Study of poison frogs the first to show that the Andes Mountains have been a major source of diversity for the Amazon basin.

AUSTIN, Texas—Colorful poison frogs in the Amazon owe their great diversity to ancestors that leapt into the region from the Andes Mountains several times during the last 10 million years, a new study from The University of Texas at Austin suggests.

This is the first study to show that the Andes have been a major source of diversity for the Amazon basin, one of the largest reservoirs of biological diversity on Earth. The finding runs counter to the idea that Amazonian diversity is the result of evolution only within the tropical forest itself.

“Basically, the Amazon basin is a ‘melting pot’ for South American frogs,” says graduate student Juan Santos, lead author of the study. “Poison frogs there have come from multiple places of origin, notably the Andes Mountains, over many millions of years. We have shown that you cannot understand Amazonian biodiversity by looking only in the basin. Adjacent regions have played a major role.”

Santos and Dr. David Cannatella, professor of integrative biology, published their findings this month in the journal PLoS Biology.

It has been assumed that much of the evolution of biodiversity in the Amazon basin occurred over the last one to two million years, a mere snapshot in time.

Santos and Cannatella peered about 45 million years into the past using novel biogeographical techniques to create a deep evolutionary history of poison frogs in space and time. Because of the lack of an extensive fossil record for the tropical forest, their work used DNA sequences to discover the frogs’ evolutionary history.

The poison frogs, or dendrobatids, are diverse and widely distributed across the Neotropics, an area that includes Central and South America. The scientists created an evolutionary tree, or phylogeny, using 223 of the 353 species of poison frogs known from throughout this region.

In analyzing the evolutionary relationships among the poison frogs, they discovered that Amazonian diversity is the result of at least 14 dispersals of ancestral frogs into the region beginning about 23 million years ago.

All living Amazonian poison frogs evolved from these ancestors, most of which (11 dispersals) came from the Andes Mountains.

The Amazon basin has changed dramatically over that long time. A large inland system of water has come and gone, the Andes Mountains started their uplift (about 15 million years ago) and the Amazon River was formed (about nine million years ago).

Most of the frog dispersals from the Andes occurred between one and seven million years ago, when the modern tropical rainforest of the Amazon River basin was forming.

“There was a repeated dispersal of frogs from the foothills of the Andes after the extensive inland wetlands retreated from the Amazon,” says Santos.

These frogs then evolved into about 70 species found today in the Amazon basin.

The scientists also discovered that frogs have historically immigrated out of the Amazon basin to adjacent areas, and to and from other regions within the Neotropics.

Evolution and diversification of the poison frogs is ongoing, especially in the Amazon rainforest, the Chocó (a narrow region of tropical forest along the northwest Pacific Coast of South America) and in adjacent Central America.

Cannatella says many other tropical plants and animals in the Amazon may share this more complex geographical and temporal history with the poison frogs.

“The Amazon rainforest is not just gradually accumulating diversity over time,” says Cannatella. “Ancestral frog species moved into and out of the area, and we can predict that other organisms restricted to these wet tropical forests may show a similar pattern of dispersal, evolution and diversification.”

Source: University of Texas at Austin.

SALT LAKE CITY – More than 150 years after a small Eurasian tree named tamarisk or saltcedar started taking over river banks throughout the U.S. Southwest, saltcedar leaf beetles were unleashed to defoliate the exotic invader.

Now, University of Utah scientists say their new study shows it is feasible to use satellite data to monitor the extent of the beetle’s attack on tamarisk, and whether use of the beetles may backfire with unintended environmental consequences.

“We don’t have any idea of the long-term impacts of using the beetles; their release may have unexpected repercussions,” says Philip Dennison, an assistant professor of geography and first author of the study scheduled for online publication later this month in the journal Remote Sensing of Environment.

“The impact of this defoliation is largely unknown,” says study co-author Kevin Hultine, a research assistant professor of biology at the University of Utah. “The net impact of controlling tamarisk could be positive or negative.”

“We would like on-the-ground scientists and managers to understand and think about the long-term impact – what are these riparian [riverbank] areas going to look like 15 years from now, and how can we can maintain ecosystems” as well as water flows for farms, cities and river recreation, Hultine says.

