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Biology Blog From Networlddirectory


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May 29, 2011, 2:16 PM CT

Tiny bubbles signal to coral reefs

Tiny bubbles signal  to coral reefs
A new study of Papua New Guinea's "champagne reefs" in Nature Climate Change by the University of Miami, the Australian Institute of Marine Science and the Max-Planck Institute for Marine Microbiology in Germany concludes that ocean acidification, along with increased ocean temperatures, will likely severely reduce the diversity and resilience of coral reef ecosystems within this century. These reefs provide sobering illustrations of how coral reefs may look in 100 years if ocean acidification conditions continue to worsen.

Credit: Katharina Fabricius/Australian Institute of Marine Science

A newly released study from University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science researchers Chris Langdon, Remy Okazaki and Nancy Muehllehner and his colleagues from the Australian Institute of Marine Science and the Max-Planck Institute for Marine Microbiology in Gera number of concludes that ocean acidification, along with increased ocean temperatures, will likely severely reduce the diversity and resilience of coral reef ecosystems within this century.

The research team studied three natural volcanic CO2 seeps in Papua New Guinea to better understand how ocean acidification will impact coral reefs ecosystem diversity. The study details the effects of long-term exposure to high levels of carbon dioxide and low pH on Indo-Pacific coral reefs, a condition that is projected to occur by the end of the century as increased man-made CO2 emissions alter the current pH level of seawater, turning the oceans acidic.

"These 'champagne reefs' are natural analogs of how coral reefs may look in 100 years if ocean acidification conditions continue to get worse," said Langdon, UM Rosenstiel School professor and co-principal investigator of the study.

The study shows shifts in the composition of coral species and reductions in biodiversity and recruitment on the reef as pH declined from 8.1 to 7.8. The team also reports that reef development would cease at a pH below 7.7. The IPCC 4th Evaluation Report estimates that by the end of the century, ocean pH will decline from the current level of 8.1 to 7.8, due to rising atmospheric CO2 concentrations.........

Posted by: Ashley      Read more         Source


April 7, 2011, 8:48 AM CT

Precedent-setting and biodiversity

Precedent-sEtting and biodiversity
The loss of biodiversity through species extinctions may be compromising the ability of the planet to cleanse itself of human-caused pollution.

Credit: © 2011 Jupiter Images Corporation

Frequent reports of accelerating species losses invariably raise questions about why such losses matter and why we should work to conserve biodiversity.

Biologists have traditionally responded to such questions by citing societal benefits that are often presumed to be offered by biodiversity--benefits like controlling pests and diseases, promoting the productivity of fisheries, and helping to purify air and water, among a number of others. Nevertheless, a number of of these presumed benefits are have yet to be supported by rigorous scientific data.

But Bradley J. Cardinale of the University of Michigan has produced a newly released study that finally verifies that biodiversity promotes water quality and explains how it does so. Specifically, the study reveals how biodiversity helps remove excess levels of nutrients from streams that usually degrade water quality.

Cardinale said, "This is the first study that nails the mechanism by which biodiversity promotes water quality. And by nailing the mechanism, it provides solid evidence of a cause-and-effect relationship between biodiversity and water quality that was previously missing".

Here's how Cardinale's mechanism works: as the number of species of algae in a stream increases, the geographical distribution of these organisms within the stream expands, and the more water these widely distributed organisms may cleanse through a pollution-removing process common to algae.........

Posted by: Tyler      Read more         Source


March 20, 2011, 9:56 PM CT

Think globally, but act locally

Think globally, but act locally
The endangered Quino checkerspot butterfly experiences pressures in Southern California from climate change, but also urban development, invasive species and pollution.

Credit: Lawrence Gilbert and Michael C. Singer. The University of Texas at Austin.

Global warming is clearly affecting plants and animals, but we should not try to tease apart the specific contribution of greenhouse gas driven climate change to extinctions or declines of species at local scales, biologists from The University of Texas at Austin advise.

Camille Parmesan, Michael C. Singer and their coauthors published their commentary online this week in Nature Climate Change

"Yes, global warming is happening. Yes, it is caused by human activities. And yes, we've clearly shown that species are impacted by global warming on a global scale," says Parmesan, associate professor of integrative biology.

Policy makers have been recently pressing biologists to dissect how much of the changes observed in wild species are due specifically to greenhouse gas driven climate change verses other possible factors, including natural changes in the climate.

