Climate change caused mass extinction of mammals 50,000 years ago

May 19, 2010 By Leave a Comment

Washington, May 19 (ANI): Climate change played a major role in causing mass extinction of mammals in the late quaternary era, 50,000 years ago, an international team of scientists have discovered.

Their study 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 percent of mammal species weighing over 44kg went extinct, together with a lower proportion of small mammals. Why these species became extinct in such large numbers has been hotly debated for over a century, ”said lead author Dr David Nogues-Bravo working from the Center for Macroecology, Evolution and Climate in University of Copenhagen.

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,” Dr Nogues-Bravo added.

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.

The study has been published in Evolution. (ANI)

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Poplars, just like humans, also feel stressed

May 7, 2010 By Leave a Comment

Washington, May 7 (ANI): Just like humans, trees too, feel stressed. And scientists have now claimed that hormone suppression could help common poplars— cottonwoods and aspens—deal with stress.

Trees’ stress can come from a lack of water or too much water, from scarcity of a needed nutrient, from pollution or a changing climate.

A new study led by Michigan Technological University scientists, has identified the molecular mechanism that Populus—the scientific name for common poplars—uses to adapt to changing soil conditions, as well as some of the genes that turn the process off or on.

And now they look forward to apply what they’ve learned to find ways to use biotechnology or selective breeding to modify the trees to make them more stress-tolerant.

“Our hope is that by understanding how this works, we can manipulate the system so the plants can adapt faster and better to stressful conditions,” explained Dr. Victor Busov.

The researchers analysed thousands of genes in the Populus genome, the only tree genome that has been completely sequenced.

They were searching for the mechanism that regulates the plant’s decision to grow tall or to spread its roots out in an extensive underground exploration system that can sample the soil near and far until it finds what the rest of the plant needs.

The key players turned out to be a family of hormones called gibberellins, referred to by the scientists as GAs.

“GAs’ role in root development is poorly understood and the role of GAs in lateral root formation is almost completely unknown,” said Busov.

Lateral roots are the tangle of tiny roots that branch out from the primary root of a plant.

”They are the sponges, the ones that go looking for nutrients, for water—the ones that do most of the work,” explained Busov.

The researchers found that GAs interact with other plant hormones such as auxin to tell the plant whether to concentrate on reaching for the sky or on building a bigger, better network of roots under ground.

“The GAs and auxin are definitely talking, molecularly,” said Busov.

Growing poplar seedlings mutated to make them GA-deficient, the scientists compared their root and stem growth to others that contained moderate amounts of GAs and a control group of wild-type plants with normal GAs.

They found that the more GAs, the more a plant’s stem flourished, but its roots remained spindly.

When GA production was shut down, either by using mutants that lacked the necessary genes or by silencing the genes that form the molecular on-off switch, the resulting plants looked dwarfed, but their lateral roots grew luxuriant and full.

Application of GA to the GA-deficient dwarf plants rapidly reversed the process. The plants grew tall, but their lateral root systems shrivelled.

“Clearly, lack of the hormone promotes growth below ground, while the hormone itself promotes growth above ground. This is a natural mechanism that we don’t know much about. It’s always a tradeoff between growth above ground and growth below ground. Normally there is a fine balance, and this balance is a little disturbed under stress,” said Busov.

The study has been published in a recent issue of the journal The Plant Cell. (ANI)

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CSIRO chief defends climate science

March 16, 2010 By Leave a Comment

The head of Australia’s peak science body has spoken out in defence of climate scientists, saying the link between human activity and climate change is beyond doubt.

The head of the CSIRO, Dr Megan Clark, says the evidence of global warming is unquestionable, and in Australia it is backed by years of robust research.

Dr Clark says climate records are being broken every decade and all parts of the nation are warming.

“We are seeing significant evidence of a changing climate,” she said.

“If we just take our temperature, all of Australia has experienced warming over the last 50 years. We are warming in every part of the country during every season and as each decade goes by, the records are being broken.

“We are also seeing fewer cold days so we are seeing some very significant long-term trends in Australia’s climate.”

