May 16, 2006, 0:07 AM CT

Global Warming May Have Damaged Coral Reefs Forever

Global warming has had a more devastating effect on some of the world's finest coral reefs than previously assumed, suggests the first report to show the long-term impact of sea temperature rise on reef coral and fish communities.

Large sections of coral reefs and much of the marine life they support may be wiped out for good, say the international team of researchers, who surveyed 21 sites and over 50,000 square metres of coral reefs in the inner islands of the Seychelles in 1994 and 2005.

Their report is the first to show the long-term impact of the 1998 event where global warming caused Indian Ocean surface temperatures to increase to unprecedented and sustained levels, killing off (or 'bleaching') more than 90 per cent of the inner Seychelles coral.

The team, led by the University of Newcastle upon Tyne, and which comprises scientists from the UK, Australia and the Seychelles, publishes its findings today, Monday May 15, in the Proceedings of the National Academy of Sciences.

The research showed that, while the 1998 event was devastating in the short term, the main long-term impacts are down to the damaged reefs being largely unable to reseed and recover. A number of simply collapsed into rubble which became covered by unsightly algae.........

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May 14, 2006, 3:49 PM CT

How did cactuses evolve?

In a groundbreaking new study in the recent issue of American Naturalist, Erika J. Edwards (Yale University and University of California, Santa Barbara) and Michael J. Donoghue (Yale University) explore how leafy, "normal" plants evolved into the leafless succulent cactus.

"The cactus form is often heralded as a striking example of the tight relationship between form and function in plants," write the authors. "A succulent, long-lived photosynthetic system allows cacti to survive periods of extreme drought while maintaining well-hydrated tissues."

Recent molecular phylogenetic work has confirmed that Pereskia, a genus that consists of 17 species of leafy shrubs and trees, is where the earliest cactus lineages began. Using field studies and environmental modeling, Edwards and Donoghue found that the Pereskia species already showed water use patterns that are similar to the leafless, stem-succulent cacti.

"[Our] analyses suggest that several key elements of cactus ecological function were established previous to the evolution of the cactus life form," explain the authors. "Such a sequence may be common in evolution, but it has rarely been documented as few studies have incorporated physiological, ecological, anatomical, and phylogenetic data."........

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May 12, 2006, 0:10 AM CT

Ray Grizzle Is Restoring Oyster Reefs

In the past decade, the oyster population in New Hampshire's Great Bay estuary has plummeted by 90 percent, due to the 1995 arrival of the oyster disease MSX. The prior century saw a slower but equally devastating demise of oysters from exuberant overharvesting. "We have seen local extinction on some reefs," says Ray Grizzle, research associate professor at the University of New Hampshire's Jackson Estuarine Laboratory.

Now Grizzle is working to bring oysters back to Great Bay - lots of them. He's helping the state of New Hampshire meet its established goal of restoring 20 acres of oyster reefs by 2010. "I hope we're going to have a bay with a healthy oyster population, and we're going to work hard to do it," he says. His research explores which are the best reef restoration techniques for the Great Bay estuarine system (www.oysters.unh.edu).

Oyster reef restoration involves providing sufficient hard substrate - typically oyster shells on which young oysters settle and grow - and seeding it with disease-resistant young oysters. Natural oyster reefs are formed by live oysters atop mounds of empty shells; one initiative of Grizzle's lab is soliciting "recycled" empty shells from oyster harvesters that will eventually be returned to the bay to provide substrate.........

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May 11, 2006, 0:26 AM CT

Wasps Queue For Top Job

Researchers at UCL (University College London) have discovered that even wasps are driven by their status. The study, published recently in Nature, shows that lower-ranked female wasps work harder to help their queen than those higher up the chain because they have less to lose, and consequently are prepared to take more risks and wear themselves out.

The study, funded by the Natural Environment Research Council (NERC), reveals that those higher up the chain and therefore with a greater chance of being the next in line to breed are much lazier than their lower-ranked nest-mates: rather than use up their energy in foraging to feed the queen's larvae, high-rankers sit tight on the nest and wait for their chance to become queen themselves.

