Some good news in improving technologies!

Perhaps one of the more salient benefits of our work on ocean noise pollution is that unlike solid and chemical pollution, when the noise goes away, it is gone. This gives us reasons for optimism, particularly as we see efforts to improve technologies and practices by a broadening base of ocean stakeholders.

The first inkling that this could happen occurred a few years back when the United Nations International Maritime Organization (IMO) issued guidelines for the quieting of ocean vessels.

Just this year the “International Quiet Ocean Experiment” brought together scientists and stakeholders to craft a cooperative plan for understanding and mitigating the impacts of human generated noise in the ocean.

Bolt E Source Airgun

Bolt Airgun

And just this month three items came across the boards. An article in Sea Technology about Ultra Electronics Sonar Systems developments of a biomimetic sonar that uses biologically derived signals instead of synthetic or digital signals. The article examines the relative effectiveness of sperm whale echolocation clicks against synthetic signals, but it also suggests that animals would be less threatened by signals that are “natural sounding” and thus less likely to respond negatively.

Seismic Survey

Seismic Survey Array

In the same issue there is another article about the benefits of using continuous sonar signals as opposed to periodic blasts. Typical surveillance and navigation sonars kick out a blast or “ping” and waits for an echo to return off of a target. By using some advanced integration techniques the continuously active sonar can lock on to a target and track it using an equivalent amount of energy but spread over time – allowing for a decreased source level and potentially less impacts on marine life.

The third piece coming across my desk was in a local newsletter from Norwalk CT, where the seismic airgun manufacture Bolt Technologies is collaborating with Schlumberger on limiting the bandwidth and thus quieting down the collateral noise from seismic airguns. In an ideal setting the seismic signals would sound less like “bangs” and more like waves crashing, which again sounds more “natural” and should also decrease the impacts on marine life.

I spoke with John Andros with Bolt today, and while the actual product is not ready for prime time yet, they wanted to announce the project and the collaboration.

It is nice to know that some big stakeholders are taking this noise issue to heart. If we continue to move forward, pernicious ocean noise pollution could end up being “a thing of the past.”

The International Quiet Ocean Experiment

By the time you might be reading this I will have been conferring with colleagues and associates at the UNESCO Headquarters in Paris under the rubric of the “International Quiet Ocean Experiment” (IQOE). The purpose of the meeting is to develop a Science Plan for the IQOE, a focused international research effort that may last a decade or so exploring the sources, impacts, and potential solutions to the ocean noise pollution problem.



The meeting will be set up in a number of concurrent sessions to work out details on monitoring, technology development, needed science, soundscape impact assessment, experimental approaches, and research design.

While the decadal time frame may seem anti-climactic in the urgency of our times, it is in the scale of the entire ocean and under the auspices of the United Nations that these grand, cooperative plans slowly unfold. And as it took quite a number of us three years to get a single sentence into the “UN Convention on the Law of the Sea” qualifying “noise” as a “trans-boundary energy pollution,” the ten year timeframe gives all of us an international toe-hold on the steep face of global policy.

It was only 20 years ago that the “Acoustic Thermography of Ocean Climate” (ATOC) program got my attention and I embarked on the ocean noise mission. At that time there were those who thought I was over-reacting, but we have seen that the problems caused by human-generated ocean noise are real. They are an increasing issue as we expand our ocean activities. The full magnitude of the effects need to be gauged and addressed.

Location of ATOC Sound Sources and Receivers

While there may have been doubt in the past, time has a way to iron our reason. In the meantime, at events like the IQOE, I get to meet with some of the best and brightest in the field to share our knowledge, explain our perspectives, and weigh our concerns. In the end we get a chance to advance the discussion a little further down the road – and get a bit closer to solving some of the challenging acoustical problems brought about by our engagement with the sea.

Wish us magnanimity and luck!

The Noisy Cost of Power

It has been thoroughly established that harvesting power from fossil fuel is extremely expensive. Global warming and oil spills notwithstanding, from an ocean noise perspective the hydrocarbon industry is responsible for the lions share of marine noise pollution.

Figure 1: Global seismic airgun operations

Figure 1: Global seismic airgun operations

Most of the known noise comes from seismic airgun surveys – air-driven explosive impulses that penetrate the seafloor (and spread throughout the ocean) to derive geological maps of the sub-floor strata. At any given time there may be 40-50 of these surveys running concurrently, creating a din that can be heard all across the seas. [Figure 1 and Video]

Video: Seismic Survey Methods

Additionally, as offshore operations push deeper into the ocean, seafloor mounted processing equipment and thruster stabilized operations platforms bring in their own suite of noises. [Figurez 2 and 3]

Figure 2: Acoustic communications on seafloor equipment

Figure 2: Acoustic communications on seafloor equipment

Figure 3: Thruster-stabilized operations platform

Figure 3: Thruster-stabilized operations platform

Figure 4: Wind farm

Figure 4: Wind farm

While some of these noise costs will go away as we shift to carbon-neutral energy such as wind power, the shift doesn’t entirely exempt us from generating noise. There are some places where wind turbines will be mounted on tethered, floating platforms, but in most cases they will be mounted on pilings or piers which have to be sunk – or rather pounded into the seabed. The pile-driving noise is already causing problems with sea life, as indicated in a recent der Spiegel article.

Additionally, with blade diameters of up to 100 m (325 ft.) even while spinning slowly, the tip velocities can approach mach speeds with tip vortices creating a loud “thwap” as the blade tip passes by (like a slow helicopter). [Figure 4] And then there is the whining of the gear boxes…

A single ocean-sited wind turbine would probably not be much of a problem because the acoustical coupling between the ocean and the air above is not very efficient. But with wind farms and turbine parks spreading thousands of these devices over hundreds of square miles of ocean surface, the noises will combine in unpredictable ways and may create other marine noise problems.

It remains to be seen (or heard) if and what these problems might be but we do know that fossil fuel is a dead end, so we need to move ahead. The problem is that we have grown our modern civilization on the idea of “cheap energy” and have habituated to its lusty flavor. Mitigating the costs of power will ultimately be best served by using less of it.

The Neutrino and the Whale

photo: Brain Skerry

photo: Brain Skerry

A nicely written article in the Dec. 3 2009 issue  Nature reveals how a how a neutrino detection experiment conducted in the Mediterranean Sea by nuclear physicists actually uncovered an abundance of sperm whales.

The experiment involved placing hydrophones down 2000 meters below the surface; the idea being that these hydrophones could detect little pops from neutrinos – sub-atomic particles zipping in from deep space.

Marine Biologists Giovanni Pavan was brought in to help filter out the background noise. What they found though was a proliferation of biological sounds, and a surprising high density of Sperm Whale vocalizations – which ended up shifting the focus of the study to monitoring populations of sperm whales.

The article mentions that the Nuclear Physicists somehow thought that the deep ocean would be a “quiet test chamber” for their studies. I find it telling that some of the smartest guys in the room (nuclear physicists) would be so siloed in their field that they would lose track of the fact that the ocean is teaming with ‘biologicals.’

This speaks volumes about our education model that focuses on specialization. It makes me worry about what I am missing when I scan the field I inhabit. But this tale also helps me cultivate more patience for those folks who “can not seem to grasp” the importance of our mission of preserving the ocean’s bio-acoustic sanctity.

This little sound sample is of the “carpenter fish” – an old mariner’s name for sperm whales, representative of what the scientists heard.

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