Dr Clark says the long-term data across a number of measures stacks up in favour of climate change proponents and against those who say the planet is not warming.

“We can certainly look at the long-term trends and any event here or there or a storm here or there really doesn’t explain away what we are seeing in these major long-term trends,” she said.

“We are also seeing consistency. I think the consistency between our temperatures, what we are seeing in our rainfall, what we are seeing in the increase of carbon dioxide and methane in our atmosphere and of course, what we are now seeing in our oceans.

“So it is not just one measurement that is telling us. It is our observations and science that we are seeing in many areas being consistent.”

Strong evidence

Dr Clark says the evidence strongly suggests human activity is responsible for the rise.

“We know two things. We know that our CO2 has never risen so quickly. We are now starting to see CO2 and methane in the atmosphere at levels that we just haven’t seen for the past 800,000 years, possibly even 20 million years,” she said.

“We also know that that rapid increase that we’ve been measuring was at the same time that we saw the industrial revolution so it is very likely that these two are connected.”

Dr Clark says scepticism is a healthy part of the scientific process and has been considered as part of the climate change debate.

But she says the data needs to be looked at in a systematic way and the evidence backs those who say humans are contributing to global warming.

“Whenever we come into groups with very complex issues as a society, every time we have done that, we should challenge and we do challenge and it brings us back to our observations,” she said.

“It makes us re-look at what we are really seeing. It makes us ask those questions, so I think challenge is simply part of coming to understand an issue.

“But at the same time, plucking out a snow storm in the US or a flood in Queensland or a cold day somewhere and trying to use that to explain away some of these long-term trends, of course, we know is not the right way to do it.”

Dr Clark says the data the CSIRO has based its conclusions on is both long-term and solid.

“We have been recording and the [weather] bureau has been recording our climate for over 100 years,” she said.

“Our records here are extremely robust and of course, CSIRO is studying and researching and looking at those trends for over 50 years so I think we are very blessed in this country to have some very, very robust data and very long-term [data].”

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Human impacts and environmental factors changing northwest Atlantic ecosystem

September 2, 2009 By Leave a Comment

Washington, Sept 2 (ANI): A new report by researchers at the National Oceanic and Atmospheric Administration (NOAA) has determined that human impacts and environmental factors are changing the northwest Atlantic ecosystem.

According to the report, fish in US waters from Cape Hatteras to the Canadian border have moved away from their traditional, long-time habitats over the past four decades because of fundamental changes in the regional ecosystem.

The 2009 Ecosystem Status Report also points out the need to manage the waters off the northeastern coast of the United States as a whole rather than as a series of separate and unrelated components.

Known as the Northeast US Continental Shelf Large Marine Ecosystem (NES LME), the ecosystem spans approximately 100,000 square miles and supports some of the highest revenue-generating fisheries in the nation.

During the past 40 years, the ecosystem has experienced extensive fishing by domestic and foreign fleets, changes in ocean water temperatures due to climate change, and pressures from increasing human populations along the coast.

According to Michael Fogarty, who heads the Ecosystem Assessment Program at the Northeast Fisheries Science Center (NEFSC) of NOAA’s Fisheries Service in Woods Hole, Massachusetts, his team’s report highlights the need to understand natural and human-related changes in this region and to develop effective management and mitigation strategies.

“There are many pressures on the ecosystem including fishing, pollution, habitat loss from coastal development, and impacts on marine life from shipping and other uses of the ocean,” Fogarty said.

“In addition, changing climate conditions are warming ocean waters, changing ocean chemistry and circulation patterns, and altering atmospheric systems. These changes have, in turn, been linked to changes in the distribution and abundance of fish species in the region and their major sources of food,” he added.

The report is the first in a planned series of ecosystem status reports by Fogarty and his colleagues in the NEFSC’s Ecosystem Assessment Program to document changes in the NES LME, one of 64 regions in the world’s ocean designated as a large marine ecosystem.

Fogarty said that sustained long-term monitoring by many agencies and institutions in the Northeast region has enabled scientists and others to trace changes in the ecosystem.