However, research funding is limited, and the researchers feel it should be directed more toward studies on species adaptations and conservation of compromised species rather than trying to figure what percent of each species' decline is due to rising greenhouse gases. One reason is that, from the perspective of wildlife, it doesn't matter what proportion of climate-change impacts are caused by humans.........

Posted by: Tyler      Read more         Source


January 16, 2011, 8:51 PM CT

Choosing organic milk

Choosing organic milk
Gillian Butler with cows at Newcastle University's Nafferton Farm, Northumberland.

Credit: Newcastle University


Wetter, cooler summers can have a detrimental effect on the milk we drink, according to new research published by Newcastle University.

Researchers found milk collected during a particularly poor UK summer and the following winter had significantly higher saturated fat content and far less beneficial fatty acids than in a more 'normal' year.

But they also discovered that switching to organic milk could help overcome these problems. Organic supermarket milk showed higher levels of nutritionally beneficial fatty acids compared with 'ordinary' milk regardless of the time of year or weather conditions.

The study, which is published in this month's Journal of Dairy Science (January 2011), leads on from previous research undertaken nearly three years ago which looked at the difference between organic and conventional milk at its source � on the farms.

"We wanted to check if what we found on farms also applies to milk available in the shops," said Gillian Butler, who led the study. "Surprisingly, the differences between organic and conventional milk were even more marked. Whereas on the farms the benefits of organic milk were proven in the summer but not the winter, in the supermarkets it is significantly better quality year round".

There was also greater consistency between organic suppliers, where the conventional milk brands were of variable quality.........

Posted by: Tyler      Read more         Source


December 16, 2010, 7:49 AM CT

New study about Arctic habitat

New study about Arctic habitat
Alaska Sea-ice habitats essential to polar bears would likely respond positively should more curbs be placed on global greenhouse gas emissions, as per a new modeling study published recently in the journal, Nature

The study, led by the U.S. Geological Survey, included university and other federal agency scientists. The research broke new ground in the "tipping point" debate in the scientific community by providing evidence that during this century there does not seem to be a tipping point at which sea-ice loss would become irreversible.

The report does not affect the decision made by the U.S. Fish and Wildlife Service in 2008 to list the polar bear as a threatened species.

This newly released study builds and expands upon studies published by the USGS in 2007. The newly released study evaluates additional scenarios in which greenhouse gas emissions are reduced compared to the business-as-usual scenario that was exclusively used in the prior research. Modeling outcomes for the additional scenarios provided evidence that the projected continuation of Arctic sea-ice decline could be altered if greenhouse gas emissions were mitigated in a manner that stabilizes atmospheric CO2 levels at or less than around 450 parts per million. Current CO2 levels are around 390 ppm.........

Posted by: Tyler      Read more         Source


December 7, 2010, 7:44 AM CT

Learning the language of bacteria

Learning the language of bacteria
Bacteria are among the simplest organisms in nature, but a number of of them can still talk to each other, using a chemical "language" that is critical to the process of infection. Sending and receiving chemical signals allows bacteria to mind their own business when they are scarce and vulnerable, and then mount an attack after they become numerous enough to overwhelm the host's immune system.

This system, called "quorum sensing," is an interesting example of sophistication among microbes, says Helen Blackwell, an associate professor of chemistry at the University of Wisconsin-Madison. In practical terms, she adds, quorum sensing may provide an alternative therapeutic target as bacteria continue to evolve resistance to antibiotics.

Theoretically, blocking quorum sensing would prevent the bacteria from turning pathogenic and producing the toxins that are an immediate cause of disease in bacterial infections.

Bacteria use simple chemical signals to control quorum sensing, and Blackwell is interested in how these compounds work and in developing new ways to intercept them. In a study just published online in the journal ChemBioChem, Blackwell and his colleagues Andrew Palmer, Evan Streng and Kelsea Jewell showed that several species of bacteria can respond to identical signals, suggesting that one drug could battle quorum sensing in several types of bacteria.........

Posted by: Ashley      Read more         Source


October 15, 2010, 6:41 AM CT

Using poplars for biofuels

Using poplars for biofuels
A potential solution for global energy demands is the use of Poplar, a fast-growing tree with high yields, for biofuels. To get the most out of Poplar plantations, varieties that are the best fit for the conditionsones with disease resistance or higher yields, for exampleare desired. But do these plantations of new, non-native (exotic) species impact nearby native populations of Poplar? In particular, is the genetic makeup of the native populations being altered by interactions with the exotic species?.

