The Chesapeake Bay was once carpeted with oysters, but that was before centuries of overfishing, pollution, and disease took their toll: Today the oyster population has been reduced to less than 1 percent of its historical population. But a new restoration effort has shown unprecedented progress in bringing the bivalves back. In the Great Wicomico River, a tributary of the Bay, researchers have created a 87-acre oyster colony that contains about 185 million oysters.
The Chesapeake’s oyster reefs were destroyed by centuries of watermen towing rakelike metal “dredges” and silted over by dirt flowing from the mid-Atlantic’s farms and growing cities. The final blow came in the mid-20th century: A pair of new diseases killed oysters by the millions. Now, in many places, the bay bottom is a flat expanse of green mud. “Just picture, you know, a clear-cut forest,” said Kennedy Paynter, a biology professor [Washington Post].
The world’s fisheries may be seriously depleted, but a comprehensive new study shows that all is not lost–and suggests that when humans really put the effort into turning the tide, fish stocks can be returned to good health. The researchers found that efforts introduced to halt overfishing in five of the 10 large marine ecosystems they examined were showing signs of success. A combination of measures – such as catch quotas, no-take zones, and selective fishing gear – had helped fish stocks recover [BBC News].
The new study sprang from another report from marine ecologist Boris Worm in 2006, in which he made an alarming prediction: if current trends continue, by 2048 overfishing will have destroyed most commercially important populations of saltwater fish. Ecologists applauded the work. But among fisheries management scientists, reactions ranged from skepticism to fury over what many called an alarmist report [The New York Times]. Eventually the two groups agreed to collaborate on a study that would bring both their perspectives to the table, and which would determine the best ways to revive and manage the ocean’s fish stocks.
The motion of jellyfish and other sea creatures might mix the oceans just as much as the winds and tides do, according to a study published in Nature. The study’s findings provide support for a theory called Darwin drift, which was developed by Charles Galton Darwin (the grandson of the Darwin). The theory holds that a body moving through water brings along some of the wet stuff.
To test the theory of Darwin drift, researchers first modeled the motion of swimming organisms in a lab, using liquids of various viscosities, or levels of internal resistance. They found that bodies drag more liquid along with them when the liquid is thicker. This effect can be significant; in fact, when marine plankton-sized objects moved a couple of body lengths forward in the most viscous liquids, they carried with them up to four times their volume in liquid. Next the researchers monitored jellyfish as they swam through clouds of dye in a lake on the Pacific island of Palau. A trail of dye followed each animal, as Darwin’s mechanism would predict. Using a laser-equipped camera, the team then measured the dye’s movement and the stirring of suspended particles in the animal’s wake [Nature News]. The scientists found that the mechanism proposed by Galton Darwin provided for 90 percent of the mixing between the water and the dye.
Five patent applications for technology that aims to control the weather bear the signature of a man who knows how to think big: Microsoft founder Bill Gates. The applications made public by the U.S. Patent Office last week describe floating devices that could reduce the strength of hurricanes by drawing warm water from the ocean’s surface and channeling it down to the depths through a long tube. A second tube would reverse the process and bring deep, cold water up to the surface.
The applications were filed by an entity called Searete, which is part of the company Intellectual Ventures that was founded by former Microsoft executives as an “invention business;” Bill Gates is an investor in the company. Gates is listed as one of the inventors on each hurricane-quelling patent application, along with scientists like the geoengineering expert Ken Caldeira. One of the patent applications describes how part or all of the cost of building and maintaining the hurricane-killer ships could be raised by selling insurance to coastal residents whose risk would be reduced by using the new system [New Orleans Times-Picayune].
Human beings are increasingly making their homes on the coasts of continents, but this demographic shift is taking a toll on a sensitive coastal ecosystem that is often overlooked: seagrass meadows. A new analysis of seagrass abundance around the world found that 27 percent of these meadows have disappeared since 1879, and the rate of loss is accelerating. The study’s authors write: “Seagrass loss rates are comparable to those reported for mangroves, coral reefs and tropical rainforests, and place seagrass meadows among the most threatened ecosystems on earth….. Our report of mounting seagrass losses reveals a major global environmental crisis in coastal ecosystems, for which seagrasses are sentinels of change” [Nature News].