“In the future, we need to continue to monitor the oceanographic, ecological, and human indicators analyzed in this report to detect any additional changes in the system. These indicators also provide important inputs to models that can be used to help guide management decisions and to forecast future changes,” he said. (ANI)

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Human-generated aerosols from northern hemisphere may affect rainfall patterns in Australia

August 27, 2009 By Leave a Comment

Washington, August 27 (ANI): Australian scientists, using a climate model, have suggested that human-generated aerosols from the northern hemisphere may have contributed to increased rainfall in north-western and central Australia, and decreased rainfall in parts of southern Australia.

According to lead researcher, Dr Leon Rotstayn, Principal Research Scientist at the Centre for Australian Weather and Climate Research, a partnership between CSIRO and the Bureau of Meteorology, “Perhaps surprisingly, inclusion of northern hemisphere aerosols may be important for accurate modelling of Australian climate change.”Aerosols come from many different sources.

Sulphur is released when we burn coal and oil. More dust, also an aerosol, circulates in the atmosphere when land is cleared, burned or overgrazed.

Some aerosols occur naturally like sea spray and volcanic emissions, but NASA estimates ten percent of the total aerosols in the atmosphere are caused by people.

Most of this ten percent is in the northern hemisphere.
European researchers, attending the international ‘Water in a changing climate’ science conference in Melbourne from August 24-28, will discuss a new forecasting service that will identify in unprecedented detail where these aerosols are coming from and where they are going.

The new service, part of Europe’s Global Monitoring for Environment and Security (GMES) initiative, will give global information on how pollutants move around the world across oceans and continents, and will refine estimates of their sources and sinks.

According to Dr Adrian Simmons from the European Centre for Medium-Range Weather Forecasts, which is coordinating the multi-institution initiative, “The service will give much more detailed forecast information on air quality over Europe and provide the basis for better health advice across Europe and beyond”.

The service has clear implications for environmental policy and legislation. (ANI)

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Global warming may cause Earth’s axis to tilt in coming century

August 21, 2009 By Leave a Comment

London, August 21 (ANI): A new study has suggested that gloabal warming may heat up oceans to the extent that it could cause Earth’s axis to tilt in the coming century.

According to a report in New Scientist, the warming effect was previously thought to be negligible, but researchers now say the shift will be large enough that it should be taken into account when interpreting how the Earth wobbles.

The Earth spins on an axis that is tilted some 23.5 degrees from the vertical. But this position is far from constant – the planet’s axis is constantly shifting in response to changes in the distribution of mass around the Earth.

“The Earth is like a spinning top, and if you put more mass on one side or other, the axis of rotation is going to shift slightly,” said Felix Landerer of NASA’s Jet Propulsion Laboratory in Pasadena, California.

The changing climate has long been known to move Earth’s axis. The influx of fresh water from shrinking ice sheets also causes the planet to pitch over.

Landerer and colleagues estimate that the melting of Greenland’s ice is already causing Earth’s axis to tilt at an annual rate of about 2.6 centimetres – and that rate may increase significantly in the coming years.

Now, they calculate that oceans warmed by the rise in greenhouse gases can also cause the Earth to tilt – a conclusion that runs counter to older models, which suggested that ocean expansion would not create a large shift in the distribution of the Earth’s mass.

The researchers modelled the changes that would occur if moderate projections made by the Intergovernmental Panel on Climate Change – a doubling of carbon dioxide levels between 2000 and 2100 – were to become reality.

The team found that as the oceans warm and expand, more water will be pushed up and onto the Earth’s shallower ocean shelves.

Over the next century, the subtle effect is expected to cause the northern pole of Earth’s spin axis to shift by roughly 1.5 centimetres per year in the direction of Alaska and Hawaii.

The motion is strong enough that it needs to be taken into account when interpreting shifts in Earth’s axis.

Tracking the motion of the poles could help place limits on the total amount of sea level rise over decades.

