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Showing posts with label INVASIVE SPECIES. Show all posts
Showing posts with label INVASIVE SPECIES. Show all posts

Description of Telamoptilia grewiae sp. n. and the consequences for the definition of the genera Telamoptilia and Spulerina (Lepidoptera, Gracillariidae, Gracillariinae)

Written By Unknown on Tuesday, February 3, 2015 | 7:36 PM

Adult, host plant and mines of Telamoptilia grewiae sp. n. 1 Adult in habitus, paratype 2 Live adult 3 Host plant 4 Linear mines by early instar larvae 5 Blotch mine by later instar larva 6 Seriously damaged leaves found in September. Credit: Zookeys

The genus Telamoptilia Kumata & Kuroko, 1988 is globally represented by five species that may be found in the Oriental and African regions. The type species T. cathedraea (Meyrick, 1908) is geographically shared by the Oriental Region and Madagascar (De Prins and De Prins 2014). Three species are currently known from China, including T. cathedraea, T. hemistacta (Meyrick, 1924), and T. prosacta (Meyrick, 1918).

The larvae of Telamoptilia species are leaf miners. Three plant families are known as hosts for Telamoptilia: Malvaceae, Amaranthaceae and Convolvulaceae (De Prins and De Prins 2014). Vári (1961) briefly described the biology of T. geyeri (Vári, 1961). Kumata et al. (1988) described the biology and the larval body chaetotaxy of three species: T. cathedraea, T. prosacta and T. tiliae (Kumata & Ermolaev, 1988). However, no larval head chaetotaxy and pupal features of Telamoptilia have been described so far.

Telamoptilia grewiae sp. n. is associated with Malvaceae and is described in the present paper from adult external characters, male and female genitalia, wing venation and immature stages. The larval head and pupal features are described for the first time in Telamoptilia.

Methods

Field investigations were carried out in Mt. Baxian National Nature Reserves (40°11'N, 117°32'E), 300−600 m, Tianjin, China, from May to September in 2013 and June 2014. Leaves containing mines with larvae were placed in sealed plastic bags, or rearing containers with moist cotton. Larvae removed from mines were immersed in nearly boiling water for 30 seconds, and then were kept in 75% ethanol for morphological examination. Last instar larval skins, pupae, and exuviae were kept in 75% ethanol. Pupae in rearing containers were placed outdoors to overwinter, and were transferred into the laboratory at 20 °C on February 6, 2014. Emergence successively occurred from March 9 to early-April 2014. Adults were collected chiefly by rearing from immature stages, and occasionally by light trap.

Adult photographs were taken with a Leica M250A stereo microscope. Genitalia and wings were dissected and mounted according to the methods introduced by Li (2002), but stained with Eosin Y and/or Chlorazol Black, and the illustrations were prepared by using a Leica DM750 microscope, and refined in Photoshop® CS4 software. For scanning electron microscopy, larvae and pupae were dehydrated in gradient ethanol, dried in vacuum and coated with gold in a SCD 005 Sputter Coater (BAL-TEC), then operated with a voltage of 15 kV using Quanta 200 environmental scanning electron microscope (SEM) (FEI, Oregon). Line drawings were outlined from the photos taken by the Leica M250A stereo microscope, using path tool in Adobe Photoshop® CS4 software. Photographs of host plant, mines and a live adult were taken in the field using Canon PowerShot G10 digital camera.

Terminology of immature stages follows Davis and De Prins (2011) and De Prins et al. (2013), and that of adults follows Kumata et al. (1988). Thoracic segments I−III and abdominal segments 1−10 are abbreviated as TI−TIII and A1−A10, respectively.

All the specimens studied, including the types of the new species and the vouchered larvae and pupae, are deposited in the Insect Collection, Nankai University, Tianjin, China.

