THE SKY IS NOT FALLING: POLLUTION IN EASTERN CHINA CUTS LIGHT, USEFUL RAINFALL

0 comentarios 9/02/2009 04:59:00 PM Publicado por Jorge Franchín
Etiquetas: Ecology
New research shows that air pollution in eastern China has reduced the amount of light rainfall over the past 50 years and decreased by 23 percent the number of days of light rain in the eastern half of the country. The results suggest that bad air quality might be affecting the country's ability to raise crops as well as contributing to health and environmental problems.

The study links for the first time high levels of pollutants in the air with conditions that prevent the light kind of rainfall critical for agriculture. Led by atmospheric scientist Yun Qian at the Department of Energy's Pacific Northwest National Laboratory, the study appears August 15 in the Journal of Geophysical Research-Atmospheres.

"People have long wondered if there was a connection, but this is the first time we've observed it from long-term data," said Qian. "Besides the health effects, acid rain and other problems that pollution creates, this work suggests that reducing air pollution might help ease the drought in north China."

China's dramatic economic growth and pollution problems provide researchers an opportunity to study the connection between air quality and climate. Rain in eastern China — where most of the country's people and pollution exist — is not like it used to be.
Over the last 50 years, the southern part of eastern China has seen increased amounts of total rainfall per year. The northern half has seen less rain and more droughts. But light rainfall that sustains crops has decreased everywhere. A group of climate researchers from the U.S., China and Sweden wanted to know why light rain patterns haven't followed the same precipitation patterns as total rainfall.

Previous work has shown that pollution can interfere with light rain above oceans, so the team suspected pollution might have something to do with the changes over land. Light rain ranges from drizzles to 10 millimeters of accumulation per day and sustains agriculture. (Compared to heavy rain that causes floods, loss of light rain has serious consequences for crops.)

While the light rains have diminished, pollution has increased dramatically in China in the last half of the 20th century. For example, while China's population rose two and a half times in size, the emissions of sulfur from fossil fuel burning outpaced that considerably — rising nine times.

Air pollution contains tiny, unseen particles of gas, water and bits of matter called aerosols. Aerosols — both natural and human-caused (anthropogenic) — do contribute to rainfall patterns, but the researchers needed to determine if pollution was to blame for China's loss of rain and how.

To find out, the team charted trends in rainfall from 1956 to 2005 in eastern China, which has 162 weather stations with complete data collected over the entire 50 years.

From this data, the team determined that both the north and south regions of eastern China had fewer days of light rain — those getting 10 millimeters per day or less — at the end of the 50 year timespan. The south lost more days — 8.1 days per decade — than the north did, at 6.9 days per decade. However, the drought-rattled north lost a greater percentage of its rainy days, about 25 percent compared to the south's 21 percent.

"No matter how we define light rain, we can see a very significant decrease of light rain over almost every station," said Qian.

To probe what caused the loss of rainfall, the team looked at how much water the atmosphere contained and where the water vapor traveled. Most parts of eastern China saw no significant change in the amount of water held by the atmosphere, even though light rains decreased. In addition, where the atmosphere transported water vapor didn't coincide with light rain frequency.

These results suggested that changes in large-scale movement of water could not account for the loss of the precipitation. Some of pollution's aerosols can seed clouds or form raindrops, depending on their size, composition and the conditions in which they find themselves. Because these skills likely contribute to rainfall patterns, the researchers explored the aerosols in more depth.

Cloud droplets form around aerosols, so the team determined the concentration of cloud droplets over China. They found higher concentrations of droplets when more aerosols were present. But more droplets mean that each cloud droplet is smaller, in the same way that filling 10 ice cream cones from a quart of ice cream results in smaller scoops than if the same amount were put in only five cones.

This result suggested that aerosols create smaller water droplets, which in turn have a harder time forming rainclouds. The team verified this with computer models of pristine, moderately polluted or heavily polluted skies. In the most heavily polluted simulation, rain fell at significantly lower frequencies than in the pristine conditions.

An examination of the cloud and rain drops showed that these water drops in polluted cases are up to 50 percent smaller than in clean skies. The smaller size impedes the formation of rain clouds and the falling of rain.

Qian said the next step in their research is to examine new data from the DOE's Atmospheric Radiation Measurement Climate Research Facility in the central eastern Chinese city of Shouxian. The data was collected from April to December of 2008.

"This work is important because modeling studies of individual cases of pollution's effect on convective clouds have shown varying results, depending on the environmental conditions," said coauthor Ruby Leung. "The ARM data collected at Shouxian should provide more detailed measurements of both aerosols and clouds to enable us to quantify the impacts of aerosols on precipitation under different atmospheric and pollution conditions."

Pacific Northwest National Laboratory

TRACKING TRASH

8/05/2009 04:28:00 PM Publicado por Jorge Franchín
Etiquetas: Engineering


What if we knew exactly where our trash was going and how much energy it took to make it disappear? Would it make us think twice about buying bottled water or "disposable" razors?

A team of MIT researchers today announced a major project called Trash Track, which aims to get people thinking about what they throw away. Trash Track relies on the development of special electronic tags that will track different types of waste on their journey through the disposal systems of New York and Seattle. The project will monitor the patterns and costs of urban disposal and create awareness of the impact of trash on our environment - revealing the last journey of our everyday objects.

"Trash is one of today's most pressing issues - both directly and as a reflection of our attitudes and behaviors," says Professor Carlo Ratti, head of the MIT SENSEable City lab. "Our project aims to reveal the disposal process of our everyday objects, as well as to highlight potential inefficiencies in today's recycling and sanitation systems. The project could be considered the urban equivalent of nuclear medicine - when a tracer is injected and followed through the human body.

"The study of what we could call the 'removal chain' is becoming as important as that of the supply chain," the lab's associate director, Assaf Biderman, explains. "Trash Track aims to make the removal chain more transparent. We hope that the project will promote behavioral change and encourage people to make more sustainable decisions about what they consume and how it affects the world around them."

Trash Track will enlist volunteers in two target cities - New York and Seattle - who will allow pieces of their trash to be electronically tagged with special wireless location markers, or "trash tags." Thousands of these markers, attached to a waste sample representative of the city's overall consumption, will calculate their location through triangulation and report it to a central server, where the data will be analyzed and processed in real time. The public will be able to view the migration patterns of the trash online, as well as in an exhibit at the Architectural League in New York City and in the Seattle Public Library, starting in September 2009.

Trash Track was initially inspired by the Green NYC Initiative, the goal of which is to increase the rate of waste recycling in New York to almost 100 percent by 2030. Currently, only about 30 percent of the city's waste is diverted from landfills for recycling. "We hope that Trash Track will also point the way to a possible urban future: that of a system where, thanks to the pervasive usage of smart tags, 100 percent recycling could become a reality," says project leader, Musstanser Tinauli.