“The oceans take up at least 80 per cent of the heat that is added from greenhouse gases,” Landerer told New Scientist. “They have a huge heat capacity, so this effect is going to be there for quite a bit,” he said. (ANI)

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Global warming may make sea level rise between 7- 82 cm by century end

July 29, 2009 By Leave a Comment

Washington, July 28 (ANI): New predictions indicate that the amount of sea level rise by the end of this century will be between 7- 82 cm – depending on the amount of warming that occurs.

Placing limits on the amount of sea level rise over the next century is one of the most pressing challenges for climate scientists.

Dr Mark Siddall from the University of Bristol, together with colleagues from Switzerland and the US, used fossil coral data and temperature records derived from ice-core measurements to reconstruct sea level fluctuations in response to changing climate for the past 22,000 years, a period that covers the transition from glacial maximum to the warm Holocene interglacial period.

By considering how sea level has responded to temperature since the end of the last glacial period, Siddall and colleagues predict that the amount of sea level rise by the end of this century will be similar to that projected by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).

According to Dr Siddall, “Given that the two approaches are entirely independent of each other, this result strengthens the confidence with which one may interpret the IPCC results. It is of vital importance that this semi-empirical result, based on a wealth of data from fossil corals, converges so closely with the IPCC estimates.”

“Furthermore, as the time constant of the sea level response is 2,900 years, our model indicates that the impact of twentieth-century warming on sea level will continue for many centuries into the future. It will therefore constitute an important component of climate change in the future,” he said.

The IPCC used sophisticated climate models to carry out their analysis, whereas Siddall and colleagues used a simple, conceptual model that is trained to match the sea level changes that have occurred since the end of the last ice age.

The new model explains much of the variability observed over the past 22,000 years and, in response to the minimum and maximum warming projected for 2100 AD by the IPCC model, this new model predicts, respectively, 7 and 82 cm of sea-level rise by the end of this century.

The IPCC model predicted a slightly narrower range of sea level rise – between 18 and 76 cm. (ANI)

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Expanding tropics mean less rain globally

July 6, 2009 By Leave a Comment

Sydney, July 6 (ANI): Australian experts have warned that the globe’s tropical zone is expanding rapidly and more research is needed to help humans adapt to the changing climate, which means less rain.

According to a report by ABC News, the finding is a result of a review of over 70 scientific papers done by climate researchers Professor Steve Turton and Dr Joanne Isaacs of James Cook University in Cairns, who have documented the rapid advance of the tropical zone.

“The review suggests that the tropics have expanded over the last 25 to 30 years, between 2 and 5 degrees of latitude in both hemispheres,” said Turton, who examined evidence from weather balloons, satellite imagery, sea surface temperatures and climate models.

“That’s between 300 and 500 kilometres just in that short period of time,” he added.

Turton said that given the impacts on everything from farming and healthcare to viticulture and tourism, much more research is needed to help respond to this change.

“The tropics have half the world’s population, 80 percent of the world’s biodiversity, very high infant mortality, high rates of tropical diseases and they make up around 20 percent of Gross World Product,” he said.

Turton said that Australia is the only the first world country that has a significant amount of tropical land mass, and yet investment in research does not reflect this.

“Around half of Australia is tropical and the proportion is increasingly,” he said. “But very little money goes into tropical medicine, compared to general medicine,” he added.

According to Turton, for most of Australians, who live in the southern half of the continent, the spread of the tropics will actually mean more drought because of the southward spread of the dry subtropical zone.

“As humid temperate climate zones will be replaced by the dry subtropical zone, cities like Sydney will get more rain in the summer but less rain overall,” he said.

“Sydney will be more like Brisbane by the end of century,” he added.

He said that the climate of Melbourne and parts of Tasmania will become more Mediterranean with a hot dry season and more rain in winter, until the mid-latitude jet stream moves further south and rainfall misses Australia’s landmass altogether. (ANI)

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Change in fertilizer subsidy policy can help India save crores, ensure food security: Greenpeace

July 1, 2009 By Leave a Comment

New Delhi, July 1 (ANI): Moving away from current Government subsidies on synthetic fertiliser that lead to poor soils and less food, and investing in ecological farming will have triple benefits: save public money, ensure food security under less rain and a changing climate, and reduce greenhouse gas emissions, says a scientific report released by Greenpeace today.