Taxonomy

Adults (Figs 1–2) with wing span 6.0−8.0 mm. Head silvery white, tinged with gray on face. Labial palpus grayish white, colored blackish gray on outer surface of distal half of second segment and before apex of third segment. Maxillary palpus white, with middle or distal half blackish fuscous. Antenna with scape white on posterior half, blackish gray on anterior half and distal portion, flap blackish gray tinged with white, as wide as scape in frontal view; flagellum silvery grayish fuscous, with each unit blackish distally. Thorax and tegula blackish gray mixed with white. Legs mostly white; foreleg with coxa blackish fuscous basally and distally, femur and tibia blackish fuscous, tarsus blackish gray distally on each except last segment; midleg with coxa blackish fuscous distally, femur blackish fuscous, except white medially and distally on dorsal surface, with ventral scale expansion blackish fuscous, tibia blackish fuscous basally and distally, white medially, tarsus white, each except last segment dotted blackish fuscous distally; hindleg with coxa blackish fuscous distally, femur blackish fuscous distally on outer surface, tibia blackish fuscous basally and distally, tarsus with basal three segments blackish fuscous distally, fourth segment dotted blackish fuscous dorso-distally. Forewing grayish fuscous to blackish fuscous; costal margin with a white spot basally at about 1/10 and one before apex, the former sometimes touching fold posteriorly, with white stria at distal 3/10 and 1/6 obliquely outward, reaching middle of wing and near termen respectively; transverse white fascia from costal 1/3 and 1/2 obliquely outward, reaching dorsal 1/2 and before end of fold respectively, edged with blackish fuscous to black scales, inner fascia wider than outer one, widened on posterior half; small white dot on distal end of M3, two or three small white dots along termen; apex blackish fuscous; cilia mostly blackish fuscous basally, gray distally, white adjacent to white markings, white on basal 1/4, black on median part, gray distally at apex, gray along dorsal margin. Hindwing and cilia uniformly gray.

Source: Read Full Artical at - ZOOKEYS

Why do zebras have stripes?

Written By Unknown on Saturday, January 31, 2015 | 7:19 PM

A mother zebra with a foal in Tanzania’s Tarangire National Park. Credit: Brenda Larison/UCLA
One of nature’s fascinating questions is how zebras got their stripes.

A team of life scientists led by UCLA’s Brenda Larison has found at least part of the answer: The amount and intensity of striping can be best predicted by the temperature of the environment in which zebras live.

In the January cover story of the Royal Society’s online journal, Open Science, the researchers make the case that the association between striping and temperature likely points to multiple benefits — including controlling zebras’ body temperature and protecting them from diseases carried by biting flies.

“While past studies have typically focused their search for single mechanisms, we illustrate in this study how the cause of this extraordinary phenomenon is actually likely much more complex than previously appreciated, with temperature playing an important role,” said Thomas B. Smith, professor of ecology and evolutionary biology in the UCLA College and senior author of the research.

Larison, a researcher in UCLA’s department of ecology and evolutionary biology and the study’s lead author, and her colleagues examined the plains zebra, which is the most common of three zebra species and has a wide variety of stripe patterns. On zebras in warmer climes, the stripes are bold and cover the entire body. On others — particularly those in regions with colder winters such as South Africa and Namibia — the stripes are fewer in number and are lighter and narrower. In some cases, the legs or other body parts have virtually no striping.

Zebras evolved from horses more than 2 million years ago, biologists have found. Scientists have previously hypothesized that zebras’ stripes evolved for one, or a combination of, four main reasons: confusing predators, protecting against disease-carrying insects, controlling body temperature and social cohesion. And while numerous previous studies of the phenomenon focused on a single hypothesis, the Larison-led study was the first to fully test a large set of hypotheses against one another.

Analyzing zebras at 16 locations in Africa and considering more two dozen environmental factors, the researchers found that temperature was the strongest predictor of zebras’ striping. The finding provides the first evidence that controlling body temperature, or thermoregulation, is the main reason for the stripes and the patterns they form.
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Separate research by Daniel Rubenstein, a Princeton University professor of ecology and evolutionary biology and a co-author of the Open Science paper, and Princeton undergraduate Damaris Iriondo strongly suggests that boldly striped zebras have external body temperatures about five degrees Fahrenheit cooler than other animals of the same size — like antelopes — that do not have stripes but live in the same areas. The Rubenstein study is not yet published, but it is cited in the Open Science paper.

Larison has studied many zebras during her field work throughout Africa — including in Kenya, South Africa, Tanzania, Uganda and Zimbabwe. Using the fact that their stripes are unique like fingerprints, she is able to distinguish one zebra from another.

In addition to Rubenstein, arguably the world’s leading expert on zebras, the study’s co-authors were Alec Chan-Golston and Elizabeth Li, former UCLA undergraduates in mathematics; Ryan Harrigan, an assistant adjunct professor in UCLA’s Center for Tropical Research; and Henri Thomassen, a former UCLA postdoctoral scholar and current research associate at the Institute for Evolution and Ecology at Germany’s University of Tübingen.

The research was supported by the National Geographic Society Committee for Research and Exploration.