Dennison and Hultine conducted the study with Jim Ehleringer, a distinguished professor of biology at the University of Utah; physical scientist Pamela Nagler, of the U.S. Geological Survey in Tucson, Ariz.; and Edward Glenn, a University of Arizona environmental scientist.

A Shady Invader from Eurasia

Anyone who has rafted Southwestern rivers like the Green and Colorado knows about the shady thickets of tamarisk that line the riverbanks. The trees can grow up to 30 feet tall. There are about 10 species of tamarisk.

This 2007 infrared image from the ASTER instrument on NASA’s Terra satellite shows the effects of saltcedar leaf beetles that were released to defoliate tamarisk. An alfalfa field along the Colorado River remains vegetated and thus is bright red. But the wet “bottom” area along the Dolores River (lower right) appears much darker than in the 2006 image because the beetles have eaten tamarisk leaves. Remaining areas of bright red within the “bottom” area are due to willow and cottonwood trees. University of Utah researchers propose using satellites to monitor tamarisk defoliation by beetles in remote areas of the Southwest.

Credit: Phil Dennison, University of Utah, from NASA data.

The U.S. Animal and Plant Health Inspection Service (APHIS) says saltcedar or tamarisk is “a highly invasive, exotic weed” in the form of “a large shrub or small tree that was introduced to North America from Asia in the early 1800s. The plant has been used for windbreaks, ornamentals, and erosion control. By 1850, saltcedar had infested river systems and drainages in the Southwest, often displacing native vegetation.”

“By 1938, infestations were found from Florida to California and as far north as Idaho,” according to APHIS. “Saltcedar continues to spread rapidly and currently infests water drainages and areas throughout the United States.”

Tamarisk dominates riverbank habitats, limiting camping areas for river runners, reducing diversity and providing poor habitat for some species of wildlife. Tamarisk also raises the risk of fires that destroy cottonwoods and other native plants but not tamarisk, which re-sprouts from roots. And tamarisk forms a dense canopy, also helping wipe out competing plants. Finally, tamarisk has a bad rap as a water-sucking wastrel that dries springs, lowers water tables and reduces stream flows, even impairing boating.

Dennison and Hultine say recent research indicates tamarisk’s thirst is overstated.

“Some of the earliest research on tamarisk water use suggested tamarisk uses dramatically more water than other tree species,” Hultine says. “So a lot of estimates on water loss over entire river reaches are based on information that now has been discredited in the scientific literature.”

Hultine believes that unless aggressive programs to restore defoliated areas are implemented, tamarisk will be replaced by other invaders – Russian knapweed, Russian olive and pepperweed – that may use more water than tamarisk. Eradicating tamarisk with beetles also may reduce bird habitat, he adds.

Monitoring the Attack of the Tamarisk-Munching Beetles

The saltcedar leaf beetle, Diorhabda elongata, was brought to the U.S. from Kazakhstan. After an environmental assessment, APHIS approved them for tamarisk control.

Dennison says thousands of the beetles first were released in Utah during summer 2004, then again in summer 2005 and 2006 at locations along the Colorado River near Moab. Widespread defoliation of tamarisk in the area was noted during summer 2007.

Because long stretches of rivers in the Colorado River Basin are remote, Dennison and colleagues decided to test the feasibility of using satellite images to detect tamarisk leaf loss due to the spread of the saltcedar leaf beetles.

This 2006 infrared image of the confluence of the Colorado and Dolores rivers in Utah was taken by the ASTER instrument on NASA’s Terra satellite. The Colorado flows from north to south and the Dolores enters the image from the east. Vegetation appears bright red, including an alfalfa field along the Colorado and a wet “bottom” area along the Dolores that has extensive tamarisk, an invasive tree from Eurasia.

Credit: Phil Dennison, University of Utah, from NASA data.

They mapped 56 accessible areas already defoliated by tamarisk, and studied if the defoliation could be detected using two instruments on Terra, one of the National Aeronautics and Space Administration’s Earth-observing satellites.