Titled ‘Subsidising Food Crisis’, the report, a joint effort by scientists from Greenpeace and Institute of Agriculture Visva Bharathy University, West Bengal, offers a scientific analysis linking the increasing fertiliser subsidies to yield stagnation in agriculture.

In 2008/09 the Government of India had set aside an amount of 119,772 crore Rupees for synthetic fertiliser subsidies.

Releasing the report, Greenpeace India’s Sustainable Agriculture campaigner Gopikrishna said, “The irrational subsidy doled out by the government provokes the excessive usage of synthetic fertilisers leading to soil degradation, a major cause for yield stagnation”. He further opined that “The potential for a shift from synthetic to organic nitrogen fertilisers is real: India can save a substantial amount of taxpayers’ money along the way”.

The report points out that in Punjab, the state with highest use of synthetic fertilisers in India, data on the relationship between food grain production and fertiliser consumption from 1960 to 2003 show that in spite of consistent increment in N-P-K fertiliser consumption, grain yield has not only stagnated, but also showed a declining trend with fertiliser application during the later period, 1992 to 2003.

The average crop response to fertiliser use was around 25 kg of grain per kg of fertiliser during 1960s, the said value has reduced drastically to 8 kg/kg only during late 1990s. High use of chemical fertilisers is mostly also associated with high level of water consumption and micro-nutrient deficiency in soil leading to decline in water table and further deterioration of the soil.

“Subsidising Food Crisis” for the first time calculates the greenhouse gas emissions from the synthetic nitrogen fertiliser, both by its manufacture and use.

Synthetic nitrogen fertilisers contribute 6 percent of the India’s total greenhouse gas emissions, comparable to the road transport sector. A shift from synthetic nitrogen fertilisers to efficient and ecological fertilisers will reduce this contribution from six to two percent.

“At a time when it is extremely urgent that the whole world fights climate change, the Government of India could save significant emissions by shifting subsidies to ecological farming. The good news is that this is also a proven way to make agriculture more resilient to upcoming climate change conditions, like less water and more unpredictable rains,” said Reyes Tirado, one of the authors and senior research scientist at the Greenpeace Research Laboratories in the University of Exeter in the UK.

Based on the report, Greenpeace India has demanded that the Government needs to:

1. Look into an alternate subsidy system that promotes ecological farming and use of organic soil amendments.

2. Shift the irrational subsidy policy for synthetic fertilisers to sustainable ecological practices in agriculture.

3. Re-focus scientific research on ecological alternatives, to identify agro-ecological practices that ensure future food security under a changing climate.

The report is authored by Dr B.C Roy and Dr G N Chattopadhyay of Visva Bharathy University and Dr Reyes Tirado, from Greenpeace Research laboratories at the University of Exeter. (ANI)

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Sulfate particles enhance climate warming properties of atmospheric soot

June 30, 2009 By Leave a Comment

Washington, June 30 (ANI): A new study has found that particles of sulfate, thought to be holding climate change in check by reflecting sunlight, instead enhances warming when combined with airborne soot.

Recent atmospheric models have ranked soot, also called black carbon, second only to carbon dioxide in potential for atmospheric warming.

But particles, or aerosols, such as soot mix with other chemicals in the atmosphere, complicating estimates of their role in changing climate.

“Until now, scientists have had to assume how soot is mixed with other chemical species in individual particles and estimate how that ultimately impacts their warming potential,” said Kimberly Prather, professor in the Department of Chemistry and Biochemistry and the Scripps Institution of Oceanography at the University of California, San Diego.

“Our measurements show that soot is most commonly mixed with other chemicals such as sulfate and this mixing happens very quickly in the atmosphere. These are the first direct measurements of the optical properties of atmospheric soot and allow us to better understand the role of soot in climate change,” she added.