"Carlo Ratti and his team have come up with a visionary project to help people take ownership of their pollution," says Roger Highfield, editor of New Scientist magazine, which will be helping to deploy a third batch of tags in London, U.K. "It's all too easy to throw something in the garbage and wash your hands of it if you don't know what effect you are directly having on the environment."

(Photo: E Roon Kang at SENSEable City Lab)

Massachusetts Institute of Technology

The first global map of ammonia emissions measured from space

Paris, June 21, 2009

The first complete map of global ammonia emissions has recently been achieved using to satellite data. It reveals an underestimation of some of the ammonia concentrations detected by current inventories, and identifies new hotspots. This work, carried out by a team from LATMOS-IPSL (CNRS/UPMC/UVSQ) in collaboration with Belgian researchers from the Université Libre de Bruxelles, was facilitated by the infrared measurements of the French IASI instrument, part of the MetOp meteorological satellite developed by CNES. These results were published online in Nature Geoscience on 21 June 2009.
Ammonia (NH3) contributes significantly to the formation of the particles that give rise to pollution episodes. It mainly emanates from the use of agricultural fertilizers and increasingly intensified livestock breeding practices. Ammonia is the least well-understood pollutant regulated by European Directives on air quality. Mapping of its emissions are imprecise and systematic global monitoring of this compound is difficult. Once emitted, ammonia only remains in the atmosphere for a short period but triggers a cascade of environmental effects. At a local level, high ammonia concentrations affect fauna, flora and air quality.

Although the IASI instrument (part of the MetOp meteorological satellite) was not initially intended to detect ammonia in the Earth's atmosphere, researchers developed a methodology that could isolate the signature of ammonia from its background signal. By filtering the data and accumulating them continuously over a one-year observation period (more than a million measurements per day, with two passes over each part of the globe), the scientists were able to generate maps of its concentrations and to compare them with recent atmospheric models.

This work has demonstrated an underestimation of the ammonia emissions supplied by current inventories in agricultural valleys of the northern hemisphere, and particularly in the USA (the regions of San Joaquin in California and Snake River Valley in Idaho) and Europe (the Po and Ebre valleys). The most marked differences were found in Central Asia, with the identification of some sources not mentioned in current inventories.


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© Image MODIS © L. Gonzalez/C. Deroo LOA; Image IASI © ULB & INSU-CNRS

Distribution of ammonia in 2008, measured using the IASI instrument on board the /MetOp satellite, superimposed on an image of Europe obtained on August 30, 2008 by MODIS. Yellow to red colors indicate regions with high ammonia concentrations. The white structures are clouds.

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© CNES/Eumetsat

The MetOp satellite launched at the end of 2006. The IASI instrument is shown by an arrow.

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Notes:
1) Laboratoire atmosphères, milieux, observations spatiales (CNRS/UPMC/UVSQ), which forms part of Institut Pierre-Simon Laplace

2) The measurements available are local, occasional or even inexistent in some regions.

3) Interféromètre Atmosphérique de Sondage Infrarouge (Infrared Atmospheric Sounding Interferometer), an instrument constructed by CNES and launched on board the MetOp satellite at the end of 2006

4) The MetOp program is a CNES/Eumetsat partnership that for 15 years will generate continuous observations of the atmosphere's composition through the launch of three successive satellites.


References:
Global ammonia distribution derived from infrared satellite observations, Lieven Clarisse, Cathy Clerbaux, Frank Dentener, Daniel Hurtmans, Pierre-François Coheur, Nature Geoscience, online 21 June 2009.

Plants may affect the effect of wildfires

LIVERMORE, Calif. – Rising temperatures may lead to more tinder-dry vegetation, but that doesn’t mean there will be a higher risk for wildfires in a particular area.

It all depends on the type of vegetation in the area.

A new study on the cover of the May issue of Ecological Monographs shows that, in some cases, the types of plants growing in an area could override the effects of climate change on wildfire occurrence.

Lawrence Livermore National Laboratory scientist Tom Brown along with Philip Higuera of Montana State University and colleagues looked at the direct and indirect impacts of millennial scale climate change on fire occurrence in the south-central Brooks Range in Alaska.

The team looked at historical fire occurrence by analyzing sediments found in the bottom of lakes.

Using the Lab’s Center for Accelerator Mass Spectrometry, they carbon dated the deposits in the sediment and reconstructed fire occurrences from 15,000 B.C. to the present. They then measured the amount of plant parts, such as fossil pollen, to figure out what type of vegetation dominated the area during the different time periods. Like rings in a tree, different layers of sediment represent different times in the past.

The conclusion: historical changes fire frequencies coincided with changes in the type of vegetation in the area, more so than to rising temperatures alone.

Although changing temperatures and moisture content set the stage for changes in wildfire frequency, they can often be trumped by changes in the distribution and abundance of plants.

Earlier studies have shown that the area burned across arctic and boreal regions will increase over the next century as climate change lengthens the fire season, decreases moisture and increases ignition rates. However, vegetation can alter the direct link between climate and fire by influencing the abundance, structure and moisture content of fuels across space and time, Brown said.

“There’s a complex relationship between fuels and climate,” he said. “Vegetation can have a profound impact on fire occurrences that are opposite or independent of climate’s direct influence on fire.”

In the recent study, the researchers found that changes in climate were less important than changes in vegetation. Despite a transition from a cool, dry climate to a warm, dry climate about 10,500 years ago, the researchers found a sharp decline in the frequency of fires. Their sediment cores from that time period revealed a vegetation change from flammable shrubs to fire-resistant deciduous trees.


The research implies that the impacts of climate change on modern-day fire frequencies could be strongly mediated by changes in vegetation. Thus, in some cases, the impacts of climate change on fire may be less intuitive than initially perceived.

“This could give fire managers a good indication that vegetation can substantially alter the direct effects of climate change on fire occurrence,” Brown said.

Other contributors include the University of Washington and the University of Illinois-Urbana.

