OCEAN REFLUX Corrosive seawater burps up temporarily

IN DEEP WATER: Cold water, in blue, indicates where researchers measured a corrosive upwelling from the deep.Image courtesy of Dana Greeley and Simone Alin of PMEL

Seawater with the potentially shell-disrupting chemistry predicted for the open ocean after 2050 has already surfaced along North America’s West Coast, scientists report.

In spring 2007, the corrosive, deep water rose temporarily to the Pacific surface some 40 kilometers roughly west of the California-Oregon border, says Richard Feely of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory in Seattle. Elsewhere on the continental shelf, corrosive water rolled up but didn’t surge all the way to the surface, Feely and his colleagues report in an upcoming Science.

Deeper water normally swells upward at this time of year. But so much carbon dioxide — from natural and human-related processes — had dissolved in the water that the upwelling had a pH around 7.7. Surface water in the region typically has a pH of between 8.0 and 8.3 (a pH below 7 is acidic).

Gloomy estimates hadn’t predicted such a pH drop at the ocean surface until the second half of the century, Feely says. “This means that ocean acidification may be seriously impacting marine life on our continental shelf right now,” he says.

Feely blames human releases of greenhouse gas for creating the conditions that led to the upwelling. Deeper water naturally dips closer to acidity and carbonate scarcity, and human additions of carbon dioxide have expanded this zone upward.

“I was expecting that upwelling systems would be the first place where corrosive waters would reach the surface, but I hadn't really thought we were already there,” says Corinne Le Quéré of the University of East Anglia, in Norwich, England, after hearing about the work.

"What this study will really do is to point at where the biologists should come and study the impact of ocean acidification," says Le Quéré.

Just what the slosh of unusually low pH meant to the sea creatures isn’t clear, says Victoria Fabry of California State University, San Marcos. Lab tests, including her work on free-swimming pteropod snails, suggest that many species in shallower waters fail to make proper calcium carbonate shells and skeletons in lowered pH waters, where carbonate is scarce. Mussels, oysters and other commercial species could be at risk. So might fish, such as juvenile salmon that fatten up on pteropods and other calcifying nuggets.

Feely and his colleagues discovered the extent of the upwelling during a research cruise last May and June. The research team sampled water along a series of paths sticking out from the shore like teeth on a somewhat splayed comb. The cruise data can’t tell them how the water moved along the coast in later days or months, but Feely says he’s seen signs that it rolled down toward San Francisco Bay.

Some colder water normally rises toward the sea surface along the coast at this time of year, says coauthor Christopher Sabine, also of NOAA’s Seattle lab. Spring and summer wind patterns nudge surface waters westward, drawing up water from 150 to 200 meters below the surface.

With the industrial age, extra carbon dioxide wafts into the atmosphere and gets picked up by the sea. The oceans now take up 30 million metric tons of carbon dioxide a day, Sabine says. The extra dose makes the pH decline in the water column more dramatic so lower pH water is closer to the surface, where the upwelling originates.

“The water it’s grabbing is now corrosive, and it wasn’t before,” he says.

The California report looks like only the second report of low-carbonate, or undersaturated, water on any sea surface, says Toby Tyrrell of the National Oceanography Centre at the University of Southampton in England. He and his colleagues reported the first, in the Baltic Sea, but he notes that the chemistry there is different because the brackish sea ranks between freshwater and open-ocean in salinity.

Other regions with water dynamics similar to those off the California coast might have their own corrosive upwellings, Fabry says. Waters along the eastern edges of oceans, such as those off South America or Africa, now need surveying.

Penguins wash up closer to equator in Brazil

RIO DE JANEIRO, Brazil - Penguins from frigid waters near the bottom of the world are washing up closer to the equator than ever before, Brazilian wildlife authorities said Wednesday. Adelson Cerqueira Silva of the federal environmental agency said that about 300 penguins have been found dead or alive in recent days along the coast of Bahia state, better known for sunbathers in bikinis than for seabirds native to Antarctica and Patagonia. Its capital of Salvador is roughly 600 miles (1,000 kilometers) closer to the equator than Miami is and temperatures in the current Southern Hemisphere winter are in the mid-70s (low 20s centigrade). "This is unheard of. There have even been reports of penguins washing up as far as Aracaju," Silva said, referring to a beachside state capital even closer to the equator.

Silva said biologists believe stronger-than-usual ocean currents have pulled the birds north. Others have suggested the increase might be due to overfishing near Patagonia and Antarctica that has forced the penguins to swim further in search of food. Silva said the environmental authority was receiving hundreds of phone calls reporting penguin sightings. "We're telling people if the penguins don't appear to be injured or sick to leave them alone so they can swim back," Silva said in telephone interview from the Bahia state capital of Salvador. Rescued penguins have swamped a triage center for rescued birds, and Silva said about 90 of the birds found alive have since died. Penguins have been sweeping up on Brazilian shores in ever greater numbers this year, for reasons that are not entirely clear. While penguins commonly wash up as far north as Rio de Janeiro state in July and August - hundreds have done so this year. Bahia is roughly 750 miles (1,200 kilometers) northeast of Rio. P. Dee Boersma, a conservation biologist at the University of Washington who works with penguins in Argentina, said that while she has heard of penguins occasionally washing up as far north as Bahia, the numbers washing up this year are extremely high. "The last time that you got a lot of penguins was in 2000, mostly in Rio but some further north. That year the sea surface temperature was a degree lower than the 30 year average so the penguins just keep swimming in search of food without noticing where they're going," said Boersma in a telephone interview from Seattle. She also said overfishing near Patagonia and Antarctica could be a factor. In the past decade, penguins have had to swim an average of 40 miles (60 kilometers) further north to find food, Boersma said. The majority of penguins turning up are baby birds that have just left the nest and are least able to outswim the strong ocean currents.

NOT-OK CORAL Full review of status finds a quarter of reef-building species in peril

TOUGH TIMES Porites pukoensis coral (top left, close-up of polyps each some 2 millimeters in diameter when

expanded) now ranks as critically endangered. Corals are beset by invading species such as the crown of thorns

starfish (lower left, in the Philippines) and Drupella gastropods (damage on Acropora coral in Australia's Great Barrier

Reef).D. Potts; S. Livingstone; C. Page

At least a quarter of the planet’s reef-building corals face a noticeable risk of extinction, according to the first large scale review of hundreds of species.

Out of 845 known species of warm-water corals, 231 meet the criteria for listing in worrisome categories on the international IUCN Red List of Threatened Species, says marine biologist Kent Carpenter of Old Dominion University in Norfolk, Va.

The troubled species fall into the vulnerable, endangered or critically endangered categories on the Red List, which is maintained by the conservation group International Union for Conservation of Nature and Natural Resources.

If the coral species keep declining, coasts could lose the storm protection and other ecological benefits healthy reefs provide, Carpenter warns. Reef breakdown would have “huge economic effects on food security for hundreds of millions of people dependent on reef fish,” Carpenter and 38 co-authors conclude in a paper to be published in Science that appeared online July 10.

“The Carpenter paper has some scary conclusions,” says marine biologist Jenny Waddell of the National Oceanic and Atmospheric Administration’s reef programs in Silver Spring, Md. She points out that the new paper’s proportion of corals in trouble exceeds the threatened portion of most other big groups of land animals except amphibians.

Carpenter says the new roll of threatened reef corals will be added to the IUCN’s list, increasing 20-fold the number of corals the group tracks.

Monitoring of marine species has lagged compared with terrestrial species, he says. Out of some 40,000 total species the IUCN had evaluated up to now, only 1,400 species live in the sea.

To catch up, the IUCN and environmental group Conservation International fund the Global Marine Species Assessment to review major groups of creatures. For a year and a half, Carpenter has led an international team of marine biologists working through the known species that build classic shallow-water reefs.

Skimpy information kept the researchers from evaluating 141 coral species. For the others, the biologists worked out trends in population growth or decline.

Reports on shrinking areas of reefs have long indicated trouble for corals, but “we brought a new dimension,” Carpenter says. At the final tally of 231 imperiled species, “everyone’s jaw absolutely dropped.”

Two main kinds of miseries beset the corals, Carpenter says.

Climate change is taking a toll as warming sea water raises the risks of disease and coral bleaching (when corals lose their symbiotic algae and thus face nutrient shortages).

Abundant local threats also hammer corals. Sediments erode into the sea from frenetic development booms along coasts, and boats drag anchors over reefs, smashing structures that took hundreds of years to build.

“If we can control local threats, it will buy us some time,” says Andrew Baker of the University of Miami. “But ultimately corals will face some pretty tough challenges due to high temperatures and acidity.”

That worldwide process of ocean acidification is already altering surface water chemistry as those waters absorb excess carbon dioxide from the atmosphere. Though seawater is not acid now and isn’t expected to become so, the shift could disrupt ecosystems. “The new species analysis’ methods didn’t address this threat,” comments Maoz Fine of Bar-Ilan University in Ramat-Gan, Israel, so it “may require a category updating very soon.”

In the audit’s regional view, Caribbean reefs have the largest proportion of corals in the most threatened categories, the paper shows. “I used to dive in the Caribbean — the reefs were gorgeous,” Carpenter says. “Now, to use a technical term repeated frequently around here, they’re toast.”

Caribbean reef vulnerability also showed up in a NOAA report co-edited by Waddell and released July 7 at the International Coral Reef Symposium in Fort Lauderdale, Fla. Every three years, the NOAA reef research program presents a status report on the reef communities off the continental coast and U.S.-related islands.

The 2008 report found 69 percent of Pacific reefs in good or excellent condition but only 25 percent of Caribbean and Atlantic ones ranking that high.

Disturbing as both reports are, Carpenter calls for action, saying “there is hope.”

UNDER ICE Expedition yields first evidence of explosive volcanism on Arctic seafloor

ASH DRIFTS: Layers of volcanic ash (samples shown in inset) blanket the Arctic seafloor 4,000 meters down. The

ash is evidence of an explosive eruption, long thought impossible at those depths.Reves-Sohn et al.; A. Soule and C.

Willis/WHOI

A two-week cruise on an icebreaker to the top of the world last summer gave scientists a look at the aftermath of an event once thought impossible: a violent volcanic eruption on the deep-sea floor.

In 1999, a global network of seismic instruments detected the largest swarm of earthquakes ever to occur along the planet’s system of mid-ocean ridges, where tectonic plates spread to form new ocean crust. Several aspects of the recorded vibrations suggested that the quakes were generated by volcanic activity, says Robert A. Reves-Sohn, a geophysicist at the Woods Hole Oceanographic Institution in Massachusetts.

However, he notes, many scientists have doubted that explosive volcanism can take place at the 4,000-plus-meter depth where these quakes occurred because the immense pressure of overlying water prevents seawater from flashing into steam, a major driving force for such eruptions.

The source of the quakes was the Gakkel Ridge, a mid-ocean ridge that runs along the bottom of the Arctic Ocean. Sonar scans at a stretch of the ridge about 500 kilometers from the North Pole revealed several distinctive volcanic features, says Reves-Sohn. The largest of these undersea features, which usually have flat tops scarred with prominent central craters, are about 2 kilometers across and a few hundred meters tall.

Images gathered by a remotely operated vehicle show that the ocean floor is blanketed by layers of loose volcanic ash up to 10 centimeters thick. This material is piled on top of rocks and other high-standing features on the ocean floor, a sign that the jagged, glassy particles of ash — each typically measuring no more than a couple of millimeters across — gently rained down upon the ocean floor rather than sweeping down the flanks of the undersea volcanoes, Reves-Sohn says.

He and his colleagues don’t know the full extent of the volcanic deposits, but they did find ash in all parts of the 5-by-10-kilometer area that they surveyed, they report in the June 23 Nature.

The size and shape of the larger particles hint that one of the area’s undersea volcanoes spewed 1-kilometer-tall fountains of lava during an explosive eruption. When that molten material hit the near-freezing seawater, it quickly chilled into golf-ball-size chunks and then fractured into tiny bits that rained to the seafloor, Reves-Sohn speculates. Many of the ash bits are jagged, thin, Christmas-ornament-like fragments of glass, a testament to the violence of the eruption and the bubbles contained in the molten material.

Because steam couldn’t have driven the eruption, the volcano must have been fueled by another volatile component of the magma, the researchers say. The most likely culprit, says Reves-Sohn, is carbon dioxide. The amount of gas needed to fuel a deep-sea eruption like the ones that occurred along the Gakkel Ridge, however, is about 100 times the amount normally found dissolved in molten rock, he notes.

The tectonic plates at most mid-ocean ridges spread apart about 30 millimeters each year, around the same rate at which a fingernail grows. However, the Gakkel Ridge is an ultra-slow spreading center where the plates diverge only half that fast. Whereas volcanic eruptions in many shallow seafloor locales may occur every 10 years or so, eruptions at deep-sea, slow-spreading centers may happen only once

every 10,000 years or so, Reves-Sohn speculates. If so, sufficient reservoirs of carbon dioxide can easily build up in the magma chambers beneath the undersea peaks.

Such a scenario for deep-sea eruptions is “quite plausible,” says James W. Head III, a geoscientist at Brown University in Providence, R.I. The profuse deposits of ash along the Gakkel Ridge “are a big find,” he notes, adding that apparently “things don’t happen often at slow-spreading centers, but when an eruption occurs there’s a lot going on.”

STRANDED: A WHALE OF A MYSTERY Scientists generally agree that sonar can trigger strandings of certain whales, but no one really knows what leads these deep divers to the beach

ELUSIVE CETACEANS Scientists generally agree that sonar can trigger strandings of certain whales, such as

Cuvier's beaked whales. But no one really knows what leads these deep divers to the beach. Click on the image for

more.A. Frantzis

Off the eastern edge of Andros Island lies the Tongue of the Ocean, a hundred-mile, inky blue swathe of sea over the Great Bahama Canyon. Bounded on the south and east by the shallow sands of the Bahamas banks, the seafloor drops precipitously from 3 meters near shore to more than 2,000 meters farther out.

