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Oceans Are Getting Louder, Posing Potential Threats To Marine Life (nytimes.com)
An anonymous reader quotes a report from The New York Times: Slow-moving, hulking ships crisscross miles of ocean in a lawn mower pattern, wielding an array of 12 to 48 air guns blasting pressurized air repeatedly into the depths of the ocean. The sound waves hit the sea floor, penetrating miles into it, and bounce back to the surface, where they are picked up by hydrophones. The acoustic patterns form a three-dimensional map of where oil and gas most likely lie. The seismic air guns probably produce the loudest noise that humans use regularly underwater, and it is about to become far louder in the Atlantic. As part of the Trump administration's plans to allow offshore drilling for gas and oil exploration, five companies have been given permits to carry out seismic mapping with the air guns all along the Eastern Seaboard, from Central Florida to the Northeast, for the first time in three decades. The surveys haven't started yet in the Atlantic, but now that the ban on offshore drilling has been lifted, companies can be granted access to explore regions along the Gulf of Mexico and the Pacific. And air guns are now the most common method companies use to map the ocean floor.
Some scientists say the noises from air guns, ship sonar and general tanker traffic can cause the gradual or even outright death of sea creatures, from the giants to the tiniest — whales, dolphins, fish, squid, octopuses and even plankton. Other effects include impairing animals' hearing, brain hemorrhaging and the drowning out of communication sounds important for survival, experts say. So great is the growing din in the world's oceans that experts fear it is fundamentally disrupting the marine ecosystem, diminishing populations of some species as the noise levels disturb feeding, reproduction and social behavior. A 2017 study, for example, found that a loud blast, softer than the sound of a seismic air gun, killed nearly two-thirds of the zooplankton in three-quarters of a mile on either side. Tiny organisms at the bottom of the food chain, zooplankton provide a food source for everything from great whales to shrimp. Krill, a tiny crustacean vital to whales and other animals, were especially hard hit, according to one study.
Some scientists say the noises from air guns, ship sonar and general tanker traffic can cause the gradual or even outright death of sea creatures, from the giants to the tiniest — whales, dolphins, fish, squid, octopuses and even plankton. Other effects include impairing animals' hearing, brain hemorrhaging and the drowning out of communication sounds important for survival, experts say. So great is the growing din in the world's oceans that experts fear it is fundamentally disrupting the marine ecosystem, diminishing populations of some species as the noise levels disturb feeding, reproduction and social behavior. A 2017 study, for example, found that a loud blast, softer than the sound of a seismic air gun, killed nearly two-thirds of the zooplankton in three-quarters of a mile on either side. Tiny organisms at the bottom of the food chain, zooplankton provide a food source for everything from great whales to shrimp. Krill, a tiny crustacean vital to whales and other animals, were especially hard hit, according to one study.
Honestly, scuba diving even a good few miles away from a cruise ship leaving port leaves you feeling the horrible rumbling and hearing the dull droning sound. It's pretty obvious that even floating tenements that allow poor people to pretend they're on a luxury holiday because they get to experience the odd day here and there in paradise whilst spending the rest of the time on a giant council estate with more pollution than Delhi (as opposed to actually going on holiday in paradise) clearly have an effect on the oceans around them for a good few miles, it seems likely that any area seeing that day in day out multiple times a day is going to clearly have some kind of impact in an environment not previously accustomed to that noise or rumbling effect and that's a fraction of the sound being talked about in TFA from Sonar and air guns.
I've never experienced it myself but there are plenty of reports of divers having been in the water during sonar pings significant distances away and feeling fairly severe pain as a result of it.
Contrary to popular belief, even without boat traffic reefs are noisy places, the sound of a thousand parrot fish covering a few square miles can be heard as a constant crackling biting bits of reef when diving, and that's a relatively small sound. It should be obvious how big a problem this is with much louder noises.
Remember sound travels further and faster in water, so any sound being generated has the potential to culminate to much higher levels than we're used to on land because sound sources from vast distances away can combine much more easily underwater for this reason. Depending on th sounds generated for example you might not hear two sound sources miles apart on land if you're between them, but placed in the same positions in water, you could well hear not one, but both at once in contrast, so yes, sound underwater can be a much bigger problem.
I think the biggest problem is that sound travels something like 5 times faster in water, such that one ship could be equivalent to 5 land vehicles emitting the same noise. Depending on temperature and pressure, sound can travel significantly further too, there is a body evidence that suggests that whales can communicate over literally thousands of miles because of this.
This coupled with the fact that things like Sonar are sufficiently loud (200db+) as to be able to rupture the tissues in your brain or rupture you lungs, thus killing you close up, hopefully demonstrates the issue here.
Effectively, imagine something that loud on land, then imagine it travelling 5 times as fast and much much further. It's easy to think the ocean is big, so something like that is a drop in the ocean, but then when something is travelling at 1500m/s it stops being quite so big.
Regarding effects on whales, it's been found that whales can get the bends just like humans can if they ascend too quickly. There has been evidence of whales surfacing too quickly and getting the bends, and descending too quickly and injuring themselves to try and escape from Sonar because the Sonar is even more painful for them. Whether you believe in conservation or not, I think it's hard to not at least have some sympathy, facing a noise so loud and painful it pushes you to be willing to rupture your blood vessels, or surface so fast you burst your lungs or allow an air bubble to expand so quickly it severs the bones in your spine or other bones to escape it is a pretty fucking horrible thing for any living thing to have to suffer.
Even the hunting lobby who typically don't care about conservation at least mostly respect the importance of a quick clean kill, so it's pretty barbaric suffering that these sounds can cause. How widespread it is, I don't know however.