NASA Satellite Detects Red Glow to Map Global Ocean Plant Health

05.28.09
This data-based map shows the "fluorescence yield" of phytoplankton in the oceans during 2004. "Fluorescence yield" is the fraction of absorbed sunlight that is given off by the plants as fluorescence and it changes with the health or stress of the phytoplankton. More fluorescence is emitted when waters are low in key nutrients such as iron. Credit: NASA's Scientific Visualization Studio

The MODIS instrument on NASA’s Aqua satellite compiled this global view of the amount of fluorescent light emitted by phytoplankton in the ocean. The amount of fluorescent light is not constant; it changes with the health of the plant life. Credit: Mike Behrenfeld, Oregon State University

Phytoplankton -- such as this colony of chaetoceros socialis -- naturally give off fluorescent light as they dissipate excess solar energy that they cannot consume through photosynthesis. Credit: Maria Vernet, Scripps Institution of Oceanography
› Larger image


This data-based map shows iron dust deposition on the oceans in spring 2004. Areas with low dust deposition have high fluorescence yields. Credit: NASA's Scientific Visualization Studio
› Larger image
Researchers have conducted the first global analysis of the health and productivity of ocean plants, as revealed by a unique signal detected by a NASA satellite. Ocean scientists can now remotely measure the amount of fluorescent red light emitted by ocean phytoplankton and assess how efficiently the microscopic plants are turning sunlight and nutrients into food through photosynthesis. They can also study how changes in the global environment alter these processes, which are at the center of the ocean food web.

Single-celled phytoplankton fuel nearly all ocean ecosystems, serving as the most basic food source for marine animals from zooplankton to fish to shellfish. In fact, phytoplankton account for half of all photosynthetic activity on Earth. The health of these marine plants affects commercial fisheries, the amount of carbon dioxide the ocean can absorb, and how the ocean responds to climate change.

“This is the first direct measurement of the health of the phytoplankton in the ocean,” said Michael Behrenfeld, a biologist who specializes in marine plants at the Oregon State University in Corvallis, Ore. “We have an important new tool for observing changes in phytoplankton every week, all over the planet.”

The findings were published this month in the journal Biogeosciences and presented at a news briefing on May 28.

Over the past two decades, scientists have employed various satellite sensors to measure the amount and distribution of the green pigment chlorophyll, an indicator of the amount of plant life in the ocean. But with the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite, scientists have now observed “red-light fluorescence” over the open ocean.

“Chlorophyll gives us a picture of how much phytoplankton is present,” said Scott Doney, a marine chemist from the Woods Hole Oceanographic Institution and a co-author of the paper. “Fluorescence provides insight into how well they are functioning in the ecosystem.”

All plants absorb energy from the sun, typically more than they can consume through photosynthesis. The extra energy is mostly released as heat, but a small fraction is re-emitted as fluorescent light in red wavelengths. MODIS is the first instrument to observe this signal on a global scale.

“The amount of fluorescent light emitted is not constant; it changes with the health of the plant life in the ocean,” said Behrenfeld. “The challenge with global MODIS fluorescence data is to uncover the important biological information that is hidden in it.”

Red-light fluorescence reveals insights about the physiology of marine plants and the efficiency of photosynthesis, as different parts of the plant’s energy-harnessing machinery are activated based on the amount of light and nutrients available. For instance, the amount of fluorescence increases when phytoplankton are under stress from a lack of iron, a critical nutrient in seawater. When the water is iron-poor, phytoplankton emit more solar energy as fluorescence than when iron is sufficient.

The fluorescence data from MODIS gives scientists a tool that enables research to reveal where waters are iron-enriched or iron-limited, and to observe how changes in iron influence plankton. The iron needed for plant growth reaches the sea surface on winds blowing dust from deserts and other arid areas, and from upwelling currents near river plumes and islands.

The new analysis of MODIS data has allowed the research team to detect new regions of the ocean affected by iron deposition and depletion. The Indian Ocean was a particular surprise, as large portions of the ocean were seen to “light up” seasonally with changes in monsoon winds. In the summer, fall, and winter – particularly summer – significant southwesterly winds stir up ocean currents and bring more nutrients up from the depths for the phytoplankton. At the same time, the amount of iron-rich dust delivered by winds is reduced.

“On time-scales of weeks to months, we can use this data to track plankton responses to iron inputs from dust storms and the transport of iron-rich water from islands and continents,” said Doney. “Over years to decades, we can also detect long-term trends in climate change and other human perturbations to the ocean.”

Climate change could mean stronger winds pick up more dust and blow it to sea, or less intense winds leaving waters dust-free. Some regions will become drier and others wetter, changing the regions where dusty soils accumulate and get swept up into the air. Phytoplankton will reflect and react to these global changes.

“NASA satellites are powerful tools,” said Behrenfeld. “Huge portions of the ocean remain largely unsampled, so the satellite view is critical to seeing the big picture that complements the process-oriented understanding we get from work on ships and in laboratories.”

The research was funded by NASA and involved collaborators from the University of Maine, the University of California-Santa Barbara, the University of Southern Mississippi, NASA’s Goddard Space Flight Center, the Woods Hole Oceanographic Institution, Cornell University, and the University of California-Irvine.

‘Invasive aliens’ threaten global biodiversity

While the implications of climate change for biodiversity have been widely recognised, the insidious effect of invasive alien species (IAS) on global biodiversity stays under the radar.
22 May 2009
That is why this year’s theme for the United Nations’ International Day for Biological Diversity (IDB) on 22 May is IAS.

The International Convention on Biological Diversity sees IAS as “one of the greatest threats to biodiversity, and to the ecological and economic well-being of society and the planet”.

“All our efforts in managing the impact of climate change on biodiversity could be brought undone by invasive species,” CSIRO Biodiversity Research Director, Dr Mark Lonsdale said.

“All our efforts in managing the impact of climate change on biodiversity could be brought undone by invasive species,” CSIRO Biodiversity Research Director, Dr Mark Lonsdale said.“Increasing globalisation has led to greater movement of new species around the world, and native species killed or stressed by global change will all too often be replaced by these weeds and feral animals.

“Invasive species are already a major cause of biodiversity loss and we need new tools to tackle them.

“Because of this CSIRO is putting considerable resources into research on IAS and their effect on Australia’s biodiversity, as well as actively participating in international groups such as DIVERSITAS and the Global Invasive Species Programme.”

Current CSIRO research targets invasive species already in Australia as well as trying to anticipate and avert the next generation of IAS. The threats are diverse and hard to predict so excellence in risk-based research to make sense of the complexity is essential.

“Our research ranges from weeds, rabbits, carp and risk analysis of potential invasive species to biological collections that underpin much of the research,” Dr Lonsdale said.

“Our weeds research, for example, ranges from individual weeds such as lantana to the resistance of our ecosystems to weed invasion.”

The Australian National Herbarium, with its collection of native and exotic plants, underpins much of Australia’s weeds research and provides a vital resource when a new invasive plant species is found.

Dr Lonsdale stressed that invasive species are one of many direct threats to global biodiversity and, in Australia, CSIRO is responding to the magnitude of the challenge.