Both instruments make images using red and near-infrared light. Plant pigments absorb red from sunlight and reflect near-infrared. In near-infrared images, tamarisk-covered areas appear red. Defoliated areas appear brown or black because there are no leaves to absorb red light and reflect near-infrared light. The two instruments are:

• ASTER, the Advanced Spaceborne Thermal Emission and Reflection Radiometer, obtains relatively high-resolution images, with each pixel covering an area about 50 feet long by 50 feet wide. It can detect big changes like tamarisk defoliation on an even smaller scale. It only obtains one to three images of a given area every summer.
• MODIS, the Moderate Resolution Imaging Spectroradiometer, which can detect less detail – a pixel measures about 820 feet by 820 feet. But it can see where large swaths of tamarisk have been defoliated, Dennison says. MODIS makes daily images.

Dennison says the infrequent, higher-resolution ASTER images allow researchers to map defoliated areas, while the frequent, lower-resolution MODIS images help them detect changes in vegetation over time.

The area studied included four sites along the Colorado River northeast of Moab, and a fifth site along the tributary Dolores River at the Entrada Field Station operated by the University of Utah for education and research. The five sites covered 589 acres, and within them, researchers mapped 56 polygon-shaped areas totaling 57 acres where tamarisk had been defoliated by the beetles.

ASTER measured what is known as NVDI – the normalized difference vegetation index, which is the difference between red light absorbed by plants and near-infrared light reflected by them. The index is high when plants are present, low when they are absent.

Those satellite measurements showed minor changes in vegetation at the test sites from 2005 to 2006, but a large change between 2006 and 2007 – indicating extensive defoliation of tamarisk, even though the defoliated plants regrow within about six weeks.

The satellite’s MODIS instrument used another vegetation index that also revealed widespread tamarisk defoliation at the five sites in July 2007.

While some tamarisk has died in Nevada where the beetles first were established, “we don’t understand whether repeated defoliation eventually will kill most of the trees, or will they reach some point where they’ll just have less leaf area over the entire year,” Hultine says.

The researchers also used the satellite to estimate “evapotranspiration” – the evaporation of water from soil and the transpiration or use of water by plants – to learn more about how defoliation of tamarisk affects water use. For comparison, Hultine measured sap flow through trees, which reflects how much water is used by the trees.

Satellite estimates of tamarisk water use declined modestly as the plants were defoliated, Dennison says. The findings also were consistent with earlier research indicating tamarisk is less of a water hog than previously thought.

Dennison says he and his colleagues did the study to test the feasibility of using satellites to monitor tamarisk defoliation on an ongoing basis. That, he says, could be done by federal agencies such as the Bureau of Land Management, Bureau of Reclamation and U.S. Geological Survey.

Source: University of Utah

New England lobstermen have gone high tech by adding low-cost instruments to their lobster pots that record bottom temperature and provide data that could help improve ocean circulation models in the Gulf of Maine.

Environmental Monitors on Lobster Traps, or eMOLT, is a partnership involving NOAA, the Maine, Massachusetts, Downeast and Atlantic Offshore Lobstermen’s Associations, the Gulf of Maine Lobster Foundation, and the Marine Science Department at Southern Maine Community College (SMCC) in Portland, Maine.

The data collected from temperature sensors on the lobster pots and from GPS surface drifters deployed as part of the eMOLT program help ocean circulation modelers better understand processes in the Gulf of Maine, such as how lobster larvae and other planktonic animals and plants, including those that cause harmful algal blooms, drift and settle. This information may also help determine how ocean currents disperse, condense and transport pollutants, invasive species, and food for whales in portions of the Gulf of Maine.

“Local fishermen already spend their days at sea, have the biggest stake in preserving our coastal marine resources, and are the most knowledgeable of the local waters,” said Jim Manning, an oceanographer at the Woods Hole Laboratory of the Northeast Fisheries Science Center (NEFSC), part of NOAA’s Fisheries Service. “They are interested, curious and enthusiastic to learn more about lobster science and the environment. It seemed like a natural fit, a win-win situation.”

Manning got the idea for eMOLT while conducting research on Georges Bank in the 1990s and seeing many lobster boats in the area. In 1995, he deployed some large moorings to collect oceanographic data, but soon recognized that this was a very expensive effort in terms of time and money. He realized lobstermen had many moorings of their own in the area at fixed locations and depths which could provide needed time-series data at more sites and at far less cost.

With the help of NEFSC port agent John Mahoney, Manning approached some local lobstermen in Sandwich and Hyannis, Mass. to see if they were interested in helping collect bottom environmental data, whenever their lobster pots were out. They agreed. The pilot project started with three lobstermen who each took the temperature-measuring devices and attached them via a plastic tie-wrap to one or two of their pots.

