Don’t be alarmed, but on a remote island in Scotland the sheep are shrinking.
Instead of gradually increasing in size as expected due to evolution, the average weight of the wild sheep has decreased as average temperatures heat up. The discovery shows that a species’ response to global warming can be unpredictable, and can be based on multiple factors. According to a study published in Science, warmer and wetter winters have made it easier for smaller sheep to survive the hard months and go on to bear offspring, thus passing these “small” genes onto the next generation of sheep.
Since 1985, the average weight of the wild Soay sheep living on the island of Hirta has decreased by about 5 percent. Due to global warming, the winters on the Scottish isles are becoming becoming shorter and milder. That makes food more abundant and allows some of the smaller, more vulnerable and younger sheep to survive. Then they go on to have offspring that tend to be small themselves — and have a better chance of survival because of the increasingly mild winters. “The environmental and evolutionary processes are intertwined. There’s still natural selection, but it’s not leaving as big a signature as it used to. There’s still a disadvantage to being small, but not as much” [Time], says lead researcher Tim Coulson.
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Human beings are increasingly making their homes on the coasts of continents, but this demographic shift is taking a toll on a sensitive coastal ecosystem that is often overlooked: seagrass meadows. A new analysis of seagrass abundance around the world found that 27 percent of these meadows have disappeared since 1879, and the rate of loss is accelerating. The study’s authors write: “Seagrass loss rates are comparable to those reported for mangroves, coral reefs and tropical rainforests, and place seagrass meadows among the most threatened ecosystems on earth….. Our report of mounting seagrass losses reveals a major global environmental crisis in coastal ecosystems, for which seagrasses are sentinels of change” [Nature News].
Endangered species expert Susanne Livingstone notes that despite these losses seagrass rarely makes it into the public consciousness. “It’s probably because they’re not as sexy [as corals], they’re not as attractive,” she says. “They’re just as ecologically important if not more so” [Nature News]. Seagrass meadows provide grazing for a variety of marine animals, including the green turtle and the manatee-like dugong. The coastal areas also serve as nurseries for fish; both coral reefs and commercial fisheries would feel the impact if seagrass meadows vanish.
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The union between the native California tiger salamander and the non-native barred tiger salamander, which was brought in huge numbers from Texas beginning 60 years ago by California bait dealers [The New York Times], has produced an alarming hybrid offspring. A new study of the hybrid’s behavior in artificial ponds serves as a reminder that invasive species can alter ecosystems in unexpected ways: in this case, by getting too cozy with the natives of central California.
The new hybrid “superpredator” grows larger than either of its parent species, and its bigger mouth enables it to suck up a wide variety of amphibian prey, said lead study author Maureen Ryan…. Mostly on the menu are smaller pond species, such as the Pacific chorus frog and the California newt—both of which were “dramatically reduced” in population by the hybrid in the experiments [National Geographic News].
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In a 219-212 vote, the House of Representatives passed on Friday a climate bill designed to decrease U.S. dependence on oil and create “green” jobs. It’s now up to the Senate to pass or veto the American Clean Energy and Security Act, which also proposes a cap-and-trade system to impose historic limits on U.S. greenhouse gas emissions.
The bill has been tweaked since it was approved in May by the House Energy and Commerce Committee, and it remains unclear how much progress the Senate will make on the bill. In it, U.S. emissions of carbon dioxide and other greenhouse gases would be reduced 17 percent by 2020 from 2005 levels. That is less ambitious than the 20 percent initially sought, but slightly more aggressive than the approximately 15 percent Obama proposed. The legislation sets further pollution reduction goals — 42 percent by 2030 and 83 percent by 2050, with the latter just slightly higher than Obama suggested [Reuters]. The bill also speeds up the administration of $346 million in stimulus funds for the development and implementation of energy efficient technology.
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Global warming is expected to cause such alarming climate disruptions that talk of hurricanes and heat waves can overshadow another drastic process at work: Burning fossil fuels and otherwise producing excess carbon dioxide makes oceans and other bodies of water more acidic, as the water absorbs the gas. This acidification can change a fish’s physiology in ways that were previously unpredicted and could affect the fish’s survival, according to a study in Science.
Scientists raised groups of white sea bass in water of varying concentrations of carbon dioxide. They found that the fish in the most highly acidified water had the largest rock-shaped ear bones, known in biology parlance at otoliths. That contradicts what the researchers had hypothesized: The ear structure in fish, known as an otolith, is made up of minerals. Scientists knew that increasing carbon dioxide in the oceans — absorbed from the atmosphere — is making the sea more acidic, which can dissolve and weaken shells. They wondered if it also would reduce the size of the otoliths [Los Angeles Times]. Instead, the ear bones of fish growing in the tank with six times as much carbon dioxide than normal were 15 to 17 percent larger than normal. An water with a CO2 concentration about 3.5 times higher than current levels yielded fish with otoliths that were 7 to 9 percent larger than those raised in water with today’s carbon dioxide levels. That’s the CO2 level predicted by the year 2100.