While the region boasts a colorful history of pirates and shipwrecks, scientists will head there this summer seeking treasure of a different sort: beaked whales, some of the deepest diving and least known animals on Earth. The research aims to solve one of the most contentious mysteries in marine biology today—the relationship between military sonar and stranded, dying whales.

In recent decades, a string of whale strandings have coincided with military testing that uses mid-frequency sonar to detect the low murmur of diesel and nuclear submarines. Beaked whales have washed up on the beach, sometimes with blood in their ears and eyes, but often with no obvious cause of death. After scientists first drew the connection between sonar and the strandings, environmental groups took note, embarking on a campaign to restrict sonar use in certain times and places. The hostilities reached a crescendo this winter in a U.S. federal court. A judge rejected the Bush administration’s attempts to override a ruling that ordered the Navy to take measures to protect marine mammals while conducting sonar exercises. Now the Supreme Court is scheduled to hear the Navy’s appeal this fall.

The wrangling over the stranded whales brings home how science can get lost in the scuffle between advocacy and policy. It also illustrates the highly charged nature of issues involving large, charismatic mammals. And then there’s the attraction of simplicity—the Navy makes a tidy, singular foe. But there is no Moby Dick in this story.

Scientists agree that under certain conditions, sonar does trigger strandings of certain whales. But no one really knows why. Hypotheses, like fish in the sea, are plentiful. Sonar may be so forceful that it damages the whales’ ears. Some researchers speculate that the sounds spur bubble formation in tissue, bringing on deadly embolisms. Or the sonar might distress and disorient the creatures, prompting them to surface too quickly and get the bends. Other researchers have suggested that certain frequencies of sonar might sound like killer whales on the hunt, stimulating beaked whales to seek shallower, safer waters.

Several research groups are trying to untangle what is happening, with the hope of developing strategies that minimize harm to marine life.

The National Oceanographic and Atmospheric Administration Marine Fisheries Service is partnering with the Navy to undertake some of the first controlled behavior experiments with beaked whales at a Navy Atlantic test center in the Tongue of the Ocean. Others are constructing computer models, looking at CT scans and studying beaked whale anatomy. There are efforts to compile stranding-related information in public databases.

In the meantime, providing policy-makers and the public with advice on how to alleviate the problem has been stymied by holes in the data big enough to swim a whale through. Ziphius cavirostris, or Cuvier’s beaked whales—the animals most associated with the unusual strandings—are understudied, elusive creatures. They spend little time in surface waters and, until the strandings, people rarely saw these whales at all. Then there are ethical and practical concerns with experiments that involve 2 ½–ton mammals that spend much of their time nearly a mile beneath the surface of the sea.

Unusual beachings: Scientists recognized a link between mid-frequency sonar and strandings after several Cuvier's beaked whales washed up on the Mediterranean coast in 1996.A. Frantzis

The mystery is compounded by several factors. No one knows where the whales are before they strand, so assigning safe distances from sonar is problematic. The strandings have been associated with specific

geologic features, such as deep oceanic trenches near land, but by definition, stranded whales end up near or on land, so teasing out cause and effect is difficult. Because no one knows where and when a stranding will happen, experts might not arrive on the scene until days after the event. By then tissues are often decomposed, as are clues to the animal’s death.

“One of the problems is we’ve really only had information on single exposures—one sound, one mammal,” says Brandon Southall of the NOAA Fisheries Service, who is leading the Bahamas study. “We really need more data.”

Some environmental groups and scientists argue that waiting for such data is folly. It is better to act quickly—perhaps by banning Navy sonar altogether—than it is to wait. But others express frustration at the bulldog approach, and at the time and money tied up in lawsuits that might be better spent on research. And while blame is slung in the courts, marine mammals face many threats beyond sonar.

“It is absolutely critical that we understand what is going on,” says Darlene Ketten, a senior scientist at the Woods Hole Oceanographic Institution in Massachusetts and a researcher at Harvard Medical School in Boston. “But when people ask, ‘Why don’t you shut down the Navy?’ the answer is we’re talking about five animals a year, and I have to balance that with over 100,000 deaths a year from fisheries interactions. I don’t know that shutting down the Navy is going to do anything. And if you are worrying about noise in the oceans, how about the 3-decibel increase per decade from shipping?”

Signal from the noise

Scientists realized the link between whale strandings and mid-frequency sonar in 1996, several months after a stranding in the Mediterranean’s Kyparissiakos Gulf. In early May, Cuvier’s beaked whales began washing up along a 24-mile stretch of sandy beach. The spread of the 12 whales in time and space was unusual, but there was no smoking gun. The whales had stranded alive and appeared healthy—they had no obvious wounds, such as blunt trauma from a ship, and no signs of disease. A few animals appeared to be bleeding from their eyes, which prompted more questions than answers. There were various squid remains in the whales’ stomachs—beaks, ocular lenses and flesh—suggesting that they had recently eaten.

“For a beaked whale to have been diving at depths great enough to find squids means they must have been healthy a few hours before they stranded,” says Alexandros Frantzis of the Pelagos Cetacean Research Institute in Greece. The usual suspects—extreme weather, earthquakes, pollution, parasites, irregular geochemical or magnetic circumstances—were absent. “We had no idea what was happening,” he says.

Several months later Frantzis discovered that around the time of the stranding event the NATO research vessel Alliance was performing “sound-detecting system trials” in the area of the strandings. Although the available data couldn’t prove that the Alliance’s sonar activities caused the event, the abruptness, timing and distribution of the strandings implicated sound, says Frantzis. He reported his conclusions in Nature in 1998.

TESTING THE CONNECTION in the Tongue of the Ocean's AUTEC range, scientists are conducting some of the first controlled experiments on how whales respond to sonar using the Navy's interconnected grid of underwater microphones (inset).B. Southall/NOAA

In the 10 years since Frantzis’ write-up, scientists have linked about a dozen stranding events to military sonar, depending on whom you ask. But whales have been stranding long before the advent of mid-frequency sonar use, which became widespread around 1963. Ketten, who has been compiling records of whale strandings, estimates that since 1950, fewer than 300 whale deaths can be attributed to naval sonar. Other researchers put that estimate at fewer than 100.

Ketten did necropsies on several of the beaked whales whose fatal strandings were concurrent with Navy sonar exercises. These include the oft-cited stranding in the northern Bahamas of nine Cuvier’s beaked whales and three Blainville’s beaked whales, a stranding of three Cuvier’s beaked whales in Madeira and two strandings off Puerto Rico.

The evidence from Puerto Rico was inconclusive. The response team buried most of the heads—standard procedure in tropical areas—but one that destroys crucial soft tissue. Scans of the one intact head suggested it was an old male who had suffered prolonged infection.

Necropsies from the Bahamas and Madeira were more telling. Beaked and other toothed whales such as dolphins have a large pad of fat inside their lower jaw. Sound may enter the whale’s head through the fat, which surrounds a very thin section of the lower jaw next to the middle and inner ears.

“There were no blown-out membranes, no broken middle ear bones,” Ketten says, which would have suggested direct acoustic trauma to the ears. But in a few of the animals, blood had leaked from the brain case, pooling around the ear bones and the fat pad of the lower jaw. This suggested stress and possible pressure-related trauma, she says.

Researchers have raised other pressure-related hypotheses as well—unusual gas bubbles have been found in the tissues of beaked whales that stranded off the Canary Islands. The bubbles hinted at decompression sickness—what SCUBA divers call the bends—but later reports of dolphin strandings off the United Kingdom found similar bubbles in tissues, which led many scientists to deem the bubble evidence inconclusive.

It’s been difficult for scientists to understand pressure-related injuries in animals built for the crushing pressure of the deep sea. These whales spend more than an hour at depths greater than 1,200 meters—more than three times the height of the Empire State Building. Down where it is as dark as a starless night, the whales, like bats, hunt with their ears, not their eyes. Beaked whales have three times as many

nerve cells devoted to hearing as people do, Ketten says. They use echolocation—emitting sounds that bounce off objects and return to the whale, giving a “picture” of prey shape, size and location.

“These are acoustic animals in the way that we are visual animals,” Southall says.

Beaked whales also have a convoluted circulatory system that during dives sends blood to essential areas like the heart and brain, but cuts off flow to the extremities. Below roughly 70 meters the whales’ lungs collapse, preventing gases from diffusing into blood and tissue where they could cause embolisms.

“These animals have been around 35 million years,” says Ted Cranford of San Diego State University, who in April published in The Anatomical Record an analysis of how sound travels in and out of a beaked whale’s body. “It doesn’t make sense that a few nitrogen bubbles are going to cause chaos. Perhaps if the whales are at their physiological limit. But if it is nitrogen, why don’t we see it affecting other deep divers?” he says.

This question bothers other researchers as well. Beaked whales are often seen around the Navy’s testing site for mid-frequency sonar in the Bahamas. “So we know that marine mammals and beaked whales can live where there is sonar,” Southall says. “It is not like a death ray where as soon as they hear it, they swim to the beach and strand.”

Sound science

The ambiguous data suggest to many researchers that the sonar-related strandings result from a perfect storm of environmental, physiological and acoustic conditions. A recent analysis by Gerald D’Spain of the Scripps Institution of Oceanography in La Jolla, Calif., and colleagues, hinted at the role of surface ducts—areas in the water where sound waves are trapped.

Sound travels about four times faster underwater than in air—about 1,500 meters per second versus 340 m/s on land. It slows in colder water, but increases with pressure, speeding up with the weight of the overlying water column. These factors, along with others such as the topography of the ocean floor and surface winds and weather, may mean sound sometimes creeps up on and startles deep divers.

Under certain conditions, as sonar sweeps an area, the pings and clicks could get trapped in a surface duct, making them less audible from below. If a beaked whale is down deep, it might not notice the sound until the ship is quite close, which could prompt the whale to surface. If the animal emerged to surface-duct depth, it would suddenly find itself in an intense, confusing zone of noise, D’Spain says.

Experiments planned by Southall’s team for this summer in the Bahamas are designed to sift through these ideas and get at the peculiar set of circumstances that sends beaked whales to the beach. Using the Navy’s 600-square-mile grid of interconnected, underwater microphones at the Atlantic Undersea Test and Evaluation Center, researchers will continue playback experiments that began last summer, exposing the animals to low levels of sounds and tracking their responses.

The team is also investigating the notion that beaked whales confuse sonar with a pack of killer whales, which emit noises in a frequency similar to the mid-range Navy sonar. Beaked whales’ primary predators,

killer whales and great white sharks, tend to hang out near the water’s surface, notes Peter Tyack of Woods Hole, a member of the NOAA investigation team. If beaked whales think they hear the enemy, they might embark on repeated shallow dives for quick escape. Work by Tyack and colleague Walter Zimmer modeling nitrogen bubble growth suggests that if the dives are too shallow, the whales’ lungs may not collapse, a physiological safety mechanism that doesn’t kick in until the animals reach depths of 70 meters. Then even these deep divers might get decompression sickness, and visible bubbles might form in the whales’ tissues, the researchers reported in Marine Mammal Science last fall and June 30 at the Acoustics ’08 meeting in Paris.

Hampered by storms, last summer’s first field season yielded data from only 10 tagged animals, six Blainville’s beaked whales and four pilot whales, Southall says. Pilot whales, which are deep divers and frequent stranders, have similar biology to the beaked whales. But they haven’t shown up in the sonar-associated strandings, so tracking them could reveal important behavioral differences, he says.

“We’re seeing some avoidance,” Southall says. “The animals become quiet and move away from the sound.”

If the behavioral experiments reveal that the whales stop shallow diving as soon as the noise stops, the duration of sonar transmission could be limited, which might limit harm. Precautionary measures such as holding off from sonar exercises when surface ducts are likely to form may keep the creatures from becoming startled and disoriented.

When the Bahamas study is done, researchers may have enough data to solve the stranding puzzle and give policy-makers, the Navy and the courts sound advice on reducing harm to whales.

RESONATING WITH THE OCEAN Tides may be the source of mysterious underwater waves that shape continental slopes

REACHING THE SURFACE Internal waves sometimes reach the surface and become visible, like these in the Red

Sea. Internal waves can form from resonance created by tidal waves, researchers suggest in a new study.Zhang

Every day huge, underwater waves surge and ebb far outside the rims of continents. Flowing much faster than the visible tides, these “internal tides” usually don’t make it to the surface or close to the coast. But,

because they move around the sediment as it collects below, these waves play big roles in shaping the edges of continental shelves.

Physicists may have now solved the riddle of the waves’ origin.

Around most coasts, relatively shallow waters cover the submerged part of each continent. Farther offshore, sediment constantly falls from the continental crust to the deeper oceanic floor. Internal tides come up at an angle that’s influenced by the physics of deep ocean water. In turn, these internal tides will shape the sediment at the edge of the crust into a continental slope of the same angle.

Internal tides may be generated by the slower ordinary tides as a resonance effect, similar to the way a repeated, gentle push can make a child sitting on a swing go higher and higher, researchers suggest in the June 20 Physical Review Letters.

“To me, it’s fascinating because it provides an explanation as to the origin of the internal waves,” comments Lincoln Pratson, a geologist at Duke University in Durham, N.C.

Inside a one-meter–long pool, Hepeng Zhang and his collaborators at the University of Texas at Austin created a small-scale version of the ocean around a continent’s coastline. On one side of the tank, a slanted surface represented the continental slope.

To simulate tides, the researchers set up their miniature continental slope so they could move it in and out of the water. Although in a real tide it’s the water that moves while the coast stays still, from the point of view of the ocean’s surface, it’s as if the coast slides up and down.