In the recent issue of the American Journal of Botany (http://www.amjbot.org/cgi/reprint/97/10/1688), Dr. Nathalie Isabel and his colleagues tackled these issues by conducting a scientific risk evaluation on the introduction of exotic species of Poplar (complex hybrids primarily made up of Populus nigra, P. trichocarpa, and P. maximowiczii) and the resulting impact on three native populations of Poplar species (P. deltoides and P. balsamifera) at two different locations over 3 years.

The scientists monitored gene flowthe passing of genetic information (alleles) between two populationsresulting from spontaneous hybridization between exotic and native populations. By looking for specific DNA signatures, called SNPs, they determined who the father species was for individual offspring. These paternity tests revealed that complex patterns of hybridization were occurring. All five species were capable of producing hybrids with the native populations, but when the native population was large, the native species were more successful; native species represented more than 95% of the parental alleles.........

Posted by: Ashley      Read more         Source


August 31, 2010, 7:26 AM CT

Climate Change and Decline of Horseshoe Crabs

Climate Change and Decline of Horseshoe Crabs
A distinct decline in horseshoe crab numbers has occurred that parallels climate change linked to the end of the last Ice Age, as per a research studythat used genomics to assess historical trends in population sizes.

The new research also indicates that horseshoe crabs numbers may continue to decline in the future because of predicted climate change, said Tim King, a scientist with the U.S. Geological Survey and a main author on the newly released study published in Molecular Ecology.

While the current decline in horseshoe crabs is attributed in great part to overharvest for fishing bait and for the pharmaceutical industry, the new research indicates that climate change also appears to have historically played a role in altering the numbers of successfully reproducing horseshoe crabs. More importantly, said King, predicted future climate change, with its accompanying sea-level rise and water temperature fluctuations, may well limit horseshoe crab distribution and interbreeding, resulting in distributional changes and localized and regional population declines, such as happened after the last Ice Age.

"Using genetic variation, we determined the trends between past and present population sizes of horseshoe crabs and observed that a clear decline in the number of horseshoe crabs has occurred that parallels climate change linked to the end of the last Ice Age," said King.........

Posted by: Tyler      Read more         Source


May 7, 2009, 10:16 PM CT

Cutting cattle methane

Cutting cattle methane
Beef farmers can breathe easier thanks to University of Alberta scientists who have developed a formula to reduce methane gas in cattle.

By developing equations that balance starch, sugar, cellulose, ash, fat and other elements of feed, a Canada-wide team of researchers has given beef producers the tools to lessen the methane gas their cattle produce by as much as 25 per cent.

"That's good news for the environment," said Stephen Moore, a professor of agricultural, food and nutritional science at the University of Alberta in Canada. "Methane is a greenhouse gas, and in Canada, cattle account for 72 per cent of the total emissions. By identifying factors such as diet or genetics that can reduce emissions, we hope to give beef farmers a way to lessen the environmental footprint of their cattle production and methane reductions in the order of 25 per cent are certainly achievable".

Using information from prior studies, the scientists compiled an extensive database of methane production values measured on cattle and were able to formulate equations to predict how much methane a cow would produce based on diet.

The study was jointly conducted with the universities of Guelph and Manitoba, Agriculture and Agri-Food Canada and the International Atomic Energy Agency in Austria. It published recently in the Journal of Animal Science........

Posted by: Tyler      Read more         Source


April 24, 2009, 5:14 AM CT

What makes a cow a cow?

What makes a cow a cow?
Scientists report today in the journal Science that they have sequenced the bovine genome, for the first time revealing the genetic features that distinguish cattle from humans and other mammals.

The six-year effort involved an international consortium of scientists and is the first full genome sequence of any ruminant species. Ruminants are distinctive in that they have a four-chambered stomach that with the aid of a multitude of resident microbes allows them to digest low quality forage such as grass.

The bovine genome consists of at least 22,000 protein-coding genes and is more similar to that of humans than to the genomes of mice or rats, the scientists report. However, the cattle genome appears to have been significantly reorganized since its lineage diverged from those of other mammals, said University of Illinois animal sciences professor Harris Lewin, whose lab created the high-resolution physical map of the bovine chromosomes that was used to align the sequence. Lewin, who directs the Institute for Genomic Biology, also led two teams of scientists on the sequencing project and is the author of a Perspective article in Science on the bovine genome sequence and an accompanying study by the Bovine Genome and Analysis Consortium.