Download images at: 'Invasive aliens' threaten global biodiversity

The Fragility of the World's Coral is Revealed Through a

April 6, 2009


Click for downloadable image
This map of the
Northwestern Hawaiian Islands,
which stretch over 2,000
kilometers beyond the principal
Hawaiian islands, shows how much
humans have impacted the
region's coral reefs



Click for downloadable image
Pocillopora coral at
Maro Reef in the
Northwestern Hawaiian Islands.

Photo courtesy
of PNMN/NOAA



Click for downloadable image
Benjamin S. Halpern and
Kimberly A. Selkoe



(Santa Barbara, Calif.) –– A new study by researchers from UC Santa Barbara's National Center for Ecological Analysis and Synthesis (NCEAS) sheds light on how threats to the world's endangered coral reef ecosystems can be more effectively managed.

In a recent issue of the journal Coral Reefs, lead authors Kimberly A. Selkoe and Benjamin S. Halpern, both of NCEAS, explain how their maps of the Northwestern Hawaiian Islands (NWHI) –– a vast area stretching over 1,200 miles –– can be used to make informed decisions about protecting the world's fragile reefs.

Coral reef ecosystems are at risk due to the direct and indirect effects of human activities. This study was designed to help natural resource managers make decisions on issues such as surveillance priorities, granting of permits for use, and discernment of which areas to monitor for climate change effects.

"Our maps of cumulative human impact are a powerful tool for synthesizing and visualizing the state of the oceans," said first author Selkoe, who is also affiliated with Hawaii Institute of Marine Biology at the University of Hawaii. "The maps can aid in strategically zoning uses of oceans in an informed way that maximizes commercial and societal benefits while minimizing further cumulative impact."

"President (George W.) Bush declared the Northwestern Hawaiian Islands a National Monument in 2006, in part because it is one of the last places in the oceans that have not been heavily altered by human activities," said Halpern. "Our maps of cumulative human impact on these islands show that, despite their extreme isolation, humans are already significantly impacting this special place, and that many of the key threats, such as those associated with climate change, are not mitigated with Monument designation. We must continue to act to protect these islands and coral atolls if we hope to preserve them for future generations."

The authors studied 14 threats specific to NWHI. The threats, all generated by humans, included alien species, bottom fishing, lobster trap fishing, ship-based pollution, ship strike risks, marine debris, research diving, research equipment installation, and wildlife sacrifice for research. Human-induced climate change threats were also studied, including increased ultraviolet radiation, seawater acidification, the number of warm ocean temperature anomalies relevant to disease outbreaks and coral bleaching, and sea level rise.

Risk of increased rates of coral disease due to warming ocean temperature was found to have the highest impact, along with other climate-related threats. However, the authors noted that climate issues cannot be resolved by managers at the regional level. It was noted that threats related to ship traffic are most easily managed by regional management.

"With the scientific justification provided by our study, the managers of the Monument have an opportunity to make addressing the worst threats a top priority as they decide on management strategies," said Selkoe. "By updating the map of cumulative impacts through time, success of management plans in reducing cumulative impacts can be measured, and permits for new uses can be evaluated in the context of how they add to the landscape of cumulative impacts.

"The coral reefs of the Northwestern Hawaiian Islands make up the majority of U.S. coral reef area, and we should all be proud that they are some of the most pristine in the world, and fully protected under U.S. law," said Selkoe. "However, threats like marine debris, pollution from shipping, climate change effects and alien species still threaten to degrade these reefs. Our effort to systematically inventory and map the ongoing threats to these reefs, as we have done in this project, is an important part of protecting them."

The authors note that this analysis can serve as a case study for other areas and managers who are interested in mapping region-specific cumulative human impacts and in making assessments.

NCEAS, located in downtown Santa Barbara, is a research center of UCSB, largely funded by the National Science Foundation. NCEAS supports cross-disciplinary research that uses existing data to address fundamental issues in ecology and allied fields, and their application to management and policy. NCEAS is a unique institution with an explicit mission to foster synthesis and analysis, turn information into understanding and, through effective collaboration, alter how science is conducted.

Fire Is Important Part of Global Climate Change

Report Scientists
April 23, 2009

(Santa Barbara, Calif.) –– Fire must be accounted for as an integral part of climate change, according to 22 authors of an article published in the April 24 issue of the journal Science. The authors determined that intentional deforestation fires alone contribute up to one-fifth of the human-caused increase in emissions of carbon dioxide, a heat-trapping gas that raises global temperature.

The work is the culmination of a meeting supported by the Kavli Institute for Theoretical Physics (KITP) and the National Center for Ecological Analysis and Synthesis (NCEAS), both based at UC Santa Barbara and funded by the National Science Foundation.

The authors call on the Intergovernmental Panel on Climate Change (IPCC) to fully integrate fire into their assessments of global climate change, and to consider fire-climate feedbacks, which have been largely absent in global models.

The article ties together various threads of knowledge about fire, which have, until now, remained isolated in disparate fields, including ecology, global modeling, physics, anthropology, and climatology.

Increasing numbers of wildfires are influencing climate as well, the authors report. "The tragic fires in Victoria, Australia, emphasize the ubiquity of recent large wildfires and potentially changing fire regimes that are concomitant with anthropogenic climate change," said first author David Bowman, professor at the University of Tasmania. "Our review is both timely and of great relevance globally."

Carbon dioxide is the most important and well-studied greenhouse gas that is emitted by burning plants. Other atmospheric changes caused by fires are increases in the greenhouse gas methane, increased aerosol particulates from smoke, and the changing reflectance of a charred landscape. Consequences of large fires also have huge economic, environmental, and health costs, report the authors.

The authors state, "Earth is intrinsically a flammable planet due to its cover of carbon-rich vegetation, seasonally dry climates, atmospheric oxygen, widespread lightning, and volcano ignitions. Yet, despite the human species' long-held appreciation of this flammability, the global scope of fire has been revealed only recently by satellite observations, available beginning in the 1980s."

They note, however, that satellites cannot adequately capture fire activity in ecosystems with very long fire intervals, or those with highly variable fire activity.

Co-lead author Jennifer Balch, a postdoctoral fellow at NCEAS, explains that there are bigger and more frequent fires from the western U.S. to the tropics. There are "fires where we don't normally see fires," she says, noting that in the humid tropics a lot of deforestation fires are occurring, usually to expand agriculture or cattle ranching. "Wet rainforests have not historically experienced fires at the frequency that they are today. During extreme droughts, such as in 97-98, Amazon wildfires burned through 39,000 square kilometers of forest."

She explains the importance of the article: "This synthesis is a prerequisite for adaptation to the apparent recent intensification of fire feedbacks, which have been exacerbated by climate change, rapid land cover transformation, and exotic species introductions –– that collectively challenge the integrity of entire biomes."