Dr Jeremy Field, UCL Department of Biology, said: "Helpers wait peacefully in an age-based queue to inherit the prize of being the queen or breeder in the group. The oldest female almost always becomes the next breeder. The wasps in this queue face a fundamental trade-off: by working harder, they help the group as a whole and as a result indirectly benefit themselves, but they simultaneously decrease their own future survival and fecundity because helping is costly. It involves energy-expensive flight to forage for food, and leaving the nest is dangerous. We have found that the brighter the individual wasp's future, the less likely it is to take risks by leaving the safety of its nest to forage for food".........

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May 10, 2006, 0:17 AM CT

Importance Of Fungi In Arctic Nitrogen Cycle

A new method to calculate the transfer of nitrogen from Arctic mushrooms to plants is shedding light on how fungi living symbiotically on plant roots transfer vital nutrients to their hosts. The analytical technique, developed by John E. Hobbie, MBL Distinguished Scientist and co-director of the laboratory's Ecosystems Center and his son, Erik A. Hobbie of the University of New Hampshire, may be applied to nearly all conifers, oaks, beeches, birch and shrubs such as blueberry and cranberry-all nitrogen-poor ecosystems-and will be an important tool for future studies of plant nitrogen supply.

It has long been known when soil nitrogen is in short supply, mycorrhizal fungi (those living symbiotically on the roots of plants) transfer nutrients to their host plants in exchange for plant sugars derived from photosynthesis, but the rates of transfer have never been quantified in the field. John and Erik Hobbie's study, reported in the April 2006 issue of the journal Ecology, quantifies the role.

of mycorrhizal fungi in nitrogen cycling for the first time through measurements of the natural abundance of nitrogen isotopes in soils, mushrooms and plants. The scientists tested their technique using data from the Arctic LTER (Long Term Ecological Research) site near Toolik Lake, Alaska, in the northern foothills of the Brooks Range.........

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May 8, 2006, 11:45 PM CT

Social Stress Prompts Hamsters To Overeat

Put a mouse or a rat under stress and what does it do? It stops eating. Humans should be so lucky. When people suffer nontraumatic stress they often head for the refrigerator, producing unhealthy extra pounds.

When Syrian hamsters, which are normally solitary, are placed in a group-living situation, they also gain weight. So researchers at the Center for Behavioral Neuroscience at Georgia State University are using hamsters as a model for human stress-induced obesity. They want to begin unraveling the complex factors that lead people to eat when under stress and hope that the information can eventually be used to block appetites under this common scenario.

The study, "Social defeat increases food intake, body mass, and adiposity in Syrian hamsters," by Michelle T. Foster, Matia B. Solomon, Kim L. Huhman and Timothy J. Bartness, Georgia State University, Atlanta, appears in the recent issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology published by The American Physiological Society.

Hamsters similar to humans

In the study, the scientists look at nontraumatic stress -- the stress we experience in everyday life, such as getting stuck in traffic or trying to complete a major project at work. It is distinct from traumatic stress, such as suffering the death of a loved one. Traumatic stress typically dulls the human appetite, said Bartness, the study's senior researcher and an authority on obesity.........

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May 8, 2006, 11:27 PM CT

Where Have All the Butterflies Gone?

Cold, wet conditions early in the year mean that 2006 is shaping up as the worst year for California's butterflies in almost four decades, according to Art Shapiro, professor of evolution and ecology at UC Davis.

That's a turnaround from last spring, when millions of painted lady butterflies migrated through the Central Valley. But other species have seen steep declines in recent years and could disappear from the region altogether.

"It has been the worst spring for butterflies of my 35 in California," Shapiro said. "There will probably be long-term repercussions, especially for species already in serious decline".

