopher Harley. The study, published in the current issue of the journal Science, examined the response of rocky shore barnacles and mussels to the combined effects of warming and predation by sea stars. Harley surveyed the upper and lower temperature limits of barnacles and mussels from the cool west coast of Vancouver Island to the warm shores of the San Juan Islands, where water temperature rose from the relatively cool of the1950s to the much warmer years of 2009 and 2010. "Rocky intertidal communities are ideal test-beds for studying the effects of climatic warming," says Christopher Harley, an associate professor of zoology at UBC and author of the study. "Many intertidal organisms, like mussels, already live very close to their thermal tolerance limits, so the impacts can be easily studied." At cooler sites, mussels and rocky shore barnacles were able to live high on the shore, well beyond the range of their predators. However, as temperatures rose, barnacles and mussels were forced to live at lower shore levels, placing them at the same level as predatory sea stars. Daily high temperatures during the summer months have increased by almost 3.5 degrees Celsius in the last 60 years, causing the upper limits of barnacle and mussels habitats to retreat by 50 centimeters down the shore. However, the effects of predators, and therefore the position of the lower limit, have remained constant. "That loss represents 51 per cent of the mussel bed. Some mussels have even gone extinct locally at three of the sites I surveyed," says Harley. Meanwhile, when pressure from sea star predation was reduced using exclusion cages, the prey species were able to occupy hotter sites where they don't normally occur, and species richness at the sites more than doubled. "A mussel bed is kind of like an apartment complex -- it provides critical habitat for a lot of little plants and animals," says Harley. "The mussels make the habitat cooler and wetter, providing an environment for crabs and other small crustaceans, snails, worms and seaweed." These findings provide a comprehensive look at the effects of warming and predation, while many previous studies on how species ranges will change due to warming assume that species will simply shift to stay in their current temperature range. Harley says the findings show that the combined effects of warming and predation could lead to more widespread extinction than are currently predicted, as animals or plants are unable to shift their habitat ranges. "Warming is not just having direct effects on individual species," says Harley. "This study shows that climate change can also alter interactions between species, and produce unexpected changes in where species can live, their community structure, and their diversity."

  40. 30-11-2011 eco nws - global warming - impact - weather - views - Climate Change May Happen More Quickly Than Expected - ScienceDaily (Nov. 30, 2011) � As global temperatures continue to rise at an accelerated rate due to deforestation and the burning of fossil fuels, natural stores of carbon in the Arctic are cause for serious concern, researchers say. In an article scheduled to be published Dec. 1 in the journal Nature, a survey of 41 international experts led by University of Florida ecologist Edward Schuur shows models created to estimate global warming may have underestimated the magnitude of carbon emissions from permafrost over the next century. Its effect on climate change is projected to be 2.5 times greater than models predicted, partly because of the amount of methane released in permafrost, or frozen soil. "We're talking about carbon that's in soil, just like in your garden where there's compost containing carbon slowly breaking down, but in permafrost it's almost stopped because the soil is frozen," Schuur said. "As that soil warms up, that carbon can be broken down by bacteria and fungi, and as they metabolize, they are releasing carbon and methane, greenhouse gases that cause warmer temperatures." As a result of plant and animal remains decomposing for thousands of years, organic carbon in the permafrost zone is distributed across 11.7 million square miles of land, an amount that is more than three times larger than previously estimated. The new number is mainly based on evidence the carbon is stored much deeper as the result of observations, soil measurements and experiments. "We know the models are not yet giving us the right answer -- it's going to take time and development to make those better, and that process is not finished yet," Schuur said. "It's an interesting exercise in watching how scientists, who are very cautious in their training, make hypotheses about what our future will look like. The numbers are significant, and they appear like they are plausible and they are large enough for significant concern, because if climate change goes 20 or 30 percent faster that we had predicted already, that's a pretty big boost." The survey, which was completed following a National Science Foundation-funded Permafrost Carbon Network workshop about six months ago, proposed four warming scenarios until 2040, 2100 and 2300. Researchers were asked to predict the amount of permafrost likely to thaw, how much carbon would be released, and what amount would be methane, which has much more warming potential than carbon dioxide. The occurrence of carbon in northern soils is natural and the chemical does not have an effect on climate if it remains underground, but