The authors acknowledge that their estimate of fire's influence on climate is just a start, and they highlight major research gaps that must be addressed in order to understand the complete contribution of fire to the climate system.

Balch notes that a holistic fire science is necessary, and points out fire's true importance. "We don't think about fires correctly," she said. "Fire is as elemental as air or water. We live on a fire planet. We are a fire species. Yet, the study of fire has been very fragmented. We know lots about the carbon cycle, the nitrogen cycle, but we know very little about the fire cycle, or how fire cycles through the biosphere."

Research Contacts:

Jennifer Balch is available at
(202) 360-0923 (cell),
(805) 892-2522 (office),
or balch@nceas.ucsb.edu


David Bowman is available at
042 88 94 500 (cell),
Tel (Int) +61 3 6226 1943,
Tel (Aus) 03 6226 1943,
or david.bowman@utas.edu.au

New Ocean Circulation Experiment has Potential Big Climate Model Impact

From: Editor, ENN, based on an artilce from eurekalert
Published May 15, 2009 02:00 PM

New research by Duke University, in conjunction with the Woods Hole Oceanographic Institution is casting doubt on long-held theories of North Atlantic Ocean circulation patterns. This research, supported by the National Science Foundation is important since oceanic circulation is one of the key factors in current atmospheric circulation models, and therefore critical starting points for climate modeling.


A 50-year-old model of ocean currents had shown this southbound subsurface flow of cold water forming a continuous loop with the familiar northbound flow of warm water on the surface, called the Gulf Stream.

"Everybody always thought this deep flow operated like a conveyor belt, but what we are saying is that concept doesn't hold anymore," said Duke oceanographer Susan Lozier. "So it's going to be more difficult to measure these climate change signals in the deep ocean."

And since cold Labrador seawater is thought to influence and perhaps moderate human-caused climate change, this finding may affect the work of global warming forecasters.


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"To learn more about how the cold deep waters spread, we will need to make more measurements in the deep ocean interior, not just close to the coast where we previously thought the cold water was confined," said Woods Hole's Amy Bower.

Lozier, a professor of physical oceanography at Duke's Nicholas School of the Environment and Bower, a senior scientist in the department of physical oceanography at the Woods Hole Institution, are co-principal authors of a report on the findings to be published in the May 14 issue of the research journal Nature.

For More: http://www.eurekalert.org/pub_releases/2009-05/du-cwo051309.php

NEW STORAGE SYSTEM DESIGN BRINGS HYDROGEN CARS CLOSER TO REALITY

Monday, 13 April 2009 14:14
Researchers have developed a critical part of a hydrogen storage system for cars that makes it possible to fill up a vehicle's fuel tank within five minutes with enough hydrogen to drive 300 miles.

The system uses a fine powder called metal hydride to absorb hydrogen gas. The researchers have created the system's heat exchanger, which circulates coolant through tubes and uses fins to remove heat generated as the hydrogen is absorbed by the powder.

The heat exchanger is critical because the system stops absorbing hydrogen effectively if it overheats, said Issam Mudawar, a professor of mechanical engineering who is leading the research.

"The hydride produces an enormous amount of heat," Mudawar said. "It would take a minimum of 40 minutes to fill the tank without cooling, and that would be entirely impractical."

Researchers envision a system that would enable motorists to fill their car with hydrogen within a few minutes. The hydrogen would then be used to power a fuel cell to generate electricity to drive an electric motor.

The research, funded by General Motors Corp. and directed by GM researchers Darsh Kumar, Michael Herrmann and Abbas Nazri, is based at the Hydrogen Systems Laboratory at Purdue's Maurice J. Zucrow Laboratories. In February, the team applied for three provisional patents related to this technology.

"The idea is to have a system that fills the tank and at the same time uses accessory connectors that supply coolant to extract the heat," said Mudawar, who is working with mechanical engineering graduate student Milan Visaria and Timothée Pourpoint, a research assistant professor of aeronautics and astronautics and manager of the Hydrogen Systems Laboratory. "This presented an engineering challenge because we had to figure out how to fill the fuel vessel with hydrogen quickly while also removing the heat efficiently. The problem is, nobody had ever designed this type of heat exchanger before. It's a whole new animal that we designed from scratch."

The metal hydride is contained in compartments inside the storage "pressure vessel." Hydrogen gas is pumped into the vessel at high pressure and absorbed by the powder.

"This process is reversible, meaning the hydrogen gas may be released from the metal hydride by decreasing the pressure in the storage vessel," Mudawar said. "The heat exchanger is fitted inside the hydrogen storage pressure vessel. Due to space constraints, it is essential that the heat exchanger occupy the least volume to maximize room for hydrogen storage."

Conventional automotive coolant flows through a U-shaped tube traversing the length of the pressure vessel and heat exchanger. The heat exchanger, which is made mostly of aluminum, contains a network of thin fins that provide an efficient cooling path between the metal hydride and the coolant.

"This milestone paves the way for practical on-board hydrogen storage systems that can be charged multiple times in much the same way a gasoline tank is charged today," said Kumar, a researcher at GM's Chemical & Environmental Sciences Laboratory and the GM R&D Center in Warren, Mich. "As newer and better metal hydrides are developed by research teams worldwide, the heat exchanger design will provide a ready solution for the automobile industry."

The researchers have developed the system over the past two years. Because metal hydride reacts readily with both air and moisture, the system must be assembled in an airtight chamber, Pourpoint said.

Research activities at the hydrogen laboratory involve faculty members from the schools of aeronautics and astronautics, mechanical engineering, and electrical and computer engineering.

http://news.uns.purdue.edu/x/2009a/090402MudawarHydrogen.html

ALGAE COULD FUEL CARS AND JOBS

(Photo: CSIRO)
Wednesday, 18 March 2009 17:32
CSIRO Energy Transformed researcher Dr Tom Beer and his team discovered the humble organisms’ green credentials during a detailed life-cycle analysis of the benefits of algal biodiesel.


"Our research has shown that under ideal conditions it is possible to produce algal biodiesel at a lower cost and with less greenhouse gas emissions than fossil diesel," Dr Beer said.

"The greenhouse gas reductions are the result of avoiding the use of a fossil resource for fuel production, capturing methane produced by the processed algae to generate energy and taking into account the potential greenhouse gas offsets from industry."

Algae thrive on carbon dioxide (CO2), which means that environmentally damaging CO2 emissions from industry could also become a useful resource.

Algal biodiesel could also offer a number of other benefits.

"Making biodiesel from algae removes the issue of competing land use because the facilities would not be established on land that might otherwise be used to grow food and the algal farm has a very low environmental impact in comparison to crops that are grown for biodiesel," Dr Beer said.

