Weird 'Engine Of The Reef' Revealed

Source:

http://www.sciencedaily.com/releases/2007/08/070830165013.htm

Science Daily — A team of coral researchers has taken a major stride towards revealing the workings of the mysterious ‘engine’ that drives Australia’s Great Barrier Reef, and corals the world over.

The science has critical importance in understanding why coral reefs bleach and die, how they respond to climate change – and how that might affect humanity, they say.
Scientists at the ARC Centre of Excellence for Coral Reef Studies, James Cook University and the University of Queensland have compiled the world’s first detailed gene expression library for Symbiodinium, the microscopic algae that feed the corals – and so provide the primary energy source for the entire Reef.
“Symbiodinium uses sunlight to convert CO2 into carbohydrates for the corals to feed on. At the same time there’s evidence the corals control its output, suggesting that they are farming their captive plants” Professor David Yellowlees explains.
“But these microscopic algae are quite weird and unlike any other lifeform. They have different photosynthetic machinery from all other light harvesting organisms. They have 100 times more DNA than we do and we have no idea why such a small organism needs so much. They really are like no other living creature we know.
This is echoed by team member Prof Ove Hoegh-Guldberg who comments it is ‘like no other organism on planet’, jokingly labeling it “like an alien”.
This strange beast not only rules the fate of the world’s coral reefs – it also plays a significant role in soaking up carbon dioxide from the atmosphere, turning it into nourishment for the corals and powering calcification. Its decline would not only kill the reefs but accelerate CO2 buildup.
Dr Bill Leggat says the team has focused particularly on understanding the biochemical relationship between Symbiodinium and corals when they are stressed by heat, light, increased CO2 levels and pollutants from land run-off.
These stressful conditions cause corals to ‘bleach’ by expelling the Symbiodinium and – if they do not recover them within a few days – the corals die. Large-scale bleaching struck half of the Great Barrier Reef in 2002, and eight major bleaching episodes have been reported worldwide in the last 30 years due to warming sea water.
“Our aim is to identify the genes that make the symbiotic plants susceptible to these stresses, and lead to the coral expelling them,” Dr Leggat says.
In experiments at Heron Island Research Station they exposed corals to various stresses associated with climate change and then analysed the gene composition in the symbiotic algae. Another team analysed the effects in corals.
Working together and using the powerful micro-array technology, they hope to assemble a picture of the ‘chemical conversation’ that goes on between the corals and its symbiotic plants that leads to a breakdown in the relationship, a divorce - and the corals starving themselves to death.
“An example of the challenge we face is the gene which is expressed the most when Symbiodinium is stressed. It’s obviously important - but at this stage we have no idea what it does. It is even stranger when you consider that this gene was originally acquired from a bacterium” Prof Yellowlees says.
So far the team has identified about 4500 genes in Symbiodinium, compiling them into the world’s first gene expression library for this symbiotic organism. It is hoped this will have value for understanding other symbiotic relationships in nature.
Symbiodinium is part of a larger group of organisms called dinoflagellates, responsible for events like red tides and ciguatera poisoning. Together, the dinoflagellates process about one third of all CO2 entering the oceans – and are thus vital players in helping to remove CO2 from the atmosphere. Understanding how they function will help fill in one of the critical gaps in our understanding of climate change – how much CO2 the oceans can trap and how this will affect ultimate climate change.
Details of the team’s research findings will be published in the Journal of Phycology later this year.
Note: This story has been adapted from a news release issued by ARC Centre of Excellence in Coral Reef Studies.

Fausto Intilla

www.oloscience.com

Monkeys Use 'Baby Talk' To Interact With Infants

Source:

http://www.sciencedaily.com/releases/2007/08/070824095804.htm

Science Daily — Female rhesus monkeys use special vocalizations while interacting with infants, the way human adults use motherese, or "baby talk," to engage babies' attention, new research at the University of Chicago shows.