Larison and her research team have also collected zebra tissue samples and have used cutting-edge technology to sequence zebra DNA to try to identify which genes code for striping. The team is continuing to study the benefits stripes provide.

Source: UCLA

Physicians seeing increase in brown recluse spider bites

Written By Unknown on Thursday, December 25, 2014 | 2:29 AM

The brown recluse spider has a violin-shaped marking on its back. Credit: CDC image library
Vanderbilt medical toxicologists are reporting an increase in patients seen with brown recluse spider bites this summer.

The venomous bites usually heal well if left alone, according to Tennessee Poison Center Medical Director Donna Seger, M.D., but there are so many urban legends about these bites, patients frequently apply many treatments before seeking medical advice.

There are two components to spider bites -- the cutaneous lesion and, more rarely, the systemic symptoms that can occur following the bite. The syndrome known as systemic loxsoscelism consists of brown recluse spider bites accompanied by a fever, rash, muscle pain, with or without hemolysis (breaking down of red blood cells), which can be life threatening, especially in children, Seger said.

"Our recommendations are that all children under 12 with a brown recluse spider bite should have a urine test for the presence of hemoglobin in blood which indicates hemolysis," Seger said.

"If the urine is positive for blood and/or the child has other signs of systemic loxsoscelism (rash, fever), the child should be admitted and observed for hemolysis. If the urine dip is negative, and there are no other signs of systemic loxsoscelism, the child should be seen by a physician the next day."

If adults with a brown recluse spider bite do not have rash, fever or muscle pain there is no need to do a urine test, Seger said.

"As physicians, it is hard for us to do nothing. The cutaneous lesion has classic characteristics, but if physicians are not familiar with this bite, the tendency is to debride and cut out the lesion. This actually slows the healing process and can result in disfigurement that would not occur if the lesion were left alone. Ointments, antibiotics, and dapsone are not recommended. Ice works better than opiates for pain," Seger said.

"We don't know why systemic loxsoscelism occurs in some people with a brown recluse spider bite and not in others but it is life-threatening and does require immediate medical attention. Toxin-induced hemolysis can occur very rapidly and therein lies the life threat, especially in children."

The brown recluse spider, also known as the violin spider, is usually between 6-20 mm. It is typically light to medium brown but can range in color from cream-colored to dark brown or blackish gray. It has six eyes instead of eight and can be identified by the violin-shaped marking on its back.

Source: Vanderbilt University Medical Center

Potential biological control for avocado-ravaging disease

Written By Unknown on Tuesday, December 23, 2014 | 8:47 AM

University of Florida scientists think they’ve found the first potential biological control strategy against laurel wilt, a disease that threatens Florida’s avocado industry. The redbay ambrosia beetle, see here, bores holes into avocado trees, bringing the disease that causes laurel wilt. Credit: Lyle Buss, UF/IFAS
University of Florida scientists believe they've found what could be the first biological control strategy against laurel wilt, a disease that threatens the state's $54 million-a-year avocado industry.

Red ambrosia beetles bore holes into healthy avocado trees, bringing with them the pathogen that causes laurel wilt. Growers control the beetles that carry and spread laurel wilt by spraying insecticides on the trees, said Daniel Carrillo, an entomology research assistant professor at the Tropical Research and Education Center in Homestead.

But a team of researchers from the Tropical REC and the Indian River Research and Education Center in Fort Pierce have identified a potential biological control to use against redbay ambrosia beetles that could help growers use less insecticide.

First, they exposed beetles to three commercially available fungi, and all of the beetles died. Then they sprayed the fungi on avocado tree trunks, and beetles got infected while boring into the trunk. About 75 percent of those beetles died, said Carrillo, an Institute of Food and Agricultural Sciences faculty member.

Ideally, the fungal treatments could prevent beetles from boring into the trees, eliminating the risk that the pathogen would enter the trees, the study said. But tests showed female beetles bored into the trees and built tunnels regardless of the treatment. Still, researchers say their treatment can prevent the female beetles from laying eggs.

UF/IFAS scientists don't know yet how much less chemical spray will be needed to control the redbay ambrosia beetle. But Carrillo sees this study as the first step toward controlling the beetle in a sustainable way.

"When you want to manage a pest, you want an integrated pest management approach," Carrillo said. "This provides an alternative that we would use in combination with chemical control."

The redbay ambrosia beetle -- native to India, Japan, Myanmar and Taiwan -- was first detected in 2002 in southeast Georgia. It was presumably introduced in wood crates and pallets, and its rapid spread has killed 6,000 avocado trees in Florida, or about 1 percent of the 655,000 commercial trees in Florida. The beetle was first discovered in South Florida in 2010.