Endangered species expert Susanne Livingstone notes that despite these losses seagrass rarely makes it into the public consciousness. “It’s probably because they’re not as sexy [as corals], they’re not as attractive,” she says. “They’re just as ecologically important if not more so” [Nature News]. Seagrass meadows provide grazing for a variety of marine animals, including the green turtle and the manatee-like dugong. The coastal areas also serve as nurseries for fish; both coral reefs and commercial fisheries would feel the impact if seagrass meadows vanish.
Global warming is expected to cause such alarming climate disruptions that talk of hurricanes and heat waves can overshadow another drastic process at work: Burning fossil fuels and otherwise producing excess carbon dioxide makes oceans and other bodies of water more acidic, as the water absorbs the gas. This acidification can change a fish’s physiology in ways that were previously unpredicted and could affect the fish’s survival, according to a study in Science.
Scientists raised groups of white sea bass in water of varying concentrations of carbon dioxide. They found that the fish in the most highly acidified water had the largest rock-shaped ear bones, known in biology parlance at otoliths. That contradicts what the researchers had hypothesized: The ear structure in fish, known as an otolith, is made up of minerals. Scientists knew that increasing carbon dioxide in the oceans — absorbed from the atmosphere — is making the sea more acidic, which can dissolve and weaken shells. They wondered if it also would reduce the size of the otoliths [Los Angeles Times]. Instead, the ear bones of fish growing in the tank with six times as much carbon dioxide than normal were 15 to 17 percent larger than normal. An water with a CO2 concentration about 3.5 times higher than current levels yielded fish with otoliths that were 7 to 9 percent larger than those raised in water with today’s carbon dioxide levels. That’s the CO2 level predicted by the year 2100.
As the International Whaling Commission wound down this week with no progress made on the stalemate between pro-whaling and anti-whaling nations, some experts are beginning to question the commission’s central tool: the moratorium on commercial whaling established more than 20 years ago.Some experts wonder whether the ban is really protecting the world’s whale populations. Japan’s so-called “scientific whaling” program is a loophole in the ban, and the program is widely seen as a cover for commercial whaling. Japan catches more than 1,000 whales a year, and most cetacean researchers argue that whale populations exist at only a fraction of their former abundance and are far from large enough to sustain commercial harvesting for meat or oil — or even the culling of some 1,000 whales a year for science. Australia, a party to the IWC, campaigned this year to end any ”scientific whaling” that involves the deliberate killing of whales [Science News].
A report released by the commission on Monday also states that a quarter of the whales harvested from the Antarctic Ocean in the last seven months by Japanese researchers were pregnant. To many, the destruction of these whales and their unborn calves makes a mockery of the moratorium on whaling, given that the goal of the ban is to preserve whale populations. However, the Japanese Whaling Association contends on its Web site that “No whales have ever been hunted to extinction, nor are they likely to be. . . . [And] there are species which are abundant enough that marine management is needed,” such as for the Antarctic and northwestern Pacific minke whales and northwestern Pacific Bryde’s whales [Science News].
Extinction threatens four more species of deep-sea sharks and rays than a year ago, bringing the total species classified as “threatened” to 20 species, or nearly a third of the world’s 64 species, according to a report (pdf) released today by the International Union for Conservation of Nature. Rays and sharks are already two of the most endangered fish groups, researchers say.
The threat facing pelagic sharks and rays stems largely from overfishing; in many parts of the world, shark meat is considered a delicacy, and some animals become ensnared in fishing nets intended to catch tuna or swordfish. The report also urges governments to halt shark “finning,” the slicing of fins from captured sharks which are then tipped back into the sea to die, which it says is a growing industry providing ingredients for the Asian delicacy, shark fin soup. Although finning bans have been declared in most global waters, little effort is made to enforce them, said the IUCN [Reuters].
The most menacing predator of the seas has something in common with the most terrifying human predator: A new study has revealed similarities between great white sharks and serial killers. When a great white shark gets hungry, it doesn’t simply head for a crowd of seals and pick off the closest one. Instead, the great white lurks in its favorite hunting spot, waiting for a young and unwary seal to venture into the invisible danger zone. Then, it strikes silently from below.
Researchers used a serial killer profiling method to figure out just how the fearsome ocean predator hunts, something that’s been hard to observe beneath the surface. “There’s some strategy going on,” said study co-author Neil Hammerschlag…. “It’s more than sharks lurking at the water waiting to go after them” [AP].