"Motherese is a high pitched and musical form of speech, which may be biological in origin," said Dario Maestripieri, Associate Professor in Comparative Human Development at the University. "The acoustic structure of particular monkey vocalizations called girneys may be adaptively designed to attract young infants and engage their attention, similar to how the acoustic structure of human motherese, or baby talk, allows adults to visually or socially engage with infants."
In order to determine if other primates also use special vocalizations while interacting with infants, researchers studied a group of free-ranging rhesus macaques, which live on an island off the coast of Puerto Rico. They studied the vocalizations exchanged between adult females and found that grunts and girneys increased dramatically when a baby was present. They also found that when a baby wandered away from its mother, the other females looked at the baby and vocalized, suggesting that the call was intended for the baby.
"Adult females become highly aroused while observing the infants of other group members," explains lead author of the article, Jessica Whitham, a recent Ph.D. graduate of the University of Chicago, who investigated this topic as a doctoral student at the University and currently works at Brookfield Zoo near Chicago. "While intently watching infants, females excitedly wag their tails and emit long strings of grunts and girneys.
"The calls appear to be used to elicit infants' attention and encourage their behavior. They also have the effect of increasing social tolerance in the mother and facilitating the interactions between females with babies in general. Thus, the attraction to other females' infants results in a relatively relaxed context of interaction where the main focus of attention is the baby," Maestripieri and his colleagues write in the article, "Intended Receivers and Functional Significance of Grunt and Girney Vocalizations in Free-Ranging Rhesus Macaques" published in the current issue of the journal Ethology. In addition to Whitham and Maestripieri, Dr. Melissa Gerald, a researcher at the University of Puerto Rico, was also a co-author.
Researchers have long been interested in the noises that non-human primates make and how they are used for communication. Monkey vocalizations could be carrying information that the sender expects the recipient to understand, or they could be noises that the recipient can draw inferences from, but are not intended to carry information. A human sneeze, for instance, is a noise that people understand may be associated with a cold, but it did not develop evolutionarily to convey information.
The study by Maestripieri's team showed that the grunts and girneys emitted by the rhesus macaques fall into the category of vocalizations not intended to convey specific information, and appear to be used to attract other individuals' attention or change their emotional states. When females vocalize to young infants, however, the infants' mothers infer that the females simply want to play with the infants and are unlikely to harm them. Therefore, these vocalizations may facilitate adult females' interactions not only with infants, but with the infants' mothers as well. They found, for instance, that the grunts and girneys were sometimes followed by an approach and grooming of the mothers.
Additionally they discovered that, unlike human mothers, the rhesus macaque mothers did not direct grunts or girneys toward their own offspring. It could be that the monkey mothers are familiar with their own offspring and use the vocalizations with other babies because they are excited about the novelty of seeing a new infant, Maestripieri said.
Note: This story has been adapted from a news release issued by University of Chicago.

Fausto Intilla

www.oloscience.com

Sharks' 'Bite Force' Under The Spotlight

Source:

http://www.sciencedaily.com/releases/2007/08/070823122441.htm

Science Daily — While sharks instill fear in beachgoers worldwide, they instill a deep sense of curiosity in UT assistant professor and shark expert Dan Huber.