"Among the mammals, cattle have one of the more highly rearranged genomes," Lewin said. "They seem to have more translocations and inversions (of chromosome fragments) than other mammals, such as cats and even pigs, which are closely correlation to cattle.........

Posted by: Ashley      Read more         Source


Thu, 23 Apr 2009 04:05:32 GMT

4.18.2009

4.18.2009


The coincidental sequence repeated itself! After we had crossed the dam (see yesterday’s post), we continued hiking around the lake. I steered my feet deeper into the forest though. I was hoping to see anything that might be blooming. On the drive down we passed many trees with white flowers on them — serviceberry perhaps? — and I wondered if there might be some in my forest. There weren’t that we found, but there was a nice log to sit upon and contemplate the universe for a while.

When we resumed our stumblings, we were soon back at the shoreline. Although the frogs were singing lustily, we didn’t see any eggs in the water. It may still be a bit early for that or it may be that the wild fish in the lake are big enuf to eat amphibian eggs now.

Our hike along the southern side of the lake had us facing west, which allowed us to see what was massing in the western sky. The rainstorm that we’d seemed to have outrun on our drive to the woods earlier that morning was catching up. In fact, the clouds were so dark and tumbling up there in the western sky that I was sure we would not complete our hike around the lake before the clouds released their rain to soak us. Of course had we been able to scurry back to the shelter area in time, we would have found no protection there since the tarp has been gone for weeks. We’d have to climb into the truck to wait out the storm. If it came.

The clouds seemed to be giving us a break. We visited our usual stops around the lake as our hike continued, continued unhurried by the threats of the weather. Some of our best visits to the forest have been in the rain, so we weren’t too worried if it happened to us then.

Once we were on the north side of the lake, we steered our stumbling steps farther up the slope, away from the water. I had a notion that I might find some nice round rocks if I went up into the trees. (There is a certain level in the slope where the rocks appear more frequently.) We ventured up one side of a ravine we don’t visit very often. It is the most rugged of the ravines, and a hike directly up its center would be a difficult task. So we stayed above in on the western side, the ravine falling to our right and a particularly amorous turkey calling lustily in the forest to our right. We couldn’t see the turkey through the trees, but we could certainly hear him as he sang his plaintive song. Despite being up on the slope, we could still hear the ceaseless frog chorus from the lake. Love was in the air.

Once we’d hiked far enuf to the north for the ravine to become passable, we stepped across it and started back toward where we’d left the truck. All the while the clouds were giving us a pass. It was still dark and ominous overhead, but the rain held back.

We don’t hike this part of the forest much. The road along our northern property line is not far away, and if we need to get from one end of the forest to the other, we generally use that. The lake, of course, is to the south, and we spend a lot of time in that area. So this part of the forest gets overlooked. Because it is on the south-facing slope, it is dryer. There are still some Blackjack oaks here (though they are concentrated more to the west), so passage through the understory can be difficult and indirect. There are patches filled with blackberries and others with sumac (though not nearly enuf). It’s a different hiking experience through here, but then it ends where our road cuts south through the trees and to our truck with the feed bag awaits. And that’s where we ended up.

Since we don’t carry watches when we’re at Roundrock, we had no idea what the actual time was, but we decided that the lunch bell was sounding. We gathered our cooler and the comfy chairs then carried them down to the lake so we could chew our food while we drank in the scenery. The clouds, in the meantime, had held off as long as they could, and the sprinkling began. It was pleasant for a while to watch it dimpling the surface of the lake, but it did hasten us through our sandwiches. I’d saved the last corner of mine to break apart and throw in the water. In the past, this has attracted a lot of fishy attention, but no one was interested in it on that day. The bits of bread floated unmolested on the water, and I suspect that the fish were in the deep water where it was probably warmer for them. I don’t suppose the bits of bread and turkey will go to waste in that dark water.

The rain grew more serious then, and we soon found ourselves retreating to the truck. For a while it was pelting down on the roof of the truck very hard. This would have been a pleasant state of affairs had we been under a tarp with the rain pounding down around us, but in the cab of the truck it was a cacaphonous assault.

We really had only one other chore for the day. I wanted to reset the game camera to shoot the suet feeder to see if I could get a shot of an ivory-billed woodpecker. This involved putting a nail in the opposite side of the tree where we normally hang the feeder. Had I wanted to shoot it where it normally hung, the camera would be pointing to the south, and all of the shots would have been washed out by the sun. Still, I wanted to keep the suet cage in the same general area since the birds know it’s there. The rain let up enuf for Pablo to get to work on this project, and without getting too wet, I soon had it all arranged.