A French nuclear submarine has joined the search for the “black box” of Air France Flight 447, which disappeared over the Atlantic last week with all of its 228 passengers. The “black box” is actually an orange cylinder — about 13 pounds of metal wrapped around a stack of memory chips and designed to withstand the force of being slammed high-speed into a brick wall. Actually a pair of devices — the flight data recorder and a voice and audio recorder — the equipment records virtually everything about how an airplane is working [CNN].
Aviation experts hope that the black box, if it can be located on the seafloor, will provide an explanation for what went wrong on the flight, which vanished so mysteriously. On board the French sub, the Emeraude, crewmen called “golden ears” were straining to pick up in their headsets the acoustic pings aircraft black boxes are supposed to transmit for 30 days under water. Nothing is better equipped for such faint sounds than an attack submarine with sophisticated sonar gear for detecting vessels deep in the ocean, naval officers said [Times Online].
Scientists have long known that coral reefs are being threatened by disease, global warming and other factors. Now a new study shows that that majority of Caribbean reefs have, in fact, been “flattened” in the past four decades, as ornate branched corals have died out and been replaced by flatter, fast-growing “weedy” species. Most of the reefs have lost all the intricate, tree-like corals that until the 1970s provided sanctuary for unique reef fish and other creatures, as well as protecting coastlines by sapping the energy of waves [New Scientist], according to the report, published in the journal Proceedings of the Royal Society B.
The coral reefs that were initially the most complex have almost been completely eliminated, says the researchers, who analysed changes in the structure of reefs using 500 surveys across 200 reefs conducted between 1969 and 2008. They found that 75 per cent of the reefs are now largely flat, compared with 20 per cent in the 1970s [ScienceDaily]. That’s bad news for sea life and storm defenses, says study coauthor Lorenzo Alvarez-Filip: “For many organisms, the complex structure of reefs provides refuge from predators…. This drastic loss of architectural complexity is clearly driving substantial declines in biodiversity, which will in turn affect coastal fishing communities” [ScienceDaily].
From pandas to polar bears, animals have served as icons for wildlife conservation. Now a new documentary called The End of the Line has helped the bluefin tuna, an endangered species, swim into the limelight by highlighting the overfishing common in fisheries today. Based on a book by journalist Charles Clover, the film has spurred some retailers to remove bluefin from their menus and stores and even moved some celebrities to pose naked with the fish to advocate conserving them.
A growing demand for bluefin tuna, commonly found in sushi and now as endangered as the giant panda, has not only decreased the fish’s population, but also increased the number of undersized fish that are harvested, preventing the fish from reaching maturity. “Bluefin tuna has become the poster boy for the overfishing campaign. It’s on the buffers – it’s really on the slide down now,” Clover says. “There are no large tuna anymore. There were bluefins of 250lb in Japanese fish markets when I went there four years ago – there are none now. A third of the catch is undersize” [BBC News].
The solution, experts say, doesn’t necessarily have to entail eschewing tuna altogether. Instead, consumers should stick to skipjack tuna, a more common variety, that has been caught using a method called pole-and-line, which avoids accidentally netting bluefish tuna and other sea life. Most commercial fishing operations that target skipjack use nets, Clover says, but “the skipjack run with all these other tuna species, like bigeye and bluefin. The skipjack are close to the surface and the bluefins swim further down, so there is often bluefin bycatch” [BBC News].
Robotic explorers on Mars get a lot of veneration for their daring feats, as well they should–but let’s not neglect the robots that are busy exploring the most inaccessible regions of our own planet. On Sunday, a robot submarine known as Nereus dove to a depth of 6.8 miles to investigate the Mariana Trench in the western Pacific Ocean. Nereus descended all the way to the deepest cranny of the trench, a spot known as the Challenger Deep, and spent more than 10 hours making observations in a spot that is deeper than Mount Everest is high.
For the expedition, the team had to build a new breed of remotely-operated submarine … which is capable of going deeper than any other while still filming and collecting samples. Sunday’s dive makes it the world’s deepest-diving vehicle [currently in operation], and the first vehicle to explore the Mariana Trench since 1998 [New Scientist]. So far, researchers have released only a single image (pictured), showing Nereus’s robotic arm scooping up sediment.