There are still many mysteries surrounding what makes sharks such perfect predators, so Huber’s research on sharks’ “bite force” – their hunting performance – may offer new insights on sharks’ habits, capabilities and evolution. The research may also lead to advances in protective swimwear, shark-proofing equipment and a better understanding of flexible cartilage – which forms the sharks’ whole skeletons, much like human ears and noses.
“There’s a ton of bad data on how hard sharks bite,” Huber said. “And the more we learn the more we can understand these animals, educate the public, and keep people safer.”
Huber traveled to Australia in July to study an 8-foot great white shark that had become entangled in netting, and is now helping create a 3-D digital recreation of the shark that should reveal the animal’s biological mechanics. A CAT scan was taken of the shark’s skull and data from the dissection will be used to create the digital model. The digital model will include millions of bits of information, which together will allow a simulation of a great white’s bite at full force.
A shark’s hunting performance, Huber said, is not just based on its teeth, but on its muscles, behavior and streamlined body.
Huber, who is working with biologists at the University of New South Wales in Sydney, Australia and the University of Newcastle in Newcastle, Australia, is also studying similar characteristics on feeding performance in tiger and bull sharks, which, along with the great white, are responsible for most attacks on humans. Huber believes the great white probably will not wind up at the top of the list of bite force.
“The white has the narrowest head of the three, so it has less space for jaw muscles,” Huber said. “Consequently, we’re expecting that it will have a lower bite force on a pound-for-pound basis.”
There are currently no accurate estimates of the maximum bite force of the great white, but according to Huber, the 3-D model will provide the world’s first accurate estimates.
But, Huber added that the great white – due to its excellent hunting abilities – doesn’t necessarily need to have the most powerful bite to take down prey.
“Much of the damage inflicted by white sharks is due to their teeth, and not necessarily to the force,” he said. Great white sharks have approximately 3,000 serrated teeth, and often shake whatever it bites into from side to side to initiate a sawing action.
View the 3-D model here: http://www.ut.edu/public_info/3D-white.gif
Note: This story has been adapted from a news release issued by University of Tampa.

Fausto Intilla

www.oloscience.com

Giant Panda Can Survive

Source:

http://www.sciencedaily.com/releases/2007/08/070824104831.htm

Science Daily — The giant panda is not at an "evolutionary dead end" and could have a long term viable future, according to new research involving scientists from Cardiff University.

Previous studies have found that the giant panda's isolation, unusual dietary requirements and slow reproductive rates have led to a lack of genetic diversity that will inevitably lead the species to extinction.
Now a study by Professor Michael Bruford and Dr Benoît Goossens from the School of Biosciences, in collaboration with Professor Fuwen Wei and colleagues from the Institute of Zoology along with the China West Normal University in Sichuan, has found that the decline of the species can be linked directly to human activities rather than a genetic inability to adapt and evolve.
"Our research challenges the hypothesis that giant panda's are at an 'evolutionary dead end'" said Professor Bruford. "It is however clear that the species has suffered demographically at the hands of human activities such as deforestation and poaching".
The study gives a new genetic perspective on the giant panda, as well as tracing its demographic history. The research also shows that in areas where habit conservation projects are in place, the giant panda is flourishing and population numbers are increasing.
"Our research suggests we have to revise our thinking about the evolutionary prospects for the giant panda" said Professor Bruford. "The species has a viable future and possesses the genetic capacity to adapt to new circumstances. Conservation efforts should therefore be directed towards habitat restoration and protection. In their natural environment, the giant panda is a species that can have a bright future."
The research is reported in the journal Molecular Biology and Evolution.
Note: This story has been adapted from a news release issued by Cardiff University.

Fausto Intilla

www.oloscience.com

How Snakes Survive Starvation

Source:

http://www.sciencedaily.com/releases/2007/08/070824173005.htm

Science Daily — Starving snakes employ novel survival strategies not seen before in vertebrates, according to research conducted by a University of Arkansas biologist. These findings could be used in conservation strategies to determine the health of snake populations.

