University of British Columbia researchers have observed one of the fastest evolutionary responses ever recorded in wild populations. In as little as three years, stickleback fish developed tolerance for water temperature 2.5 degrees Celsius lower than their ancestors.
The study, published in the current issue of the Proceedings of the Royal Society B, provides the some of the first experimental evidence that evolution may help populations survive effects of climate change.
Measuring three to 10 centimetres, stickleback fish originated in the ocean but began populating freshwater lakes and streams following the last ice age. Over the past 10,000 years, marine and freshwater sticklebacks have evolved different physical and behavioural traits, making them ideal models for Darwin's natural selection theory.
To learn how quickly this adaptation took place, Barrett and colleagues from Switzerland and Sweden "recreated history" by transplanting marine sticklebacks to freshwater ponds and found that in as little as three generations (or three years), they were able to tolerate the same minimum temperature as freshwater sticklebacks, 2.5 °C lower than their ancestral populations.
It is crucial that knowledge of evolutionary processes is incorporated into conservation and management policy.
Monday, August 30, 2010
Monday, August 16, 2010
Human Noise Pollution
The growing amount of human noise pollution in the ocean could lead fish away from good habitat and off to their death, according to new research from a UK-led team working on the Great Barrier Reef.
After developing for weeks at sea, baby tropical fish rely on natural noises to find the coral reefs where they can survive and thrive. However, the researchers found that short exposure to artificial noise makes fish become attracted to inappropriate sounds.
In earlier research, Dr Steve Simpson, Senior Researcher in the University of Bristol's School of Biological Sciences discovered that baby reef fish use sounds made by fish, shrimps and sea urchins as a cue to find coral reefs. With human noise pollution from ships, wind farms and oil prospecting on the increase, he is now concerned that this crucial behaviour is coming under threat.
He said: "When only a few weeks old, baby reef fish face a monumental challenge in locating and choosing suitable habitat. Reef noise gives them vital information, but if they can learn, remember and become attracted towards the wrong sounds, we might be leading them in all the wrong directions."
Using underwater nocturnal light traps, Dr Simpson and his team collected baby damselfish as they were returning to coral reefs. The fish were then put into tanks with underwater speakers playing natural reef noise or a synthesised mix of pure tones. The next night the fish were put into specially designed choice chambers (long tubes with contrasting conditions at each end in which fish can move freely towards the end they prefer) with natural or artificial sounds playing. All the fish liked the reef noise, but only the fish that had experienced the tone mix swam towards it, the others were repelled by it.
Dr Simpson said: "This result shows that fish can learn a new sound and remember it hours later, debunking the 3-second memory myth."
His collaborator, Dr Mark Meekan added: "It also shows that they can discriminate between sounds and, based on their experience, become attracted to sounds which might really mess up their behaviour on the most important night of their life."
In noisy environments the breakdown of natural behaviour could have devastating impacts on success of populations and the replenishment of future fish stocks.
Dr Simpson said: "Anthropogenic noise has increased dramatically in recent years, with small boats, shipping, drilling, pile driving and seismic testing now sometimes drowning out the natural sounds of fish and snapping shrimps. If fish accidentally learn to follow the wrong sounds, they could end up stuck next to a construction site or follow a ship back out to sea."
The study is published in Behavioral Ecology and was carried out at Lizard Island Research Station. The work was supported with a fellowship for Dr Simpson from the UK Natural Environment Research Council and by the Australian Institute of Marine Science for Dr Mark Meekan.
Source: http://www.sciencedaily.com/
After developing for weeks at sea, baby tropical fish rely on natural noises to find the coral reefs where they can survive and thrive. However, the researchers found that short exposure to artificial noise makes fish become attracted to inappropriate sounds.
In earlier research, Dr Steve Simpson, Senior Researcher in the University of Bristol's School of Biological Sciences discovered that baby reef fish use sounds made by fish, shrimps and sea urchins as a cue to find coral reefs. With human noise pollution from ships, wind farms and oil prospecting on the increase, he is now concerned that this crucial behaviour is coming under threat.