About the time I finished, something happened. All of the clouds blew away, the sky was filled with blue, and some bright orange ball up there started to make my skin feel warm.

We took a different route home. I thought that maybe Toad Suck was open, but it’s still too early. Then I went in search of a dragon, but I must have turned down the wrong country road, for I didn’t see it. But there’s always tomorrow.

Missouri calendar:

  • Giant Canada goose goslings begin hatching.
  • Columbines bloom.

Posted by: Roundrockjournal      Read more     Source


Fri, 27 Feb 2009 04:35:28 GMT

Fish With Transparent Head

Check out this fish called Macropinna microstoma.
It has tubular eyes and a see-through head.

Posted by: Gerard      Read more     Source


December 16, 2008, 9:52 PM CT

Ecosystem changes and climate warming

Ecosystem changes and climate warming
Biology research scientists John Smol and Kathleen Ruhland examine sediment samples that show the history of a lake system.

Credit: Photo by Stephen Wild

Unparalleled warming over the last few decades has triggered widespread ecosystem changes in a number of temperate North American and Western European lakes, say scientists at Queen's University and the Ontario Ministry of the Environment.

The team reports that striking changes are now occurring in a number of temperate lakes similar to those previously observed in the rapidly warming Arctic, eventhough typically a number of decades later. The Arctic has long been considered a "bellwether" of what will eventually happen with warmer conditions farther south.

"Our findings suggest that ecologically important changes are already under way in temperate lakes," says Queen's Biology research scientist, Dr. Kathleen Ruhland, from the university's Paleoecological Environmental Assessment and Research Lab (PEARL) and lead author of the study.

The research was recently reported in the international journal Global Change Biology Also on the team are Biology professor John Smol, Canada Research Chair in Environmental Change, and Andrew Paterson, a research scientist at the Ontario Ministry of the Environment and an adjunct professor at Queen's.

One of the biggest challenges with environmental studies is the lack of long-term monitoring data, Dr. Ruhland notes. "We have almost no data on how lakes have responded to climate change over the last few decades, and certainly no data on longer term time scales," she says. "However, lake sediments archive an important record of past ecosystem changes by the fossils preserved in mud profiles".........

Posted by: Tyler      Read more         Source


Mon, 07 Jul 2008 04:24:01 GMT

Everywhere I look

Everywhere I look
Remember the early days of this humble blog when I anguished about the lack of walnut trees in my woods at Roundrock? There was a point where any time I happened upon a walnut tree, it gave it a post of its own, keeping a count. I even tried plotting their location on a map once.

Okay, I’m older now, and I don’t have to be so stupid. It seems like just about everywhere I look though, I see the distinctive leaves of a walnut tree over my head. (Well, not really everywhere.) When Seth and I were stumbling about the north-facing slope on our last visit, tracking the interloping cattle, I happened to look up and see this walnut tree you see above. It obviously has been growing there for years, far longer than my tenure at Roundrock, yet this was the first time I had seen it.

So let’s say that my powers of observation are set pretty low. And let’s say that I probably have three times as many walnut trees in my woods as I have seen. That means I have a pretty good population of walnuts in the 80+ acres of Roundrock. I can say that I’ve seen them in nearly every part of my woods, so I think it is safe to say they are throughout.

What I haven’t seen is an actual walnut. I’m not sure why that is. Are my walnut trees not fertile? That doesn’t seem likely. They got here on their own, so it is probably that they are as vigorous and complete as any walnut tree anywhere. Are the squirrels getting all of the nuts before I can even glimpse them? Perhaps, but while we have seen squirrels in our woods, we haven’t see a lot of them. Surely one or two nuts have escape their notice long enuf for me to notice them. Or are my powers of observation set on low? Are there walnuts in the trees and I’m just not seeing them? Let’s say that.

Missouri calendar:

  • Smoketrees bloom on southwestern Missouri glades.
Today in Missouri history:

  • Rose O''Neill was born on this date in 1874. From her home near Springfield, Missouri she created Kewpie dolls in illustrations and figurines. In the Roaring Twenties these sweet elvish creatures became an international craze.