"Our study also found that the establishment of a 500 hectare algal biodiesel plant in a rural area might create up to 45 jobs and provide opportunities to diversify in the agricultural sector."

The CSIRO Energy Transformed Flagship is working with a number of partners, both national and international, to develop a strong algal biofuel research program.

"The Flagship’s research has made significant progress in a short time and our extensive biofuels program will continue to develop solutions that result in a secure fuel future for Australia," Dr Beer said.

Despite the global interest in the production of biodiesel from algae, further research is required to create a viable industry with widespread uptake and impact.

"Although the findings of our study are very promising, challenges still exist in relation to cost, infrastructure needs and the scale of production required to make algal plants feasible," Dr Beer said.

"We see biodiesel from algae as one potential option for sustainable fuel production amongst a range of other technologies."

CSIRO

SUNLIGHT TURNS CARBON DIOXIDE TO METHANE

(Photo: Penn State)
Tuesday, 17 March 2009 16:18

Burning fossil fuels like oil, gas and coal release large amounts of carbon dioxide, a greenhouse gas, into the atmosphere. Rather than contribute to global climate change, producers could convert carbon dioxide to a wide variety of hydrocarbons, but this makes sense to do only when using solar energy.


"Recycling of carbon dioxide via conversion into a high energy-content fuel, suitable for use in the existing hydrocarbon-based energy infrastructure, is an attractive option, however the process is energy intense and useful only if a renewable energy source can be used for the purpose," the researchers note in a recent issue of Nano Letters.

Craig A. Grimes, professor of electrical engineering and his team used titanium dioxide nanotubes doped with nitrogen and coated with a thin layer of both copper and platinum to convert a mixture of carbon dioxide and water vapor to methane. Using outdoor, visible light, they reported a 20-times higher yield of methane than previously published attempts conducted in laboratory conditions using intense ultraviolet exposures.

The chemical conversion of water and carbon dioxide to methane is simple on paper -- one carbon dioxide molecule and two water molecules become one methane molecule and two oxygen molecules. However, for the reaction to occur, at least eight photons are required for each molecule.

"Converting carbon dioxide and water to methane using photocatalysis is an appealing idea, but historically, attempts have had very low conversion rates," said Grimes who is also a member of Penn State's Materials Research Institute. "To get significant hydrocarbon reaction yields requires an efficient photocatalyst that uses the maximum energy available in sunlight."

The team, which also included Oomman K. Varghese and Maggie Paulose, Materials Research Institute research scientists and Thomas J. LaTempa, graduate student in electrical engineering, used natural sunlight to test their nanotubes in a chamber containing a mix of water vapor and carbon dioxide. They exposed the co-catalyst sensitized nanotubes to sunlight for 2.5 to 3.5 hours when the sun produced between 102 and 75 milliwatts for each square centimeter exposed.

The researchers found that nanotubes annealed at 600 degrees Celsius and coated with copper yielded the highest amounts of hydrocarbons and that the same nanotubes coated with platinum actually yielded more hydrogen, while the copper coated nanotubes produced more carbon monoxide. Both hydrogen and carbon monoxide are normal intermediate steps in the process and as the building blocks of syngas, can be used to make liquid hydrocarbon fuels.

When the team used a nanotube array with about half the surface coated in copper and the other half in platinum, they enhanced the hydrocarbon production and eliminated carbon monoxide. The yield for these dual catalyst nanotubes was 163 parts per million hydrocarbons an hour for each square centimeter. The yield from titania nanotubes without either copper or platinum catalysts is only about 10 parts per million.

"If we uniformly coated the surface of the nanotube arrays with copper oxide, I think we could greatly improve the yield," said Grimes.

Grimes also found that lengthening the titanium dioxide tubes, which for other applications increases yield, does not improve results.

"We think that distribution of the sputtered catalyst nanoparticles is at the top surface of the nanotubes and not inside and that is why increased length does not improve the reaction," says Grimes.

Although all these experiments were done with nitrogen-doped titanium dioxide nanotubes, the researchers conclude that the nitrogen did not enhance the conversion of carbon dioxide to hydrocarbons. The catalysts, however, did shift the reaction from one that used only the energy in ultraviolet light to one that used other wavelengths of visible light and therefore more of the sun's energy.

The researchers are now working on converting their batch reactor into a continuous flow-through design that they believe will significantly increase yields.

The researchers have filed a provisional patent on this work.

Penn State

U.S.-LED, INTERNATIONAL RESEARCH TEAM CONFIRMS ALPS-LIKE MOUNTAIN RANGE EXISTS UNDER EAST ANTARCTIC

(Photo: Zina Deretsky / NSF)

Wednesday, 11 March 2009 10:33
Flying twin-engine light aircraft the equivalent of several trips around the globe and establishing a network of seismic instruments across an area the size of Texas, a U.S.-led, international team of scientists has not only verified the existence of a mountain range that is suspected to have caused the massive East Antarctic Ice Sheet to form, but also has created a detailed picture of the rugged landscape buried under more than four kilometers (2.5 miles) of ice.

"Working cooperatively in some of the harshest conditions imaginable, all the while working in temperatures that averaged -30 degrees Celsius, our seven-nation team has produced detailed images of last unexplored mountain range on Earth," said Michael Studinger, of Columbia University's Lamont-Doherty Earth Observatory, the co-leader of the U.S. portion of the Antarctica's Gamburstev Province (AGAP) project. "As our two survey aircraft flew over the flat white ice sheet, the instrumentation revealed a remarkably rugged terrain with deeply etched valleys and very steep mountain peaks."

The National Science Foundation (NSF), in its role as manager of the U.S. Antarctic Program, provided much of the complex logistical support that made the discoveries possible. NSF also supported U.S. researchers from Columbia University, Washington University in St. Louis, Pennsylvania State University, the Center for Remote Sensing of Ice Sheets (CReSIS) at the University of Kansas, the U.S. Geological Survey (USGS) and the Incorporated Research Institutions in Seismology (IRIS).

The initial AGAP findings--which are based on both the aerogeophysical surveys and on data from a network of seismic sensors deployed as part of the project--while extremely exciting, also raise additional questions about the role of the Gamburtsevs in birthing the East Antarctic Ice Sheet, which extends over more than 10 million square kilometers atop the bedrock of Antarctica, said geophysicist Fausto Ferraccioli, of the British Antarctic Survey (BAS), who led the U.K. science team.

"We now know that not only are the mountains the size of the European Alps but they also have similar peaks and valleys," he said. "But this adds even more mystery about how the vast East Antarctic Ice Sheet formed."