He said: "When only a few weeks old, baby reef fish face a monumental challenge in locating and choosing suitable habitat. Reef noise gives them vital information, but if they can learn, remember and become attracted towards the wrong sounds, we might be leading them in all the wrong directions."
Using underwater nocturnal light traps, Dr Simpson and his team collected baby damselfish as they were returning to coral reefs. The fish were then put into tanks with underwater speakers playing natural reef noise or a synthesised mix of pure tones. The next night the fish were put into specially designed choice chambers (long tubes with contrasting conditions at each end in which fish can move freely towards the end they prefer) with natural or artificial sounds playing. All the fish liked the reef noise, but only the fish that had experienced the tone mix swam towards it, the others were repelled by it.
Dr Simpson said: "This result shows that fish can learn a new sound and remember it hours later, debunking the 3-second memory myth."
His collaborator, Dr Mark Meekan added: "It also shows that they can discriminate between sounds and, based on their experience, become attracted to sounds which might really mess up their behaviour on the most important night of their life."
In noisy environments the breakdown of natural behaviour could have devastating impacts on success of populations and the replenishment of future fish stocks.
Dr Simpson said: "Anthropogenic noise has increased dramatically in recent years, with small boats, shipping, drilling, pile driving and seismic testing now sometimes drowning out the natural sounds of fish and snapping shrimps. If fish accidentally learn to follow the wrong sounds, they could end up stuck next to a construction site or follow a ship back out to sea."
The study is published in Behavioral Ecology and was carried out at Lizard Island Research Station. The work was supported with a fellowship for Dr Simpson from the UK Natural Environment Research Council and by the Australian Institute of Marine Science for Dr Mark Meekan.
Source: http://www.sciencedaily.com/
Saturday, August 14, 2010
Generating Energy from Ocean Waters Off Hawaii
Average ocean temperature differences (at water depths of between 20 meters and 1000 meters depths) around the main Hawaiian Islands for the period July 1, 2007, through June 30, 2009, (the color palette is from 18°C to 24°C); the relatively more favorable area in the lee of the islands is clearly visible. (Credit: Data from HYCOM (an academia-industry consortium, see: http://www.hycom.org/ and NCODA, public data from the U.S. Navy, see: https://www.fnmoc.navy.mil/public/. Image provided by Gerard Nihous.)
Researchers at the University of Hawaii at Manoa say that the Leeward side of Hawaiian Islands may be ideal for future ocean-based renewable energy plants that would use seawater from the oceans' depths to drive massive heat engines and produce steady amounts of renewable energy.
The technology, referred to as Ocean Thermal Energy Conversion (OTEC), is described in the Journal of Renewable and Sustainable Energy, which is published by the American Institute of Physics (AIP).
It involves placing a heat engine between warm water collected at the ocean's surface and cold water pumped from the deep ocean. Like a ball rolling downhill, heat flows from the warm reservoir to the cool one. The greater the temperature difference, the stronger the flow of heat that can be used to do useful work such as spinning a turbine and generating electricity.
This small difference translates to 15 percent more power for an OTEC plant, says Nihous, whose theoretical work focuses on driving down cost and increasing efficiency of future facilities, the biggest hurdles to bringing the technology to the mainstream.
"Testing that was done in the 1980s clearly demonstrates the feasibility of this technology," he says. "Now it's just a matter of paying for it."
Source: http://www.sciencedaily.com/
Researchers at the University of Hawaii at Manoa say that the Leeward side of Hawaiian Islands may be ideal for future ocean-based renewable energy plants that would use seawater from the oceans' depths to drive massive heat engines and produce steady amounts of renewable energy.
The technology, referred to as Ocean Thermal Energy Conversion (OTEC), is described in the Journal of Renewable and Sustainable Energy, which is published by the American Institute of Physics (AIP).
It involves placing a heat engine between warm water collected at the ocean's surface and cold water pumped from the deep ocean. Like a ball rolling downhill, heat flows from the warm reservoir to the cool one. The greater the temperature difference, the stronger the flow of heat that can be used to do useful work such as spinning a turbine and generating electricity.
