A healthy sea is, if not noisy, at least as full of sound as a Vermont orchard in April--buzzing, humming, grunting, even chirping with the audio output of its varied life.

A healthy sea, though most of us cannot hear it, rings with the signals marine animals make to track prey, find mates, swim fast, yell "trouble!" and otherwise interact.

"Snapping shrimp" make the sounds you'd expect. So do croakers. Black drum make such a loud gulping noise that people living near canals down south can hear them from their time-share condos. Male crabs clap claws to wow girlfriends, schools of menhaden shred water as they leap to avoid bluefish, dolphins fire bursts of sonar to locate squid, whales emit complex "songs" that likely contain messages in Cetacean. On the surface, near the shore, seabirds shriek.

The hearing sense in all species is the alarm sense. There are many species of blind fish but no deaf ones. Sound travels five times faster in water than in air, and much farther. For all these reasons, a healthy sea is a symphony.

The Gulf of Mexico is no longer a healthy sea. While it would be naïve to believe the mercenary hysteria of TV news, it's clear that a good portion of the gulf will be poisoned, its life muted by the millions of gallons of raw oil leaked from BP's Deepwater Horizon well, and the chemical dispersants with which the oil giant seeks to break up the most visible components of the spill. Not enough research has been done to quantify exactly what a spill on the scale of BP's does to the marine environment in the long run, but there is plenty of evidence to prove the medium-term effects are dire. Oil suffocates and mutates fish eggs and larvae as well as the plankton fish feed on. Hydrocarbons have been shown to sicken adult fish, such as plaice. Drilling muds reduce the variety and number of codfish larvae around North Sea oil rigs. Areas of the Brittany coast covered with both oil and dispersants after the 1978 Amoco Cadiz spill show greater damage, even thirty years later, than areas covered with oil only; this suggests dispersants-plus-oil is a more lethal agent than oil by itself. Sea birds--well, we've all seen the pelican pictures. It seems highly likely that the Gulf of Mexico will go relatively silent for the foreseeable future.

Maybe I should qualify that statement. The Gulf will lose much of the complex symphony that healthy animal life plays. On the other hand, it will rock to an increasingly brassy techno beat as it fills with the noise of machines. Even while the sounds of life diminish, the rumble and whine of mechanical activity will fill its blue caverns and green shallows. Skimming vessels, boom boats, rig supply ships, rigs drilling relief wells, rigs pumping oil on other sites, will be churning up the waters between Florida and Mexico for months, for years.

This is not only true of the Gulf of Mexico. All the world's oceans have been growing louder thanks to increased human activity. In some of the more active areas, ambient underwater sound has doubled every ten years since the 1950s. Underwater noise off Point Sur in California, mostly due to commercial shipping, increased by 15 decibels, or fivefold, between 1950 and 1975. An oil company's seismic survey, by setting off charges on the seabed, will saturate 300,000 square kilometers of ocean for days at a time with damaging levels of noise. Active naval sonar--the "pings" the submarine crew listens for, sweating bullets, in WWII movies--routinely soaks 3.9 million square miles of the Pacific, according to studies by Linda Weilgart of Dalhousie University in Canada. The fact that whale strandings are often caused by such sonar is so thoroughly proven that even the US Navy admits it. Further evidence suggests that noise pollution throws off the direction-finding apparatus of deep-diving whales such as the Cuvier, causing them to stay down too long and drown. (All these data are discussed and sourced in my book, Zero Decibels.)

It's a sad fact that an increase in human activity, in most cases, seems to result in the hurt and muting of the non-human natural world. This is sad because that world is complex, beautiful, and still full of songs we have not yet heard, mysteries we have not yet solved. Thousands of species yet exist that we will barely have time to record before we stamp them out. All this is doubly sad because while humans are clever and versatile machine makers we are still products of a biosphere and we depend on its ability to provide us with food, and water, even soundscape. Given our soaring population, our scarcely checked pollutants, our obsession with growth, it is possible, even likely, that our species will not survive the harm we are doing to the rest of the world without undergoing trauma that will make the wars and depressions of the twentieth century seem like a Junior League cotillion by comparison.

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