The researchers also filled the tank with water that was progressively saltier — and thus denser — the deeper it got, to simulate differences in ocean water density, which changes as both salinity and temperature change.

As they created their artificial tidal waves, Zhang and his colleagues saw that a layer of water right above the continental slope started flowing as much as 10 times faster than the simulated tides. The researchers calculated that energy from the simulated tide could progressively accumulate by resonance, generating an internal wave that would oscillate between water layers of different densities.

Density differences allow waves to form, Zhang explains. For example, surf waves arise at the interface between the air and the much denser water. The same can happen at the interface between two liquids of different densities, like water and oil.

In the case of the deep ocean, however, density varies smoothly rather than abruptly, which allows waves to propagate at an angle instead of just horizontally.

However, the team only saw the resonance, and thus the internal waves, appear at a particular angle, an observation corroborated by their theoretical calculations. This would explain why continental slopes don’t get any steeper than about 3 degrees. The twice-daily shear of the internal tides keeps removing any excess sediment.

Previous research into how internal waves affect continental slopes assumed that the waves originated somewhere other than near the continental slope. “In our picture, we don’t require this external source,” Zhang says.

David Cacchione, a retired USGS oceanographer in Camas, Wash., who helped discover the internal tides’ effects on the continental slopes, says that a more accurate experiment should also include the effects of the Earth’s rotation.

NEARLY IMMORTAL SEA CREATURE SPREADS Hydrozoan with reversible life cycle now found worldwide.

HIDDEN INVADER Small but pervasive, this jellyfish-like hydrozoan takes several forms. It can survive tough times

by collapsing into a blob and then growing back into its youthful, stalklike form. No wonder genetic testing is finding

that it has quickly and stealthily spread throughout the oceans.Courtesy of M.P. Miglietta

A jellyfish-like hydrozoan with a novel power to rewind its life cycle has been spreading rapidly around the world’s oceans without anyone taking much notice, researchers say.

The life history of Turritopsis dohrnii takes such twists and turns that only a new genetic analysis has revealed that the creature is invading waters worldwide, says Maria Pia Miglietta of Pennsylvania State University in University Park.

The first peculiarity of the seven species of Turritopsis had inspired biologists to describe these hydrozoans as “potentially immortal.” The adults form filmy bells reminiscent of their jellyfish relatives. When times get tough, faced with scarce food or other catastrophe, Turritopsis often don’t die. They just get young again.

Normally the organisms reproduce like grown-ups with sperm and eggs. In case of emergency, though, a bedeviled bell sinks down and the blob of tissue sticks to a surface below. There Turritopsis’ cells seem to reverse their life stage. When the blob grows again, it becomes the stalklike polyp of its youth and matures into a free-floating bell all over again. “This is equivalent to a butterfly that goes back to a caterpillar,” Miglietta says.

LOOK ALIKE, NOT Only its geneticist knows for sure that this hydrozoan from Florida has very similar genetic makeup to the creature with a different look, above, from Panama.Courtesy of M.P. Miglietta

That’s a fine trick for surviving the strains of being swallowed in a huge gulp of water for a ship’s ballast and being hauled around the world, Miglietta says. The creatures can restart their life cycles right in the bottom of the ballast tank. Ballast water has become the major route for moving alien species from one ocean to another, and that’s probably what’s happening to T. dohrnii, Miglietta said June 21 in Minneapolis during the Evolution 2008 meeting.

DNA analysis of these reversible hydrozoans shows signs of recent travel, she said. She and colleague Harilaos Lessios of the Smithsonian Tropical Research Institute compared mitochondrial DNA from T. dohrnii collected off Florida and Panama with DNA sequences from around the world, analyzed and collected in previous studies. In this comparison, she found a group of very similar DNA sequences distributed from Panama to Japan, she reported. Within that lineage, 15 individuals had identical DNA in the stretch she sequenced, even though they came from Spain, Italy, Japan and the Atlantic side of Panama. To get that pattern, there’s been some fast travel going on.

Miglietta said that the DNA revealed a new peculiarity of the hydrozoan lifestyle, a sort of shape shifting that depends on where the individuals grow. Around Panama, the 259 adults she examined had eight tentacles. But in temperate waters, decades of observations have found higher, more variable numbers, such as 14 to 24 off Japan and 12 to 24 in the Mediterranean. Yet the work confirms the different forms belong to the same species, despite their remarkably similar DNA.

As far as she knows now, Miglietta said, the hydrozoans aren’t disrupting the ecosystems they’re invading. But they do demonstrate how marine invasions can be difficult to understand.

That statement drew heartfelt agreement from John Darling of the U.S. Environmental Protection Agency’s National Exposure Research Laboratory in Cincinnati. Genetics has also revealed hidden twists in a marine invasion he described at the Evolution meeting.

The Cordylophora caspia hydrozoans he studies, originally from the Ponto-Caspian region, don’t have a reversible lifestyle, but genetic differences may expand the species’ range of salt tolerance. Some colonize fresh water while others live in brackish water. Taxonomists now mostly call the invader one species regardless of water tolerance, Darling said, but his genetic analysis would support at least two species.

SMART MICROBES Bacteria anticipate changing environments

It doesn’t take brains to have some smarts. New research shows that even bacteria can evolve to predict upcoming events based on clues, like a dog salivating at the sound of the dinner bell.

“It’s really the first evidence that single-celled organisms — bacteria — also have this ability for associative learning,” says Saeed Tavazoie, a molecular biologist at Princeton University who led the research on E. coli bacteria.

The discovery reveals a kind of predictive intelligence in how microbes interpret sensory cues from their environments. Understanding how this predictive ability affects bacteria's behavior could help scientists control microbes better, benefiting industry and the treatment of infectious diseases.

When E. coli enters a person’s body, its environment immediately becomes warmer. Later, as the microbe moves into the person’s gut, oxygen becomes scarce. Tavazoie and his colleagues found that warm temperatures alone triggered the microbes to switch to a less efficient, low-oxygen mode. The bacteria anticipated the coming lack of oxygen and were preparing for it, the researchers reported online May 8 in Science.

This proactive behavior challenges the view that microbes can only react after-the-fact to changes that occur in their environments.

“Sometimes people fall into this trap of sort of thinking that neurons are the only game in town for learning adaptive behavior,” comments Dave Ackley, an artificial life researcher at the University of New Mexico in Albuquerque.

Bacteria obviously have no brains or nervous systems. Instead, the microbes learn through evolutionary changes in their complex networks of interacting genes and proteins. Over hundreds of generations, the “intelligence” needed to predict a coming event based on present clues becomes encoded in these networks.

An individual bacterium can’t learn this way; later generations gain this embedded intelligence over evolutionary time. “Of course microbes can’t tell the future, but they can make educated guesses about the future based on how natural selection and past experiences have shaped their gene regulatory networks,” comments Richard Losick, a microbial geneticist at Harvard University.

Tavazoie’s team also showed that, over many generations, the bacteria can “unlearn” the link between rising temperatures and dropping oxygen. When the scientists grew the microbes in controlled conditions that divorced the rise in temperature from a change in oxygen levels, the microbes stopped anticipating lower oxygen levels after a few hundred generations.

“This new way of thinking about bacteria behavior is important not just in the industrial setting where we want them to do things, make things, but also for infectious diseases where we want to control their

growth,” Tavazoie says. Outside of a person, many infectious bacteria become semi-dormant, conserving energy because environmental cues indicate that rough times are ahead. Understanding how the microbes’ gene networks process these environmental signals could lead to ways to trick the bacteria into remaining in a slow-growth mode inside of people as well.

“There’s some hope that we could engineer some changes in environment for them, by the way we design our flu vaccines for example, to sort of fake them out,” Ackley says.

Slowing the microbes down instead of killing them with antibiotics could prevent the spread of antibiotic-resistant strains of diseases, Tavazoie says.

INVASION OF THE SALMON Chinook are rapidly spreading into the rivers of Chile and Argentina.

SALMON SPREAD Chinook salmon, introduced in South America for aquaculture, have now started self-sustaining

populations in the wild. The species has expanded its range rapidly at the southern end of the continent (dark

watersheds starting from left), and could easily spread to more river systems (right panel, shaded area).Correa,

Biological Invasions

Hard to believe it’s the same species. But the chinook salmon, conservation heartbreak of the U.S. West Coast, is invading and thriving in South America.

Chinook, or king salmon, largest of the five North American salmon species, reached South America some 25 years ago as people tried to farm them there, says Cristián Correa of McGill University in Montreal. Now a broad survey of records and stream visits finds chinook reproducing on their own in at least 10 Andean watersheds that empty into the Pacific plus more along the coast, and three Atlantic watersheds, Correa and Mart Gross of the University of Toronto report in the June Biological Invasions. Correa says he is worried that the invaders could disrupt both freshwater and marine ecosystems.

The dearth of the same species, Oncorhynchus tschawytscha, so alarmed U.S. government fisheries managers this year that they closed both commercial and recreational chinook fisheries off California and

much of Oregon for 2008. Of 17 chinook populations in the U.S. Northwest, two rank as endangered and seven as threatened on the U.S. endangered species list.

BIG CATCH The large Chinook salmon colonizing the rivers of Chile and Argentina outweigh the native fish species and join other big invaders like brown trout in shaking up the region’s water life. Correa

The news of chinook colonizing South America “absolutely, unequivocally proves how stupid we’ve been in managing our fish,” says Jack A. Stanford, who directs the University of Montana’s Flathead Lake Biological Station and also works with the Wild Salmon Center in Portland, Oregon.

Unlike their North American relatives, the South American chinook don’t have to cope with dams, extensive fishing and genetic mixing with hatchery fish that dilute the wild stock’s local adaptations, Stanford says.

The South American fish also find cool mountain rivers and rich offshore feeding grounds in the southern part of the continent, Correa says.

NUTRIENT SUPPLEMENT Chinook salmon bring a big pulse of nutrients into rivers when they return to freshwater to breed and die. Biologists now wonder if that unaccustomed blast is changing the ecosystems of the South American rivers that salmon are invading. Correa

To trace the spread of chinook, Correa interviewed passionate anglers along the Chilean coast, scrutinizing their photos of trophy fish and scouring written records. Then he surveyed rivers himself finding dozens and in rare places a hundred chinook swimming in a stretch of river the length of a city block.

Commercial operations in South America had raised chinook but now rely mostly on other salmon species, one piece of evidence Correa sites for saying the fish he saw weren’t farm escapees, but members

of a population that sustains itself in the wild. Also the ones he examined didn’t have the eroded fins typical of farm fish, and he found them in some remote watersheds. He reports witnessing chinook creating nests and spawning in rivers he visited.

Correa and Gross “are right in identifying chinook as a particularly invasive species,” says Miguel Pascual of Argentina’s National Scientific and Technical Research Council, who has also published on the invasion.

Chinook probably won’t colonize much farther north than Chile’s Toltén watershed, where they are currently found, Correa predicts.

The exotic chinook adds punch to other fish invasions already slamming rivers in South America, say both Stanford and Correa. Among other big fish, brown trout are also establishing themselves in South American rivers, and woe to less competitive natives such as Galaxias species that grow only several inches long. Stanford, who studies fish in the Rio Grande in Patagonia, says one of his students surveying there has seen two individual Galaxias fish in four years.

Correa frets that most of the southern region's river systems used to run on a sparse budget of nutrients. He says he's not sure what will happen to their ecosystems as the salmon return to breed and die, bringing massive seasonal pulses of nutrients.

“Salmon are voracious,” Pascual says. He and his colleagues have found that salmon at sea overlap in diet with established species such as the penguins along the southern Patagonian shelf. He hesitates to predict that that salmon would hog the food, but he does say, “we should scrutinize them closely.”

Chinook salmon have gone wild in New Zealand too, where they joined invader cousins such as brown trout, says Martin Unwin of the National Institute of the Water and Atmospheric Research in Christchurch. Fishing for trout and salmon has become popular, and about half of the rivers given special protection have won their honor based on the value of these alien species. “Thus we have here the slightly paradoxical situation of an exotic species acquiring a substantial conservation value,” Unwin says.

The invasions could have silver lining for science. In North America, salmon populations have adapted to the particular watershed where the fish hatch and eventually return to breed. With the ongoing invasion in South America, “we can study evolution in action,” Correa says. “I think this is going to be a good model system.”

CORAL KEEPS IT IN THE FAMILY

Spawn slick: When coral broadcast their egg-sperm bundles, the buoyant particles rise to the water's surface and

color it a bright pink, as they did here in 2005, at the Scott Reef in western Australia. The embryos and larvae stick

around for one to two days before settling to the ocean bottom and being consumed by hungry ocean dwellers.

AAAS/Science

For a few days each year, most coral in the Great Barrier Reef spawn all at once, broadcasting buoyant bundles of egg and sperm that float to neighboring coral for fertilization. Now researchers have shown how reefs efficiently trap the huge influx of nutrients. Chock-full of nitrogen and phosphorus, the gametes fuel a bloom of microalgae, which then nourishes other parts of the ecosystem, including fish and bacteria, says Ronnie Glud, a marine biochemist at the Scottish Association for Marine Science. The whole cycle occurs in eight to 10 days. Lucky gametes that don’t get devoured may grow into coral. The sandy bottom is an essential part of nutrient recycling, Glud and his colleagues also report in the current issue of Limnology and Oceanography. “Much of the sand is permeable, so it acts as a biocatalytic filter,” with microbes breaking down the spawn leftovers, he says. The findings may also have implications for human interactions with reefs, since agricultural runoff and overfishing can alter the reef’s nutrient balance, says Christian Wild, the head of the Coral Reef Ecology Work Group at the Ludwig-Maximilians University in Munich.