when released as a greenhouse gas it can add to climate warming. However, humans could slow warming temperatures as the result of greenhouse gas emissions from deforestation and the burning of fossil fuels, which are what speed up the process of permafrost thaw. "Even though we're talking about a place that is very far away and seems to be out of our control, we actually have influence over what happens based on the overall trajectory of warming. If we followed a lower trajectory of warming based on controlling emissions from the burning of fossil fuels, it has the effect of slowing the whole process down and keeping a lot more carbon in the ground," Schuur said. "Just by addressing the source of emissions that are from humans, we have this potential to just keep everything closer to its current state, frozen in permafrost, rather than going into the atmosphere." The survey shows that by 2100, experts believe the amount of carbon released will be 1.7 to 5.2 times greater than previous models predict, under scenarios where Arctic temperatures rise 13.5 degrees Fahrenheit. Some predicted effects of global warming include sea level rise, loss of biodiversity as some organisms are unable to migrate as quickly as the climate shifts and more extreme weather events that could affect food supply and water resources. "This new research shows that the unmanaged part of the biosphere has a major role in determining the future trajectory of climate change," said Stanford University biology professor Christopher Field, who was not involved in the study. "The implication is sobering. Whatever target we set for atmospheric CO2, this new research means we will need to work harder to reach it. But of course, limiting the amount of climate change also decreases the climate damage from permafrost melting." When carbon is released from the ground as a result of thawing permafrost, there is no way of trapping the gases at the source, so action to slow its effect must be taken beforehand. "If you think about fossil fuel and deforestation, those are things people are doing, so presumably if you had enough will, you could change your laws and adjust your society to slow some of that down," Schuur said. "But when carbon starts being emitted from the permafrost, you can't immediately say, 'OK, we've had enough of this, let's just stop doing it,' because it's a natural cycle emitting carbon whether you like it or not. Once we start pushing it, it's going to be releasing under its own dynamic."

  41. 04-12-2011 eco nws - global warming - impact - biodiversity - Powerful Mathematical Model Greatly Improves Predictions for Species Facing Climate Change - ScienceDaily (Dec. 4, 2011) � UCLA life scientists and colleagues have produced the most comprehensive mathematical model ever devised to track the health of populations exposed to environmental change. The research, federally funded by the National Science Foundation, is published Dec. 2 in the journal Science. The team's groundbreaking integral projection model, or IPM, unites various sub-disciplines of population biology, including population ecology, quantitative genetics, population genetics, and life-span and offspring information, allowing researchers to link many different data sources simultaneously. Scientists can now change just a single variable, like temperature, and see how that affects many factors for a population. "This is one of the most innovative and holistic models, because it unifies so many sub-fields of ecology and genetics into one predictive model," said study co-author Robert Wayne, a UCLA professor of ecology and evolutionary biology, who led the UCLA research team. "Traditionally, we have studied just a few ecological parameters at a time, like how much food there is or how the environment will change over time, and how that relates to population size. Here, we are analyzing everything at once." Among the researchers' major findings with the IPM is that gradual, sustained change in an environment over time -- a gradual increase in temperature, for example -- has a greater impact on the species in an ecosystem than fluctuating changes. "If we change the total environment, such as temperature, we change a whole suite of characteristics for a species, including viability, fertility, population size, body size and generation length," Wayne said. The new model could therefore be of great use in predicting the complex ecological impacts that could result as Earth's temperature gradually rises as a result of high carbon dioxide emissions entering the atmosphere and oceans. "Probably much of the tundra in the high Arctic will disappear with global warming," Wayne said. "Since this is a very general model, it can be applied to any population, from a polar bear to a wolf to a beetle, even plants. We want to use this model to make predictions about populations that are in dire situations, as their environments will be changing quickly." Just as physicists are searching for a unified field theory to bring the physics of the very large in harmony with the physics of the very small, the IPM "is the version in ecology and population genetics of a similar unified theory," Wayne said. The collaboration that led to the new model followed a fortuitous meeting between Wayne and collaborator Tim Coulson, a professor of population biology at Imperial College London. Following a talk by Coulson at UCLA , Wayne and his research team combined their decades of expertise on