Most American-grown avocados come from California, with the rest coming from Florida and Hawaii. The domestic avocado market is worth $429 million, according to Edward Evans, a UF associate professor of food and resource economics, also at the Tropical REC. Florida's avocados are valued at about $23 million, or about 5 percent of the national market.

The redbay ambrosia beetle is not an issue with California avocados, so the new tactic found by Florida scientists wouldn't apply to this pest in the Golden State, said Mark Hoddle, a biological control Extension specialist with the University of California-Riverside. Hoddle studies biological pest control for California avocados. Scientists there are exploring ways to control a different ambrosia beetle, he said, and bug-killing fungi may be useful for the new California pest.

More than 95 percent of Florida's commercial avocados grow in Miami-Dade County, although many Floridians have avocado trees in their yard.
The redbay ambrosia beetle feeds and reproduces on a very wide variety of host plants, native oaks, sycamores, and of course it is very detrimental to avocados.

Source:University of Florida Institute of Food and Agricultural Sciences

Colorado's Front Range fire severity not much different than past

Written By Unknown on Saturday, December 20, 2014 | 5:19 AM

A new study indicates present-day forest fires on Colorado's Front Range are not significantly more intense than historical fires. Credit: Glenn Asakawa, University of Colorado
The perception that Colorado's Front Range wildfires are becoming increasingly severe does not hold much water scientifically, according to a massive new study led by the University of Colorado Boulder and Humboldt State University in Arcata, Calif.

The study authors, who looked at 1.3 million acres of ponderosa pine and mixed conifer forest from Teller County west of Colorado Springs through Larimer County west and north of Fort Collins, reconstructed the timing and severity of past fires using fire-scarred trees and tree-ring data going back to the 1600s. Only 16 percent of the study area showed a shift from historically low-severity fires to severe, potential crown fires that can jump from treetop to treetop.

The idea that modern fires are larger and more severe as a result of fire suppression that allowed forest fuels to build up in the past century is still prevalent among some, said CU-Boulder geography Professor Thomas Veblen, a study co-author. "The key point here is that modern fires in these Front Range forests are not radically different from the fire severity of the region prior to any effects of fire suppression," he said.

A paper on the subject was published Sept. 24 in the journal PLOS ONE. The study was led by Associate Professor Rosemary Sherriff of Humboldt State University and involved Research Scientist Tania Schoennagel of CU-Boulder's Institute of Arctic and Alpine Research, CU-Boulder doctoral student Meredith Gartner and Associate Professor Rutherford Platt of Gettysburg College in Gettysburg, Pa.

The study was funded by the National Science Foundation.

"The common assumption is that fires are now more severe and are killing higher percentages of trees," said Sherriff, who completed her doctorate at CU-Boulder under Veblen in 2004. "Our results show that this is not the case on the Front Range except for the lowest elevation forests and woodlands."

One important new finding comes from a comparison of nine large fires that have occurred on the Front Range since 2000 -- including the 2002 Hayman Fire southwest of Denver, the 2010 Fourmile Canyon Fire west of Boulder and the 2012 High Park Fire west of Fort Collins -- with historic fire effects in the region.

"It's true that the Colorado Front Range has experienced a number of large fires recently," said Schoennagel. "While more area has burned recently compared to prior decades -- with more homes coming into the line of fire -- the severity of recent fires is not unprecedented when we look at fire records going back before the 1900s."
In addition, tree-ring evidence from the new study shows there were several years on the Front Range since the 1650s when there were very large, severe fires. The authors looked at more than 1,200 fire-scarred tree samples and nearly 8,000 samples of tree ages at 232 forest sample sites from Teller County to Larimer County.
The study is one of the largest of its kind ever undertaken in the western United States. The team was especially interested in fire records before about 1920, when effective fire suppression in the West began in earnest.

"In relatively dry ponderosa pine forests of the West, a common assumption is that fires were relatively frequent and of low severity, and not lethal to most large trees, prior to fuel build-up in the 20th century," said Veblen. "But our study results showed that about 70 percent of the forest study area experienced a combination of moderate and high-severity fires in which large percentages of the mature trees were killed."

Along the Front Range, especially at higher elevations, homeowners and fire managers should expect a number of high-severity fires unrelated to any kind of fire suppression and fuel build-up, said Schoennagel. "This matters because high-severity fires are dangerous to people, kill more trees and are trickier and more expensive to suppress."

