The Synthesist: Climate Change Could Amp Up Ocean Noise
In recent honor of World Oceans Day, and what would have been Jacques Cousteau’s 100th birthday, and the thirty-fifth anniversary of “Jaws,” and not least because it was hot as all global warming outside, I sought refuge in “Oceans,” the majestic new documentary film by the directors of “Winged Migration” and “Microcosmos.” Only one theater within 300 miles was showing it, at only one showtime, and I caught it on what turned out to be the last day. As I sat all but alone in the fading light, my timing felt ominously apt. I’m always struck by how quiet ocean documentaries are. One hears the ghostly soundings of whales, of course, the eager pip of dolphins, the clacking of a crab’s claws. But invariably, as if to cover for an awkward and extended natural silence, the soundtrack swoops in, alternately dreamy and orchestral, with strings or harps or xylophones. In 1953 Cousteau called the ocean “the silent world”; six decades later, despite otherwise profound advances in cinematography, one would be forgiven for thinking he was right. But in that time science has come to understand that the sea brims with biological sound. Many if not most fish, for instance, communicate audibly. The croaker, the sea robin, and the sea trout seek mates and frighten enemies with honks and gurgles they produce with their swim bladders. The parrotfish, the garibaldi, the bar jack, and the scad grind their teeth with a rasping sound (think nails on chalkboard) to ward off intruders. The toadfish hoots like an owl, the cowfish barks like a dog; herring fart. The northern seahorse, in courtship, flicks a protuberance on its bony skull that clicks and snaps like a castanet. The black drum croaks so loudly in the canals of Florida that it can be heard through the ground and into the homes of nearby residents. Blame our senses for the oversight. Slaves to light, we forget that the vast majority of sea life resides in darkness, below the photic zone, and can’t rely on visual cues. And sound behaves differently underwater. Although high-frequency noise quickly attenuates, as the water absorbs it, low-frequency sounds, especially those between 10 to 200 Hz (roughly the range of bass guitar; humans can hear frequencies up to 20,000 Hz), can travel far, even miles. Sometimes BBC video crews ask Stephen Simpson, a reef biologist at the University of Bristol, to borrow some reef sounds for a film they’re making. He regrets to tell them that he has no stereo recordings, which can be played through two separate audio channels and sound great in a movie theater; sound travels too fast under water — five times faster than in air — to be audible in anything but mono. “It’s an alien acoustic environment,” Simpson says, “one we may not be ready for, I guess.” Coral reefs are particularly loud. Some noise comes from the wind and breaking waves, but most is low-frequency fish chatter and the collective claw-clicking of snapping shrimp, which sounds “like heavy rain on a tin roof,” Simpson says, and be can loud enough to impede the use of military sonar. Put it all together and you get “a pretty complex soundscape,” he notes. Indeed, Simpson has found that different reef habitats—barrier or fringing, mangrove or sandflat, pristine or degraded by sediment or overfishing — have different, identifiable audio signatures. Biologists traditionally study the health and diversity of reefs through visual surveys, which have their limitations — night, for instance. Lately Simpson has begun thinking that reef noise could be a useful monitoring tool. One could record several reefs in a day, for a quick overview, or leave the recording equipment out for months to collect long-term data. But reef noise isn’t a mere byproduct; it is instrumental in the reefs’ very formation, Simpson has found. Biologists have long wondered how young reef fish, which are cast into the open ocean as tiny larvae, manage to find their home reef days or weeks later. In a neat experiment a few years ago, Simpson set up two light traps, one quiet and the other crackling with the piped-in sounds reef fish and crustaceans. Larval fish were clearly more drawn to the latter. The reef noise is a homing beacon, Simpson says, “a roadmap that these organisms use to find their way.” In fact, reef fish are sensitive to sound even as embryos and become more sensitive to it, and in wider range of frequencies, as they develop. Nor is the phenomenon restricted to fish. Recently Simpson and some colleagues working in the Caribbean found that baby corals — mere flea-sized sacks of cells — orient by sound before settling into a hardened station on the reef. They