Posted by: Roundrockjournal      Read more     Source


June 25, 2008, 10:31 PM CT

Primate's Scent Speaks Volumes

Primate's Scent Speaks Volumes
Credit: David Haring, Duke Lemur Center
Perhaps judging a man by his cologne isn't as superficial as it seems.

Duke University researchers, using sophisticated machinery to analyze hundreds of chemical components in a ringtailed lemur's distinctive scent, have observed that individual males are not only advertising their fitness for fatherhood, but also a bit about their family tree as well.

"We now know that there's information about genetic quality and relatedness in scent," said Christine Drea, a Duke associate professor of biological anthropology and biology. The male's scent can reflect his mixture of genes, and to which animals he's most closely related. "It's an honest indicator of individual quality that both sexes can recognize," she said.

Lemurs, distant primate cousins of ours who split from the family tree before the monkeys and apes parted ways, have a complex and elaborate scent language that until recently was completely undiscovered by humans. Drea said it's language that is undoubtedly richer than we can imagine.

"All lemurs make use of scent," she said. "The diversity of glands is just amazing".

Ringtailed males have scent glands on their genitals, shoulders and wrists, each of which makes different scents. Other lemur species also have glands on their heads, chests and hands. Add to these scents the signals that can be conveyed in feces and urine, and there's a lot of silent, cryptic communication going on in lemur society.........

Posted by: Ashley      Read more         Source


May 15, 2008, 7:30 PM CT

Gravity-defying bird beak mystery

Gravity-defying bird beak mystery
As Charles Darwin showed nearly 150 years ago, bird beaks are exquisitely adapted to the birds' feeding strategy. A team of MIT mathematicians and engineers has now explained exactly how some shorebirds use their long, thin beaks to defy gravity and transport food into their mouths.

The phalarope, commonly found in western North America, takes advantage of surface interactions between its beak and water droplets to propel bits of food from the tip of its long beak to its mouth, the research team reports in the May 16 issue of Science.

These surface interactions depend on the chemical properties of the liquid involved, so phalaropes and about 20 other birds species that use this mechanism are extremely sensitive to anything that contaminates the water surface, especially detergents or oil.

"Some species rely exclusively on this feeding mechanism, and so are extremely vulnerable to oil spills," said John Bush, MIT associate professor of applied mathematics and senior author of the paper.

Wildlife biologists have long noted the unusual feeding behavior of phalaropes, which spin in circles on the water, creating a vortex that sweeps small crustaceans up to the surface, just like tea leaves in a swirling tea cup.

The birds peck at the surface, picking up millimetric droplets of water with their prey trapped inside. Since the birds point their beaks downward during the feeding process, gravity must be overcome to get those droplets from the tip of the bird's long beak to its mouth. Until now, scientists have been puzzled as to how that happens.........

Posted by: Ashley      Read more         Source


April 1, 2008, 8:58 PM CT

Some Migratory Birds Can't Find Success In Urban Areas

Some Migratory Birds Can't Find Success In Urban Areas
New research finds fresh evidence that urbanization in the United States threatens the populations of some species of migratory birds.

But the six-year study also refutes one of the most widely accepted explanations of why urban areas are so hostile to some kinds of birds.

Most ecologists have assumed that common nest predators in urban areas - such as house cats and raccoons - were destroying eggs or killing young birds in greater numbers than in rural areas, said Amanda Rodewald, co-author of the study and associate professor of wildlife ecology at Ohio State University's School of Environment and Natural Resources.

But this study was one of the first to actually test that assumption by monitoring natural nests over several years. And the results showed that predators weren't the main problem: instead, the birds just didn't seem to like urban areas and gave up more easily.

Urban areas attracted lower-quality birds which, in comparison to those in rural areas, arrived later in the spring, left earlier in the fall, made fewer nesting attempts and were much less likely to return to nesting spots from year to year.

"There is something about these urban forests that strikes the birds as unsuitable," Rodewald said. "Even when they try nesting, they are less likely to renest after failure or to return in subsequent years".........

Posted by: Ashley      Read more         Source


February 26, 2008, 5:19 PM CT

Giant Fossil Frog from Hell

Giant Fossil Frog from Hell
The giant frog Beelzebufo, or "devil frog," was the largest frog ever to live on Earth.

Credit: SUNY-Stony Brook
A team of researchers, led by Stony Brook University paleontologist David Krause, has discovered the remains in Madagascar of what may be the largest frog ever to exist.

