Like humans, sea stars enjoy lounging on the shore during the hot summer months. But when they get too hot, they can’t run for shade, so they have a back-up plan—fattening themselves with cold ocean water before the tide recedes, according to new research published in the journal The American Naturalist. This finding shows that sea stars, or ochre starfish, aren’t as helpless as previously thought. The sea stars are likely cued during low tide that it’s a hot day, the researchers say, and that signals them to soak up more water during the next high tide. “It would be as if humans were able to look at a weather forecast, decide it was going to be hot tomorrow, and then in preparation suck up 15 or more pounds of water into our bodies,” said study researcher Brian Helmuth [LiveScience]. Talk about staying hydrated.
The researchers first studied starfish in an aquarium using heat lamps to simulate a scorching summer day, an infrared camera to measure their internal temperatures, and a scale to weigh the sea stars and determine how much water they had absorbed. The researchers say the amount of water a starfish absorbs can decrease its body temperature by almost 4 degrees Celsius. But researcher Sylvain Pincebourde is concerned that this novel strategy may have limitations in a rapidly changing world…. As oceans warm together with air temperature the thermoregulatory mechanism used by the starfish will cease to work, he warns. “The colder the sea water, the more it is able to lower its body temperature. The efficiency of this thermoregulation strategy therefore might be annihilated by ocean warming” [BBC News]. Yet another reason to get a handle on global carbon emissions.
Related Content:
80beats: An Ostentatious Air Conditioner: The Toucan’s Big Beak
80beats: T. Rex May Have Been a Hot-Blooded, Sweaty Beast
80beats: Extinct Goat Tried out Reptilian, Cold-Blooded Living (It Didn’t Work)
80beats: How Did Dinosaurs Get So Big? Maybe Because They Were Couch Potatoes
Image: flickr / laszio-photo
It was a twisted cycle: In the 1970s, Bangladeshis used surface ponds or rivers to collect rainwater for drinking. But thanks to garbage dumping and sewage, that water became a breeding ground for disease. So UNICEF sought to fix the problem—the agency helped residents drill simple wells that drew water from a shallow aquifer. But this remedy became a tragedy. Bangladesh’s groundwater was laced with arsenic. Now, in a study in Nature Geoscience, a team from MIT has answered one of the outstanding pieces of the Bangladesh puzzle: Just how all that arsenic got into the water in the first place.
Bangladesh occupies the flood-prone delta of the river Ganges [New Scientist], and that river brought the arsenic to the region’s sediments. But why doesn’t it just stay in the sediments once it’s there? Back in 2002, another MIT team began to answer the question by showing that microbes digest organic carbon in the soil in such a way that frees up the arsenic, but they couldn’t say where that carbon itself came from until Rebecca Neumann and colleagues figured it out this year: man-made ponds left behind by excavations.
(more…)
Bomb and you shall find.
NASA today claimed success in its quest to find water on the moon. “Indeed, yes, we found water. And we didn’t find just a little bit, we found a significant amount,” said Anthony Colaprete, a principal project investigator at NASA’s Ames Research Center [AP].
Scientists had been analyzing data for more than a month since NASA crashed the LCROSS craft into the moon on October 9, which created a tiny crater in the polar region and kicked up a plume of material that had been beneath the lunar surface. NASA worried when the original impact didn’t create the easily visible plume of material that they’d anticipated, but later images showed that the mystery plume had been created and scientists were free to analyze its composition.
The results are clear: both infrared and ultraviolet spectrometers indicated the presence of water, and those readings got stronger over time, which is what you’d expect if you bombed the moon and created a plume full of water.
(more…)
The lack of fireworks after a NASA probe struck a crater on the moon’s surface disappointed observers watching from Earth, and many initially questioned the mission’s success. However, new images show a mile-high plume of lunar debris from the Cabeus crater shortly after the space agency’s Centaur rocket struck Oct. 9 [AP]. This is almost exactly what the mission’s engineers had in mind when they proposed slinging an empty rocket hull into a crater at the moon’s south pole, so that the LCROSS probe that followed could analyze the dust plume for traces of water ice. Researchers had initially predicted a 6-mile-high plume that would be visible from Earth’s observatories, but they’re presumably thankful for what they got.