This small difference translates to 15 percent more power for an OTEC plant, says Nihous, whose theoretical work focuses on driving down cost and increasing efficiency of future facilities, the biggest hurdles to bringing the technology to the mainstream.
"Testing that was done in the 1980s clearly demonstrates the feasibility of this technology," he says. "Now it's just a matter of paying for it."
Source: http://www.sciencedaily.com/
Tuesday, August 3, 2010
Census of Marine Life Publishes Historic Roll Call of Species in 25 Key World Areas
Representing the most comprehensive and authoritative answer yet to one of humanity's most ancient questions -- "what lives in the sea?" -- Census of Marine Life scientists today released an inventory of species distribution and diversity in key global ocean areas.
Scientists combined information collected over centuries with data obtained during the decade-long Census to create a roll call of species in 25 biologically representative regions -- from the Antarctic through temperate and tropical seas to the Arctic.
Scientists find that the number of known, named species contained in the 25 areas ranged from 2,600 to 33,000 and averaged about 10,750, which fall into a dozen groups. On average, about one-fifth of all species were crustaceans which, with mollusks and fish, make up half of all known species on average across the regions.
The full breakdown follows:
•19% Crustaceans (including crabs, lobsters, crayfish, shrimp, krill and barnacles),
•17% Mollusca (including squid, octopus, clams, snails and slugs)
•12% Pisces (fish, including sharks)
•10% Protozoa (unicellular micro-organisms)
•10% algae and other plant-like organisms
•7% Annelida (segmented worms)
•5% Cnidaria (including sea anemones, corals and jellyfish)
•3% Platyhelminthes (including flatworms)
•3% Echinodermata (including starfish, brittle stars, sea urchins, sand dollars and sea cucumbers)
•3% Porifera (including sponges)
•2% Bryozoa (mat or 'moss animals')
•1% Tunicata (including sea squirts)
The rest are other invertebrates (5%) and other vertebrates (2%). The scarce 2% of species in the "other vertebrates" category includes whales, sea lions, seals, sea birds, turtles and walruses. Thus some of the best-known marine animals comprise a tiny part of marine biodiversity.
How much is unknown?
In October, the Census will release its latest estimate of all marine species known to science, including those still to be added to WoRMS and OBIS. This is likely to exceed 230,000.
Greatest threats
According to the Census studies published in PLoS ONE, the main threats to marine life to date have been overfishing, lost habitat, invasive species and pollution, although the relative importance of the threats varied among regions. Emerging threats include rising water temperature and acidification, and the enlargement of areas characterized by low oxygen content (called hypoxia) of seawater. These too will vary regionally (surface temperature, for example) whereas others are more global (such as acidification).
Overfishing not only depletes the exploited fish themselves but also depletes other species like turtles, albatrosses, sharks and mammals, caught unintentionally. It alters food webs within ecosystems.
Coastal urbanization, sediment runoff and nutrients in sewage and fertilizer washed from the land and causing eutrophication and hypoxia are destroying marine habitats.
The more enclosed seas -- Mediterranean, Gulf of Mexico, China's shelves, Baltic, and Caribbean -- were reported to have the most threatened biodiversity.
Source: www.sciencedaily.com
Scientists combined information collected over centuries with data obtained during the decade-long Census to create a roll call of species in 25 biologically representative regions -- from the Antarctic through temperate and tropical seas to the Arctic.
Scientists find that the number of known, named species contained in the 25 areas ranged from 2,600 to 33,000 and averaged about 10,750, which fall into a dozen groups. On average, about one-fifth of all species were crustaceans which, with mollusks and fish, make up half of all known species on average across the regions.