For the study, Prather and Ryan Moffet, a former graduate student at UC San Diego who is now at the Lawrence Berkeley National Laboratory, measured atmospheric aerosols over Riverside, California and Mexico City.

Using an instrument that measures the size, chemical composition and optical properties of aerosols in real time, they showed that jagged bits of fresh soot quickly become coated with a spherical shell of other chemicals, particularly sulfate, nitrate, and organic carbon, through light-driven chemical reactions.

Within several hours of sunrise, most of the atmospheric carbon they measured had been altered in this way.

Particles of sulfate or nitrate alone reflect light, and some have proposed pumping sulfate aerosols into the atmosphere to slow climate change.

But, these chemicals play a different role when they mix with soot.

“The coating acts like a lens and focuses the light into the center of the particle, enhancing warming,” Prather said.

“Many people think sulfate aerosols are a good thing because they are highly reflective and cool our planet,” he said.

“However, we are seeing that sulfate is commonly mixed with soot in the same particles, which means in some regions sulfate could lead to more warming as opposed to more cooling as one would expect for a pure sulfate aerosol,” he added.

Their measurements showed that in the atmosphere the lens-like shell of sulfate and nitrate enhances absorption of light by coated soot particles 1.6 times over pure soot particles. (ANI)

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New crops needed in case of continued rise in CO2 levels

June 29, 2009 By Leave a Comment

Washington, June 29 (ANI): A new research has determined that new crops would be needed to be grown in the future if carbon dioxide (CO2) levels continue to rise.

Global food security in a changing climate depends on the nutritional value and yield of staple food crops.

Researchers at Monash University in Victoria, Australia, have found an increase in toxic compounds, a decrease in protein content and a decreased yield in plants grown under high CO2 and drought conditions.

The research has shown that the concentration of cyanogenic glycosides, which break down to release toxic hydrogen cyanide, increased in plants in elevated CO2.

This was compounded by the fact that protein content decreased, making the plants overall more toxic as the ability of herbivores to break down cyanide depends largely on the ingestion of sufficient quantities of protein.

Data have also shown that cassava, a staple food crop in tropical and subtropical regions due to its tolerance of arid conditions, may experience yield reductions in high CO2.

Combined with an increase in cyanogenic glycosides, this has major implications for the types of crops that can be grown in the future if CO2 levels continue to rise.

“We need to be preparing for the predicted reduction in nutritional value of many plants in the coming century by developing and growing different cultivars which, for cassava in particular, may not be easy,” said Dr Gleadow. (ANI)

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NASA satellite detects red glow to map global ocean plant health

May 29, 2009 By Leave a Comment

Washington, May 29 (ANI): Scientists have conducted the first global analysis of the health and productivity of ocean plants using a unique red glow detected by NASA’s Aqua satellite.

Using the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite, scientists have now observed “red-light fluorescence” over the open ocean.

MODIS is the first instrument to observe this signal on a global scale.

Ocean scientists can now remotely measure the amount of fluorescent red light emitted by phytoplankton and assess how efficiently these microscopic plants turn sunlight and nutrients into food through photosynthesis.

Researchers also can study how changes in the global environment alter these processes 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.

Phytoplankton account for half of all photosynthetic activity on Earth and play a key role in the balance of carbon dioxide in the atmosphere.

The health of these marine plants affects the amount of carbon dioxide (CO2) the ocean can absorb from the atmosphere and how the ocean responds to a changing climate.

“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 Oregon State University.

“We have an important new tool for observing changes in phytoplankton every week, all over the planet,” he added.

All plants absorb energy from the sun, typically more than they can consume through photosynthesis. A small fraction of this extra energy is re-emitted as fluorescent light in red wavelengths.

“The amount of fluorescent light emitted is not constant; it changes with the health of the plant life in the ocean,” said Behrenfeld.

With this new measurement, the scientists discovered large areas of the Indian Ocean where phytoplankton were under stress from iron deficiency.

They were surprised to see large portions of the ocean “light up” seasonally as phytoplankton responded to a lack of iron in their diet.

The amount of fluorescence increases when phytoplankton have too little iron, a nutrient in seawater.