The devices, which cost about $150 each, internally record temperature every hour around the clock while the pots are in the water. At the end of the season when the pots are hauled out, the instruments are removed and shipped back to Manning in an envelope he provides. He downloads and processes the data and then puts the temperature information on the eMOLT web site. Each lobsterman has his/her own personal web page to see the data from their own pots, while everyone including the general public can see the overall data collected each year.

By 2000, results from the pilot study were encouraging enough for Manning to apply for funding from the Northeast Consortium to formally establish eMOLT. The Consortium has funded the project since. Each year, more lobstermen participate in the program and new instruments are tried, some with success and others that need further development.

One of the program’s successes has been low-cost surface drifters equipped with Global Positioning System (GPS) chips, developed by Manning and since 2004 built by students in the marine science program at Southern Maine Community College (SMCC). The students build about 50 drifters a year, each costing about one third that of commercially-made instruments.

“About half of the cost goes to pay the students to build the drifters, so it gives them practical working experience plus the knowledge they are participating in marine research, and the other half is used for parts and other related expenses,” Manning said. The drifters have been deployed by students and researchers in studies by a number of colleges and universities, including Bowdoin College, the University of Southern Maine, University of New Hampshire, University of New England, Endicott College, and the University of Massachusetts Dartmouth.

The Woods Hole Oceanographic Institution has deployed some of the drifters for NOAA-funded studies on harmful algal blooms, commonly called red tides, in the Gulf of Maine. Other researchers have used the drifters for oceanographic studies ranging from where coastal currents in the Gulf of Maine could spread pollutants and invasive species to the distribution of plankton and zooplankton that serve as a major food for whales and other marine life.

Manning and colleagues published drifter observations in the journal Continental Shelf Research in January 2009. The temperature observations will be published in the March 2009 issue of the Journal of Operational Oceanography.

Close to 100 lobstermen have provided sensor data since the program started, and about 60 lobstermen have been long-term active participants. Manning says he is a bit surprised but very pleased so many lobstermen are interested in the project. The eMOLT partners have contributed to a database with more than three million hourly temperature records, 80,000 salinity records, and 260,000 satellite drifter fixes (locations).

Lobsterman Jason Day of Vinalhaven, Maine heard about eMOLT from his father, Walter Day, also a lobsterman and program participant. A year-round lobsterman, Jason Day puts his traps in the water in late April or early May and hauls them out in December. He became involved with eMOLT three years ago and has one trap equipped with a temperature sensor in shallow water near Vinalhaven.

“I’m interested in what is happening on the bottom, and eMOLT helps me keep up,” Day said. “The program covers a large area and provides a lot of data at a reasonable cost.” Day says he looks at the program’s web site, and although the data has been pretty much what he expected, he occasionally sees a change that he can relate to his catch.

What’s next? Manning says the partners are working on a real-time bottom temperature sensor attached to the traps that would wirelessly transmit data via satellite once the trap is hauled on deck. They are also working on a combined tilt meter-bottom current meter with digital compass to measure both bottom currents and the angle at which the trap rests on the seafloor. The information collected should provide insight in whether bottom currents affect how lobsters move, and whether currents influence lobsters to enter a trap. In the near future, Manning would like to add sensors to measure oxygen, nutrients, and pH to determine ocean acidification levels in the region.

“There used to be a debate on the docks about whether it was cold or warm on the bottom,” Manning said of the lobstermen, whom he meets regularly at their annual meetings and who send in updates. “Now there is no debate. The lobstermen see the data for themselves over time, and can take note of trends or changes that might affect their catches. It is a baseline that helps both lobster science and the scientists and ocean circulation modelers in the Gulf of Maine who, in partnership with the eMOLT lobstermen, constitute part of our nation’s integrated ocean observing systems.”

Source: NOAA National Marine Fisheries Service

An analysis of the engineering and economics for a solar water-heating system shows it to have a payback period of just two years, according to researchers in India. They report, in the International Journal of Global Energy Issues, on the success of the 1000-liter system operating at a university hostel.