He added that "if the ice sheet grew slowly then we would expect to see the mountains eroded into a plateau shape. But the presence of peaks and valleys could suggest that the ice sheet formed quickly--we just don't know. Our big challenge now is to dive into the data to get a better understanding of what happened" millions of years ago.

The AGAP survey area covered roughly 2 million square kilometers of the ice sheet.

The initial data also appear to confirm earlier findings that a vast aquatic system of lakes and rivers exists beneath the ice sheet of Antarctica, a continent that is the size of the U.S. and Mexico combined.

"The temperatures at our camps hovered around -30 degrees Celsius, but three kilometers beneath us at the bottom of the ice sheet we saw liquid water in the valleys," said AGAP U.S. Co-leader Robin Bell, also of Lamont Doherty. "The radar mounted on the wings of the aircraft transmitted energy through the thick ice and let us know that it was much warmer at the base of the ice sheet."

The AGAP data will help scientists to determine the origin of the East Antarctic Ice Sheet and the Gamburtsevs' role in it. It will also help them to understand the role the subglacial aquatic system plays in the dynamics of ice sheets, which will, in turn, help reduce scientific uncertainties in predictions of potential future sea level rise. The most recent report of the Intergovernmental Panel on Climate Change (IPCC) said that it is difficult to predict how much the vast ice sheets of Greenland and Antarctica will contribute to sea-level rise because so little is known about the behavior of the ice sheets.

The data also will be used to help locate where the world's oldest ice is located.

The AGAP discoveries were made through fieldwork that took place in December and January, near the official conclusion of the International Polar Year (IPY), the largest coordinated international scientific effort in five decades. Ceremonies marking the conclusion of IPY fieldwork will take place in Geneva, Switzerland on Feb. 25.

NSF is the lead U.S. agency for IPY. Through the Antarctic Program, NSF manages all federally funded research on the southernmost continent.

Fully in the spirit of IPY, noted Detlef Damaske of Germany's Federal Institute for Geosciences and Natural Resources, teams of scientists, engineers, pilots and support staff from Australia, Canada, China, Germany, Japan, the U.K. and the U.S. pooled their knowledge, expertise and logistical resources to deploy two survey aircraft, equipped with ice-penetrating radar, gravimeters and magnetic sensors as well as the network of seismometers, an effort that no one nation alone could have mounted.

"This is a fantastic finale to IPY," added Ferraccioli.

Bell meanwhile, noted that AGAP is "emblematic of what the international science community can accomplish when working together."

In one of the most ambitious, challenging and adventurous 'deep field' Antarctic IPY expeditions, AGAP scientists gathered the terabytes of data needed to create images of the enigmatic Gamburtsevs, first discovered by Russian scientists in 1957 during the International Geophysical Year (IGY), the predecessor to IPY.

While the planes made a series of survey flights, covering a total of 120,000 square kilometers, the seismologists flew to 26 different sites throughout an area larger than the state of Texas using Twin Otter aircraft equipped with skis, to install scientific equipment that will run for the next year on solar power and batteries.

The seismology team, from Washington University, Penn State, IRIS, and Japan's National Institute of Polar Research, also recovered ten seismographs that have been collecting data since last year over the dark Antarctic winter at temperatures as low as -73 degrees Celsius (-100 degrees Fahrenheit).

"The season was a great success," said Douglas Wiens, of Washington University in St. Louis. "We recovered the first seismic recordings from this entire part of Antarctica, and operated seismographs over the Antarctic winter at temperatures as low as -100 F for the first time. Now, we are poring over the data to find out what is responsible for pushing up mountains in this part of Antarctica."

National Science Foundation

MICROBE SURVIVES IN OCEAN'S DEEPEST REALM, THANKS TO GENETIC ADAPTATIONS

Photo: University of Delaware

Friday, 27 February 2009 00:34
The genome of a marine bacterium living 2,500 meters below the ocean's surface is providing clues to how life adapts in extreme environments, according to a paper published Feb. 6, 2009, in the journal PLoS Genetics.


The research focused on the bacterium Nautilia profundicola, a microbe that survives near deep-sea hydrothermal vents. It was found in a fleece-like lining on the backs of Pompeii worms, a type of tubeworm that lives at hydrothermal vents, and in bacterial mats on the surfaces of the vents' chimney structures.

One gene, called rgy, allows the bacterium to manufacture a protein called reverse gyrase when it encounters extremely hot fluids from the Earth's interior released from the sea floor.

"The discovery of reverse gyrase in Nautilia profundicola suggests that it plays a key role in this microbe's ability to thrive near deep-sea hydrothermal vents, where conditions are thought to resemble those found on early Earth," said Matt Kane, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research. "Knowledge of microbes living near vents may aid our understanding of how life evolved."

The study involved scientists at the University of Delaware, the University of California, the Universities of Louisville, Ky., and Waikato, New Zealand, and the J. Craig Venter Institute.

They combined genome analysis with physiological and ecological observations to investigate the importance of one gene, rgy, in N. profundicola's ability to adapt to the extreme changes it's exposed to in the deep sea.

"Previous studies found the gene only in microorganisms growing in temperatures greater than 80 degrees Celsius, but Nautilia profundicola thrives best at much lower temperatures," said Barbara Campbell, a marine scientist at the University of Delaware.

"The gene's presence in Nautilia profundicola suggests that it might play a role in the bacterium's ability to survive rapid and frequent temperature fluctuations in its environment."

Photosynthesis doesn't occur in this dark environment, where hot, toxic fluids oozing from below the seafloor combine with cold seawater at very high pressures.

Microorganisms that thrive at hydrothermal vents must adapt to fluctuations in temperature and oxygen levels, ranging from the hot, sulfide- and heavy metal-laden plume at the vents' outlets to cold seawater in the surrounding region.

The researchers uncovered further adaptations to the vent environment in Nautilia profundicola, including genes necessary for growth and for sensing environmental conditions. They also proposed a new route for bacterial nitrate assimilation related to how other bacteria use ammonia as an energy source.

Nautilia profundicola contains all the genes necessary for life in conditions widely believed to mimic those in our planet's early biosphere.

"It will be an important model system," said Campbell, "for understanding early microbial life on Earth."



The National Science Foundation

ATMOSPHERIC SUNSHADE COULD REDUCE SOLAR POWER GENERATION

Photo: Department of Energy/National Renewable Energy Laboratory

Tuesday, 24 March 2009 13:24 The concept of delaying global warming by adding particles into the upper atmosphere to cool the climate could unintentionally reduce peak electricity generated by large solar power plants by as much as one-fifth, according to a new NOAA study. The findings appear in Environmental Science and Technology.


“Injecting particles into the stratosphere could have unintended consequences for one alternative energy source expected to play a role in the transition away from fossil fuels,” said author Daniel Murphy, a scientist at NOAA’s Earth System Research Laboratory in Boulder, Colo.