"Severe fires are not new to most forests in this region," said Sherriff. "What is new is the expanded wildland-urban interface hazard to people and property and the high cost of suppressing fires for society."

In addition, a warming Colorado climate -- 2 degrees Fahrenheit since 1977 -- has become a wild card regarding future Front Range fires, according to the team. While fires are dependent on ignition sources and can be dramatically influenced by high winds, the team expects to see a substantial increase in Front Range fire activity in the low and mid-elevations in the coming years as temperatures continue to warm, a result of rising greenhouses gases in Earth's atmosphere.

Source: University of Colorado at Boulder

Mountain pine beetles get bad rap for wildfires, study says

Following wildfires in 2011, a UW-Madison research team studied lodgepole pine trees in the Northern Rocky Mountains to examine whether earlier outbreaks of mountain pine beetles changed the ecological impact of the wildfires. Credit: Turner Lab
Mountain pine beetles get a bad rap, and understandably so. The grain-of-rice-sized insects are responsible for killing pine trees over tens of millions of acres in the Western U.S. and Canada over the last decade.

But contrary to popular belief, these pests may not be to blame for more severe wildfires like those that have recently swept through the region. Instead, weather and topography play a greater role in the ecological severity of fires than these bark-boring beetles.

New research led by the University of Wisconsin-Madison and the Washington State Department of Natural Resources provides some of the first rigorous field data to test whether fires that burn in areas impacted by mountain pine beetles are more ecologically severe than in those not attacked by the native bug.
In a study published this week in the Proceedings of the National Academy of Sciences, UW-Madison zoology professor Monica Turner and her graduate student, Brian Harvey, show pine beetle outbreaks contributed little to the severity of six wildfires that affected more than 75,000 acres in the Northern Rocky Mountains in 2011. They also show that the beetle outbreaks, which occurred from 2000 through 2010, have not directly impacted post-fire recovery of the forests. The study does not, however, address fire behavior, such as how quickly fires spread or how dangerous they are to fight.
While the findings may exonerate the insect scapegoats, they should also help ecosystem managers better respond to changes in the face of climate-driven disturbances, like drought and warmer temperatures.

Large, severe fires are typical in the lodgepole pine forests found throughout the region, even without mountain pine beetle outbreaks. However, as the climate has warmed, outbreaks and big fires have both become more common. The phenomenon of more beetles has meant more dead trees, and some have grown concerned about how beetle attacks and wildfires may interact.

"The conventional wisdom is that a forest of dead trees is a tinder box just waiting to burn up," says Turner, who has long studied the forest landscape of the Mountain West. "There were very little data out there but a lot of concern."

Forests attacked by bark beetles -- which burrow into the bark of lodgepole pines to mate and incubate their larvae -- can seem nothing more than ample kindling for a raging blaze, with their dead wood and dry, reddish-brown needles.

The burrows the beetles carve under the bark of pines, called galleries, choke off water and nutrient circulation in the trees. The trees die and, for the first couple of years, they hold on to their dry, lifeless needles. Scientists call this the "red stage," and some believe these trees could fuel more severe fires.

By year three, most beetle-attacked trees have entered the "gray stage," dropping their once green pine foliage, becoming needleless wood carcasses.

Earlier studies from Turner's group suggested that beetle outbreaks would not lead to more severe fires. But without actual fires, the interaction could not be tested.

However, in 2011, wildfires throughout eastern Idaho and western Montana -- in forests that had experienced varying mountain pine beetle outbreak impacts -- provided opportunity for the research team to begin to answer the question: Do the two disturbances, beetle attacks and wildfire, together change the ecological response of the forest to fire?

Fortunately for the team, among the burned areas studied were pine stands that had not been attacked by beetles. These areas served as controls. Others suffered a range of mortality from the beetles; in some stands, beetles killed nearly 90 percent of the trees prior to wildfire. The fires that raged also ran the spectrum of severity, allowing the researchers to compare a number of variables.

Some study plots comprised mostly live trees, while others contained mostly red-stage or gray-stage trees -- allowing the researchers to assess whether plots with red-stage trees (with dry needles) experienced greater levels of fire severity than plots with mostly gray-stage trees (no needles), as they and others had expected.

The study team examined ecosystem indicators of fire severity, such as how many trees were killed by fire and how much char covered the forests.

Engaging in what Harvey calls "post-fire detective work," in 2012, the scientific team evaluated fire severity in each study plot and stripped sections of bark from over 10,000 trees to determine what killed them, beetles or fire. Beetle galleries can remain visible under the bark even after fire.