The current focus in the developed world is on advanced technological approaches to alternative energy sources, such as photovoltaic cells for solar power and harnessing wind and wave with elaborate systems to generate electricity. However, the cost of such systems may be prohibitive for some applications in the developing world. They also often ignore the fact that a mundane process such as heating water might best be carried out using direct heat from the sun rather than including a waste energy-conversion step.

Vivek Khambalkar, Sharashchandra Gadge, and Dhiraj S. Karale at the Dr Panjabrao Deshmukh Agricultural University, in Maharashtra, India, explain how they have evaluated the various costs and benefits involved in solar hot-water production. They have compared solar hot-water production per liter with electrical energy approaches and found that solar heating is 57 percent of the internal rate of return.

“Solar energy is the only renewable energy source that has wide range of uses with commercial viability. Solar energy provide water heating, air heating and electricity through various modes of applications. The use of solar energy for thermal purposes is the most cost-effective way of utilizing the resource. A solar water heating system satisfies the need of warm water,” the researchers explain.

Importantly, the payback time for the initial investment in equipment and installation is just two years. This compares very well to a photovoltaic system used for electricity generation if it were only being used to heat water. Photovoltaics have a payback period of several at least a decade and sometimes double that.

The solar hot water system used in the study is installed at the Jijau hostel, part of the Dr Panjabrao Deshmukh Agricultural University campus, in Akola, Maharashtra state, India. The team estimates that the system will effectively pay for itself five times over, given an estimated working life of about twenty years.

Source: Inderscience Publishers

Research led by the University of Warwick has found a way to use doughnuts shaped by-products of quantum dots to slow and even freeze light, opening up a wide range of possibilities from reliable and effective light based computing to the possibility of “slow glass”.

The key to this new research is the “exciton”. This describes the pairing of an electron that has been kicked into a higher energy state by a photon, with a hole or gap it (or another electron) leaves within the shell or orbit around the nucleus of an atom. Despite its new high energy state the electron remains paired with one of the holes or positions that has been vacated by electrons moving to a higher energy state. When an electron’s high energy state decays again it is drawn back to the hole it is linked to and a photon is once again emitted.

That cycle usually happens very quickly but if one could find a way to freeze or hold an exciton in place for any length of time one could delay the reemitting of a photon and effectively slow or even freeze light.

The researchers, led by PhD researcher Andrea Fischer and Dr. Rudolf A. Roemer from the University of Warwick’s Department of Physics, looked at the possibilities presented by some tiny rings of matter accidentally made during the manufacture quantum dots.

When creating these very small quantum dots of a few 10-100nm in size physicists some times cause the material to splash when depositing it onto a surface leaving, not a useful dot, but a doughnut shaped ring of material. Though originally created by accident these “Aharonov-Bohm nano rings” are now a source of study in their own right and in this case seemed just the right size for enclosing an exciton.

However simply being this useful size does not, in itself, allow them to contain or hold an exciton for any length of time.

However, remarkably the Warwick led research team have found that if a combination of magnetic and electric fields is applied to these nano-rings they can actually then simply tune the electric field to freeze an exciton in place or let it collapse and re-emit a photon.

While other researchers have used varying exotic states of matter to dramatically slow the progress of light this is the first time a technique has been devised to completely freeze and release individual photons at will.

Dr Roemer said:

“This has significant implications for the development of light based computing which would require an effective and reliable mechanism such as this to manipulate light. “

The technique could also be used to develop a “buffer” of incoming photons which could re-release them in sequence at a later date thus creating an effect not unlike the concept of “Slow Glass” first suggested by science fiction author Bob Shaw several decades ago.

Source: University of Warwick

Credit: Drawing: Justus Liebig University, H. Felle

Using ion-selective micro-electrodes electrical signals in plants moving from leaf to leaf could be measured. The speed of the signals spreading as voltage changes over cell membranes ranged from 5 to 10 cm per minute. The scientists discovered this new kind of electrical signal transmission system by applying a novel method: Filamentary electrodes were inserted through open stomata directly into the inner leaf tissue and then placed onto the cell walls (see picture). Stomata are microscopically small openings in the leaf surface which plants facilitate regulating evaporation and gas exchange.