DOWN WITH CARBON Scientists work to put the greenhouse gas in its place

One morning each week, a scientist takes a stroll on the barren upper slopes of Hawaii’s Mauna Loa volcano, a basketball-sized glass sphere in hand. At some point, the researcher faces the wind, takes a deep breath, holds it and strides forward while twisting open a stopcock. With a whoosh lasting no more than a few seconds, 5 liters of the most pristine air on the planet replaces the vacuum inside the thick-walled orb.

Once every couple of weeks, a parka-clad researcher at the South Pole conducts the same ritual. At these remote sites and dozens of others, instruments also sniff the air, adding measurements of atmospheric chemistry to a dataset that stretches back more than 50 years. The nearly continuous record results from one of the longest-running, most comprehensive earth science experiments in history, says Ralph F. Keeling, a climate scientist at Scripps Institution of Oceanography in La Jolla, Calif. He carries on the effort his father, Charles Keeling, began as a graduate student in the 1950s.

Several trends pop out of the data, says Ralph Keeling. First, in the Northern Hemisphere the atmospheric concentration of carbon dioxide rises and falls about 7 parts per million over the course of

the year. The concentration typically reaches a peak each May, then starts to drop as the hemisphere’s flush of new plant growth converts the gas into sprouts, vegetation and wood. In October, the decomposition of newly fallen leaves again boosts CO2 levels. Populations of algae at the base of the ocean’s food chain follow the same trend, waxing each spring and waning each autumn.

A second trend is that each year’s 7-ppm, saw-tooth variation in CO 2 is superimposed on an average concentration that is steadily rising. Today’s average is more than 380 ppm, compared with 315 ppm 50 years ago. And it’s still rising, about 2 ppm each year, mainly from burning fossil fuels.

Largely because CO2 traps heat, Earth’s average temperature has climbed about 0.74 degrees Celsius over the past century (SN: 2/10/07, p. 83), a trend that scientists expect will accelerate. In the next 20 years, the average global temperature is projected to rise another 0.4 degrees C.

Squelching additional temperature increases depends on limiting, if not eliminating, the rise in CO 2

levels, many scientists say. And, Keeling says, “It’s clear that if we want to stabilize CO2 concentrations in the atmosphere, we need to stop the rise in fossil fuel emissions.”

But halting the increase in amounts of CO2 in the air doesn’t necessarily mean doing away with fossil fuels. Many experts suggest that capturing CO2 emissions, rather than only reducing them, could ultimately provide climate relief.

Possible solutions range from boosting natural forms of carbon capture and storage, or sequestration — fertilizing the oceans to enhance algal blooms, say, or somehow augmenting the soil’s ability to hold organic matter — to schemes for snatching CO2 from smokestacks and disposing of it deep underground or in seafloor sediments.

Success in sequestering carbon comes down to meeting two challenges: How to remove CO 2 from the air (or prevent it from getting there in the first place) and what to do with it once it has been collected.Doing it naturally

Organisms that dominate the base of the world’s food chains soak up quite a bit of CO2 — currently about 2 percent of the atmosphere’s stockpile each growing season. That gas, plus sunlight and other nutrients, is converted into carbon-rich sugars and biological tissues that nourish humans and all other animals. Unfortunately, most of that carbon makes its way back to the atmosphere rather quickly: Animals metabolize their food, breathing out CO2. Decomposition of dead plants and animals likewise produces the greenhouse gas.

Over the long haul, though, ecosystems can sequester significant amounts of carbon. About 30 percent of the carbon in the world’s soil is locked in peat lands of the Northern Hemisphere, for instance, with most of that accumulating since the end of the last ice age about 10,000 years ago (SN: 2/10/01, p. 95).

Recent data suggest that North American ecosystems sequester, on average, 505 million metric tons of carbon each year. Some accumulates as organic material in soil, wetlands or the carbon-rich sediments deposited in the continent’s rivers and lakes. More is stored in woody plants that have invaded grasslands or trees that have taken over shrublands. Most of the sequestered carbon, about 301 million tons, is locked away in North American forests or in the wood products harvested from them, notes Anthony W. King, an ecosystem scientist at Oak Ridge National Laboratory in Tennessee. He and his colleagues reported their analysis of these carbon sinks last November in an assessment issued by a consortium of ten U.S. government agencies.

“New, vigorously growing forests are where most carbon sequestration takes place,” King says.Some researchers, including Ning Zeng, an atmospheric scientist at the University of Maryland,

College Park, seek to harness the prodigious carbon-storing power of forests. Right now, forest floors worldwide are lined with coarse wood — everything from twigs and limbs shed during growth to entire fallen trees — containing about 65 billion tons of carbon, says Zeng. Left undisturbed, that material would return its carbon to the atmosphere via decomposition or wildfire. Bury that wood in an oxygen-poor environment, however, and the carbon could be locked away for centuries.

Furthermore, Zeng notes, each year the world’s forests naturally produce enough coarse wood to lock away about 10 billion tons of carbon. Burying just half of that amount would significantly counteract the estimated 6.9 billion tons of carbon released into the atmosphere each year via fossil fuel emissions.

While the price tag for this technique would be relatively reasonable — photosynthesis is free, and burying the wood would cost about $14 per ton — the environmental toll could be substantial. Coarse wood collected from the average square kilometer of forest could contain about 500 tons of carbon, Zeng reported in December in San Francisco at a meeting of the American Geophysical Union. That volume of wood would fill a trench 10 meters wide, 10 meters deep and 25 meters long. To sequester 5 billion tons of carbon each year, logging crews would need to dig and fill 10 million such trenches, about one every three seconds.

“This is not an environmentally friendly method” of carbon sequestration, Zeng admits.Life at seaIn certain parts of the oceans, especially along the western coasts of large continents, nutrient-rich waters fuel the growth of algae and other phytoplankton. Their growth pulls CO2 from the atmosphere. Many parts of the ocean, however, lack one or more vital nutrients, particularly dissolved iron, and are therefore nearly devoid of life (SN: 8/4/07, p. 77).

Adding iron to the surface waters in some seas could help reduce CO2 buildup in the atmosphere and forestall climate change, some scientists suggest. In the late 1980s, oceanographer John Martin, an early proponent of this idea, boasted: “Give me half a tanker of iron, and I’ll give you the next ice age.”

Or maybe not. Recent studies in the North Atlantic and North Pacific confirm that natural algal blooms can indeed sequester CO2, but in many cases the phenomenon may be only temporary, with little if any carbon making its way into deep water or seafloor sediments (SN: 5/19/07, p. 307). In late 2004 and early 2005, a similar study near the Crozet Islands southeast of South Africa further demonstrated that natural algal blooms result in only modest carbon sequestration.

Peter Statham, a marine biogeochemist at the National Oceanography Centre in Southampton, England, and his colleagues installed sediment traps at a depth of 2,000 meters at several spots near the islands. South of the islands, particles drifting down through a 1-square-meter area together carry only 0.087 grams of carbon each year, the researchers estimate. North of the islands, where ocean currents have carried dissolved iron and other minerals eroded from the islands, the carbon flux to deep water is almost five times higher, Statham and his colleagues reported in Orlando, Fla., in March at the Ocean Sciences Meeting.

Many uncertainties remain about how effective any artificial attempts to boost algal growth might be, says Statham. First of all, he notes, scientists aren’t sure which forms of iron are the ones that marine phytoplankton find most nutritious. And the long-term effects of adding the wrong type of iron — or maybe even the right one, he adds — could damage marine ecosystems for years. “There’s a huge gap in our understanding of these phenomena,” he says.

Finally, fertilizing the seas to sequester carbon, even with no bad side effects, may have little if any effect on climate. “Even in the most favorable circumstances, oceans would sequester only a small fraction of the carbon dioxide that humans are emitting,” Statham argues.Down and awayToday, coal and petroleum each account for about 40 percent of global CO2 emissions. Of the two, however, coal poses by far the larger threat to future climate. For one thing, coal produces more CO2 per unit of energy than any other fossil fuel — about twice that generated by burning natural gas, for example. Also, coal is abundant and therefore relatively cheap: The amount of carbon found in the world’s coal reserves is about triple that locked away in petroleum and natural gas deposits.

Worldwide, coal-fired power plants each year generate about 8 billion tons of CO2, an amount that contains about 2.2 billion tons of carbon. And, says Daniel Schrag, a geochemist at Harvard University,

emissions are poised to get even worse: About 150 power plants fueled by pulverized coal are now at various stages in the permitting process in the United States, and China reportedly cuts the ribbon on one such plant every week or so.

All told, the coal-fired power plants built in the next 25 years will, during their projected 50- to 60-year lifetimes, generate about 660 billion tons of CO2, says George Peridas, an analyst with the Natural Resources Defense Council office in San Francisco. That’s about 25 percent more than all the CO 2 that humans have produced by burning coal since 1751, a period that encompasses the entire Industrial Revolution.

Because coal-fired power plants are point sources of immense volumes of CO 2, they’re tempting targets for sequestration efforts, says Tom Feeley, an environmental scientist at the National Energy Technology Laboratory in Pittsburgh. He and his colleagues are studying ways to capture emissions, ranging from using CO2-hungry materials to sop CO2 from smokestacks to building new types of plants that burn coal altogether differently. The goal is to develop techniques for large-scale field tests by 2012 that can capture at least 90 percent of a power plant’s CO2 emissions but boost the price of its electricity by no more than 20 percent.

In current power plants, CO2-absorbing materials would be placed in a stream of 200°C emissions, mostly nitrogen with between 3 and 15 percent CO 2. The active materials could either absorb the gas, just as a sponge sops up water, or chemically bind to it.

Materials called metal-organic frameworks (SN: 1/7/06, p. 4) fall into the category of CO2 sponges. In their gaseous state, CO2 molecules fly about at great speeds and keep a considerable distance from each other, but inside the pores of some of these crystalline sieves, the molecules line up and cram close together, says Rahul Banerjee, a chemist at the University of California, Los Angeles.

Discovering the reactions that produce a substance that effectively captures CO2 takes time. So, Banerjee and his colleagues recently adopted a technique common in the pharmaceutical industry: They used a computer-controlled device to automatically dispense various combinations and concentrations of reactants into each of 96 tiny wells on a single plate — each well, in essence, its own 300-microliter beaker — which was then heated. The researchers then assessed the CO 2-sopping ability of the resulting crystals.

In less than three months, the researchers generated 16 new zeolites, a type of metal-organic framework composed of aluminum silicates, Banerjee and his colleagues reported in the Feb. 15 Science. Three of the zeolites are highly porous, with each gram of the material having a large surface area — where CO 2

molecules can attach — of between 1,000 and 2,000 square meters. A 1-liter sample of one of those supersponges, a substance dubbed ZIF-69, could hold up to 83 liters of CO2 under normal atmospheric pressure.

Another team of scientists has produced a CO2-absorbing substance — one that binds the gas via a chemical reaction — by painting an organic compound called aziridine on a wafer of silica. Unlike previously developed aminosilica materials, the new substance has a high storage capacity for CO 2, says Christopher W. Jones, a chemical engineer at Georgia Institute of Technology in Atlanta. The chemical reaction can be reversed by heating the CO2-saturated material, enabling researchers to capture the gas and dispose of it. A series of lab tests indicates that the material, whose amine-rich coating is tightly bound to the silica substrate, retains its capacity to soak up CO2 after nearly a dozen cycles, the researchers reported in the March 12 Journal of the American Chemical Society.Dump sitesCapturing vast amounts of power plant emissions is just half the task. The next step is storage. Many scientists propose locking CO2 underground or in the deep ocean.

Under high pressure, as in ocean depths below 500 meters, CO 2 is a dense liquid, not a gas, and doesn’t mix well with water. Therefore it’s possible to deep six CO2 on the ocean floor, but many researchers have concerns about how large pools of concentrated CO2 might affect ecosystems there (SN: 6/19/99, p. 392). The CO2 might slowly dissolve into the surrounding water, creating acidic conditions.

A new and relatively simple twist on the deep-ocean technique may address many such concerns. If liquid CO2 is blended with a mixture of seawater and pulverized limestone, the CO2 breaks up into globules that are 200 to 500 micrometers in diameter and coated with limestone powder, says Dan Golomb, a physical chemist at the University of Massachusetts, Lowell. The resulting emulsion has a consistency between that of milk and mayonnaise. Injected into the deep sea, the limestone-veneered droplets sink about 200 meters per day, lab tests suggest. As the droplets dissolve into the surrounding water or break up as they jostle about on the seafloor, the limestone’s carbonate dissolves too, buffering much of the resulting acidity, like a tiny Tums. Golomb and his colleagues described their carbon-dumping process last July in Environmental Science & Technology.

Immense volumes of subterranean strata are a tempting dumping ground, too. Some types of rock formations are naturally impervious to the flow of gases and liquids. In fact, some of these geological reservoirs have already proven themselves by sequestering naturally formed CO2 for millions of years. Oil companies have been mining that CO2, transporting it through pipelines and pumping it into the ground to enhance the recovery of petroleum from faltering oil fields for decades — an irony indeed to think that CO2 is being pumped into the ground so that petroleum, a raw material for even more CO2, can be extracted.

In many regions of the world, saline aquifers lie deep beneath the ground. Because that salty water isn’t suitable for drinking, some of those strata, especially those sandwiched between or capped by impervious rocks, could be used to store CO2. Scientists estimate that such reservoirs might hold hundreds of years’ worth of captured emissions.

Disposal of CO2 in ancient volcanic rocks may provide an even more secure sequestration technique. A multimillion-dollar field test soon to be under way in southeastern Washington state is designed to find out.