The fishing boats that relentlessly sweep the northern Atlantic Ocean looking for cod may be changing the genetics of the species, researchers say, in a case of “fisheries-induced evolution.” Commercial fishing techniques used to harvest the valuable fish are wiping out the cod that swim at shallower depths, which have a genetic variant that’s not seen in cod that stick to deeper water. If overfishing of cod continues, the research team believes the genetic variant will be lost all together. “Man the hunter has become a mechanised techno-beast,” the team writes. “Modern fisheries are uncontrolled experiments in evolution” [New Scientist].
Evolutionary biologist Einar Árnason and his colleagues studied the changing population of the cod fishery around Iceland; it’s one of the largest in the world, yielding roughly 200,000 metric tons a year. The stocks are in far better shape than the collapsed fisheries in the western Atlantic [ScienceNOW Daily News]. In the new study, published in the journal PLoS ONE, the researchers examined how the genotypes of Icelandic cod have changed between 1994 and 2003.
As global warming gradually melts away the sea ice in the Arctic Ocean, the oil and gas deposits buried in that inaccessible region are becoming a lot less theoretical to the five northern nations with claims to those riches. “For better or worse, limited exploration prospects in the rest of the world combined with technological advances make the Arctic increasingly attractive for development,” said Paul Berkman, … who specialises in the politics of the Arctic [The Guardian]. Now, a new study has estimated how much oil and gas may lie beneath the Arctic seabed, declaring that it contains about 30 percent of the planet’s undiscovered natural gas reserves and 13 percent of its undiscovered oil.
Researchers estimate that the Arctic holds about about 83 billion barrels of undiscovered oil, but say that’s not enough to challenge the dominance of the oil-rich Persian Gulf states. Meanwhile, the researchers say that the Arctic’s estimated 1,550 trillion cubic feet of natural gas is concentrated in marine territory claimed by Russia, ensuring that Russia will continue to be the world’s largest producer of gas. “These findings suggest that in the future the … pre-eminence of Russian strategic control of gas resources in particular is likely to be accentuated and extended,” said Donald L. Gautier, lead author of the study [AP].
Russia has not been shy about pressing its claim to the polar region: In 2007 two Russian civilian mini-submarines descended to the seabed to collect geological and water samples and drop a titanium canister containing the Russian flag [AP]. The other four northernmost nations — Canada, the United States, Norway, and Denmark (via Greenland) — have also sought some jurisdiction over parts of the Arctic.
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The Chesapeake Bay was once carpeted with oysters, but that was before centuries of overfishing, pollution, and disease took their toll: Today the oyster population has been reduced to less than 1 percent of its historical population. But a new restoration effort has shown unprecedented progress in bringing the bivalves back. In the Great Wicomico River, a tributary of the Bay, researchers have created a 87-acre oyster colony that contains about 185 million oysters.
The world’s fisheries may be seriously depleted, but a comprehensive new study shows that all is not lost–and suggests that when humans really put the effort into turning the tide, 
Five patent applications for technology that aims to control the weather bear the signature of a man who knows how to think big: Microsoft founder Bill Gates. The applications made public by the U.S. Patent Office last week describe floating devices that could reduce the strength of 
Human beings are increasingly making their homes on the coasts of continents, but this demographic shift is taking a toll on a sensitive coastal 
Global warming is expected to cause such alarming climate disruptions that talk of hurricanes and heat waves can overshadow another drastic process at work: Burning fossil fuels and otherwise producing 
As the 
The most menacing predator of the seas has something in common with the most terrifying human predator: A new study has revealed similarities between great white 
A French nuclear submarine has joined the search for the “black box” of Air France Flight 447, which disappeared over the Atlantic last week with all of its 228 passengers. The “black box” is actually an orange cylinder — about 13 pounds of metal wrapped around a stack of memory chips and designed to withstand the force of being slammed high-speed into a brick wall. Actually a pair of devices — the flight data recorder and a voice and audio recorder — the equipment records virtually everything about how an airplane is working [
Scientists have long known that coral reefs are being threatened by disease, 
From pandas to polar bears, animals have served as icons for wildlife conservation. Now a new documentary called 
Robotic explorers on Mars get a lot of veneration for their daring feats, as well they should–but let’s not neglect the 
The fishing boats that relentlessly sweep the northern Atlantic Ocean looking for cod may be changing the genetics of the species, researchers say, in a case of “fisheries-induced 
As 