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The state of Louisiana is losing its coastal wetlands to the Gulf of Mexico, and a new study suggests that conservationists won’t be able to turn the tide. If engineers don’t divert sediment-rich waters from the Mississippi River to help replenish a sinking river delta, about 10 percent of [the] state will slip beneath the waves by the end of this century. However, even if the engineers do try to abate the subsidence, the Mississippi doesn’t carry enough sediment to offset more than a small fraction of that loss, a new analysis suggests [Science News].
Before American settlers subdued the Mississippi and its tributaries, the river periodically overflowed its banks and spilled muddy water, thick with sediment, into surrounding wetlands. But the new study found that the Mississippi and Atchafalaya rivers today carry only half the sediment they did a century ago — between 400 million and 500 million tons a year then, compared with just 205 million tons today. The rest is now captured by more than 40,000 dams and reservoirs that have been built on rivers and streams that flow into the main channels [The Times-Picayune].
So even if Louisiana officials embark on an all-out campaign to restore the marshes through controlled levee breaks and diversion projects that bring back river water, it wouldn’t be enough to save the land–especially since sea levels are rising due to global warming. “We conclude that significant drowning is inevitable” [The Guardian], the study’s authors wrote.
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As of tomorrow, 101 years will have passed since the Tunguska Event, the mysterious explosion that flattened 800 square miles of Siberian forest. Just in time for the anniversary researchers have come up with yet another explanation for what may have caused the baffling blast. Previously, researchers best hypothesis was that a meteor struck the forest, but scientific expeditions failed to turn up an impact crater or any fragments of rock. The new hypothesis, which will be published in the journal Geophysical Research Letters, suggests that the Earth was hit by the icy core of a comet, which exploded in the atmosphere.
Researchers say that a comet strike would have released huge volumes of water vapour at very high altitude, creating highly reflective clouds that may explain why the sky was lit up for days after the collision, with people as far away as London saying that they could read newspapers outdoors at midnight, the scientists said [The Independent]. In an usual twist, the evidence for the new theory comes from studies of the water vapor exhaust created by space shuttle launches.
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As the International Whaling Commission wound down this week with no progress made on the stalemate between pro-whaling and anti-whaling nations, some experts are beginning to question the commission’s central tool: the moratorium on commercial whaling established more than 20 years ago.Some experts wonder whether the ban is really protecting the world’s whale populations. Japan’s so-called “scientific whaling” program is a loophole in the ban, and the program is widely seen as a cover for commercial whaling. Japan catches more than 1,000 whales a year, and most cetacean researchers argue that whale populations exist at only a fraction of their former abundance and are far from large enough to sustain commercial harvesting for meat or oil — or even the culling of some 1,000 whales a year for science. Australia, a party to the IWC, campaigned this year to end any ”scientific whaling” that involves the deliberate killing of whales [Science News].
A report released by the commission on Monday also states that a quarter of the whales harvested from the Antarctic Ocean in the last seven months by Japanese researchers were pregnant. To many, the destruction of these whales and their unborn calves makes a mockery of the moratorium on whaling, given that the goal of the ban is to preserve whale populations. However, the Japanese Whaling Association contends on its Web site that “No whales have ever been hunted to extinction, nor are they likely to be. . . . [And] there are species which are abundant enough that marine management is needed,” such as for the Antarctic and northwestern Pacific minke whales and northwestern Pacific Bryde’s whales [Science News].
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When Chicago’s Sears Tower was completed in 1973 the 110-story building was the tallest in the world, and it offered a bold example of the human potential to build towards the clouds. Now, although the tower lost the title of tallest building to other skyscrapers in the 1990s, the tower hopes to dazzle the world anew with a fresh vision of urban architecture: The building will soon receive a $350 million environmental retrofit, with wind turbines, solar panels, and gardens all added to the building’s staggered rooftops.
The 5-year project would reduce the tower’s electricity use by 80 percent and save 24 million gallons of water a year, building owners and architects said…. “Our plans are very ambitious,” said John Huston of American Landmark Properties, who represents the building ownership. “Our plans to modernize and transform this icon will re-establish Sears Tower as a leader, a pioneer” [AP].
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In the heat and humidity of the tropics you might expect that mammals take it slow and easy–but on the genetic level, they’re accelerating past their mammalian relations that live in more temperate zones. A new study has discovered that tropical mammals are accumulating mutations more quickly and are therefore evolving faster, in a finding that could help account for the phenomenal biodiversity of the rainforests. But the study’s unexpected results have posed a puzzle for biologists. “[It’s] an empirical pattern that is begging for an explanation” [The Scientist], says evolutionary ecologist James Brown, who was not involved in the current study.
Previous research had shown that plants and marine microorganisms evolve more quickly in the tropical zone near the equator, but scientists believed that pattern would hold true only for cold-blooded creatures, whose body temperatures and metabolisms are determined by the temperature of the surrounding environment. Scientists believe that this link between temperature and metabolic rate means that, in warmer climates, the germ cells that eventually develop into sperm and eggs divide more frequently. “An increase in cell division provides more opportunities for mutations in the population over a given time,” explained [lead researcher Len] Gillman. “This increases the probability of advantageous mutations that are selected for within the species” [BBC News]. But this mechanism wouldn’t work in warm-blooded mammals, whose body temperatures remain roughly constant regardless of environmental factors.