Lab tests suggest that liquid CO2 will chemically react with basalt to produce various minerals, including calcium carbonate, in a matter of months, says Pete McGrail, an environmental engineer at Pacific Northwest National Laboratory in Richland, Wash. Therefore, concerns about the CO 2 escaping from its underground prison are minimized. Thick layers of basalt, the result of widespread volcanic activity in the region between 6 million and 17 million years ago, underlie the tristate area surrounding McGrail’s lab. Although most think of basalt as impervious, many of these deposits are porous because they were frothy when they cooled or they cracked extensively when subsequent flows of lava heated them up or weighed them down.

Later this year, McGrail and his colleagues will inject between 1,000 and 3,000 tons of liquid CO2 — enough, give or take, to fill an Olympic-sized swimming pool — into the porous rocks at a depth of about 1 kilometer. Then, researchers will assess the effectiveness of their sequestration by occasionally collecting fluid samples at the injection site. Analyses suggest that this volume of CO2 will react to form carbonate minerals within five years, says McGrail.

If this sequestration technique is deemed suitable, the region’s ancient basalts could hold a volume of CO2 approaching that emitted by every coal-fired power plant in the United States over a 20- to 50-year period, McGrail and his colleagues estimate. Across the nation, deep geologic formations such as saline aquifers and coal layers could sequester 150 years’ worth of worldwide power-plant emissions, possibly providing a rock-solid solution to one of the world’s most pressing problems.

The United States and the world need carbon sequestration—not right now, says Harvard’s Schrag, but soon, and on an enormous scale. The challenge, he notes, is to ensure that carbon capture and sequestration technologies are ready when serious political action on climate change is finally taken.

And that time may be coming soon, says Oak Ridge’s King. “It’s beginning to dawn on people,” he says, “that they can change the planet in ways larger than the planet can change itself.”

CLIMATE FIX COULD DEPLETE POLAR OZONE Effect would be especially large after extremely cold winters

Scientists seeking to cool Earth’s climate by injecting millions of tons of sulfuric acid droplets high in the atmosphere might trim rising temperatures but could also destroy much of the ozone in polar regions, a new study suggests.

Major volcanic eruptions spew large amounts of tiny particles, or aerosols, high into the atmosphere, where they scatter light back to space and significantly cool Earth for months to years (SN: 2/18/06, p. 110). Some researchers have proposed lofting tons of aerosols into the stratosphere to achieve the same result, but that process — often dubbed geoengineering — could have a number of detrimental side effects. Last year, for example, scientists noted that average precipitation worldwide dropped significantly in the 16 months immediately following the 1991 eruption of Mount Pinatubo (SN: 8/25/07, p. 125).

Now, count ozone destruction among the drawbacks of geoengineering. High-altitude ozone helps block damaging ultraviolet radiation from reaching Earth’s surface. Ozone-destroying chemical reactions occur most readily on the surfaces of high-altitude ice crystals and droplets of sulfuric acid spewed by volcanoes, says Simone Tilmes, an atmospheric scientist at the National Center for Atmospheric Research in Boulder, Colo.

So, Tilmes and her colleagues estimated the ozone loss that would be triggered by two geoengineering scenarios, each designed to counteract the warming effect caused by doubling the pre-industrial atmospheric levels of carbon dioxide, as expected to occur late this century.

In one scenario, scientists inject about 2 million metric tons of sulfur-bearing aerosols into the stratosphere each year, each droplet approximately 0.46 micrometers in diameter. The other scenario lofts only 1.5 million metric tons of sulfur each year but in the form of smaller aerosols, which are more effective at scattering sunlight back into space.

Ozone destruction estimates are based on observations gathered during the last couple of decades, says Ross Salawitch, an atmospheric chemist at the University of Maryland, College Park. Results indicate that over the next few decades, ozone loss high above the Arctic after a particularly cold winter — one that produced large numbers of high-altitude ice crystals — could approach 75 percent, Tilmes, Salawitch and their colleagues report in an upcoming Science.

The effects of sulfate-aerosol geoengineering would be smaller later this century than today, primarily because atmospheric levels of ozone-destroying chemicals such as chlorofluorocarbons are now declining. Nevertheless, injecting sulfates into the atmosphere could delay the recovery of the ozone hole over Antarctica by 30 to 70 years.

Ozone loss due to geoengineering “is a real concern, but I don’t see it as a showstopper,” says Ken Caldeira, a climate modeler at the Carnegie Institution of Washington in Stanford, Calif. Even in the worst case cited by Tilmes and her colleagues, polar residents would experience levels of ultraviolet

radiation no higher than those routinely seen in San Diego today, he contends. There are several ways to address detrimental side effects of geoengineering, he suggests. For example, scientists could design the aerosols to drop out of the atmosphere before they reach polar regions, where they wreak most of their havoc.

Other researchers aren’t so sanguine. The new research is “a valuable first step that shows both the limits and the strengths of such analyses,” says Michael J. Mills, an atmospheric scientist at the University of Colorado, Boulder. “Climate is a complex system, and before we do something like this, a lot more modeling needs to be done.”

“It’s always been clear that geoengineering would have some detrimental effect, but this paper quantifies it,” says Bill Chameides, an atmospheric chemist at Duke University in Durham, N.C. Also, he notes, masking the planet-warming effects of carbon dioxide emissions rather than reducing them doesn’t do anything to reduce ocean acidification, another harmful side effect of burgeoning atmospheric concentrations of carbon dioxide (SN: 3/15/08, p. 170).

Among other uncertainties in geoengineering, it would be tough to fine-tune the lifetime, composition and size distribution of aerosols being injected into the atmosphere, says Adrian Tuck, formerly an atmospheric scientist at the Earth System Research Laboratory in Boulder, Colo. “Most of us share worries about geoengineering, which is seen as a cure-all to avoid having to bite the bullet about carbon emissions,” he adds.

HIDDEN DEPTHS: ANTARCTIC KRILL STARTLE DEEP-OCEAN SCIENTISTS

KRILL ZONE. This female krill, full of eggs, from the surface waters of the Southern Ocean belongs to the same

species glimpsed 3,000 meters down, researchers say.British Antarctic Survey

Biologists looked into the abyss and the abyss looked back, with lots of little compound krill eyes.

The shrimplike Antarctic krill, a major player in polar ecosystems, is supposedly a creature of the upper ocean. Yet the first science cruise to lower a camera to the abyssal seabed of the Southern Ocean off Antarctica found what looked like krill 3,000 meters down, says Andrew Clarke of the British Antarctic Survey based in Cambridge, England.

The cruise, during the South Pole summer of 2006-2007, inaugurated the United Kingdom's remotely operated, camera-carrying Isis vehicle. Clarke says that he and several other biologists were just piggybacking on a mission primarily designed for glaciologists and geophysicists to examine the deep continental slope and seabed beyond.

By that time of year, photosynthesizing plankton have multiplied in a great burst at the surface of the ocean and drifted down. When the scientists lowered their camera to the sea bottom, they saw a layer of still-green plankton-fall—and the krill feeding on it. These animals were the classic Antarctic krill species, Euphausia superba, say Clarke and Paul Tyler of the National Oceanography Center in Southampton, England, in the Feb. 26 Current Biology.

The Antarctic krill species matures to 6 centimeters in length, a giant among krill kind, and its red markings show up in the Isis video. The animals, including females ready to spawn, even made nosedives into the sediment, a behavior seen in shallow water that sends up puffs of fallen plankton. The krill then scooped debris out of the water with spiny structures on their legs, held to form what biologists call a feeding basket.

Based on the video evidence, "there isn't really much else it could be" other than the Antarctic krill, says Stephen Nicol of the Australian Antarctic Division in Kingston, Tasmania. Previous camera missions at some 600 m down have sighted these krill now and then, he says.

With so few observations of krill in the deep, biologists can only speculate about what's going on. Nicol says krill swarm in ravenous schools at the surface, reminding him of locusts. He guesses that krill feeding on a plankton bloom may have just kept eating as their lunch sank.

"Maybe what you've got is another link between the bottom and the surface," Nicol says, a matter of import in the study of nutrient cycling. If masses of krill routinely do this, the already uncertain estimates of their population could be even more so, he adds.

"I have heard rumors about this finding," e-mailed Peter Wiebe, of the Woods Hole Oceanographic Institution in Massachusetts, who is currently shipboard on a krill survey cruise. "If the observation proves true about the krill at 3,000 m, then it shows how little we really understand about how the ocean ecosystem is structured and functions."

SEAFLOOR CHEMISTRY: LIFE'S BUILDING BLOCKS MADE INORGANICALLY

TALL TOWERS. Small amounts of hydrocarbons emitted from the Lost City hydrothermal vent field (map below

shows location) were probably produced by inorganic chemical reactions.D.S. Kelley/Univ. of Washington, IFE, URI-IAO,

NOAA

Hydrocarbons in the fluids spewing from a set of hydrothermal vents on the seafloor of the central Atlantic were produced by inorganic chemical reactions within the ocean crust, scientists suggest. The finding holds possibly profound implications for the origins of life.

The Lost City hydrothermal field, which sits on the side of an undersea mountain about 2,500 kilometers east of Bermuda, was discovered in December 2000 (SN: 7/14/01, p. 21). Unlike most hydrothermal vents, which crop up along midocean ridges where tectonic plates spread to form new seafloor, those of the Lost City lie about 15 km west of the Mid-Atlantic Ridge on ocean crust that's about 1.5 million years old. Accordingly, the chemistry of the fluids surging from the Lost City vents differs radically from that found at other hydrothermal sites, says Giora Proskurowski, a geochemist at Woods Hole (Mass.) Oceanographic Institution.

Most hydrothermal vents spew a highly acidic, mineral-rich broth at temperatures as high as 400°C. The sulfide minerals that precipitate when those hot fluids mix with near-freezing seawater form dark, crumbly chimneys that typically reach heights of only 20 meters or so before they collapse. At the Lost City site, however, vent fluids are alkaline, have temperatures between 28°C and 90°C, and are rich in dissolved carbonates, Proskurowski notes. Because carbonate minerals are much stronger than sulfides, the lofty white chimneys that form in the Lost City can grow at least 60 m tall.

E. Roell

Lost City fluids also contain small quantities of hydrocarbons such as methane, ethane, and butane. A number of clues suggests that those substances, whose natural production usually results from the long-term heating of sediment rich in organic matter, were actually produced by inorganic chemical reactions, Proskurowski says. First, the rocks beneath the Lost City don't contain large amounts of organic matter. Second, the hydrothermal fluids are rich in dissolved hydrogen but contain a much lower than normal concentration of dissolved carbon dioxide. This suggests that what are called Fischer-Tropsch inorganic chemical reactions, which convert carbon dioxide, carbon monoxide, and hydrogen into hydrocarbons, generated the substances.

Finally, the proportion of the carbon-13 isotope in the hydrocarbons found in the Lost City fluids drops as the size of the hydrocarbon molecule grows, a trend opposite that found in sediment-derived hydrocarbons but characteristic of those generated by inorganic reactions, Proskurowski and his colleagues report in the Feb. 1 Science.

Although some types of microorganisms that inhabit the mineral chimneys in the Lost City may have generated a portion of the fluids' dissolved methane, none found there could have produced the ethane, butane, or other organic compounds in the vents' brew. Finding butane in the fluids is particularly important, because that hydrocarbon is a building block for some of the organic substances found in cell membranes, Proskurowski notes.

"If what they've found is right, it has significant implications for the origin of life," says Allan J. Hall, a geochemist at the University of Glasgow in Scotland.

Robert M. Hazen, a geophysicist at the Carnegie Institution of Washington (D.C.), agrees: "This is an exciting finding ... that demonstrates there are so many ways to make hydrocarbons in an abiogenic setting." The largest barrier to making the complex, sulfur- and nitrogen-bearing molecules characteristic of living organisms is creating long-chain hydrocarbon precursors like those found in the Lost City fluids, he says.

PORTRAIT OF A MELTDOWN: MANY FACTORS LED TO 2007'S RECORD LOW IN ARCTIC SEA ICE

GOING DOWN. The long-term decline in the extent of the Arctic Ocean's end-of-summer sea ice is shown

superimposed on a graphic depicting this year's record-low ice coverage.NASA

A variety of climatological factors converged this year in a perfect storm that dramatically melted the Arctic Ocean's ice cover to a record low. The abrupt downturn could be a harbinger of ice-poor summers for decades to come.

In late summer, scientists reported that Arctic sea ice had shrunk to cover only about 4.2 million square kilometers (SN: 10/13/07, p. 238). That area is about 38 percent below the long-term average for late-summer ice coverage. Moreover, it's a striking 23 percent below the previous record low, set just 2 years ago. An adverse combination of factors contributed to this year's steep decline, researchers noted last week at a meeting of the American Geophysical Union in San Francisco.

First, a long-term trend in thinning and shrinkage of Arctic ice set the stage for this year's meltdown, says Jinlun Zhang, an oceanographer at the University of Washington in Seattle. End-of-summer ice coverage has been declining by about 11.4 percent per decade since 1979. Also, average ice thickness decreased by about 1.13 meters, or 22 percent, between 1981 and 2000.

Second, Zhang notes, unusually strong summer winds pushed much of the ice out of the central Arctic, leaving a large area of thin ice and open water. Third, a decrease in cloud cover in the Arctic—a trend suspected but not confirmed earlier this year (SN: 6/16/07, p. 382)—allowed more sunlight to reach the ocean. Because open water absorbs more of the sun's radiation than snow-covered ice, it significantly boosts warming trends both for the ocean and for the atmosphere above it (SN: 11/12/05, p. 312). This so-called ice/albedo feedback accelerated this year's melting, says Zhang.