The full breakdown follows:
•19% Crustaceans (including crabs, lobsters, crayfish, shrimp, krill and barnacles),
•17% Mollusca (including squid, octopus, clams, snails and slugs)
•12% Pisces (fish, including sharks)
•10% Protozoa (unicellular micro-organisms)
•10% algae and other plant-like organisms
•7% Annelida (segmented worms)
•5% Cnidaria (including sea anemones, corals and jellyfish)
•3% Platyhelminthes (including flatworms)
•3% Echinodermata (including starfish, brittle stars, sea urchins, sand dollars and sea cucumbers)
•3% Porifera (including sponges)
•2% Bryozoa (mat or 'moss animals')
•1% Tunicata (including sea squirts)
The rest are other invertebrates (5%) and other vertebrates (2%). The scarce 2% of species in the "other vertebrates" category includes whales, sea lions, seals, sea birds, turtles and walruses. Thus some of the best-known marine animals comprise a tiny part of marine biodiversity.
How much is unknown?
In October, the Census will release its latest estimate of all marine species known to science, including those still to be added to WoRMS and OBIS. This is likely to exceed 230,000.
Greatest threats
According to the Census studies published in PLoS ONE, the main threats to marine life to date have been overfishing, lost habitat, invasive species and pollution, although the relative importance of the threats varied among regions. Emerging threats include rising water temperature and acidification, and the enlargement of areas characterized by low oxygen content (called hypoxia) of seawater. These too will vary regionally (surface temperature, for example) whereas others are more global (such as acidification).
Overfishing not only depletes the exploited fish themselves but also depletes other species like turtles, albatrosses, sharks and mammals, caught unintentionally. It alters food webs within ecosystems.
Coastal urbanization, sediment runoff and nutrients in sewage and fertilizer washed from the land and causing eutrophication and hypoxia are destroying marine habitats.
The more enclosed seas -- Mediterranean, Gulf of Mexico, China's shelves, Baltic, and Caribbean -- were reported to have the most threatened biodiversity.
Source: www.sciencedaily.com
Friday, July 30, 2010
Rising CO2
Atmospheric carbon dioxide levels rise, so does the pressure on the plant kingdom. The hope among policymakers, scientists and concerned citizens is that plants will absorb some of the extra CO2 and mitigate the impacts of climate change. For a few decades now, researchers have hypothesized about one major roadblock: nitrogen.
Scientist Adam Langley sprays plants in a test chamber with nitrogen. The additional nutrients changed the composition of the plants inside the chamber, spurring the growth of grasses that respond weakly to elevated levels of CO2. (Credit: SERC)
Plants build their tissue primarily with the CO2 they take up from the atmosphere. The more they get, the faster they tend to grow -- a phenomenon known as the "CO2 fertilization effect." However, plants that photosynthesize greater amounts of CO2 will also need higher doses of other key building blocks, especially nitrogen. The general consensus has been that if plants get more nitrogen, there will be a larger CO2 fertilization effect. Not necessarily so, says a new paper published in the July 1 issue of Nature.
The sedge, Schoenoplectus americanus, initially reacted as expected. However, after the first year something unanticipated happened. Two grass species that had been relatively rare in the plots, Spartina patens and Distichlis spicata, began to respond vigorously to the excess nitrogen. Eventually the grasses became much more abundant. Unlike sedges, grasses respond weakly to extra CO2 and do not grow faster. Thus, the nitrogen ultimately changed the composition of the ecosystem as well as its capacity to store carbon.
Megonigal and Langley placed 20 open-top chambers over random plots of plants. The chambers were 6 feet in diameter and had 5-foot-tall transparent plastic walls.
The large, plastic pods allowed the scientists to manipulate CO2 concentrations in the air and nitrogen levels in the soil. Half of the plots grew with normal, background CO2 levels; the other half were raised in an environment with CO2 concentrations roughly double that amount. Similarly, half of the chambers were fertilized with nitrogen and the other half were untreated.
This study was supported by the U.S. Geological Survey and U.S. Department of Energy. The Smithsonian scientists recently received funding from the National Science Foundation that will sustain the research for another 10 years.