As they sifted through the blackened trees and forest floor, the team became covered with ash and soot.

"We looked like coal miners when we were done," says Harvey.

They found that the severity of the outbreak and whether trees were in the red or gray stage had almost no effect on fire severity under moderate burning conditions.

Only under more extreme fire-burning conditions -- when it was hot, dry and windy -- did areas with more beetle-killed trees show signs of more ecologically severe fires, such as more deeply burned trunks and crowns (the part of the tree that includes its limbs and needles). The presence of more gray-stage trees actually had a stronger impact on fire severity than the amount of red-stage trees, to the surprise of the scientists.

Overall, however, Turner says the effects of beetle outbreaks on fire severity took a back seat to stronger drivers -- primarily weather and topography. Fire severity increased under more extreme weather, regardless of pre-fire outbreaks, and forest stands higher in the landscape burned more severely than those at lower elevation as fires moved uphill, building momentum.

"No one says beetle-killed forests won't burn," says Turner. "The data set looks at whether they burn with different severity compared to unattacked forests burning under similar conditions."

The team was also interested in whether beetle outbreaks slowed the recovery of the forests after fires. Lodgepole pines are adapted to fire, containing two types of seed-carrying cones: those that release seeds as soon as they mature and those that require fire to open, blanketing the forest floor with potential new life following a blaze.

By counting the number of post-fire tree seedlings in their plots, the researchers found very little beetle-related impact. Tree seedlings were most numerous where more of the fire-killed trees bore the fire-adapted, or serotinous, cones. Beetle-killed trees likely contributed to post-fire seedling establishment, too, as their seeds remain viable in cones if they are not consumed in fire. Only high-reaching char from tall flames reduced the number of seed-spreading cones.

The scientists emphasize the results may differ in other forest types or with different lengths of time between beetle outbreaks and fire.

"These are both natural disturbances, fire and beetle outbreaks," says Turner. "It's not surprising the ecosystem has these mechanisms to be resilient. What we as people see as catastrophes are not always catastrophes to the ecosystem."

Invasive plant wins competition against its native cousin

This iamge depicts root nodules. Credit: University of Illinois
Because of its aggressive behavior and its harmful effects, the invasive prairie plant Lespedeza cuneata has been added to several noxious weed lists. Research at the University of Illinois on how soil bacteria interact with the plants' roots to form nodules that fix nitrogen demonstrated that the invasive variety had superior performance when pitted against the native plant variety Lespedeza virginica.

"We expected Lespedeza cuneata to be a strong competitor when up against its native cousin that's planted primarily for prairie restoration," said U of I microbial ecologist Tony Yannarell. "There are a number of studies showing that L. cuneata grows quickly, is able to shade out its competitors, and has a high rate of nitrogen fixation, which allows it to 'self-fertilize' on unproductive soils."
Yannarell explained that Lespedeza plants establish a "partnership" with bacteria in the soil to form nodules that fix nitrogen. "We wanted to demonstrate that the partners in this symbiosis matter," he said.
Because the nitrogen-fixing gene is in the bacteria, the first step in the research was to identify bacteria that have the gene. "We started with isolating a pool of 50 bacteria [from the root nodules of invasive and native Lespedezas] and discovered that some of them weren't traditional nodule-forming bacteria."

Ultimately, seven bacteria were identified and used in a three-month greenhouse experiment in which various combinations of native and invasive varieties of Lespedeza were grown together in pots. Of the seven, five bacteria were found to benefit the invader and two did not benefit either of the plant varieties.

"We were hoping to be able to change the degree of competitiveness by using different varieties of Lespedeza by varying the bacteria," Yannarell said. "It turned out that none of the bacteria seemed to be better for the native plant.

"A really intriguing pattern that we found is that a lot of these strains of bacteria that are good for the invader belong to the Bradyrhizobium genus of bacteria that's been shown in other parts of the world to be good at fixing nitrogen so this was one more confirmation of that information," Yannarell said.

Yannarell said that this study provides yet another piece in the ecological puzzle.

The invasive Lespedeza cuneata was intentionally brought into the United States from Japan near the end of the 1800s. At the time, people liked its nitrogen-fixing capacity and soil fertilization. It was intended to be used to stabilize river banks and rehabilitate poor soil. Yannarell said that it has been recommended as wildlife forage, and some think that it has tannins that can act as a deworming treatment for goats. Now, however, it's considered to be a noxious weed that grows in the South and Midwest. It is commonly called silky bush clover.