In parts of the Arctic Ocean this year, sea surface temperatures were 3.5°C warmer than average and a full 1.5°C warmer than previously recorded highs, says Michael Steele, also of the University of Washington in Seattle. All that warm water chewed away at Arctic ice from below. In some parts of the Beaufort Sea, north of Alaska and western Canada, ice that started the summer 3.3 m thick ended up measuring just 50 centimeters, says Donald K. Perovich, a geophysicist at the U.S. Army Cold Regions Research and Engineering Laboratory in Hanover, N.H.

About 70 cm of that shrinkage resulted from melting of the ice's upper surface—a typical amount for the summer, says Perovich. However, a whopping 2 m or so of that erosion, about five times the normal summer loss, occurred from below.

The thinning conceals the true extent of ice loss, says Perovich. "There's a lot less ice there than we think," he notes. "And the farther we go down this path, the harder it is to get back."

Indeed, the Arctic meltback may be self-perpetuating, says Steele. In some areas, the average date for winter freeze-up is now 2 months later than usual. The extra heat absorbed during summer months will suppress ice thickness by as much as 75 cm, about half the growth in thickness during an average winter.

Has the meltdown in the Arctic reached a point of no return? Many scientists, including Perovich, speculate that it has. "Years from now, we'll look back at 2007 and be amazed," he says.

7-square-mile ice sheet breaks loose in Canada

The Canadian Press, Sam Soja, AP Photo

EDMONTON, Alberta - A chunk of ice spreading across seven square miles has broken off a Canadian ice shelf in the Arctic, scientists said Tuesday. Derek Mueller, a research at Trent University, was careful not to blame global warming, but said it the event was consistent with the theory that the current Arctic climate isn't rebuilding ice sheets. "We're in a different climate now," he said. "It's not conducive to regrowing them. It's a one-way process." Mueller said the sheet broke away last week from the Ward Hunt Ice Shelf off the north coast of Ellesmere Island in Canada's far north. He said a crack in the shelf was first spotted in 2002 and a survey this spring found a network of fissures. The sheet is the biggest piece shed by one of Canada's six ice shelves since the Ayles shelf broke loose in 2005 from the coast of Ellesmere, about 500 miles from the North Pole. Formed by accumulating snow and freezing meltwater, ice shelves are large platforms of thick, ancient sea ice that float on the ocean's surface. Ellesmere Island was once entirely ringed by a single enormous ice shelf that broke up in the early 1900s. At 170 square miles and 130-feet thick, the Ward Hunt shelf is the largest of those remnants. Mueller said it has been steadily declining since the 1930s. Gary Stern, co-leader of an international research program on sea ice, said it's the same story all around the Arctic. Speaking from the Coast Guard icebreaker Amundsen in Canada's north, Stern said He hadn't seen any ice in weeks. Plans to set up an ice camp last February had to be abandoned when usually dependable ice didn't form for the second year in a row, he said. "Nobody on the ship is surprised anymore," Stern said. "We've been trying to get the word out for the longest time now that things are happening fast and they're going to continue to happen fast."

Swarms of jellyfish hint at oceans' decline

Fishermen in Barcelona, Spain, clean the area where they have been removing jellyfish from their nets. Jellyfish have been turning up in places where they have seldom been seen previously, causing alarm among scientists. Photo by Lourdes Segade for the International Herald Tribune

BARCELONA, SPAIN - Blue patrol boats crisscross the swimming areas of beaches here with their huge nets skimming the water's surface. The yellow flags that urge caution and the red flags that prohibit swimming because of risky currents are sometimes topped now with blue ones warning of a new danger: swarms of jellyfish. In a period of hours a couple of weeks ago, 300 people on Barcelona's bustling beaches were treated for stings, and 11 were taken to hospitals. From Spain to New York, to Australia, Japan and Hawaii, jellyfish are becoming more numerous and more widespread, and they are showing up in places where they have rarely been seen before, scientists say. The faceless marauders are stinging children blithely bathing on summer vacations, forcing beaches to close and clogging fishing nets. But while jellyfish invasions are a nuisance to swimmers and a hardship to fishermen, for scientists they are a source of more profound alarm, a signal of the declining health of the world's oceans. "These jellyfish near shore are a message the sea is sending us saying, 'Look how badly you are treating me,' " said Josep-Maria Gili, one of the world's leading jellyfish experts, who has studied them at the Institute of Marine Sciences of the Spanish National Research Council in Barcelona for more than 20 years. Litany of causes The explosion of jellyfish populations, scientists say, reflects a combination of severe overfishing of natural predators such as tuna, sharks and swordfish; rising sea temperatures caused in part by global warming; and pollution that has depleted oxygen levels in coastal shallows. These problems are pronounced in the Mediterranean, a sea bounded by more than a dozen countries that rely on it for business and pleasure. Left unchecked in the Mediterranean and elsewhere, these problems could make the swarms of jellyfish plaguing coastlines an unpleasant vision of seas to come. "The problem on the beach is a social problem," said Gili, who talks with admiration of the "beauty" of the globular jellyfish. "We need to take care of it for our tourism industry. But the big problem is not on the beach. It's what's happening in the seas." Jellyfish, relatives of the sea anemone and coral, in fact are the cockroaches of the open waters, the ultimate maritime survivors who thrive in damaged environments, and that is what they are doing. Within the past year, there have been beach closings because of jellyfish swarms on the Cote d'Azur in France, the Great Barrier Reef of Australia, and at Waikiki and Virginia Beach in the United States. In Australia, more than 30,000 people were treated for stings last year, double the number in 2005. The rare but deadly Irukandji jellyfish is expanding its range in Australia's warming waters, marine scientists say.

While no good global database exists on jellyfish populations, the increasing number of reports from around the world have convinced scientists that the trend is serious and climate-related, although they caution that jellyfish populations in any one place undergo year-to-year variation. "Human-caused stresses, including global warming and overfishing, are encouraging jellyfish surpluses in many tourist destinations and productive fisheries," according to the National Science Foundation, which will issue a report on the phenomenon this fall and lists problem areas as Australia, the Gulf of Mexico, Hawaii, the Black Sea, Namibia, Britain, the Mediterranean, the Sea of Japan and the Yangtze estuary. Though the stuff of horror B movies, jellyfish are hardly aggressors. They float haplessly with the currents. They discharge their venom automatically when they bump into something warm -- a human body, for example -- from poison-containing stingers on mantles, arms or long, threadlike tendrils, which can grow to be yards long. Some, like the Portuguese man-of-war or the giant box jellyfish, can be deadly on contact. Pelagia noctiluca, common in the Mediterranean, delivers a painful sting producing a wound that lasts weeks, months or years depending on the person and the amount of contact. In the Mediterranean, overfishing of both large and small fish has left jellyfish with little competition for plankton, their food, and fewer predators. Unlike in Asia, where some jellyfish are eaten by people, here they have no economic or epicurean value. A climatic edge The warmer seas and drier climate caused by global warming work to the jellyfish's advantage, since nearly all jellyfish breed better and faster in warmer waters, according to Dr. Jennifer Purcell, a jellyfish expert at the Shannon Point Marine Center of Western Washington University. Global warming has also reduced rainfall in temperate zones, researchers say, allowing the jellyfish to better approach the beaches. Then there is pollution, which reduces oxygen levels and visibility in coastal waters. While other fish die in or avoid waters with low oxygen levels, many jellyfish can thrive in them. And while most fish need to see to catch their food, jellyfish, which filter food passively from the water, can dine in total darkness, according to Purcell's research.

In Sri Lanka, a holistic approach to recoveryIt was morning when the water unexpectedly rose and rushed ashore, destroying nearly everything in its path. The human toll was inexplicable and fears of a mass mental health crisis were profound. Those are just some of the many similarities between the Indian Ocean tsunami of 2004 and Hurricane Katrina in 2005. While the number of victims was much larger in Asia - more than 250,000 people were killed in the tsunami - the aftermath presented comparable challenges. In one such similarity in Sri Lanka, which had the second-highest death toll from the tsunami, the world responded to the crisis not just with a deluge of bottled water, food and clothes, but also with psychiatrists, trainers and counselors. This is a pattern emerging for disasters worldwide. Within a month of the disaster, according to reports, there were an estimated 300 aid organizations like the Red Cross and Oxfam in Sri Lanka, a fourfold increase. They all offered some way - sometimes unique, sometimes competing - through the grieving. Besides occasionally contradictory agendas usually not coordinated with each other, only half of those aid organizations in Sri Lanka even registered with the government, said John Mahoney, the director of the World Health Organization's mental health initiative in Sri Lanka since the tsunami. "Sri Lanka just opened its doors... there was no checking," Mahoney said. "We found one organization just handing out antidepressants to people."

Many locals began questioning whether the vast resources being poured into how to heal people were effective. Within six months, committees were formed by pre-existing aid organizations to figure out exactly what was needed and who was offering services, Mahoney said. Before long, an overall picture of the mental health situation emerged. "I was very frustrated after the tsunami because I lost everything," said Randombage Soma, 56, through a translator. Soma is a secondary school religion teacher from the village of Wattegama in southern Sri Lanka. Besides losing her home, she said her ailing mother had been unable to outrun the waves and died. For a brief while, Soma's frustration brewed. Immediately after the disaster, WHO officials estimated more than 100,000 people could have lasting psychological effects. Recently, however, they have downplayed that estimate. "We knew from previous disasters that 90 to 95 percent of people will (completely) recover, are incredibly resilient," Mahoney said. Soma was one of them. Today, she said she can face the ocean again without fear, and no one in her large circle of family or friends, all of whom lost something or someone, suffers mentally from what happened. Life goes on, she said, and people should not fear disasters. From pre-tsunami to today, there were and are only about 50 licensed, practicing Sri Lankan psychiatrists and psychologists in the country to help catch that 5 percent of survivors who might be ailing greatly. One of those, Dr. Mahesan Ganesan, was the only psychiatrist for more than 1.4 million people in eastern Sri Lanka when the tsunami hit. The northeastern province he practiced in received some of the worst damage. Because of his expertise, he and other local professionals formed an unofficial committee and began coordinating local disaster response. "We didn't take a mental health approach," said Ganesan. "We took a psychosocial approach, more kind of a preventive (approach.) There is no way we can hold back the effects of the tsunami, but what we can do is to make sure that that burden" is lessened. Ganesan said that in any traumatic event, there are two things that cause mental suffering. "One is the grieving," Ganesan said. "The other is worries: worries about housing, worries about income generation. So it was that that we needed to prevent." Throughout the rest of the country, and in some cases the world, people took notice of Ganesan's approach. Today, Dr. Hiranthi de Silva, director of mental health services in the Ministry of Health, said focusing on making everything well and not just the mind has become the official approach. Throughout the country, de Silva said, they are establishing psychosocial centers, not mental health centers, to be prepared for future disasters and to help in everyday life. This approach to post-disaster mental health, say many people like Ganesan, is a better allocation of funds than the Western approach of saturating disaster zones with psychiatrists and counselors. In explaining the reasoning for this approach to a reporter immediately after the tsunami, Ganesan gained some international renown while echoing Sri Lanka's Buddhist roots when he said, "To suffer is to survive. To bear it with grace and dignity is to live." All rights reserved. This copyrighted material may not be published, broadcast or redistributed in any manner.

Is drilling off N.C. worth the gamble?

The chance to increase the oil supply is being weighed against the inevitable changes to the ecology and economy of the state's coast

GULF OF MEXICO - The oil industry has operated off Louisiana since the early 20th century. Natural disaster, however, can wreak havoc on infrastructure. Getty Images Photo

WASHINGTON - If offshore drilling were approved sometime in the future, the Tar Heel state's coastal landscape would almost certainly change. North Carolina remains one of the East Coast's longest and most undeveloped coastlines: strung with 300 miles of barrier island beaches; home to a national park; and cushioned by sensitive marshlands that protect against floods, cater to two-thirds of the state's vulnerable species and nurse the young populations of shrimp, blue crabs and fish. Although current legislation would keep rigs at least 50 miles offshore, there would likely be onshore industry to go along with the drilling. Pipelines would come bumping across the barrier islands, and oil or natural gas processing plants would be built on shore, possibly in the bustling industrial center of Norfolk, Va., but possibly near North Carolina port towns such as Wilmington or Morehead City. While the danger of oil spills from rigs has been greatly reduced in recent decades, plenty of other environmental challenges remain should North Carolina welcome the industry in the coming decades. "You're basically imposing a major petroleum industrial activity in the ocean and along the shoreline," said Warren Chabot, vice president of the Ocean Conservancy, a national advocacy group. Tourists might never see the drilling platforms working far beyond the horizon. Under current proposals in Washington, drilling would have to occur at least 50 miles offshore. But the oil or natural gas -- or probably both -- would have to come onshore somehow. Pipelines are cheapest. Onshore factories would likely follow. So what are the environmental risks? The answer, in part, depends on the state's oversight, say experts in North Carolina and elsewhere. "With sound and solid and consistent state management, offshore drilling should be feasible off North Carolina," said Orrin Pilkey, a Duke University geologist and frequent critic of state coastal land management. "It's going to be important, but it's going to be difficult," he said. "All we need to do is look at Louisiana."