A movie screen at the Ames Research Center in Northern California was set to show the impact from the vantage point of a camera on board LCROSS, but the crowd walked away disappointed when the impact produced no visible plume of dust and debris. At the time, NASA scientists said they hoped the problem was simply that cameras aboard the satellite were not properly adjusted to detect the plume. But some scientists feared the Centaur might have hit bedrock and failed to create a plume. The new images, lifted from a different camera aboard the spacecraft, show that a plume did, in fact, occur. That means the satellite should have been capable of detecting water, if it was present [Los Angeles Times]. Scientists said it’s still too early to say what was in the plume, but other clues, such as the heat generated at the impact sight, should help the scientists interpret the data over the next few weeks.
Related Content:
80beats: So What Exactly Happened With That Crashing Moon Probe?
80beats: Lunar Impact! NASA Probe Slams Into Moon to Search for Water
80beats: NASA to Moon: We’re Back. Got Any Ice?
Image: NASA
With much fanfare, NASA’s lunar probe smashed into the moon this past Friday in an attempt to excavate and study hypothetical traces of lunar water ice. As planned, the probe slung an empty rocket hull into a crater at the moon’s south pole. The LCROSS probe itself then followed behind the rocket hull, snapping photos and beaming them back to Earth before smashing into the very same crater. The impact appears to have gone off without a hitch, however the crash left many disappointed since the expected 6.2-mile-high cloud of dust, which was to be analyzed for traces of ice, never materialized. So far, astronomers using ground-based telescopes and the Hubble Space Telescope in orbit have not reported seeing any ejecta plume, but have cautioned that more time is needed to be sure [SPACE.com].
At a post-impact briefing, many in the press expressed concern about the mission’s success. In response, LCROSS project scientist Anthony Colaprete outlined several reasons why the impacts may not have thrown up plumes immediately visible after the impacts, including the [impact] hitting the inner walls of the crater at an angle that ejected the impact pit dust sideways instead of straight up. “Luck plays a part in this,” he said, adding. “We have the data we need to address the questions we have and that’s the bottom line” [USA Today]. The researchers also say it’s possible that the rocket hull hit bedrock instead of loose, gravelly soil as expected, and therefore kicked up only a small debris cloud that wasn’t visible to LCROSS.
(more…)
NASA successfully crashed two objects into the moon early this morning, in an attempt to kick up the dust so it could be checked for traces of water ice. At 7:31 a.m. EST, an empty rocket hull plummeted towards the surface at 1.5 miles per second and plowed into a crater near the moon’s south pole, where it was expected to create a mini-crater half the size of an Olympic swimming pool. It was trailed by the LCROSS probe, which was supposed to take pictures of the first impact, fly through the dust plume, and then crash into the moon itself. According to early reports, the whole procedure went fine–except for one of the flashier details.
The live feed of images that LCROSS was supposed to beam back to Earth–and that earthlings were waiting for with baited breath–didn’t arrive on schedule. Screens got fuzz and no immediate pictures of the crash or the six-mile plume of lunar dust that the mission was all about. NASA officials said their instruments were working, but the planned live photos were missing…. People who got up before dawn to look for the crash at Los Angeles’ Griffith Observatory threw confused looks at each other instead. Telescope demonstrator Jim Mahon called the celestial show “anticlimactic” [AP].
(more…)
Mars has quite a bit more water than previously thought, according to a new report in the journal Science. NASA said its Mars Reconnaissance Orbiter spotted ice at five new Martian craters, likely kicked up by meteor impacts [Reuters]. It’s no surprise that the NASA orbiter found water, it’s the size of the find—twice as much as in Greenland’s ice sheet—that surprised scientists. The ice is just under the surface, so it was only visible after the recent meteor impacts.
The ice was found half way between the north pole and the equator, which is the farthest south ice has been found on Mars. Scientists believe that water once flowed across the planet, but most thought the surface had been largely dry and parched, with planet-wide dust storms, for billions of years. They had long known that water ice and carbon dioxide ice accumulated at the poles in winter, but until now, they had no idea how far from the poles the underground ice sheet extended [Los Angeles Times].