The scientists found out that the new electrical signal they called “system potential” was induced and even modulated by wounding. If a plant leaf is wounded, the signal strength can be different and can be measured over long distances in unwounded leaves, depending on the kind and concentration of added cations (e.g. calcium, potassium, or magnesium). It is not the transport of ions across cell membranes that causes the observed changes in voltage transmitted from leaf to shoot and then to the next leaf, but the activation of so-called proton pumps. “This is the reason why the “system potential” we measured cannot at all be compared to the classic action potential as present in nerves of animals and also in plants”, says Hubert Felle from Gießen University. Action potentials follow all-or-none characteristics: they are activated if a certain stimulus threshold is reached and then spread constantly. The “system potential”, however, can carry different information at the same time: The strength of the inducing stimulus (wound signal) can influence the amplitude of the systemic signal as well as the effect of different ions. “We may be on the trail of an important signal transmission system that is induced by insect herbivory. Within minutes the whole plant is alerted and the plant’s defense against its enemy is activated”, says Axel Mithöfer from the Max Planck Institute for Chemical Ecology in Jena.

The novel “system potential” was detected in five different plant species, among them agricultural crops like tobacco (Nicotiana tabacum), maize (Zea mays), barley (Hordeum vulgare), and field bean (Vicia faba).

Source: Max Planck Institute for Chemical Ecology

Credit: Lisa Britton/UC photographic services

The University of Cincinnati has long been known for its world-record-breaking carbon nanotubes. Now researchers at the University of Cincinnati have discovered new uses by spinning carbon nanotubes (CNTs) into longer fibers with additional useful properties.

Breakthroughs Without Broken Threads

Taking technology that has already been proven to grow carbon nanotubes of world-record breaking lengths, researchers Vesselin Shanov and Mark Schulz in the UC College of Engineering NanoWorld Lab have now found new applications by spinning these fibers into strong threads.

David Mast, from UC’s McMicken College of Arts and Sciences, saw possibilities in the threads. Mast, an associate professor of physics, took a 25-micron carbon nanotube thread and created a dipole antenna using double-sided transparent tape and silver paste. He was immediately successful in transmitting radio signals.

Mark Schulz, David Mast and Vesselin Shanov (left to right) from the University of Cincinnati have created new applications for spun carbon nanotubes for both military and consumer use.

Credit: Lisa Britton/UC photographic services

“It transmitted almost as well as the copper did, but at about one ten-thousandth of the weight,” says Mast.

“Then I decided to dismantle my cell phone,” says Mast. He created a cell phone antenna, using CNT thread and tape. Ripping the back off his own cell phone, he tore out the phone’s original antenna and replaced it with his home-made one. With the “nano-antenna” or “nantenna,” he was able to get four to five “bars” of service, compared to none when he removed it.

“That was a very pleasant surprise, how easy it was to do,” Mast says. “The hardest thing is to manipulate them. They float on ambient air.”

From there it was an easy leap to video, in which he was again successful. “I want to now set up a wireless webcam for the lab using these thread antennas so

University of Cincinnati physicist David Mast replaced the antenna in his cell phone with a “nano antenna” made from spun carbon nanotubes, made in the UC labs of Mark Schulz and Vesselin Shanov.

Credit: Lisa Britton/UC Photographic Services

Mast says that the key to the new applications is the quality of the material that Schulz and Shanov came up with using multi-wall carbon nanotubes.

“They spin thread that is of such high quality, it opens the door to incredible possibilities,” says Mast. “This is just one of many potential applications.”

Schulz explains that the carbon nanotube threads work well as an antenna because of something called the “skin effect.”

“The electrons transfer well because they want to go to the surface,” he says. “Instead of traveling through a bulk mass, they are traveling across a skin.”

“Copper wire is a bulk material,” Shanov points out. “With carbon nanotubes, all the atoms are on the surface of these carbon structures and the tubes themselves are hollow, so the CNT thread is small and light.”

“Carbon thread that is a fraction of the weight of current copper conductors and antennas could directly apply and would be significant to aerospace activities — commercial, military and space,” he adds. “On any aircraft, there are about several hundred pounds of copper as cables and wiring.”

Mast points out that the threads have what he calls an “immensely high tensile strength — perhaps five times that of steel and yet they are less dense than steel.”

Now that the team has shown the feasibility of such applications, the next steps will be to work on improvements (such as making yarn out of several threads) and to find industries that will commercialize CNT thread.