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Sleek, streamlined wind turbines have become the icons of the green movement, but for all the growth in wind power — it accounted for 42% of all new electricity generation added to the U.S. grid last year — wind still makes up less than 3% of America’s total electricity generation [Time]. Its marginal role has led many to wonder whether the technology is worth investing in, and whether wind power is capable of supplying enough electricity to meet our needs. To answer those questions, researchers analyzed wind patterns around the world and found that wind power could theoretically supply the entire world with energy, and then some.
The study, published in the Proceedings of the National Academy of Sciences, isn’t being presented as a realistic plan to achieve a renewable energy nirvana; it’s simply an attempt to provide a sense of what’s possible [Ars Technica]. But the researchers’ reckoning of what’s possible is quite impressive: maxing out deployment of current-generation technology could produce five times the total energy used in the world today, and 40 times the electricity [Ars Technica].
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The Department of Energy is handing out nearly $8 billion in loans today, and $465 million of the funds will go to Tesla Motors to produce its Model S electric sedan, the company’s first attempt at a mass-market car. The company already manufactures the Roadster, a high-performance electric sports car. Nissan and Ford Motor Company will receive the other loans; they’ll get $1.6 billion and $5.9 billion, respectively, to help produce fuel-efficient cars.
Nissan will use the funds updating a plant in Tennessee to produce the company’s upcoming electric sedan, and Ford’s loan will help expedite production of cars that go farther on less fuel. Tesla was perhaps the wild card in the funding equation because it is a small startup. The company has delivered slightly more than 500 Roadsters to customers, and the government loan will help pay for a Southern California manufacturing plant for the Model S sedan, due in 2011. A second plant in the Bay Area will make battery packs and electric drivetrains [The New York Times].
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Cleveland’s Cuyahoga River caught on fire 40 years ago June 22 when oily garbage floating in it was ignited, probably by sparks from a passing train. In turn, the fire sparked the creation of environmental agencies such as the Environmental Protection Agency, along with passage of 1972’s Clean Water Act. And the river, once a dumping ground for industrial waste and an icon for environmental disrepair, today supports more than 60 species of fish along with beavers and various bird species, and serves as an example of environmental restoration.
The river’s recovery is an inspirational account of how even the most putrid bodies of water could be cleaned up. Indeed, the first time [Cleveland resident] Gene Roberts fell into the Cuyahoga River, he worried he might die. The year was 1963, and the river was still an open sewer for industrial waste. Walking home, Mr. Roberts smelled so bad that his friends ran to stay upwind of him. Recently, Mr. Roberts returned to the river carrying his fly-fishing rod. In 20 minutes, he caught six smallmouth bass. “It’s a miracle,” said Mr. Roberts, 58. “The river has come back to life” [The New York Times].
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Who knew this spring’s soggy weather fell under the umbrella of physics research? Scientists found that when raindrops fall faster than physics predicts, the drops have actually broken into smaller droplets, according to a study in the journal Geophysical Research Letters. And because weather services gauge rainfall based on the velocity at which droplets fall–conventional wisdom holds that large drops should hit the ground at a higher speed than do smaller droplets–these results could improve the way we predict weather.
All falling objects have a so-called terminal velocity, a speed they can’t surpass due to air resistance. Therefore, larger drops generally should fall faster because their heftier size helps them power through air resistance more easily than little drops. (In the extreme case, think of fog: water droplets so small they don’t fall at all.) But data showing small drops sometimes impact the ground at the same speed as larger ones showed this conventional wisdom was wrong, and has puzzled scientists for years. To solve the mystery, the researchers collected a shower of data using optical equipment over a period of several years. The team clocked about 64,000 raindrops falling in Mexico City. The researchers measured their sizes and velocities only in extremely calm conditions, so the wind that often accompanies rain could not skew the data. They found that some drops plummeted faster than the so-called terminal velocity for their size [ScienceNOW Daily News].
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Curious how much carbon the atmosphere contains at this moment? Look no further than a giant “carbon counter” first switched on yesterday morning near New York City’s Pennsylvania Station. The 70-foot-tall screen, lit by digital low-energy LED, displays in real time the amount of greenhouse gases present in the atmosphere–and therefore gives some indication of how much trouble humanity is facing from global warming.
People outside of New York, don’t despair: The constantly scrolling numbers can be viewed at the project’s Web site as well. The numbers shown are based on measurements developed at the Massachusetts Institute of Technology and include all the long-lasting greenhouse gases in the 1997 Kyoto Protocol, which was established at the United Nations Framework Convention on Climate change [Bloomberg].
The clock, which is illuminated 24 hours a day, is also environmentally friendly. It uses low-risk carbon credits to offset its energy use, while illuminating digital numbers with 40,960 low-energy light-emitting diodes [Bloomberg]. The counter is a project Deutsche Asset Management, a branch of Deutsche Bank that invests in industries that mitigate or adapt to climate change.
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