the wolf population in Yellowstone National Park with Coulson's expertise in applied mathematics -- and the most comprehensive ecological model was born. Wolves were first introduced into Yellowstone in 1995 to control the overpopulation of elk and bison and to restore deteriorated forests. These wolves were closely monitored with radio collars in the years that followed, generating a vast array of detailed data. The effects they generated in the park -- known as a trophic cascade -- allowed many species, such as songbirds, beavers and grizzly bears, to thrive again as the elk and bison populations diminished. "A critical issue for us is how these wolves will survive into the future," Wayne said. "This model addresses that issue in a comprehensive way by taking in so many components of population health." The model also explains the persistence of the grey coat color in Yellowstone wolves, despite the fact that the gene for black coat color is dominant. Using genetic data collected in Wayne's laboratory, the IMP revealed that wolves who possessed two different versions of the coat-color gene, known as heterozygotes, lived longer and had more offspring than wolves who had two identical genes for coat color. This example demonstrates the power of the new model, as it can make sense of seemingly unrelated information on population genetics and life history and generate a clearer understanding of an observed coat-color phenotype, and beyond that, the implications for survival of these animals in a complex ecosystem. By using a model that could generate more accurate predictions, "We could potentially build scenarios predicting whether a species has no chance of recovery, and this could lead protection efforts," Wayne said. "We are not very effective at stopping global warming, but perhaps we could identify ways to alter or enrich habitats to mitigate environmental effects," he added.

  42. 04-12-2011 eco nws - global warming - impact - glaciers - mountain glaciers - human drinking water - Impacts of Climate Change On World's Highest Mountains - ScienceDaily (Dec. 4, 2011) — Findings from the most comprehensive assessment to date on climate change, snow and glacier melt in Asia's mountainous Hindu Kush-Himalayan (HKH) region -- site of Mount Everest and many of the world's tallest peaks -- highlight the region's extreme vulnerability to climate change, as rising temperatures disturb the balance of snow, ice and water, threatening millions of mountain people and 1.3 billion people living downstream in Asia's major river basins. The findings, published in three reports by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), were recently released at Mountain Day, a convening of mountain experts, policy makers, and climate change negotiators on the sidelines of UN climate talks. "These reports provide a new baseline and location-specific information for understanding climate change in one of the most vulnerable ecosytems in the world," said Dr Rajendra Pachauri, Chair of the Intergovernmental Panel on Climate Change (IPCC). "They substantially deepen our understanding of this region -- and of all mountain systems -- while also pointing to the knowledge gaps yet to be filled and actions that must be taken to deal with the challenge of climate change globally and to minimise the risks from impacts locally." The three reports published by ICIMOD provide the most up-to-date compilation of information on the current status of climate change in the HKH region and the first authoritative data on the number and extent of glaciers and the patterns of snowfall in the world's most mountainous region. "The Hindu Kush-Himalayan region is like a gentle giant. While physically imposing, it is one of the most ecologically sensitive areas in the world," said David Molden, director general of ICIMOD. "We must meet the intensity of climate change in these mountains with an equal intensity of will to mitigate and to adapt to the impacts." The region offers livelihoods to the 210 million people living there and indirectly provides goods and services to the 1.3 billion people living in river basins downstream who benefit from food and energy. Rich in biodiversity, the region is home to some 25,000 plant and animal species, and contains a larger diversity of forest types than the Amazon. Yet despite an abundance of natural resources in the region, poverty is rife. HKH countries account for 15 percent of the world's total migration. - Valuable new data on glaciers and snow - The HKH region, home to 30 percent of the world's glaciers, has been called the "Third Pole." But there are scant data on these glaciers. One of the reports, The Status of Glaciers in the Hindu Kush-Himalayan Region -- presenting findings of a three-year Sweden-funded research project led by ICIMOD -- begins to fill in the important data gaps. Using remote sensing studies, the project was able to tally the number of glaciers in the region -- more than 54,000 -- and measure the area covered, 60,000 km. Of these 54,000 glaciers, however, only ten have been studied regularly to determine the net loss or gain of ice and snow (called the mass balance). That handful of studies shows a loss of mass balance, with the rate of loss roughly doubling between 1980 and 2000 and 1996 and 2005. In the Everest area, the data show a marked acceleration in the loss of glacial mass between 2002 and 2005. Glaciers appear to be shrinking in both the central and eastern