can choose a direction and go. “When the idea was first suggested, I thought it was pretty out there,” Simpson concedes. “Look at it: it’s a blob covered in hair cells, it doesn’t have a central nervous system, an auditory apparatus, or anything.” But, he notes, those hair cells, or cilia, are akin to those in our own inner ear, where, when waggled by vibrating particles, they help detect sound. The cilia on coral larvae my serve the same purpose; they may even be tuned to specific frequencies. In effect, every larva is an inside-out ear; the reef literally broadcasts itself into existence. “Our instinct had been to assume that they’re pretty much pathetic,” Simpson says of the larvae. “But the more we learn, the more amazed we become. They can hear, smell, pick their habitats — they have control over their destiny.” Up to a point, sadly. Even as scientists expand their appreciation for the sea’s natural sounds, they have grown troubled by the rising tide of human-made noise. The deafening effect of seismic and sonar blasts on dolphins and whales is well documented. But low-frequency noise has become more pervasive too, especially near shore: more shipping traffic, more recreational boating, more underwater pile-driving. One recent study off the California coast found that underwater sound levels at the lowest frequencies have increased by an order of magnitude since the 1960s. How this aural fog might effect sea life is unclear. Could a rise in noise change where and how fish school, as traffic noise alters the flocking and nesting behavior of birds? Might it mask their ability to communicate, reproduce, seek prey and avoid predators — or, in the case of young corals, find their home reefs and build upon them? Or might they learn to hear around it, they way we acclimate to a noisy air-conditioner or the background din of a cocktail party. “When it comes to the chronic effects of sound,” Simpson says, “nobody has any real solid evidence.” Climate change will only raise the volume. As the ocean warms, it will become more acidic; that hinders animals like corals from forming carbonate shells. It also reduces the concentration of sound-absorbing chemicals like boric acid and magnesium sulphate, enabling low-frequency noise to travel farther, according to a recent study led by Tatiana Ilyina of the University of Hawaii at Honolulu. “The ocean,” Ilyina writes, “is becoming transparent to sound.” If that’s not enough, the ears of fishes may change too. Fishes rely on the otolith, a carbonate structure in the ear, to orient themselves and sense their surroundings. But a study last year from the Scripps Institution of Oceanography found that white sea bass reared in carbon-dioxide-rich water grow otoliths that are bigger than expected. It’s not yet clear if the size difference affects function, but symmetry does. In a separate study, Simpson recently found that reef fishes with asymmetrical otoliths have a harder time hearing the preferred sounds of their reef. The fish face a kind of tinnitus, from without and within. The seas are in trouble. One need only watch a few minutes of video of the Deepwater oil disaster, streaming live courtesy of a remotely operated submersible vehicle, to grasp the scale of the harm we wreak. Through the artistry of film, we can marvel at the sea life that whose grace and beauty we may soon forever miss. The shame — one of many — is we may never truly hear it.
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The Synthesist: Climate Change Could Amp Up Ocean Noise
Whales to the Rescue
What do you get when you cross a whale with a Wall Street trader? A carbon credit. Or at least that’s what one oceanographer’s latest research indicates. Andrew Pershing, an oceanographer at the University of Maine, says that nursing whale populations back to their pre-industrial levels could help mitigate climate change. "Whales are like the redwoods of the ocean," Pershing says. Blue whales can live for a hundred years or more — and they’re huge: a 100-ton blue whale contains nearly 10 tons of carbon. When a whale dies naturally, it tends to sink, locking the carbon away in the cold depths of the ocean. Commercial whaling releases carbon into the atmosphere, through the consumption of meat and oil as well as the decomposition of cast-off body parts. Rebuilding the Southern Hemisphere’s blue whale population from 1,000 to 325,000 (its pre-industrial size) would lock up as much carbon as a forest the size of Los Angeles, Pershing argues. Selling carbon credits for whale conservation could be used to fund monitoring initiatives and marine park management, he adds. "We need to use the markets creatively."
