Its a quite common problem when detonating old naval mines, torpedoes or other unexploded ordnances at sea. In Germany the Kampfmittelräumdienst (Bomb disposal service) uses bubble curtains

https://dosits.org/galleries/audio-gallery/anthropogenic-sou...

to dampen the noise when they have to detonate those at sea.

https://youtu.be/GlxADbslYHw?t=944

Not a single word on turbine foundations? Construction of offshore wind turbines often involves ramming steel foundations into the ground with a set of pulses that are really loud [1]:

> A hydraulic or diesel fuelled hammer hits the pile repeatedly to drive it into the seabed. The single acoustic pulse created during impact is between 50 and 100 ms in duration with app. 30 - 60 beats per minute. It usually takes several hours to drive one pile into the bottom. This activity creates high levels of sound pressure and acoustic particle motion that are transferred through the pile into the water and seabed. Noise is radiated from the pile itself, but it could also radiate back from the seabed into the water column. The sound from pile driving is transient and discontinuous, to be compared with the more broadband and continuous sound from an operational wind farm. Several acoustic measurements of sound pressure during piling have been performed, showing source levels of over 180 dB re 1μPa(peak) at 1 m (Madsen et al., 2006; Betke et al., 2004; Betke, 2008; Erbe, 2009).

So 180 dB re 1μPa. While this is well below air guns or sonar (around 240 db for the air guns) [2], this is definitely comparable to the noise created by tankers (around 180 dB as well) [3].

[1]: https://www.diva-portal.org/smash/get/diva2:391860/FULLTEXT0... [2]: https://www.arc.id.au/SoundLevels.html [3]: http://cetus.ucsd.edu/Publications/Publications/PAPERS/McKen...

Are the construction of offshore windfarms unique in this regard? What about other construction in the ocean? Piers, waterfront building etc. If not, I find it odd that it's framed as an "offshore wind turbine" issue and not a "ocean construction" issue.

Not only that, but construction is usually once and done, besides maintenance or repairs. Unlike ship paths that are ongoing indefinitely.

And this discussion is disregarding the net benifits of why we’re building wind farms to begin with. It’s a weird dig at wind farms.

Just to plug-in - there are technologies that don't require hammering- suction buckets and floating wind turbines.

So to summarize, a beat per second about as loud as an oil tanker (its engine?) continuing for several hours per foundation - which itself will last decades.

The mention of "broadband and continuous sound from an operational wind farm" seems included for creative effect since it leaves the matter of the intensity of such noise entirely to the readers imagination. I would guess it should be of little interest if audible at all to ocean creatures over the sound of waves, even aside from shipping and sonar.

Study to whom it is most dangerous ?

My wife's PhD project has been modeling sound in a marine environment. She is using data collected around an offshore tidal generation site in Washington state and using finite differencing to create models of the whole region. While I understand very little of the math behind the research, it has been interesting to see how complex the system really is. Her models account for bathymetry, soil density of the sea floor, salinity, and temperature to name a few of the inputs. The goal of the project is to have a general model that can be used to help determine impacts of noise in any underwater environment.

[edit] minor grammar changes

This is the premise of the 2-year old art/sci project[0] I've been working on (since last Summer in order to add interactive elements). The point of the project is to raise awareness about deafening sound affecting all creatures, especially microscopic plankton which are at the bottom of the food chain and responsible for at least 50% of global oxygen production.

[0]: www.NoiseAquarium.com

Seems like there is some opportunity here for some military tech transfer in the form of quiet turbines for shipping. Surely there are some outdated but much quieter Cold War era designs that could be declassified and put into production.

Not sure there are any easy wins here as steam turbines have fallen out of favor. Most commercial ships use diesel main engines due to lower overall costs (capital, fuel, crew, maintenance). Most new warships employ gas turbines (vs. steam turbines) due to power-to-weight and power-to-size ratios, but these are things that commercial shipping does not need and will not pay for. Steam turbines are still kicking around on older ships (like the Jones Act specials rusting up and down the West Coast) and nuclear-powered stuff, and that's about it.

A lot of time and money was spent learning how to reduce cavitation because it's the significant component of the noise produced.

It feels like more efficient screws (which are incidentally quieter) would be a fairly popular sell to the shipping industry.

We should manufacture on the moon, then send steel cylinders at mach 5 pummeling towards humanity as from Thor in order to satisfy same day delivery demand (with no air brakes of course, to satisfy the malthusains).

It's all fun and games until the Loonies figure out they can use the payload delivery mechanism to start launching rocks at us.

Wow. Humans are affecting _everything_ en masse... even in the oceans where we don't live.

We better be careful with our actions.