Himalayas. Country-specific studies have found that depletion of glacial area over the past 30 years was 22 percent in Bhutan and 21 percent in Nepal. The clean glaciers of the Tibetan plateau are retreating at a faster rate than the glaciers of the rugged central Himalayas, which have higher debris cover; debris creates an insulating effect, slowing melting. Although field verification and additional data collection will be needed before firmer conclusions about glacier retreat can be drawn, the data represent a significant step in bridging the knowledge gap on climate change in the HKH. "Up until now, there has been complete uncertainty on the numbers and area of glaciers and the present status of their environmental conditions in the region. This research give us a baseline from which to measure the potential impact of climate change in the region and to develop options for mitigating the impact of dynamic changes the region is expecting in the coming years," said Basanta Shrestha from ICIMOD. A second report, Snow-Cover Mapping and Monitoring in the Hindu Kush-Himalayas, documents the first comprehensive status report of snow cover in the region, drawn from a regional monitoring scheme. However, there was an indication of an overall decrease in snow cover over the decade in the central HKH region and overall, and a slight increase in the western and eastern parts of the region. The HKH region's glaciers and snow breathe life into the regional monsoon system and feed the headwaters of 10 major river systems that stretch across eight Asian countries -- Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan. - Status of climate change in a vulnerable region - "The HKH region is one of the most ecologically sensitive and fragile areas in the world. The effects of climate change will likely become more evident here than perhaps any where else first -- and with the greatest impact -- since this ecosystem supports the livelihoods of more people than any other coherent ecosystem in the world," said the Hon. Lyonpo Dr. Pema Gyamtsho, Minister of Agriculture and Forests and also Minister In-charge of Environment of Bhutan. "Meeting this challenge will require increased regional cooperation between governments and other actors. This research, which involved eight countries in the HKH region, represents the kind of cooperation needed to meet the climate challenge." The third report, Climate Change in the Hindu Kush-Himalayas: The State of Current Knowledge, considers the mass of data and published studies in three major areas: climate and hydrology; biodiversity and ecosystems; and atmospheric changes. It also points out the limits of current data and the short time frame of most records (few extending more than 50 years). In addition, climate-related studies in the region suffer from a lack of repeat studies, permanent plots, field validation, and peer review. Nonetheless, the report provides a snapshot of changes occurring in the HKH region. The HKH region is one of the world's hotspots for global warming. The rise in temperature has been greater at higher altitudes and more pronounced during the cooler months than in the warmer months. This imbalance narrows the seasonal variation in temperature, potentially favoring some plant species over others and already having impacts on agriculture. Warming across the region is greater than the global average of 0.74°C over the past 100 years. However, this change is not evenly distributed. It is most pronounced in higher altitude areas like the central Himalayas and the Tibetan Plateau. In Lhasa, for example, temperatures increased by 1.35°C between 1950 and 1980. - Impacts of warming and melting in the HKH - Two major land use systems in the region are changing. In mountain forests, tree lines and species are shifting to higher elevations, and species already living at the highest elevations may have nowhere to go. Meanwhile, the vast grasslands of the Tibetan Plateau are being steadily degraded. Increases in glacial melting are projected to limit the natural water storage provided by expanses of snow and ice and to heighten the risk of glacial lake outburst floods. Mass losses from glaciers and accelerating reductions in snow cover are expected to ultimately reduce water supplies and hydropower potential. Changes in the seasonality of flows in river basins supplied by melt water from snow and ice are also predicted. Droughts will likely affect greater areas, and with dry spells there will need to be greater reliance on irrigation, even as water sources become more restricted, according to the authors. The risk of flooding is also increasing with increased variability of climate. Agriculture is very sensitive to climate change, which can affect temperature, precipitation, length of growing season, the timing of climate events relative to crop development, and changes in atmospheric CO2 concentration. However, the report notes the difficulty of projecting the impact of climate change on agriculture, as it occurs along with many other drivers. This compilation of information is a vital first step. "From here, greater focus needs to be put on providing people and governments with options for climate-resilient development," said Molden. "These include adaptation and mitigation measures such as reducing emissions from deforestation and forest degradation, water storage measures, and regional cooperation around policies for managing water for energy, agriculture and development."