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Whales to the Rescue
Japan Blocks Ocean Conservation Measures
Not many filmmakers follow up an Academy Award-winning performance with an undercover sting operation. But in his continuing effort to stop the worldwide slaughter of dolphins, whales, and other marine mammals, Louie Psihoyos (who took home an Oscar this month for directing The Cove , about a secrect dolphin-killing operation in Japan) is prepared to expose renegade sushi restaurants across the United States for serving illegal whale meat. His first target — a restaurant called The Hump outside the Santa Monica airport — was forced to shut its doors on Saturday after Psihoyos’ team filmed the sale of thick, pink slices of meat and smuggled out DNA samples confirming they belonged to endangered sei whales, prompting federal charges. (Importing the meat of marine mammals is illegal under U.S. law.) Psihoyos, founder of the Oceanic Preservation Society, is now going after restaurants in San Francisco, Seattle, and New York that are rumored to also serve kujira (whale). "Wherever you are," he said in an interview outside The Hump before it closed down, "we will find you." Psihoyos’ crusades are certainly getting noticed in Japan (whose government and news media have attacked his film), but despite the bad publicity, the country continues to push for fishing and whaling policies that environmental groups say will cause further harm to ocean ecosystems and continue to push endangered fish and marine mammal populations to the brink of extinction — and beyond. Already this year, Japan has succeeded in fighting off a ban on exports of Atlantic bluefin tuna. There’s strong scientific evidence that the bluefin is nearing extinction due to overfishing; since 1970, the number of tuna harvested each year has plummeted by at least 80 percent. At the triennial gathering of the UN’s Convention on International Trade in Endangered Species (CITES) that just concluded this week in Qatar, a proposed export ban on bluefin — backed by the United States and bitterly opposed by Japan, which declared that it would ignore the ban even if it passed — failed by a vote of 68 to 20, with 30 abstentions. Many countries didn’t want to lose the revenue; Atlantic bluefin remains the most valuable fish in the sea, with Japanese brokers commonly paying $10,000 or more for a single fish. Japan consumes approximately three-quarters of the global catch, nearly all served raw as sushi or sashimi. Major bluefin exporters such as France, Spain, and Italy followed Japan’s lead. "The market for this fish is just too lucrative, and the pressure from fishing interests too great, for enough governments to support a truly sustainable future for the fish," says Sue Lieberman, director of international policy with the Pew Environment Group. Regulation of bluefin fishing will remain with an industry-dominated body whose allowable harvest quotas have ignored the advice of its own scientists and proven completely ineffective at slowing the bluefin decline. Following the failure to protect bluefin, CITES then voted down several measures (also backed by the United States and opposed by Japan, Russia, and China) designed to protect endangered shark species from "finning" — a practice in which fishermen slice the fins off of sharks and then dump them back into the ocean to die. Shark fins are prized in some Asian countries to make soup. Scalloped hammerhead, oceanic whitefish, and spiny dogfish were all among the species on the docket for protection by CITES. Japan argued, as it did on the bluefin ban, that regional fisheries groups — not CITES — should manage local shark populations. But in some areas, the rate of species decline exceeds 90 percent, according to studies. Next in Japan’s sights: ending a ban on commercial whaling imposed nearly a quarter-century ago. Despite this prohibition by the 88 member nations of the International Whaling Commission, Japan continues to hunt whales thanks to a loophole that allows for "scientific research" — something environmental groups claim is little more than a pretext that allows continued commercial hunting. Indeed, the Japanese fleet kills more than 1,000 whales annually in the Southern Ocean and then sells the meat in the country’s markets and restaurants. Two other nations, Norway and Iceland, have defied the moratorium outright and followed Japan in establishing their own yearly quotas. Since the moratorium took effect in 1986, according to IWC estimates, more than 33,000 whales have been killed — including the endangered fin, sperm and humpback species (as well as the sei whales being served at The Hump in Santa Monica). The International Whaling Commission (IWC) next meets in June, and two competing proposals are up for consideration. One would suspend the moratorium for 10 years and allow the resumption of commercial whaling. This is actually a compromise that could reduce the numbers of whales now being killed by setting annual quotas through the IWC, instead of allowing Japan, Norway, and Iceland to continue to bend (or outright flaunt) the rules by setting their own limits. Cristian Maquiera of Chile, chairman of the 88-nation IWC, has called this approach a "paradigm shift" that would achieve some consensus about whaling beyond the rancorous status quo. However, if it’s approved, Norway and Iceland could then start exporting whale meat to Japan, and South Korea has announced it will pursue its own commercial whaling venture. Another proposal, put forward by Australia, instead keeps the moratorium in place and lays out a timeline and regulatory framework to stop so-called "scientific whaling" altogether. Australia has also threatened Japan with legal action at the International Court of Justice unless it commits to ceasing its Antarctic hunts. Many conservation groups, including the Natural Resources Defense Council, are urging the Obama administration to oppose any effort to weaken the moratorium, but which way the United States will go is very much in question. Commercial whaling resulted in the demise of most of the world’s great whales, whose comeback has only begun since the moratorium was implemented. Joel Reynolds, director of NRDC’s marine mammal protection program, says "the whaling ban has been a pivotal step forward in the struggle both to save those species decimated by hunting and to recover whale populations throughout the world." But whales are far from fully recovered and still threatened by ongoing hunts, as well as factors such as military sonar, ocean pollution, and climate change. Activists hope that the whale-meat scandal brought to light by Psihoyos’ sting of the Santa Monica sushi restaurant could help step up the pressure of international public opinion before the IWC vote in June.
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