Source: www.sciencedaily.com
Scientist Adam Langley sprays plants in a test chamber with nitrogen. The additional nutrients changed the composition of the plants inside the chamber, spurring the growth of grasses that respond weakly to elevated levels of CO2. (Credit: SERC)
Plants build their tissue primarily with the CO2 they take up from the atmosphere. The more they get, the faster they tend to grow -- a phenomenon known as the "CO2 fertilization effect." However, plants that photosynthesize greater amounts of CO2 will also need higher doses of other key building blocks, especially nitrogen. The general consensus has been that if plants get more nitrogen, there will be a larger CO2 fertilization effect. Not necessarily so, says a new paper published in the July 1 issue of Nature.
The sedge, Schoenoplectus americanus, initially reacted as expected. However, after the first year something unanticipated happened. Two grass species that had been relatively rare in the plots, Spartina patens and Distichlis spicata, began to respond vigorously to the excess nitrogen. Eventually the grasses became much more abundant. Unlike sedges, grasses respond weakly to extra CO2 and do not grow faster. Thus, the nitrogen ultimately changed the composition of the ecosystem as well as its capacity to store carbon.
Megonigal and Langley placed 20 open-top chambers over random plots of plants. The chambers were 6 feet in diameter and had 5-foot-tall transparent plastic walls.
The large, plastic pods allowed the scientists to manipulate CO2 concentrations in the air and nitrogen levels in the soil. Half of the plots grew with normal, background CO2 levels; the other half were raised in an environment with CO2 concentrations roughly double that amount. Similarly, half of the chambers were fertilized with nitrogen and the other half were untreated.
This study was supported by the U.S. Geological Survey and U.S. Department of Energy. The Smithsonian scientists recently received funding from the National Science Foundation that will sustain the research for another 10 years.
Source: www.sciencedaily.com
Saturday, July 17, 2010
Camouflage by Joe Haldeman(2nd book review)
This is the second book that I am reading and its title is camouflage.
This a very interesting science fiction book about two aliens of Earth. One is the changeling and the other is the chameleon. The changeling survived by taking shapes of differnt organisms like the great whita shark and other animals, while the chameleon survived by destoying anything that threatens it. Both knew llittle about each other but the chameleon decides that he must kill the changeling. The book then continues about the adventure of the changeling and also about the chameleon and also about a biologist Russell Sutton. Russell found an artifact and is studyign it and both the aliens are also drawn to it. The chameleon and changeling later fought together and later the chameleon died and the changeling went back to its planet. This novel is very interesting in the adventures of the changeling which is the main part of this book. The story is clearly easy to understand and the ending is also satisfying. A very interecting and enjoyable book. Read it some day :)
Author: Joe haldeman
Haldeman's most famous novel is The Forever War (1975), inspired by his Vietnam experiences, which won both the Hugo and Nebula Awards. He later turned it into a series. Haldeman also wrote two of the earliest original novels based on the 1960s Star Trek TV series universe, Planet of Judgment (August 1977) and World Without End (February 1979). In October 2008 it was announced that Ridley Scott will direct a feature film based on The Forever War for Fox
Haldeman has written at least one produced Hollywood movie script. The film, a low-budget science fiction film called Robot Jox, was released in 1990. He was not entirely happy with the product, saying "to me it’s as if I’d had a child who started out well and then sustained brain damage".
He is a lifetime member of the Science Fiction and Fantasy Writers of America (SFWA), and past-president.
Haldeman is the brother of Jack C. Haldeman II (1941-2002), also a science-fiction author whose work included an original Star Trek novel (Perry's Planet, February 1980).
This a very interesting science fiction book about two aliens of Earth. One is the changeling and the other is the chameleon. The changeling survived by taking shapes of differnt organisms like the great whita shark and other animals, while the chameleon survived by destoying anything that threatens it. Both knew llittle about each other but the chameleon decides that he must kill the changeling. The book then continues about the adventure of the changeling and also about the chameleon and also about a biologist Russell Sutton. Russell found an artifact and is studyign it and both the aliens are also drawn to it. The chameleon and changeling later fought together and later the chameleon died and the changeling went back to its planet. This novel is very interesting in the adventures of the changeling which is the main part of this book. The story is clearly easy to understand and the ending is also satisfying. A very interecting and enjoyable book. Read it some day :)
Author: Joe haldeman
Haldeman's most famous novel is The Forever War (1975), inspired by his Vietnam experiences, which won both the Hugo and Nebula Awards. He later turned it into a series. Haldeman also wrote two of the earliest original novels based on the 1960s Star Trek TV series universe, Planet of Judgment (August 1977) and World Without End (February 1979). In October 2008 it was announced that Ridley Scott will direct a feature film based on The Forever War for Fox
Haldeman has written at least one produced Hollywood movie script. The film, a low-budget science fiction film called Robot Jox, was released in 1990. He was not entirely happy with the product, saying "to me it’s as if I’d had a child who started out well and then sustained brain damage".