This image shows two craters with blueish ice, which—when exposed to the Martian atmosphere—sublimates over the course of 15 weeks.
Related Content:
Bad Astronomy: Water on (shakes Magic 8 ball) Mars this time
80beats: Solar Protons + Lunar Dust = Lots of Water on the Moon
80beats: The Real Problem With a Human Trip to Mars: Radiation
80beats: Buzz Aldrin Speaks Out: Forget the Moon, Let’s Head to Mars
Image: NASA/JPL-Caltech/Malin Space Science Systems
While it’s not quite time to build the first lunar swimming pool, scientists do report that they’ve found the chemical signature for water all over the moon’s surface, not just in the permanently shadowed craters near the poles that recent studies suggested might harbor ice. The findings give new hope to people dreaming of a lunar settlement where astronauts could live off the land.
Evidence of both both water and a closely related molecule called hydroxyl was detected by India’s first lunar probe, Chandrayaan-1, which scientists later lost contact with. The findings were then backed up by measurements from NASA’s Deep Impact and Cassini probes, and the three teams’ papers have been published in Science.
Chandrayaan-1 scientist Carle Pieters explains that the water was easy to miss. “When we say ‘water on the moon’, we are not talking about lakes, oceans or even puddles. Water on the moon means molecules of water and hydroxyl that interact with molecules of rock and dust specifically in the top millimetres of the moon’s surface” [The Times], she says. The scientists say their measurements indicate that the moon has the equivalent of one quart of water per ton of material.
(more…)
A team of researchers has come up with a simple plan to halt global warming: All we need to do is turn both the Sahara and the Australian outback into vast, shady forests.
While that might sound so ambitious as to be absurd, the climate scientists say the project would be no more expensive or technologically challenging than some of the other geoengineering schemes that are currently under discussion. And researcher Leonard Ornstein says it would certainly get results. Ornstein says that if most of the Sahara and Australian outback were planted with fast-growing trees like eucalyptus, the forests could draw down about 8 billion tons of carbon a year–nearly as much as people emit from burning fossil fuels and forests today. As the forests matured, they could continue taking up this much carbon for decades [ScienceNOW Daily News].
(more…)
The groundwater of northern India is being drained away by irrigation faster than it can be replenished by the annual monsoon rains, and new satellite data shows that the process is accelerating. In an area that’s home to about 10 percent of the world’s people, that could be a recipe for disaster, policy experts say. A growing population with an increasing standard of living will only boost the demand for groundwater, a trend that could eventually lead to a reduction in agricultural yields, shortages of potable water and an increase in societal unrest [Science News].
The Gravity Recovery and Climate Experiment (GRACE) is comprised of a pair of satellites that measure subtle variations in the Earth’s gravity, caused by the movement of water either in the oceans or under the ground. Most famously, GRACE has recorded the shrinking of ice sheets; it has also detected shifting ocean currents, the desiccation of droughts, and the draining of large lakes [ScienceNOW Daily News]. Now two new studies of GRACE’s data have revealed the loss of groundwater from northern India; once water is pumped up from the aquifers for use in irrigation, it either flows away from the region or evaporates.
(more…)
The region today known as Iraq was once known as Mesopotamia, which means “Land Between the Rivers,” and since that ancient time the land between the Euphrates and Tigris rivers has been renowned for its fecund soil and thriving farms. But now the Mesopotamian cradle of civilisation seems to be returning to desert [New Scientist].
Decades of war and mismanagement, compounded by two years of drought, are wreaking havoc on Iraq’s ecosystem, drying up riverbeds and marshes, turning arable land into desert, killing trees and plants, and generally transforming what was once the region’s most fertile area into a wasteland…. “We’re talking about something that’s making the breadbasket of Iraq look like the Dust Bowl of Oklahoma in the early part of the 20th century” [Los Angeles Times], said Adam L. Silverman, a social scientist with the U.S. military.