Mast’s next step was going to be to buy a new cell phone. However, he says, “it works so well now that I decided to just upgrade to a new antenna made of carbon nanotube yarn.”

Source: University of Cincinnati

Madison, WI, March 6, 2009 — As the first plant life to emerge from the water and develop on dry earth, bryophytes offer a unique opportunity for researchers to understand the development of protections against ultraviolet radiation. The three varieties of bryophites (liverworts, hornworts, and mosses) have long been utilized as indicators of the health of local environments, but with the recent effects of climate change and the depleting ozone layer, these plants present an important measure in their ability to withstand increased exposure to UVR.

Recently, a new experiment studying bryophytes was applied at a large-enrollment undergraduate biology course at Minnesota State University. The laboratory exercise introduced students to the impacts of ultraviolet radiation on plant populations using a readily accessible and easily propagated liverwort.

The article detailing the effectiveness of the experiment, authored by Linda Fuselier and Nicole True, was published in the Journal of Natural Resources and Life Sciences Education.

The lab exercise focused on ultraviolet radiation impacts on liverwort asexual propagules, and students were required to formulate and test a hypothesis based on background reading related to impacts of ultraviolet radiation on ecological systems and humans. The experiment was also designed to improve student’s computational skills, expand their repertoire of statistical techniques, and provide an introduction to writing a full, formal lab report in the form of a “brief communication” for a scientific journal.

The researchers believe that studying the effects of ultraviolet radiation on bryophytes can help scientists understand its impacts on crops and other natural plant communities. Because plants to not have the same ability to move out of direct harm from ultraviolet radiation, they have developed a variety of systems to reduce its impacts through evolution. As bryophytes were the first plants to emerge from aquatic life, they represent a key link in this evolution.

As bryophytes are among the least understood plant life despite their abundance, another of the experiment’s goals was to familiarize students with their history of development and their functions within an environment. In addition, students also gained greater experience with experimental methods and reporting statistics in lab reports. A majority of students agreed that these goals were met.

Source: American Society of Agronomy

WASHINGTON – College women may be drinking to excess to impress their male counterparts on campuses across the country, but a new study suggests most college men are not looking for a woman to match them drink for drink.

A survey of 3,616 college students at two American universities found an overwhelming majority of women overestimated the amount of alcohol a typical guy would like his female friends, dates or girlfriends to drink. The results can be found in the March issue of Psychology of Addictive Behaviors, published by the American Psychological Association.

“Although traditionally, men drink more than women, research has shown that women have steadily been drinking more and more over the last several decades,” said the study’s lead author, Joseph LaBrie, PhD, associate professor of psychology at Loyola Marymount University. “Our research suggests women believe men find excessive drinking sexually attractive and appealing, but it appears this is a giant misperception.”

For this article, the researchers invited the participating students, ages 18 to 25, to complete an online survey during the 2007 fall semester. The students were at Loyola Marymount University in Los Angeles or the University of Washington. The women answered several questions to determine, on average, how many drinks they thought a typical college man would like his female friends to drink at a typical event, as well as the maximum number of drinks they thought the men would like their female friends to drink. They then had to say, on average, how many drinks they thought a woman would have to consume for a guy to consider being friends with her, consider dating her or consider her sexually attractive. The men were asked their actual preferences.

The researchers also asked the women to estimate how much they drank in any given week or month, and how much alcohol they thought the average woman at their university drank in any given week.

The results showed 71 percent of women overestimated the men’s actual preference of drinks at any given event. The women overestimated by an average of one-and-a-half drinks. When the researchers looked at the different subgroups, 26 percent of women said that men would most likely want to be friends with a woman who drinks five or more drinks and 16 percent said that men would be most sexually attracted to a woman who drank that much alcohol. Both estimates were nearly double what the men actually preferred. They also found the women who overestimated the men’s preferences were more likely to engage in excessive drinking.

“There is a great, and risky, disconnect here between the sexes,” said LaBrie. “While not all women may be drinking simply to get a guy’s attention, this may help explain why more women are drinking at dangerous levels. We believe universities and other public health organizations could use this information to help curb binge drinking among young women.”

LaBrie is doing a follow-up study that looks at what men think women want them to drink to see if this perception has a similar effect on increased risky drinking.