Shapiro said that at most of his study sites, he is seeing half or less than half the number of species present at this time in an average year, and far fewer individual butterflies than usual. For example, at Gates Canyon near Vacaville he counted 10 species and 43 individuals on April 18, 2006. At the same site on April 19, 2005, he counted 21 species and 378 butterflies.

This winter's weather conditions may have a lot to do with the drop in numbers. The early winter was mild, with not enough cold to end the winter dormancy or "diapause" of most butterflies, so they did not emerge to take advantage of early warm weather in February. Then March turned cold and wet, wiping out the breeding of species that had emerged.........

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May 6, 2006, 5:49 PM CT

No-Mow Grass May Be Coming Soon

For anyone tethered to a lawnmower, the Holy Grail of horticultural accomplishment would be grass that never grows but is always green.

Now, that vision of suburban bliss-and more-seems plausible as researchers have mapped a critical hormone signaling pathway that regulates the stature of plants. In addition to lawns that rarely require mowing, the finding could also enable the development of sturdier, more fruitful crop plants such as rice, wheat, soybeans, and corn.

In a paper reported in the May 4, 2006, issue of the journal Nature, Howard Hughes Medical Institute researchers report they have deciphered the signaling pathway for a key class of steroid hormones that regulates growth and development in plants.

"By manipulating the steroid pathway.....we think we can regulate plant stature and yield," said Joanne Chory, a Howard Hughes Medical Institute investigator at the Salk Institute for Biological Studies, and the senior author of the new report.

Manipulation of plant stature has been a longstanding goal in horticulture, agronomy, and forestry. The ability to precisely control plant size would have broad implications for everything from urban forestry to crop and garden plant development. Beyond perpetually short grass, trees could be made more compact for better growth in crowded cities, and berry bushes could be made taller for ease of harvesting.........

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May 4, 2006, 4:43 PM CT

Use Of Switchgrass Could Solve Energy Woes

Carnegie Mellon University scientists say the use of switchgrass could help break U.S. dependence on fossil fuels and curb costly transportation costs.

"Our report indicates the time is right for America to begin a transition to ethanol derived from switchgrass," said Scott Matthews, an assistant professor in the Civil and Environmental Engineering Department. A 25 percent hike in gas prices at the pump since December adds to the researchers' call for more ethanol derived from switchgrass, a perennial tall grass used as forage for livestock. Gasoline prices in the U.S. are approaching an average of $3 a gallon. The Carnegie Mellon findings were reported in the May 1 issue of the American Chemical Society's Journal "Environmental Science and Technology."

Matthews, along with W. Michael Griffin, executive director of the Green Design Institute at Carnegie Mellon's Tepper School of Business, and William R. Morrow, a researcher in the university's Department of Civil and Environmental Engineering, said using switchgrass as a supplement to corn to make ethanol would help ensure the availability of large volumes of inexpensive ethanol to fuel distributors and consumers.

"We need to be thinking about how we can make and deliver ethanol once our corn and land resources are maxed out. Switchgrass can be that next step," Griffin said.........

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May 3, 2006, 10:08 PM CT

Root-development Pathway Mapped

Biologists have vastly expanded understanding of the biological machinery controlling the intricate process by which plant roots burgeon from single cells into complex tissues. A Duke-led team's discovery of new components of the root-development pathway in the mustard plant, Arabidopsis thaliana, represents both a scientific and technical achievement, the researchers said.

Scientifically, Arabidopsis is a basic biological model for all flowering plants, so the finding offers insights into a critical function of all such plants, including crop plants, the scientists said. Further, since the root is a useful model for tissue development in general, basic findings regarding the root-development pathway could offer insights into how complex tissues are generated from immature cells, called stem cells.

Technically, the genomic analytical method they used also will offer biologists a highly useful approach to discovering the components of complex biological pathways governing development, the scientists said. Their statistical "meta-analysis" technique involved using computational methods to integrate data from multiple genetic analyses using several DNA microarrays -- popularly known as "gene chips." Each of these chips contained some 24,000 genes representing nearly the entire genome of the Arabidopsis plant.........

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