Yannarell stressed that there are a lot of different species of Lespedeza that are native to North America and indicative of high-quality prairie. Although Lespedeza cuneata isn't a plant that would be intentionally planted by prairie restorationists, it has been seen in prairie seed mixes.

"Invasive Lespedeza cuneata and native Lespedeza virginica experience asymmetrical benefits from rhizobial symbionts," was published in Plant and Soil and was co-authored by Lingzi Hu, Ryan R. Busby, and Dick L. Gebhart. The work was supported by a grant from the U.S. Army Engineer Research and Development Center and by the Cooperative State Research, Education and Extension Service, U.S. Department of Agriculture.

Source: University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)

Sampling rivers for genes rather than organisms

Conventional methods used to inventory macroinvertebrates are extremely time-consuming. Credit: Image courtesy of EAWAG: Swiss Federal Institute of Aquatic Science and Technology
Effective environmental management depends on a detailed knowledge of the distribution of species. But taxonomists are in short supply, and some species can be difficult to identify, even for experts. Eawag, in collaboration with Canton Zurich, is now pursuing a new approach for species identification, requiring no more than samples of DNA shed into the environment.

If amphipods are detected in a river, are they a threatened species, or organisms indicating good water quality? Or perhaps the first arrivals of an invasive species? Conservation and environmental management call for a detailed knowledge of species. But experts capable of identifying species under the microscope on the basis of morphological characteristics are increasingly rare. Alternative methods for water monitoring would therefore be welcome. Biologists at Eawag are now pursuing a new approach for the detection of species, involving the use of environmental DNA (eDNA). Because organisms continuously release genetic material into the environment in the form of faeces, hair or skin cells, water samples collected from a river or lake contain innumerable fragments of DNA. As long as the relevant genetic code is known, these DNA segments can be assigned to particular species, using the latest molecular biological techniques and global databases.

Cantonal authorities interested
In cooperation with the Canton Zurich Office of Waste, Water, Energy and Air (AWEL), the researchers investigated whether this method is suitable for the detection of macroinvertebrates: organisms such as mayflies, amphipods, mussels or snails are important bioindicators, used in the assessment of water quality and ecotoxicity. Water samples were collected from 14 lake and river habitats in Canton Zurich for eDNA analysis, and macroinvertebrate species collected by kicknet sampling were also determined in the conventional manner.

While the two methods did not always deliver the same results, five of the six target species were reliably detected by both methods. Especially for organisms occurring in small populations, the eDNA method appears to be more sensitive. With this approach, the rare mayfly Baetis buceratus was additionally detected at two sites where no Baetis specimens where found by kicknet sampling. According to project leader Florian Altermatt, the new method may also be suitable for the detection of invasive species at an early stage of colonization. In the US and France, it is already being tested for invasive carp species.

Long-term goal: routine monitoring of biodiversity
The eDNA method offers additional advantages. As eDNA is ubiquitous in freshwater throughout the year, the findings reflect the situation of an entire catchment, and surveillance is less time-critical. By contrast, kicknet sampling merely provides a snapshot, and for many species it can only be carried out at certain stages of the life cycle and certain times of the year. For eDNA analysis, organisms do not have to be removed from a river or lake and -- in principle -- hundreds of species can be detected at the same time. This means that continuous monitoring of freshwater biodiversity could one day become possible, just as chemical parameters are routinely monitored today.

This, however, is still a long way off: apart from the need for further refinements, the method is still costly and time-consuming. The cantons currently lack the necessary infrastructure and expertise. But Altermatt believes it will not take too long for technical standards to be established, permitting efficient operation: "eDNA analysis will then cost a few hundred Swiss francs and will be cheaper than conventional surveys." However, the new method will not wholly replace the conventional approach. Altermatt argues that the benefits of both approaches should be exploited. In addition, taxonomists will remain indispensable for validation and calibration of the new procedures.

Source:  EAWAG: Swiss Federal Institute of Aquatic Science and Technology

A new look at what's in 'fracking' fluids raises red flags: Some compounds toxic to mammals

Written By Unknown on Sunday, December 7, 2014 | 10:19 PM

Scientists are getting to the bottom of what’s in fracking fluids — with some troubling results.
Credit: Doug Duncan/U.S. Geological Survey
As the and gas drilling technique called hydraulic fracturing (or "fracking") proliferates, a new study on the contents of the fluids involved in the process raises concerns about several ingredients. The scientists presenting the work today at the 248th National Meeting & Exposition of the American Chemical Society (ACS) say that out of nearly 200 commonly used compounds, there's very little known about the potential health risks of about one-third, and eight are toxic to mammals.