The Earth is heating up as fossil-fuel burning produces carbon dioxide, the primary heat-trapping gas responsible for man-made climate change. To counteract the effect, some geoengineering proposals are designed to slow global warming by shading the Earth from sunlight.

Among the ideas being explored is injecting small particles into the upper atmosphere to produce a climate cooling similar to that of large volcanic eruptions, such as Mt. Pinatubo’s in 1991. Airborne sulfur hovering in the stratosphere cooled the Earth for about two years following that eruption.

Murphy found that particles in the stratosphere reduce the amount and change the nature of the sunlight that strikes the Earth. Though a fraction of the incoming sunlight bounces back to space (the cooling effect), a much larger amount becomes diffuse, or scattered, light.

On average, for every watt of sunlight the particles reflect away from the Earth, another three watts of direct sunlight are converted to diffuse sunlight. Large power-generating solar plants that concentrate sunlight for maximum efficiency depend solely on direct sunlight and cannot use diffuse light.

Murphy verified his calculations using long-term NOAA observations of direct and diffuse sunlight before and after the 1991 eruption.

After the eruption of Mt. Pinatubo, peak power output of Solar Electric Generating Stations in California, the largest collective of solar power plants in the world, fell by up to 20 percent, even though the stratospheric particles from the eruption reduced total sunlight that year by less than 3 percent.

“The sensitivity of concentrating solar systems to stratospheric particles may seem surprising,” said Murphy. “But because these systems use only direct sunlight, increasing stratospheric particles has a disproportionately large effect on them.”

Nine Solar Electric Generating Stations operate in California and more are running or are under construction elsewhere in the world. In sunny locations such systems, which use curved mirrors or other concentrating devices, generate electricity at a lower cost than conventional photovoltaic, or solar, cells.

Flat photovoltaic and hot water panels, commonly seen on household roofs, use both diffuse and direct sunlight. Their energy output would decline much less than that from concentrating systems.

Even low-tech measures to balance a home’s energy, such as south-facing windows for winter heat and overhangs for summer shade, would be less effective if direct sunlight is reduced.



National Oceanic and Atmospheric Administration

HIGH CO2 BOOSTS PLANT RESPIRATION, POTENTIALLY AFFECTING CLIMATE AND CROPS

Friday, 27 February 2009 00:43
The leaves of soybeans grown at the elevated carbon dioxide levels predicted for the year 2050 respire more than those grown under current atmospheric conditions, researchers report, a finding that will help fine-tune climate models and could point to increased crop yields as CO2 levels rise.

Photo: Don Hamerman
The study, from researchers at the University of Illinois and the U.S. Department of Agriculture, appears this week in the Proceedings of the National Academy of Sciences.

Plants draw CO2 from the atmosphere and make sugars through the process of photosynthesis. But they also release some CO2 during respiration as they use the sugars to generate energy for self-maintenance and growth. How elevated CO2 affects plant respiration will therefore influence future food supplies and the extent to which plants can capture CO2 from the air and store it as carbon in their tissues.

While there is broad agreement that higher atmospheric CO2 levels stimulate photosynthesis in C3 plants, such as soybeans, no such consensus exists on how rising CO2 levels will affect plant respiration.

“There’s been a great deal of controversy about how plant respiration responds to elevated CO2,” said U. of I. plant biology professor Andrew Leakey, who led the study. “Some summary studies suggest it will go down by 18 percent, some suggest it won’t change, and some suggest it will increase as much as 11 percent.”

Understanding how the respiratory pathway responds when plants are grown at elevated CO2 is key to reducing this uncertainty, Leakey said. His team used microarrays, a genomic tool that can detect changes in the activity of thousands of genes at a time, to learn which genes in the high CO2 plants were being switched on at higher or lower levels than those of the soybeans grown at current CO2 levels.

Rather than assessing plants grown in chambers in a greenhouse, as most studies have done, Leakey’s team made use of the Soybean Free Air Concentration Enrichment (Soy FACE) facility at Illinois. This open-air research lab can expose a soybean field to a variety of atmospheric CO2 levels – without isolating the plants from other environmental influences, such as rainfall, sunlight and insects.

Some of the plants were exposed to atmospheric CO2 levels of 550 parts per million (ppm), the level predicted for the year 2050 if current trends continue. These were compared with plants grown at ambient CO2 levels (380 ppm).

The results were striking. At least 90 different genes coding the majority of enzymes in the cascade of chemical reactions that govern respiration were switched on (expressed) at higher levels in the soybeans grown at high CO2 levels. This explained how the plants were able to use the increased supply of sugars from stimulated photosynthesis under high CO2 conditions to produce energy, Leakey said. The rate of respiration increased 37 percent at the elevated CO2 levels.

The enhanced respiration is likely to support greater transport of sugars from leaves to other growing parts of the plant, including the seeds, Leakey said.

“The expression of over 600 genes was altered by elevated CO2 in total, which will help us to understand how the response is regulated and also hopefully produce crops that will perform better in the future,” he said.

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Fish numbers outpace human population

http://www.newscientist.com/article/dn16692-fish-numbers-outpace-human-population.html
Fish numbers outpace human population

17:50 02 March 2009 by Debora MacKenzie
For similar stories, visit the Endangered Species and Mysteries of the Deep Sea Topic Guides



It's increasingly likely that the fish you eat was farmed not caught wild, according to the latest statistics of the UN Food and Agriculture Organization.
The group's two-yearly assessment of world fisheries, published today, comes with mitigated good news.
The outlook for wild ocean fish remains gloomy: 80% of all fisheries are at or beyond their maximum yields, and over-fishing continues to climb. Yet the amount of fish available to eat is growing faster than the human population, thanks to a boom in fish farming.
The FAO calculates that, for the first time, fish farms produce half the fish we eat, up from less than a third in 2002. With wild-catch fisheries maxed out, any more increases in fish production will depend on farms.
Problems in the wild?
It is unclear from the FAO data whether fish farms are indirectly putting more pressure on wild stocks.
Many farmed fish eat fishmeal and oil, made from small species like sardines. The FAO says the tonnage of these species consumed has trebled since 1992, but does not say whether this is a consequence of fish farming, or because the fish are being used for other purposes.
In a parallel report, international fisheries pressure group Oceana charges that by relying on wild-caught species like sardines, which now constitute one third of world fisheries, fish farms are starving larger predators, including tuna, marine mammals and seabirds.
The FAO observes that the unrestricted competition between companies is a waste of energy: too many boats mean that fewer fish are caught per litre of boat fuel. Meanwhile, boat owners buy more powerful, less efficient engines to beat the competition.