“These animals take energy reduction to a whole new level,” said Marshall McCue, a graduate student in biological sciences in the J. William Fulbright College of Arts and Sciences. He reported his findings in the journal Zoology.
While scientists knew that some snake species could survive for up to two years without a meal, no studies have examined the physiological changes that take place when a snake goes for prolonged periods without food. McCue examined three snake species – the ball python, the ratsnake and the western diamondback rattlesnake – to study their responses to prolonged periods without food.
The 62 snakes studied went about six months without eating – a time period that could well be duplicated in the wild, where food supplies can be scarce. McCue then looked at physiological, compositional and morphological changes in the snakes.
The results showed that the snakes could lower their standard metabolic rates, some by up to 72 percent.
“Snakes already had low energy demands. We didn’t know they could go lower,” McCue said.
Another surprising finding: The snakes continued to grow despite the lack of food – a counterintuitive finding, but a measurement that again does not appear in the research literature.
“To me, this suggests that there must be a strong selective advantage to growing longer,” McCue said. It also means the snakes have become extremely efficient in their ability to use available resources.
To illustrate the strategies employed by snakes to combat starvation, McCue uses an economic analogy of supply and demand.
“When you’re cut off from resources, you are an organism that still needs to expend energy,” he said. The “demand” end is met by decreasing their metabolic rate. The “supply” end must be met by frugal use of resources they have at hand for energy, which comes from within.
The body composition of snakes includes water, ash, protein, fats and carbohydrates. McCue found that the snakes used up selected fat stores first during starvation, but he also found crucial differences between the snake species. The ratsnakes, which typically have a more abundant rodent supply in their natural environment, began to break down proteins faster than the pythons or rattlesnakes.
“The protein use was higher in the snakes less well adapted to starvation,” McCue said.
Snakes are relatively new on the world scene, having been around for about 100 million years. Yet they currently comprise about half of all reptile species.
“Snakes are very evolutionarily successful,” McCue said. Understanding the physiology that allows them to succeed in low-energy environments will help scientists further their understanding of the snakes’ evolution and their adaptation to their current ecosystems.
Note: This story has been adapted from a news release issued by University of Arkansas, Fayetteville.

Fausto Intilla

www.oloscience.com

Elephantnose Fish 'See' With Their Chin

Source:

http://www.sciencedaily.com/releases/2007/08/070821114339.htm

Science Daily — Originating in Central Africa, Peters' elephantnose fish (Gnathonemus petersii), finds its bearings by means of weak electrical fields. Scientists from the University of Bonn have now been able to show how well this works. In complete darkness the animals can even distinguish the material of objects at a distance or dead organisms from living ones. The results have now been published in the Journal of Experimental Biology.

The fish, which is as long as a cigar, hovers with its head inclined, close to the gravel-covered bed. While it swims forward slowly, its trunk-like elongated chin sweeps steadily from right to left, always at a distance of a few millimetres from the bottom. This way the fish behaves like treasure hunters searching for buried gold coins on the beach with their metal detector. Basically, this is precisely what the fish is doing. Hidden in the sediment there are large numbers of dead nematocera larvae waiting for it, its favourite food.
Zoologists from the University of Bonn have hidden the larvae there. 'We wanted to see whether it can find them and if the answer is yes, then down to what depth,' Professor Gerhard von der Emde explains. 'It', that is the African Peters' elephantnose fish. Yet its characteristically shaped chin does not work like a particularly sensitive nose. Instead, it contains more than 500 electric sensors with which it senses its surroundings. With this sense the animal has conquered the night. During the day it hides, only under cover of darkness does it goes searching for food.
The chin of Peters' elephantnose fish is basically its eye. In its tail is the corresponding torch. Via mutated muscle cells it produces regular electrical pulses of a few volts with it. 80 times per second the fish switches this little battery on and off for the blink of an eye. 'At the same time it measures the electrical field which builds up around it via sensors in the skin,' explains Professor von der Emde. Nearby objects distort the field, so that the fish obtains an image of its surroundings, which is a surprisingly complex one.
Professor von der Emde and his team have tested what the animals can perceive with their electric sense. For this they set up a small cube and a pyramid in an aquarium, for example. Whenever the fish swam to the pyramid, they were rewarded with a nematocera larva. Their eyes were no use to these agile fish, because the experiments took place with infrared lighting, so that only the researchers could see anything, using their special cameras. They were flabbergasted themselves by their results.
In nine out of ten cases the fish swam straight towards the pyramid through the pitch black darkness. Even when the researchers used wire models instead of solid objects, the fish could not be fooled. They were even able to handle discontinuous contours. 'For example, we removed the vertical edges of a cube, i.e. we embedded two wire squares on top of each other in a gel that was permeable for electrical fields,' Professor von der Emde says. 'The fish still perceived it as a cube, so they supplied the contours very much like humans would.' Furthermore, they seem to calculate the volume of objects in water. 'A cube has a larger volume than a pyramid of the same height,' Gerhard von der Emde explains. 'If we decreased the size of the cube so much that its volume became smaller than that of the pyramid, the fish often changed their minds and swam to the cube.' So, the Peters' elephantnose fish can also internalise abstract concepts: 'Always swim to the less voluminous of two objects, irrespective of their absolute size.'
As in Starship Enterprise
What Bones, the ship's doctor of the Enterprise does, the little fish from Africa has been doing for a long time, viz. distinguishing living from dying or dead organisms without touching them. 'With its electric sense, it measures their capacitative properties, i.e. their ability to store charges,' Prof. von der Emde explains. 'Dead plants or animals cannot do that.' The electrical field image even tells it what material the object in question is made of. The image of metal is very bright, by contrast non-conductors weaken the electrical field around the fish. And it can even measure distances to a precision of several millimetres. In order to do so, it uses the fact that the electrical image becomes increasingly 'blurred'. From the degree of fuzziness it thus calculates the distance.
There is a reason for this brain power. The cerebellum of Peters' elephantnose fish is hugely enlarged. In comparison with their body length the animals have a larger brain than humans. 'They are really intelligent,' the zoologist says fondly, 'that's why it is so much fun working with them.' At one point he tried to train electric fish from South America. 'That was a flop,' he reminisces, 'the fish are beautiful, but definitely too stupid for complex tasks.'
Note: This story has been adapted from a news release issued by University of Bonn.