  43. 27-12-2011 eco nws - global warming - impact - biodiversity - evolution - Over 65 Million Years, North American Mammal Evolution Has Tracked With Climate Change - ScienceDaily (Dec. 27, 2011) � Climate changes profoundly influenced the rise and fall of six distinct, successive waves of mammal species diversity in North America over the last 65 million years, shows a novel statistical analysis led by Brown University evolutionary biologists. Warming and cooling periods, in two cases confounded by species migrations, marked the transition from one dominant grouping to the next. History often seems to happen in waves -- fashion and musical tastes turn over every decade and empires give way to new ones over centuries. A similar pattern characterizes the last 65 million years of natural history in North America, where a novel quantitative analysis has identified six distinct, consecutive waves of mammal species diversity or "evolutionary faunas." What force of history determined the destiny of these groupings? The numbers say it was typically climate change. "Although we've always known in a general way that mammals respond to climatic change over time, there has been controversy as to whether this can be demonstrated in a quantitative fashion," said Christine Janis, professor of evolutionary biology at Brown University. "We show that the rise and fall of these faunas is indeed correlated with climatic change -- the rise or fall of global paleotemperatures -- and also influenced by other more local perturbations such as immigration events." Specifically, of the six waves of species diversity that Janis and her Spanish collaborators recently describe online in Proceedings of the National Academy of Sciences, four show statistically significant correlations with major changes in temperature. The two transitions that show a weaker but still apparent correlation with the pattern correspond to periods when mammals from other continents happened to invade in large numbers, said Janis, who is the paper's senior and second author. Previous studies of the potential connection between climate change and mammal species evolution have counted total species diversity in the fossil record over similar time periods. But in this analysis, led by postdoctoral scholar Borja Figueirido, the scientists asked whether there were any patterns within the species diversity that might be significant. They were guided by a similar methodology pioneered in a study of "evolutionary faunas" in marine invertebrates by Janis' late husband Jack Sepkoski, who was a paleontologist at the University of Chicago. What the authors found is six distinct and consecutive groupings of mammal species that shared a common rise, peak, and decline in their numbers. For example, the "Paleocene fauna" had largely given way to the "early-middle Eocene fauna" by about 50 million years ago. Moreover, the authors found that these transfers of dominance correlated with temperature shifts, as reflected in data on past levels of atmospheric oxygen (determined from the isotopes in the fossilized remains of deep sea microorganisms). By the numbers, the research showed correlations between species diversity and temperature change, but qualitatively, it also provided a narrative of how the traits of typical species within each wave made sense given the changes in vegetation that followed changes in climate. For example, after a warming episode about 20 million years in the early Miocene epoch, the dominant vegetation transitioned from woodland to a savannah-like grassland. It is no surprise, therefore, that many of the herbivores that comprised the accompanying "Miocene fauna" had high-crowned teeth that allowed them to eat the foods from those savannah sources. To the extent that the study helps clarify scientists' understanding of evolution amid climate changes, it does not do so to the extent that they can make specific predictions about the future, Janis said. But it seems all the clearer that climate change has repeatedly had meaningful effect over millions of years. "Such perturbations, related to anthropogenic climatic change, are currently challenging the fauna of the world today, emphasizing the importance of the fossil record for our understanding of how past events affected the history of faunal diversification and extinction, and hence how future climactic changes may continue to influence life on earth," the authors wrote in the paper.