In the boot-shaped Pelican State, the oil industry has been operating since the early 20th century. There, drilling rigs, oil refineries and gas plants scatter the landscape near the state's coastline, forming a ribbon from Texas to Mississippi. Tens of thousands of engineers, technicians, truck drivers and support workers toil in the state's refineries and oil transportation system. Louisiana welcomes oil tankers from foreign countries into its refineries and is home to three of the nation's Strategic Petroleum Reserves. Rigs can be seen from the shoreline. About 8,200 miles of canals slice through the marshes -- troughs dug for oil pipelines that have led to the destruction of 25 square miles of wetlands a year. "We're more efficient, less disruptive, but I don't that there's anything that can be done that's vastly different from the way we're transporting oil and gas now," said Bill Delmar, assistant director of the Louisiana oil and gas agency's Technology Assessment Division, which compiles data on drilling in the state. "It's a fairly simple process, and when you get that simple, it's tough to change," Delmar said. Louisiana, which has asked for billions of dollars from the federal government for its cleanup efforts, is a major player in the nation's energy production industry. In 2001, the state produced 502 million barrels of oil, about 85 percent of the total pulled from the nation's offshore drilling operation. "It's ugly," said Lawrence Cahoon, a marine biologist for UNC-Wilmington. "The oil industry dominates things in Louisiana." A moratorium in 1990 North Carolina is protected by a line of barrier islands, but it, too, has delicate marshlands and estuaries, especially in the sounds tucked behind the Outer Banks. Back in the 1980s, environmentalists and the state fought plans by Mobil to drill off Cape Hatteras. Mobil was unable to drill because of the backlash, and in 1990 the first President Bush put in place a presidential moratorium against drilling off the Outer Continental Shelf. The current President Bush lifted that ban this month. A congressional ban remains in place. The state controls waters within three miles of the shoreline, but the federal government controls the waters from 3 miles to 200 miles offshore. Environmentalists and oil policy analysts agree that technology has changed in the past two decades. "Many of their practices, I won't say they're environmentally friendly, but I will say environmentally tolerant," said George Crozier, a marine biologist and former executive director at the Dauphin Island Sea Lab in Alabama. "I think they've minimized their impact pretty much to the level that they can." North Carolina could expect to see a variety of new infrastructure: * Drilling rigs far offshore, either floating atop the waves or anchored on the sea floor. The drilling process brings up "drilling muds," which contain toxic minerals that usually must be disposed of according to state regulations. * Pipelines bumping across the barrier islands. State rules could require those lines to be piped under the islands or buried under dunes. County ordinances in Dare and Hyde counties currently prohibit pipelines across the islands, Cahoon said. * New natural gas plants or, possibly, oil refineries sprouting in the state's easternmost regions. And other state regulations could affect where those production plants might go. * Inland pipelines built to feed natural gas into major national pipelines. Oil or propane might be loaded onto tanker freight cars or trucks to be carted away.

"You have tanks to hold the stuff," Cahoon said. "You have pipelines. You have facilities. What you wind up with is a whole suite of things. ... Getting it out of the ground is only the start of that, and that's not where all of the risk is." Environmentalists worry about several obstacles. A landslide on an unstable sea floor could rupture a sub-sea drilling operation, Cahoon said. Marine mammals such as whales use migratory paths up the East Coast. The industry's sonar operations, used to do seismic testing of where oil or gas might exist, could disturb the whales' routes, said Lincoln Pratson, faculty director of the Energy and Environment program at the Nicholas School of the Environment at Duke University. And off Cape Hatteras, in an area known as the Point, 46 of 47 North Atlantic seabird species congregate each year to mate. Oil and natural disaster Perhaps the greatest fear comes with the storms -- hurricanes and otherwise -- that churn the offshore waters or barrel across North Carolina. "Clearly, the technology has made dramatic improvements," Chabot said. "The spill rate has declined significantly." Still, when hurricanes Katrina and Rita tore through the Gulf of Mexico, more than a hundred platforms were destroyed. More than 8 million gallons of oil were spilled in Louisiana alone, according to the state's Sea Grant program. That's two-thirds the amount spilled from the Exxon Valdez accident. The storms dragged one barge across the gulf floor, stumbling across pipelines as it went. Massive drilling equipment was thrown up against Interstate 10 in Mobile, Ala. Things have changed, say those in the oil industry. For example, there are nearly 4,000 aging drilling rigs in the Gulf of Mexico, many working in small areas. But that's old technology. New technology allows for one platform to drain several oil fields through directional drilling, said Andy Radford, a policy adviser with the American Petroleum Institute, an industry advocacy group in Washington. And oil companies have grown used to working in rough seas off Nova Scotia and other harsh areas, he said. "The environment is not so hostile that we'd be reluctant to operate there," Radford said of the mid-Atlantic. Wilton Sturges, an oceanographer at Florida State University, worries about taking chances. Usually, he said, the prevailing winds and waves carry spills onshore. "The situation to me is not science, not technology, but probability," said Sturges, who has consulted for oil companies. "If something happens and screws up the beaches ... the locals take the hit." Oil companies have automatic cutoff valves in their pipelines to protect against massive spills. But those valves can be miles apart, and a ruptured line could still dump thousands of gallons of oil, said Kerry St. Pe, a marine biologist and program director of the Barataria-Terrebonne National Estuary Program in Thibodaux, La. "There's quite a bit that can escape," St. Pe said. He has led efforts to strengthen regulations in Louisiana and push for billions in federal wetlands restoration funds.

Under new rules, oil companies must report any spill that creates a sheen on the water -- even if it's just a teaspoon. "It can be done safely," St. Pe said. "It can be done in a remarkably safe way, but (regulators) have to be vigilant, and they have to enforce the regulations."

Vast oil, natural gas reserves estimated in ArcticWASHINGTON - Some 90 billion barrels of oil and a third of the world's undiscovered natural gas lie beneath an area north of the Arctic Circle, government scientists estimate in the largest-ever survey of the energy resources there. The U.S. Geological Survey, which announced the findings Wednesday, called the region, which includes parts of the United States, Russia and Canada, "the largest unexplored prospective area for petroleum remaining on Earth." All told, the area accounts for about a fifth of the world's recoverable oil and natural gas reserves, the USGS says: 13 percent of the oil, 30 percent of natural gas and 20 percent of natural gas liquids. At today's current consumption rate of 86 million barrels a day, the yet-to-be-tapped oil in the Arctic would supply global demand for three years. Pursuing it is sure to be controversial with environmental groups that want to protect the pristine wilderness and the area's endangered species. The oil is considered "technically recoverable" using existing technology, but the survey did not consider the cost of overcoming obstacles to drilling, such as permanent sea ice or deep ocean waters. Melting caused by global warming has opened up some areas that were previously considered too difficult to reach. Oil companies have already spent billions to secure leases to explore some of the uncharted waters. About 84 percent of the undiscovered oil and gas is offshore, the USGS estimated, but much of it is close enough to land to fall under national territorial claims. About a third of the oil found in the survey is off the coast of Alaska. The majority of the natural gas is concentrated in two Russian provinces. "Before we can make decisions about our future use of oil and gas and related decisions about protecting endangered species, native communities and the health of our planet, we need to know what's out there," USGS Director Mark Myers said in releasing the report Wednesday, the product of a four-year study. "With this assessment," he said, "we're providing the same information to everyone in the world so that the global community can make those difficult decisions."

Scuba divers' paradiseIn the Graveyard of the Atlantic you can find a bounty of wrecked ships to explore

A diver explores the bow of the Aeolus, a Navy cable layer long ago claimed by the waters off the coast of North Carolina. NYT PHOTOS BY CHRIS WALKER

Pirate lore has it that in the late 17th century, horses bearing lanterns were led along the barrier islands near Beaufort, luring ships to be pillaged and sunk. But that was only one of many perils by which the North Carolina coast earned the nickname Graveyard of the Atlantic. From the Queen Anne's Revenge, Blackbeard's hijacked French slaver, to the Monitor, the ironclad Civil War vessel, many a ship has been doomed by converging currents, rocky shoals, treacherous storms and, in World War II, lurking U-boats. In 1921, the schooner Carroll A. Deering was stranded in a storm on Diamond Shoals; rescuers found it abandoned, making the fate of the crew one of the enduring mysteries of maritime history. But the seascape that for centuries menaced sailors is, it turns out, a Xanadu for scuba divers. The water is clear, warmed by the Gulf Stream and populated by tropical marine life against the operatic backdrop of the mammoth, ghostly shipwrecks. Unlike reef diving, wreck diving offers both natural splendor and human narrative -- lionfish and octopus, rust and cannon. And although one doesn't scuba dive alone, there is something intensely private about it. There are no guides, no audio tours, no placards. Exploring the Indra As a novice, I began my trip on one of the shallower wrecks, the Indra, a repair ship that took two direct hits in Vietnam. The day was uninviting -- cool and drizzly, with a sea choppy enough to make the captain consider canceling the dive and, for a few scary moments, to make me wish he had. But once below the surface, I immediately forgot everything above it. Descending the line from the boat to the deck of the 328-foot Indra was like landing on the moon -- a mute, airless planet of pipes, bollards and hatches encrusted with red, bright yellow and purple coral. Fleets of silver amberjack sailed past, and jellyfish the size of bubbles caught the light. The Indra was not a victim. It was scuttled in 1992 for North Carolina's artificial reef program. But armed with fins and an air supply, I still felt like a cross between an explorer and a forensic investigator visiting a disaster scene. The feeling would only intensify as I visited tragic ships like the one commonly identified as the Papoose, a torpedoed tanker lying bottom-up, its featureless belly exposed and cracked.

Although swimming into the wreck without special training is not advisable, there were enough gaping holes and glassless windows to get a good look. I wove in and out of silent steel cathedrals and poked around amid dangling loops of cable and wire. Some ships were broken in two or their hulls were sheared away, their insides on view -- like giant dollhouses. Dramatic sights Of the hundreds of shipwrecks in the Graveyard of the Atlantic, about 30 are regularly visited by dive operators based in Beaufort or nearby Morehead City. The offshore wrecks, those between 10 and 30 miles out, are among the most dramatic. One of the most popular sites is the German U-352 submarine that was sunk by the Coast Guard in World War II. The wrecks draw people from all over, but proximity and warm water make them particularly appealing to North Americans. Claude Dumoulin, a Canadian who traveled to the Beaufort area last year with his local dive club, compared it favorably with what one might encounter on a more traditional diving trip, particularly because of the variety. "This is some of the best diving I've seen anywhere," he said. "I went to Turks and Caicos -- every day it was the same. It's neat and everything, but it's the same thing twice a day." Some sites are off limits. Because of its historic nature, the Monitor has been declared a marine sanctuary, the underwater equivalent of a landmark. The Queen Anne's Revenge, the subject of an extensive exhibition at the N.C. Maritime Museum in Beaufort and an active archaeological site, is open to small groups of divers only a few times a year through a state-sponsored program called Dive Down. The program includes a day of classroom instruction on maritime history, underwater archaeology, coastal geography and marine ecology, and a day of diving. Most of the remaining weekends this year have waiting lists. Because it was wooden, the Queen Anne's Revenge is different from most of the wrecks. After almost 300 years of exposure to surges and currents, it is not so much a ship as a pile of ruins -- cannons, anchors and other detritus -- about 30 feet below the surface in the sandy inlet where the ship ran aground. Charters run daily There are plenty of nearly intact wrecks to see, however. Dive operators run charters daily in the warm season, offering day trips, overnight trips and night dives. The founder of the Olympus Dive Center in Morehead City, George Purifoy, helped discover and explore several wrecks beginning in the 1970s, and the dive shop has a display of ship's bells and other artifacts. If you are interested, the operators also teach wreck penetration, a skill involving tight squeezes, mazelike orientation challenges and potential head injuries. If you're not going into the wreckage, wreck diving requires little special equipment besides gloves and bootees for protection from sharp objects and edges. In summer, the water temperature hovers around 80 degrees even at depth. At 100 to 170 feet the offshore sites are quite deep for an inexperienced diver, but for extra safety I hired a divemaster to be my "buddy," which had the advantage of preventing my becoming lost. I dived with both Olympus and Discovery Diving, meeting at a dive shop early in the morning and boarding a dive boat like the Outrageous V, one of Discovery's two boats, which has a roomy cabin and a binder containing a history and dive guide for each wreck. In their broadest outlines, the ships look as alien to the environment as an underwater skyscraper would. But up close, the ocean has claimed them with impersonal dispatch. Every surface is covered with marine flora, its machine-made lines corroded into fuzzy sketches. Before they are restored, cannons retrieved from the Queen Anne's Revenge look like nothing more than concrete logs. The hulls are alive

The hulls, alive with swaying coral, resemble sheer cliffs, and on the second dive at the Indra, we swam over the edge and dived to the sandy sea bottom, where I was delighted to spot an octopus lurking in a hole. The divemaster placed a gloved finger at the mouth of the hole, and the octopus offered a tentacle for a gingerly tug of war. By the time it was my turn, it had wised up. I had intended to dive on Friday and Sunday, leaving Saturday to explore the area's many other charms. The beaches of the barrier islands, accessible by ferry or water taxi, are littered with sand dollars and the graceful white bivalves known as angel wings, and some are roamed by wild horses. Snorkelers, sunbathers and shell collectors can find plenty to occupy their time. Several commercial boat tours are available, but the Rachel Carson National Estuarine Research Reserve, which includes barrier islands and marshes off the Beaufort Inlet, offers free guided tours on foot or by boat. The Beaufort historic site is a cluster of 18th- and 19th-century buildings including a jail and an apothecary. Swimming with the fishes But I was sold on diving, and over the next two sunny, boat-friendly days, I dived the Aeolus, a Navy cable layer; the Spar, a Coast Guard cutter; the Indra again; and the Papoose, a favorite place to see sand tiger sharks. Distracted by the scenery, I almost collided with one -- and can confirm that they are not aggressive. At the Indra another divemaster pointed out an eel curled up in one of the instruments jutting from the deck, as if it had made its home in a pedestal sink. Damselfish and angelfish browsed the deck. I would have liked to have seen the U-352, but it is best not to get your heart set on any one site, because the dive boat captains choose the day's itinerary based on weather, visibility and the plans of other boat operators. And some sites are not what they seem. The Papoose, for example, was a tanker torpedoed by a U-boat in 1942. But the site we visited was not the Papoose. In recent years, a diver at another wreck brought up a plaque that read "Papoose," and the Papoose is now believed to be the W.E. Hutton, another tanker sunk by the same U-boat on the same night. But it is still referred to as the Papoose, said Robert Purifoy, George's son, because, "If I were to try to get you to come down and dive the Hutton, you would say you didn't want to dive it because it's not a good spot."