William Stringfellow, Ph.D., says he conducted the review of fracking contents to help resolve the public debate over the controversial drilling practice. Fracking involves injecting water with a mix of chemical additives into rock formations deep underground to promote the release of oil and gas. It has led to a natural gas boom in the U.S., but it has also stimulated major opposition and troubling reports of contaminated well water, as well as increased air pollution near drill sites.

"The industrial side was saying, 'We're just using food additives, basically making ice cream here,'" Stringfellow says. "On the other side, there's talk about the injection of thousands of toxic chemicals.

As scientists, we looked at the debate and asked, 'What's the real story?'"
To find out, Stringfellow's team at Lawrence Berkeley National Laboratory and University of the Pacific scoured databases and reports to compile a list of substances commonly used in fracking. They include gelling agents to thicken the fluids, biocides to keep microbes from growing, sand to prop open tiny cracks in the rocks and compounds to prevent pipe corrosion.

What their analysis revealed was a little truth to both sides' stories -- with big caveats. Fracking fluids do contain many nontoxic and food-grade materials, as the industry asserts. But if something is edible or biodegradable, it doesn't automatically mean it can be easily disposed of, Stringfellow notes.
"You can't take a truckload of ice cream and dump it down the storm drain," he says, building on the industry's analogy. "Even ice cream manufacturers have to treat dairy wastes, which are natural and biodegradable. They must break them down rather than releasing them directly into the environment."
His team found that most fracking compounds will require treatment before being released. And, although not in the thousands as some critics suggest, the scientists identified eight substances, including biocides, that raised red flags. These eight compounds were identified as being particularly toxic to mammals.

"There are a number of chemicals, like corrosion inhibitors and biocides in particular, that are being used in reasonably high concentrations that potentially could have adverse effects," Stringfellow says. "Biocides, for example, are designed to kill bacteria -- it's not a benign material."

They're also looking at the environmental impact of the fracking fluids, and they are finding that some have toxic effects on aquatic life.

In addition, for about one-third of the approximately 190 compounds the scientists identified as ingredients in various fracking formulas, the scientists found very little information about toxicity and physical and chemical properties.

"It should be a priority to try to close that data gap," Stringfellow says.
He acknowledges funding from the University of the Pacific, the Bureau of Land Management and the state of California.

Source: American Chemical Society (ACS)

Are ants the answer to carbon dioxide sequestration?

A 25-year-long study provides the first quantitative measurement of in situ calcium-magnesium silicate mineral dissolution by ants, termites, tree roots, and bare ground.
A 25-year-long study published in Geology on 14 July provides the first quantitative measurement of in situ calcium-magnesium silicate mineral dissolution by ants, termites, tree roots, and bare ground. This study reveals that ants are one of the most powerful biological agents of mineral decay yet observed. It may be that an understanding of the geobiology of ant-mineral interactions might offer a line of research on how to "geoengineer" accelerated CO2 consumption by Ca-Mg silicates.

Researcher Ronald Dorn of Arizona State University writes that over geological timescales, the dissolution of calcium (Ca) and magnesium (Mg) bearing silicates has led to the graduate drawdown of atmospheric carbon dioxide (CO2) through the accumulation of limestone and dolomite. Many contemporary efforts to sequester CO2 involve burial, with some negative environmental consequences.

Dorn suggests that, given that ant nests as a whole enhance abiotic rates of Ca-Mg dissolution by two orders of magnitude (via biologically enhanced weathering), future research leading to the isolation of ant-based enhancement process could lead to further acceleration. If ant-based enhancement could reach 100 times or greater, he writes, this process might be able to geo-engineer sequestration of CO2 from the atmosphere. Similarly, ants might also provide clues on geoengineering efficient pathways of calcium carbonate precipitation to sequester atmospheric CO2.

Earth's climate has cooled significantly over the past 65 m.y., likely from hydrologic regulation, vegetation change, and interactions related to tectonism, in part mediated by Ca-Mg silicate mineral dissolution that draws down CO2. Although speculative, says Dorn, the timing of the expansion in the variety and number of ants in the Paleogene and the Neogene suggests that biologically enhanced weathering by ants could potentially be a part of the puzzle of Cenozoic cooling.

Source: Geological Society of America
 
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