Source: American Psychological Association

BOZEMAN, Mont. — Arsenic may be tough, but scientists have found a Yellowstone National Park alga that’s tougher.

The alga — a simple one-celled algae called Cyanidioschyzon — thrives in extremely toxic conditions and chemically modifies arsenic that occurs naturally around hot springs, said Tim McDermott, professor in the Department of Land Resources and Environmental Sciences at Montana State University.

Cyanidioschyzon could someday help reclaim arsenic-laden mine waste and aid in everything from space exploration to creating safer foods and herbicides, the scientists said.

The alga and how it detoxifies arsenic are described in a paper that’s posted this week (week of March 9) in the online edition of Proceedings of the National Academy of Sciences, or PNAS. Lead authors are McDermott and Barry Rosen, of Florida International University. Among the four co-authors is Corinne Lehr, who formerly worked with McDermott as a postdoctoral scientist at MSU and is now a faculty member at California Polytechnic State University.

Arsenic is the most common toxic substance in the environment, ranking first on the Superfund list of hazardous substances, the researchers wrote in their paper. McDermott said arsenic is very common in the hot, acidic waters of Yellowstone and presents real challenges for microorganisms living in these conditions. Indeed, there are challenges for the researchers. McDermott said the acid in the soil and water are strong enough that it sometimes eats holes through his jeans when he kneels to collect samples.

McDermott has worked in Yellowstone for more than a decade and travels year-round to the Norris Geyser Basin to study the microbial mats that grow in acidic springs. Over the years, he noticed thick algae mats that were so lush and green in December that they looked like Astro-Turf, McDermott said. By June, they were practically gone. While investigating the change, McDermott and his collaborators learned about the Cyanidiales alga and its ability to reduce arsenic to a less dangerous form.

“These algae are such a dominant member of the microbiology community that they can’t escape notice, but for some reason they have not attracted much attention,” McDermott said.

The Cyanidioschyzon algae grow all over Yellowstone, but the researchers concentrated on the Norris Geyser Basin, McDermott said. The alga thrives in water up to 135 degrees Fahrenheit (too hot to shower) with a very acidic pH factor ranging from 0.5 to 3.5. Creeks are considered acidic if their pH factor is less than 7.

“These algae live in areas of Yellowstone that are extremely toxic with respect to arsenic,” McDermott said. “You couldn’t drink these waters even if you changed their pH.”

The scientists cloned genes from the alga, then studied the enzymes to figure out how they transformed arsenic. They learned that the alga oxidizes, reduces and converts arsenic to several forms that are less toxic than the original.

Rosen said one significant form is a gas that can evaporate, especially at the high temperatures of the Yellowstone springs. That allows life to exist in “really deadly concentrations of arsenic,” he said.

“It gives us insight into how life adapts to extreme environments,” Rosen added. “If life can grow at high temperatures and high concentrations of heavy metals like arsenic, life might be able to evolve on other planets or moons such as Titan or Enceladus.”

McDermott said the scientists conducted basic research that may have implications someday for acid mine drainage and acid rock drainage remediation efforts.

“Any time you learn anything about eukaryotic algae and their potential application for bioremediation, that’s always good,” he said.

Eukaryotic refers to microorganisms that have cells with membranes enclosing complex structures. Cyanidioschyzon is a simple one-celled organism classified as a red algae.

Rosen added that the alga they studied is a primitive plant, so it might shed light on how plants can tolerate arsenic, which is used in several types of herbicides. The knowledge they gained could also be used someday to help create a new type of rice.

“Some plants, such as rice, accumulate high concentrations of arsenic. This endangers our food supply,” Rosen explained. “Rice with high amounts of arsenic won’t kill anyone quickly, but does increase the risk of cancers such as bladder cancer.”

McDermott said when he first thought about investigating the changing colors in the Yellowstone algae mats, he figured that something more than photosynthesis had to be involved. He thought altitude and latitude played a role. Some of the hot springs have no trees around them, so he wondered if the intense June sun was hammering the algae.

Molecular evidence suggests that the algae in these springs are comprised of two different population groups, McDermott said. One flourishes in the winter and the other in the summer. The algae that dominates in the summer can apparently tolerate high levels of ultraviolet rays.

Source: Montana State University