Iron reaches the sea surface on winds blowing dust from deserts and other arid areas, and from upwelling currents.

“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 co-author Scott Doney, a marine chemist from the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts.

“Over years to decades, we also can detect long-term trends in climate change and other human perturbations to the ocean,” he added. (ANI)

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Changing climate make mockingbirds better singers

May 22, 2009 By Leave a Comment

Washington, May 22 (ANI): Mockingbirds tend to sing fancier tunes with changing climate, say researchers.

The research team from the National Evolutionary Synthesis Centre (NESCent), the Cornell Lab of Ornithology, and McGill University showed that species in more variable climes also sing complex tunes.

“Survival and reproduction become more complicated when weather patterns are unpredictable because you don’t know when food will be available or how long it will be around,” said Carlos Botero, a postdoctoral researcher at NESCent in Durham, NC.

And the consequences of picking a mediocre mate are magnified in harsher climes.

“In really difficult or demanding environments you would expect females to be choosier,” he added.

Botero said that male mockingbirds sing primarily to impress mates and superior singing skills are a cue that a male is a good catch.

“Complexity of song display – how many song types a bird sings, how hard the songs are – is a good predictor of the quality of the individual,” he said.

“Males that sing more complex songs tend to carry fewer parasites, and have offspring that are more likely to survive,” he added.

Moreover, singing skills may be a sign that males are clever enough to cope with iffy environments.

“Individuals that are more intelligent tend to be better able to compensate for the difficulties of unpredictable climates,” said Botero.

“For example, if some individuals are able to invent new foraging techniques, then they are going to be better at surviving harsh winters than the poor guys who only know one way to forage.

“The more intelligent you are, the more resourceful you are, and the more curve balls you’re able to handle,” he added.

During the study, Botero and his colleagues studied nearly 100 tracks from 29 mockingbird species and found that species subject to more variable and unpredictable climates had more elaborate song displays.

The connection between birdsong and climate is new and somewhat surprising, Botero explains. “We’re connecting two dots that were far away before.” (ANI)

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Wild fruit trees in danger of becoming extinct

May 8, 2009 By Leave a Comment

London, May 8 (ANI): Scientists have warned that the wild ancestors of common domestic fruit trees are in danger of becoming extinct.

According to a report by BBC News, the warning has come as researchers have published a “red list” of threatened species that grow in the forests of Central Asia.

These disease-resistant and climate-tolerant fruit trees could play a role in our future food security.

But in the last 50 years, about 90 percent of the forests have been destroyed, according to conservation charity, Fauna and Flora International.

The Red List of Central Asia identifies 44 tree species in Kyrgyzstan, Kazakhstan, Uzbekistan, Turkmenistan and Tajikistan as under threat from extinction.

It cites over-exploitation and human development as among the main threats to the region’s forests, which are home to more than 300 wild fruit and nut species including apple, plum, cherry, apricot and walnut.

Antonia Eastwood, the lead author of the research, described the region as a “unique global hotspot of diversity”.

“A lot of these species are only found in this area,” she told BBC News. “It’s very mountainous and dry, so many of these species have a great deal of tolerance to cold and drought,” she said.

“A lot of our domestic fruit supply comes from a very narrow genetic base. Given the threats posed to food supplies by disease and the changing climate, we may need to go back to these species and include them in breeding programmes,” she added.

Kazakhstan and Kyrgyzstan are thought to be the ancestral homes of familiar favourites such as Red Delicious and Golden Delicious.

The US Department of Agriculture has already sponsored expeditions to Kazakhstan, during which scientists have collected samples with the aim of expanding the genetic diversity of farm-grown apples.
According to Dr Eastwood, this type of genetic foraging, explained, allows domestic lines to be crossed with wild strains, producing varieties more resistant to diseases such as apple scab, a fungus that can devastate crops.

“But, these countries lack the resources to conserve their valuable trees,” she said. (ANI)

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Ozone layer will recover in future, predict scientists

April 11, 2009 By Leave a Comment

Washington, April 11 (ANI): A new research by NASA scientists has suggested that the ozone layer might recover in the future, thanks to the changing climate and atmospheric circulation.