The 16-inch, 10-pound ancient frog, scientifically named Beelzebufo, or devil frog, links a group of frogs that lived 65 to 70 million years ago with frogs living today in South America.

Discovery of the voracious predatory fossil frog -- reported on-line this week in the journal Proceedings of the National Academy of Sciences (PNAS) -- is significant in that it may provide direct evidence of a one-time land connection between Madagascar, the largest island off Africa's southeast coast, and South America.

To identify Beelzebufo and determine its relationship to other frogs, Krause collaborated with fossil frog experts Susan Evans, lead author of the PNAS article, and Marc Jones of the University College London. The authors concluded that the new frog represents the first known occurrence of a fossil group in Madagascar with living representatives in South America.

"Beelzebufo appears to be a very close relative of a group of South American frogs known as 'ceratophyrines,' or 'pac-man' frogs, because of their immense mouths," said Krause, whose research was funded by the National Science Foundation (NSF). The ceratophryines are known to camouflage themselves in their surroundings, then ambush predators.........

Posted by: William      Read more         Source


January 24, 2008, 11:00 PM CT

When accounting for the global nitrogen budget, don't forget fish

When accounting for the global nitrogen budget, don't forget fish
Like bank accounts, the nutrient cycles that influence the natural world are regulated by inputs and outputs. If a routine withdrawal is overlooked, balance sheets become inaccurate. Over time, overlooked deductions can undermine our ability to understand and manage ecological systems.

Recent research by the Universite de Montreal (Canada) and the Cary Institute of Ecosystem Studies (Millbrook, New York) has revealed an important, but seldom accounted for, withdrawal in the global nitrogen cycle: commercial fisheries. Results, published as the cover story in the recent issue of Nature Geoscience, highlight the role that fisheries play in removing nitrogen from coastal oceans.

Nitrogen is essential to plant and animal life; however, it is possible to have too much of a good thing. During the past century, a range of human activities have increased nitrogen inputs to coastal waters. Fertilizer run-off is the best documented and most significant source of terrestrial nitrogen pollution. Nitrogen-rich fertilizer applied to farmland eventually makes its way into coastal waters via a network of streams and rivers.

Research spearheaded by Roxane Maranger (Universite de Montreal) and Nina Caraco (Cary Institute) demonstrates that commercial fisheries play an important but declining role in removing terrestrial nitrogen from coastal waters. Accounting for this withdrawal is crucial; terrestrial-derived nitrogen can stimulate coastal phytoplankton growth, leading to eutrophication. Typically typically eutrophic waters are characterized by reduced dissolved oxygen, decreased biodiversity, and species composition shifts.........

Posted by: Tyler      Read more         Source


Fri, 28 Dec 2007 14:31:09 GMT

Deadwood in winter

Deadwood in winter


Sky and snowpack are two kinds of white, and the pale skin of arboreal fungi makes a third. Within a year or two after death, a log or snag has already become an extension of the ground in one respect: it is shot through with networks of fungal hyphae, the mycelium. This is not a root structure - remember that fungi are more closely related to animals than to plants. Rather, it is like a skilled miner who has adapted to the job so well that he has become almost indistinguishable from the ore.



Wood so mined becomes lighter than paper: punk wood. It breaks easily, but does not yet crumble between the fingers. It makes an excellent tinder, burning with a green flame.



Other miners of dead trees include ants and termites and the pale grubs of beetles: stag beetles, longhorn beetles, scarabs and more. Such xylophagous insects contribute at least as much to the decomposition of trees as the fungi - indeed, some species of the latter require the openings of the former before they can begin their own infiltrations.

Various species of bees and wasps and the maggots of flies, midges and mosquitoes also make their homes in the tunnels of beetle grubs, and feed on their dried-out excrement. Though there’s very little insect activity this time of year, a half-rotted snag preserves a record as visually rich and intriguing as a Dead Sea scroll. And of course the woodpeckers also come knocking, drilling doors into larder, shelter, and sounding board. The winter woods echoes with their stacatto taps and calls.



If after all this the dead still stand, it is often at odd angles. The sun is no longer of any interest to them. They alone try the embrace of other trees, and when the wind blows, they are vociferous in their complaint.
__________

Don’t forget to send tree-related links to Lorianne - zenmama at gmail dot com - by December 30 for inclusion on the next Festival of the Trees. And be sure to visit the Insecta issue of qarrtsiluni, which is still in progress with a number of posts yet to come.

Posted by: Vianegativa      Read more     Source

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