He is a lifetime member of the Science Fiction and Fantasy Writers of America (SFWA), and past-president.
Haldeman is the brother of Jack C. Haldeman II (1941-2002), also a science-fiction author whose work included an original Star Trek novel (Perry's Planet, February 1980).
Thursday, July 15, 2010
Warmer Ecosystems
Research by scientists at Queen Mary, University of London has found that a predicted rise in global temperature of 4°C by 2100 could lead to a 13% reduction in ecosystems' ability to absorb carbon dioxide (CO2) from the atmosphere.
Research by scientists at Queen Mary, University of London has found that a predicted rise in global temperature of 4°C by 2100 could lead to a 13% reduction in ecosystems' ability to absorb carbon dioxide (CO2) from the atmosphere. (Credit: Image courtesy of Queen Mary, University of London)
"Photosynthesis by plants absorbs CO2 while respiration by animals returns CO2 to the atmosphere. Respiration has a higher 'activation energy' than photosynthesis meaning that it increases more rapidly with increasing temperature. So if climate change raises environmental temperatures, the balance between respiration and photosynthesis in the ecosystem will change, favouring more respiration and less CO2 absorption."
The work is complemented by another paper published this month by Dr Guy Woodward and other Queen Mary colleagues in the journal Global Change Biology. This research compared animals living in 15 similar Icelandic streams, a rare long-term 'natural experiment' in which geothermal activity heats some streams up to 45°C. The unique situation meant researchers could study how temperature affects Arctic ecosystems, where climate change is predicted to cause a rise of around 7.5°C within the next century.
"We saw longer food-chains, with predators becoming bigger and more abundant as temperatures increased from 5°C to 25°C. We also have more recent (as yet unpublished) data collected from the Icelandic streams by colleagues at the Macaulay Institute that show similar patterns to those seen in the experimental ponds: namely the warmer streams emitted far more CO2 than the cooler streams and acted as sources of carbon, rather than sinks."
Source: www.sciencedaily.com
Research by scientists at Queen Mary, University of London has found that a predicted rise in global temperature of 4°C by 2100 could lead to a 13% reduction in ecosystems' ability to absorb carbon dioxide (CO2) from the atmosphere. (Credit: Image courtesy of Queen Mary, University of London)
"Photosynthesis by plants absorbs CO2 while respiration by animals returns CO2 to the atmosphere. Respiration has a higher 'activation energy' than photosynthesis meaning that it increases more rapidly with increasing temperature. So if climate change raises environmental temperatures, the balance between respiration and photosynthesis in the ecosystem will change, favouring more respiration and less CO2 absorption."
The work is complemented by another paper published this month by Dr Guy Woodward and other Queen Mary colleagues in the journal Global Change Biology. This research compared animals living in 15 similar Icelandic streams, a rare long-term 'natural experiment' in which geothermal activity heats some streams up to 45°C. The unique situation meant researchers could study how temperature affects Arctic ecosystems, where climate change is predicted to cause a rise of around 7.5°C within the next century.
"We saw longer food-chains, with predators becoming bigger and more abundant as temperatures increased from 5°C to 25°C. We also have more recent (as yet unpublished) data collected from the Icelandic streams by colleagues at the Macaulay Institute that show similar patterns to those seen in the experimental ponds: namely the warmer streams emitted far more CO2 than the cooler streams and acted as sources of carbon, rather than sinks."
Source: www.sciencedaily.com
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