Salmon fishermen find slime, not sockeyeBELLINGHAM, Wash. - A strange brown slime attributed to some kind of plankton bloom is coating nets on fishing grounds in the Strait of Georgia, making it nearly impossible for many local fishermen to get their share of this year's Fraser River sockeye salmon run in Washington state. Gill net fishermen catch their quarry in long, floating curtains of monofilament that don't work if migrating fish can see them. If the brown stuff doesn't clear out in the weeks ahead, other salmon fisheries may also be affected. Fishermen expect a certain amount of debris to accumulate on their nets, but this year is different. Fishers who set their nets during the opening that ended July 31 had little to show for their efforts, and there are no assurances that the international commission regulating the Fraser harvest will grant any more openings on this year's weak run. "I've fished sockeye all my life," said Merle Jefferson, 58, Lummi Nation's director of natural resources. "This is the worst I've ever seen it. ... We cannot catch the fish because the nets are all fouled up."

Bellingham gill netter Charles Brandt agreed. "Your net just comes in solid brown," Brandt said. "It's real sludgy. You can't catch a fish with that stuff. It's the worst I've seen it since 1973." The Lummi fishers reported the problem in their favorite waters off Point Roberts. Brandt said he's heard reports of the brown slime as far south as Salmon Bank, just south of San Juan Island. Art Lane, a Lummi fisherman who sets his net out from a small skiff, said the brown coating made his net so heavy it was hard to pull it out of the water and get it back into the boat. "A lot of skiffs were darn near sinking because of the weight," Lane said. Gordon Wilson Sr., another Lummi gill netter, said his hydraulic drum wasn't powerful enough to pull his slime-laden 1,500-foot net more than halfway back into the boat. He and deckhand Michael Peters had to pull it in by hand, and the net held no salmon. "We got three dogfish, and that was it," Wilson said, adding, "It took us two days to clean our net." The Fraser River sockeye harvest has long been the most profitable for local fishers, and it is especially important to more than 200 tribal fishers who generally don't fish in Alaska. Even though this year's fishing was expected to be meager, tribal fishermen were counting on it after last year's fiasco, when a reduced sockeye run prevented any commercial catch. "We waited all year for these days to be open," Lane said. "We've been getting ready for two months," Peters added. "To go through that is pretty sad." There was no immediate information on what kind of organism is causing the problem. Jefferson said it is likely due to this year's unusual weather, with late, heavy snowfall in the mountains feeding a steady runoff into local rivers, pumping nutrients into the sea. Jefferson suggested that the stuff could be heterosigma, a type of brown algae that can kill fish, especially those confined in net pens at salmon farms. During outbreaks in past years, heterosigma has been blamed for the loss of millions of dollars' worth of fish in the region's salmon farms. But Rose Ann Cattolico, a heterosigma expert at the University of Washington, said the phenomenon fishermen were describing sounded more like a diatom bloom, since diatoms are more prone to stick to nets. Kevin Bright, marine biologist at American Gold Seafoods in Anacortes, agreed. "That stuff (diatoms) blooms and decomposes and floats up to the surface," Bright said. American Gold owns the net pens off Cypress Island in the San Juans, and Bright keeps a close eye on potentially harmful blooms of microorganisms. Diatom blooms are not known to harm fish, and he has not found heterosigma problems this year. "Our farms here at Cypress really aren't seeing anything," Bright said.

Hurricane Dolly may have shrunk Gulf 'dead zone'NEW ORLEANS - The oxygen-starved "dead zone" that forms every summer in the Gulf of Mexico is a bit smaller than predicted this year because Hurricane Dolly stirred up the water, a scientist reported Monday. There is too little oxygen to support sea life for about 8,000 square miles - just under the record of 8,006 square miles recorded in 2001, said Nancy Rabalais, head of the head of the Louisiana Universities Marine Consortium.

"If it were not for Hurricane Dolly, the size of the Dead Zone would have been substantially larger," she said in a news release sent from the consortium's research vessel, the Pelican, as she returned from her annual mapping cruise. Rabalais measures the area during the same period each year. Scientists had predicted that flood runoff would bring so much fertilizer and other nutrients into the Gulf that the area of low oxygen would be a record 8,300 to 8,800 square miles. Those nutrients feed microscopic plants at the surface, which die and fall to the bottom. Their decomposition uses up the salty layer's oxygen. Additionally, the fresh water from the Mississippi River and salt water in the gulf don't mix well and form layers, keeping oxygen from filtering through to the sea bottom. The oxygen-depleted, or hypoxic, waters can be deadly to fish, shrimp, crabs and clams. The Mississippi River's nitrogen levels in May were 37 percent higher than last year and the highest since measurements began in 1970, Rabalais said. Based on that, R. Eugene Turner of Louisiana State University predicted the oxygen-starved area would cover 8,800 square miles, and Donald Scavia of the University of Michigan estimated it would be 8,300 to 8,700 square miles. But Dolly's winds and waves mixed up the layers of water, stirring in oxygen, especially along the western and shoreward areas, Rabalais said. Another load of nutrients may be headed toward the dead zone as runoff from the mid-June floods in Iowa reach the Gulf of Mexico, said Steven F. DiMarco, an associate professor in the oceanography department at Texas A&M who also studies the dead zone. "I expect that pulse to be making its way out in a few weeks. It could extend this year's hypoxic zone or dead zone further into the summer - maybe even in September," he said.

Russian subs reach bottom of Lake BaikalMOSCOW - Two small, manned submarines reached the bottom of Lake Baikal, the world's deepest freshwater lake, on Tuesday, Russian news reports said. The "Mir-1" and "Mir-2" submersibles descended 1.05 miles (1,680 meters) to the bottom of the vast Siberian lake, reports said. Scientists on board will take samples of water and soil from Lake Baikal, which is home to more than 1,700 species of plants and animals, reports said. They also will plant a small pyramid bearing the Russian flag in the lake bed, reports said. Russian news agencies earlier cited organizers as saying the expeditions set a world record for the deepest descent in a freshwater lake. State Duma deputy and expedition leader Artur Chilingarov later said no such record was broken Tuesday, the Interfax news agency said. Mission chief Anatoly Sagalevich said the mission will make a total of 60 dives. Organizers then will compile a list of recommendations at how best to preserve Lake Baikal, a UNESCO World Heritage site. Last August, the "Mir-1" and "Mir-2" descended below the North Pole, with Russians on board planting their country's flag in a titanium capsule on the Arctic Ocean floor to symbolically claim the seabed.

Coastal towns de-salt waterKILL DEVIL HILLS - With demand for water increasing as the drought and growth continue, some coastal counties in Eastern North Carolina are tapping a saltier source: rivers of brackish water that flow underground.

Pasquotank and Currituck counties awarded contracts last month to start construction of two water treatment works that will eventually produce a combined 6.5 million gallons per day -- enough to slake the thirst of a town the size of Goldsboro. They'll produce water by filtering salt from brackish water drawn from deep wells. That will bolster existing supplies of fresh water and help meet the need for more water in the growing communities. "We're having to go to lesser-quality source waters, including brackish water on our coastal areas," said Fred Hill, a regional supervisor with the state's Public Water Supply Section. "We're getting a lot of demand for development, and people are expecting higher-quality water." North Carolina already has about a dozen water plants on the coast that remove salt from water using a process called reverse osmosis -- and at least five more are planned. Pumps force brackish water under pressure through a series of fine filters to remove salt. The process produces high-quality water, experts say, but technology won't fill everybody's glass. The process is typically more costly than conventional treatment of fresh water, and there are environmental concerns about discharging concentrated salt into estuaries or fresh water. Reverse osmosis can treat ocean water. But the plants in North Carolina typically start with brackish water, which is less salty and easier and cheaper to treat. The existing plants collectively can produce up to 14 million gallons a day -- still a small fraction of the roughly 50 million gallons a day purified by Raleigh's water plant. Sorry, Raleigh As the drought persists, some have asked why inland cities such as Raleigh don't look to the coastline as a water source. But that's not realistic, given the high cost of treating and piping the water. "Reverse osmosis plants are a good option for affluent coastal communities where people have expensive homes, and paying $100 a month for water is not that big a deal," said Bill Holman, a visiting scholar at Duke University's Nicholas Institute for Environmental Policy Solutions who is studying state water resources. "The idea of treating large quantities of ocean water and pumping them 100 miles uphill does not seem economically feasible." The new $17.5 million Pasquotank plant, which will initially produce 2 million gallons per day, will supplement an existing freshwater treatment plant that is fed by 30 freshwater wells. The brackish water is so much more plentiful than fresh water that one well will produce as much flow as eight to 10 wells in the shallow freshwater aquifer. "We were having to put so many wells around the county that we started looking at other sources," said Randy Keaton, the Pasquotank County manager. "In our area of the state, if you drill very deep, you hit salt water." Production and treatment costs vary greatly among water systems. William Koros, a professor in the School of Chemical and Biomolecular Engineering at Georgia Tech, said the cost to consumers of conventional water treatment ranges from 90 cents to $2.50 per 1,000 gallons, citing a report by the National Research Council. By comparison, the report put the cost of treating brackish water at $1.50 to $3 per 1,000 gallons. The cost of treating sea water is $3 to $8 per 1,000 gallons. The state's largest reverse osmosis plant, in Kill Devil Hills, can produce up to 5 million gallons per day. It's one of four Dare County desalination plants.

SEAFLOOR CHRONICLES

Survey of ocean floor reveals long history, from a geological fault to the wreckage of the Lusitania.

LONG SUNK The 240-meter-long ocean liner Lusitania, which was sunk by a German submarine on May 7, 1915,

now lies in 100-meter-deep water about 15 kilometers southeast of Ireland. This sonar image was collected during

the Irish National Seabed Survey. Click image twice for a larger view.Marine Institute

BARCELONA, SPAIN — Newly released images of the seafloor near Ireland depict scattered tidbits of history both old and new, from gouges scraped by icebergs during the last ice age to the wreckage of the Lusitania and hulks of German U-boats sunk by the British navy at the end of World War II.

The territorial waters of Ireland cover an area exceeding 890,000 square kilometers, about 10 times the size of the country’s land area, said John Joyce of the Marine Institute in Dublin, speaking July 21 during the Euroscience Open Forum in Barcelona, Spain.

In 1996, scientists began scanning the seafloor with sonar as part of the Irish National Seabed Survey, one of several similar programs underway in Europe, where territorial waters of the continent actually include more area than its landmass does, Joyce said. When the Irish program began, the effort was the largest civilian underwater mapping effort in the world, Joyce added.

WATERWORLDThe territorial waters of Ireland (outlined in red) cover far more area than the nation itself.Click image twice for a larger view.Marine Institute

Most of the images collected during the survey’s early days come from deep water, where sonar-equipped ships could more easily navigate and where each sonar scan could cover more territory. Among the deep-sea discoveries are broad troughs carved into the ocean floor at or near the end of the last ice age, about 10,000 years ago.

The survey also revealed a 20-kilometer-long, 20-to-30-meter-deep trench off the coast, a hint that a suspected but previously undiscovered geological fault lies beneath the seafloor there, says John Evans, co-director of the survey at the Marine Institute’s headquarters in Oranmore, Ireland. “Nobody knew this was there except the local fisherman” who capitalized on the bounty of fish drawn to the submarine feature, he notes.

The seabed scans have revealed more than 200 anomalies either known or believed to be shipwrecks. Many of those were previously undiscovered, and others sit in spots other than where they were believed to have sunk, Evans says.

MAPPING THE SHALLOWS Data collected during the Irish National Seabed Survey reveals Ireland’s Clew Bay as it would appear if drained dry. Islands in the bay are shown in red; water depths increase as colors shift from yellow to deep blue. Vertical distances are exaggerated by a factor of ten. Click image twice for a larger view.Marine Institute

Modern-day additions to the deep-sea landscape near Ireland include the Lusitania, an ocean liner whose sinking by a German submarine on May 7, 1915 helped draw the United States into World War I.

The ocean bottom north of the country also is home to a large number of German U-boats towed to sea and sunk by the British navy after World War II had ended, Joyce said.

Although the Lusitania’s final resting place was long known, no previous surveys had stumbled across these old subs, he noted. Resolution of the new sonar scans would allow researchers to spot an object the size of a refrigerator at a distance of 3 kilometers, he added

In some areas, immense dune fields cover the seafloor. Images of these previously undiscovered dunes, as well as future scans of the same features, will enable scientists to better understand the environmental forces that sculpt the ocean bottom there and how quickly — or how slowly — they work.

The Irish survey is now about 90 percent complete, Joyce reported. Today, scientists are mapping the shallow waters around Ireland using an aircraft-mounted laser altimeter. The light from that device penetrates a dozen or so meters into the water, enabling the researchers to quickly and accurately map areas that ships can’t reach. “The Irish coast is quite fragmented, and many areas are difficult to get into,” Evans adds.

Every year, the researchers visit some previously surveyed deep-sea areas to collect sediment samples, take detailed measurements of water properties and generally assess the seafloor environment, Evans

says. All data collected during the survey are available at no cost to scientists and commercial interests. More than 50 research projects in areas such as geology, oceanography and biology are now under way, he notes.

Data from the Irish survey could be a boon to more than just navigation and wreck divers. Companies seeking to exploit wave power as a source of alternative energy could use the data to help select suitable sites for their generators, Joyce contended. The seas off Ireland are some of the roughest in the world, and earlier this month researchers deployed a one-quarter-scale prototype device to assess the region’s potential to generate environmentally friendly energy.