According to the scientists, Earth’s ozone layer should eventually recover from the unintended destruction brought on by the use of chlorofluorocarbons (CFCs) and similar ozone-depleting chemicals in the 20th century, since greenhouse gases are changing the dynamics of the atmosphere.

Previous studies have shown that while the buildup of greenhouse gases makes it warmer in troposphere – the level of atmosphere from Earth’s surface up to 10 kilometers (6 miles) altitude – it actually cools the upper stratosphere – between 30 to 50 kilometers high (18 to 31 miles).

This cooling slows the chemical reactions that deplete ozone in the upper stratosphere and allows natural ozone production in that region to outpace destruction by CFCs.

But, the accumulation of greenhouse gases also changes the circulation of stratospheric air masses from the tropics to the poles, according to NASA scientists.

In Earth’s middle latitudes, that means ozone is likely to “over-recover,” growing to concentrations higher than they were before the mass production of CFCs.

In the tropics, stratospheric circulation changes could prevent the ozone layer from fully recovering.

“Most studies of ozone and global change have focused on cooling in the upper stratosphere,” said Feng Li, an atmospheric scientist at the Goddard Earth Sciences and Technology Center at the University of Maryland Baltimore County, Baltimore, Maryland, and lead author of the study.

“But, we find circulation is just as important. It’s not one process or the other, but both,” he added.

The findings are based on a detailed computer model that includes atmospheric chemical effects, wind changes, and solar radiation changes.

Working with Richard Stolarski and Paul Newman of NASA’s Goddard Space Flight Center, Greenbelt, Maryland, Li adapted the Goddard Earth Observing System Chemistry-Climate Model (GEOS-CCM) to examine how climate change will affect ozone recovery.

The team inserted past measurements and future projections of ozone-depleting substances and greenhouse gases into the model.

Then, the model projected how ozone, the overall chemistry, and the dynamics of the stratosphere would change through the year 2100.

Though the concentration of chlorine and other ozone-depleting substances in the stratosphere will not return to pre-1980 levels until 2060, the ozone layer over middle latitudes is predicted to ecover to pre-1980 levels by 2025. (ANI)

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Drop in daddy long legs devastating bird populations

March 29, 2009 By Leave a Comment

London, March 27 (ANI): A new research has determined that warm summers are dramatically reducing populations of daddy long legs, which in turn is having a severe impact on the bird populations which rely on them for food.

The new research, by a team of bird experts, including Newcastle University’s Dr Mark Whittingham, spells out for the first time how climate change may affect upland bird species like the golden plover – perhaps pushing it towards local extinction by the end of the century.

It also points a way forward to how we can attempt to strengthen habitats to help wildlife adapt to our changing climate and prevent such consequences.

Previous research has shown how changes in the timing of the golden plover breeding season as a result of increasing spring temperatures might affect their ability to match the spring emergence of their cranefly (daddy long legs) prey.

The new research shows the true effects are much more severe.

Higher temperatures in late summer are killing the cranefly larvae, resulting in a drop of up to 95 per cent in the number of adult craneflies emerging the following spring.

With these craneflies providing a crucial food source for a wide range of upland birds like the golden plover, this means starvation and death for many chicks.

“The population of Golden Plovers in our study will likely be extinct in around 100 years if temperature predictions are correct and the birds cannot adapt to feed on other prey sources,” explained Newcastle University’s Dr Mark Whittingham, who worked on the study with scientists from RSPB Scotland and Aberystwyth and Manchester universities.

“Our study models the impacts of climate change on the ecology of the animal. In this case, we show that higher August temperatures, as predicted from climate change models, are correlated with lower numbers of daddy-long legs,” he added.

“Daddy long-leg abundance is key for Golden Plover chicks in terms of growth and survival. Worryingly, our work is likely to apply to other upland bird species that also rely on daddy-long legs as a prey resource, such as Curlew,” he further added. (ANI)

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