Fausto Intilla

www.oloscience.com

How To Share A Bat

Source:

http://www.sciencedaily.com/releases/2007/08/070822143214.htm

Science Daily — New research shows how different species of plants evolve unique floral adaptations in order to transfer pollen on different regions of bats' bodies, thus allowing multiple plant species to share bats as pollinators.

A pattern of character displacement has only rarely been shown for plants, and this is the first study to examine the competitive mechanism and process driving this pattern.
When multiple plant species occur in the same habitat and share the same pollinator, large amounts of pollen may be transferred between different species. This form of plant-plant competition can reduce the fitness of all species by interfering with successful pollination. Dr. Nathan Muchhala, a post-doctorate researcher, and Dr. Matthew D. Potts, assistant professor in the University of Miami Department of Biology, studied such competition in remote cloud forests of the Ecuadorian Andes.
They found that co-occurring bat-pollinated species of the genus Burmeistera reduce competition by evolving differences in flower shape. This serves to place pollen in different regions of the bats bodies, and thus greatly reduces "incorrect" (between-species) pollen transfer. Experiments with bats and flowers showed that greater differences in flower shape between two species decreases "incorrect" pollen transfer and thus maximizes successful pollination.
"This research study clearly demonstrates that these plants are competing and the competition is strong enough for them to evolve unique characteristics in order to reduce competition for pollination," says Nathan Muchhala, Ph.D., researcher in the University of Miami Department of Biology.
Along with the experimental work, the research team also analyzed Burmeistera in 18 field sites, and found that differences in flower morphology between co-occurring species were much greater than what would be expected by chance.
The study, titled "Character displacement among bat-pollinated flowers of the genus Burmeistera: analysis of the mechanism, process and pattern", was recently published in the Proceedings of the Royal Society B.
This implies that Burmeistera evolve to use different portions of bats bodies than the co-occurring species in their habitat. This type of local divergence in some trait is termed character displacement.
Note: This story has been adapted from a news release issued by University of Miami Rosenstiel School of Marine & Atmospheric Science.

Fausto Intilla

www.oloscience.com