(more…)
Fierce dust storms this spring have stained Colorado’s snow-covered peaks with brown, red, and pink dust, and state officials point out that this isn’t just a change in scenery. The darker snow is absorbing more radiation from the sun and is therefore melting faster and sooner than it normally would, which is upsetting the careful water rationing that defines life in the American West. Twelve dust storms barreled into the southern Rockies from the deserts of Arizona, Utah and New Mexico so far this year…. That, coupled with unseasonably warm temperatures, has sped up the runoff here, swelling rivers to near flood stage, threatening to make reservoirs overflow and fueling fears that there will not be enough water left for late-summer crops [Los Angeles Times].
In Colorado, melting snow accounts for about 80 percent of the water that flows through rivers and ends up in the state’s lakes and reservoirs. Colorado water engineer Scott Brinton explains that the early snowmelt could spell disaster for thousands of farmers and ranchers in the region who depend on slowly melting snow to provide water flows over the dry summer months…. “Those people who were relying on the mountain snowpack are going to have difficulty later in the year…. There’s not a whole lot we can do about it,” Brinton said. “We’re telling people, ‘You’ll be getting your water early this year, so use it while it lasts’” [Greenwire]. But scientists note that this may not be just a year of freak storms, it may be a harbinger of things to come.
(more…)
China’s plan to build dams along the Mekong River poses the greatest threat to the river’s future, according to a United Nations report released yesterday. China is constructing a series of eight dams on the upper half of the Mekong as it passes through high gorges of Yunnan Province, including the recently completed Xiowan Dam, which — at 958 feet (292 meters) high — is the world’s tallest. Its storage capacity is equal to all the Southeast Asia reservoirs combined [AP], according to the report.
The Mekong, which is known as the Lancang in China, is an important source of water, food, and jobs for residents in the river basin, and runs through China, Myanmar, Laos, Thailand, Cambodia and Vietnam. It provides a habitat for rare species of bird and marine life. If the dams move ahead, said the report, the consequences will include “changes in river flow volume and timing, water quality deterioration and loss of biodiversity” [AP]. But Chinese Foreign Ministry spokesman Ma Zhaoxu defended the proposed plans, saying China would give equal attention to hydropower development on transnational rivers and ecological protection [Xinhua].
(more…)
Before the end of the year, the backhoes are expected to dig into the dirt on a patch of coastal land in southern California, as construction begins on a massive plant that will draw fresh water from the salty sea. California regulators have given the green light for the construction of the largest desalination plant in the Western Hemisphere in Carlsbad, California, overriding environmental protests.
Some green groups are appealing the plant’s approval to a state water board, but officials with Poseidon Resources, the development company, seem confident that construction will begin on schedule. When the plant cranks up to high gear, engineers expect it to produce enough fresh water for 110,000 households in the San Diego area.
Advocates of desalination tout its potential for limiting strain on scarce water supplies, and easing the environmental consequences of diverting freshwater from rivers and streams and pumping it long distances to urban centers. But critics cite major environmental drawbacks — namely the harm to marine life from intake pipes that suck water into desalination plants and from the highly concentrated brine byproduct that gets discharged back into the ocean [Reuters]. In the environmental agreement hammered out between Poseidon and the San Diego Regional Water Quality Control Board, the company will create 55 acres of wetlands as breeding grounds for fish to offset those killed by the plant’s operations. The company has also pledged to keep brine concentrations below toxic levels.
(more…)
If global warming trends continue unabated, the Colorado River won’t have enough water to supply the 27 million people who depend on it, according to a new study. Less runoff — the snow and rain that fortify the 1,400-mile river — caused by human-induced climate change could mean that by 2050 the Colorado won’t be able to provide all of its allocated water 60 percent to 90 percent of the time, according to two climate researchers [AP].
The Colorado River flows through seven states in the American Southwest and continues into Mexico. It supplies water to households, businesses, factories, and farms, and is also home to several endangered species of fish. The study’s lead researcher, Tim Barnett, says that the findings indicate that tough decisions will have to be made about who will get less water. Agricultural operations use about 80 percent of the water taken out of the Colorado, Barnett said. He knows the arguments, though: Shorting farms could drive up food prices. Curbing development in cities and suburbs will make developers unhappy. Whatever the case, he said, some decisions need to be made soon. “The actions that need to be taken aren’t going to be fun,” Barnett said. “It’s not going to be life as usual” [AP].
(more…)
