In recent years, there’s been a growing sense of concern in the ocean noise community about the worldwide emergence of plans for mining the seabed for a wide range of minerals.  Some of these plans are moving toward completion, as mining companies have solved the cost and technical complications and begun submitting actual project plans to regulators.  An early glimpse of this process has just emerged from New Zealand, where the EPA is now evaluating a permit to mine rock phosphate offshore from the South Island.  See this article in Pundit (a tamer Kiwi version of Huffington) for a very good summary of the process going on there.

In particular, Pundit’s Claire Browning notes that the first seabed mining proposal to come before the EPA was turned down, and she details some of the extravagant non-acoustic impacts of the current project—the process involves scooping up masses of seabed and dumping most of the material back, creating plumes of debris (including uranium and other heavy metals) in the water column.  All this in a Benthic Protected Area where no bottom-trawling is allowed.  Meanwhile, a consortium of environmental groups is stressing the insufficient acoustic and population assessments included in the application:

…the company had carried out no visual or acoustic surveys to establish what whales were in the vicinity, and there was no empirical data on noise that would be generated by the mining. Instead, CRP contractors had constructed a model extrapolating noise from a shallow-water mining operation, a model that, for example, did not take into account noise from pipes taking sediment 450 metres up to the ship – or back down.

“There are a number of potentially serious impacts on marine mammals. More rigorous environmental impact assessment would be needed to assess the severity of the impacts of this development,” said Ms Slooten.

It’s especially good to see that local watchdogs are thinking broadly about the potential acoustic emissions, including the sounds of material being pumped through pipes; our colleagues at Ocean Noise Conservation have been raising questions about such largely-ignored subsea industrial noise around oil and gas sites for several years.  Also interesting in the Pundit piece is a moderately deep dive into the question of how much the Kiwi EPA is taking the precautionary principle into account; the lack of concrete direction to do so was a controversial element of the statutory directions to the newly-formed agency, but it appears that its decisions are indeed deferring activities that carry uncertain risks to sensitive areas.  It’s worth noting that seabed mining may not always be a bad thing; much terrestrial mining has high environmental and social impact, with the resulting raw material shipped large distances to its eventual markets.  Such pressure may be relieved at times by moving offshore; in this case, the company’s website highlights the benefits of mining rock phosphate domestically rather than importing it from Morocco, the primary current source.  But of course, offshore sites need to be thoroughly assessed, and any new activity directed toward areas that will create minimal impact on marine life.

AEI lay summary of four recent papers:
Simpson SD, Purser J, Radford AN (2014). Anthropogenic noise compromises antipredator behavior in European eels. Global Change Biology (2014), doi: 10.1111/gcb.12685
Voellmy IK, Purser J, Simpson SD, Radford AN (2014). Increased Noise Levels Have Different Impacts on the Anti-Predator Behaviour of Two Sympatric Fish Species. PLoS ONE 9(7): e102946. doi:10.1371/journal.pone.0102946
Nedelec SL, Radford AN, Simpson SD, Nedelec B, Lecchini D, Mills SC (2014). Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate. Sci. Rep. 4, 5891; DOI:10.1038/srep05891 (2014).
Erica Staaterman, Claire B. Paris, Andrew S. Krough (2014). First evidence of fish larvae producing sounds. Biol. Lett. 2014 10, 20140643.

It used to be that most concern about human noise and ocean life was centered on whales and the two loudest sound sources: sonar and seismic surveys.  But in recent years, we’ve seen a growing wave of studies looking at how chronic, moderate ship noise can interfere with normal behavior and development of other creatures, including squid, fish, crustaceans, and other “lower” species.  Four recent studies add to the list of known or suspected ways that shipping and recreational boat noise may be wreaking previously unsuspected havoc throughout the oceanic web of life.

The most dramatic results came in a study of eels’ responses to predators (above). When exposed to ship noise, only half as many eels responded to an ambush attack from a predator (just 38% reacted, down from 80%); and, those that did react did so 25% slower than normal. Likewise, researchers tested eels’ ability to detect a “pursuit” predator that follows the eels before attacking; in this case, the eels in ship noise were caught twice as quickly.  Looking deeper, the researchers examined how noise affects metabolic rates, stress, and breathing rates, and an interesting feature of eel life, the preference for using one side of their body when interacting with other eels and when hunting.  The researchers explain:

“In the same way we write using our right or left hands, fish have a preferred side to approach a predator or to stay next to shoal mates with. We watched each eel as it explored a maze in ambient conditions to classify its right or left bias, then we exposed half to ship noise and half to more ambient noise. Their preferences went away when they were exposed,” says Dr Steve Simpson of the University of Exeter, lead researcher on the study. The team suspect this means ship noise affects eels’ cognitive processes, which could mean other processes, like learning, may also be affected. Alongside raised metabolic and ventilation rates, the scientists note the stress being caused by the shipping noise is similar to the levels fish exhibit in ocean acidification studies.

“We know shipping isn’t going to stop, but we can do things like move a shipping lane so it doesn’t interact with the migrations paths of animals,” Simpson suggests. “It’s a pollutant we have more control over than something like atmospheric carbon dioxide. These animals are having to deal with all the stressors globally, so if we can alleviate just one it might give the animals more resilience to other stressors like ocean acidification, which will come later.”

A study of two species of small fish highlights species differences and the ways that noise can alter behavior in unexpected ways.  Here, one species of fish exposed to ship noise actually responded more quickly to the presence of a predator,

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For the past couple of years the Lake Winds Energy Park in Mason County, Michigan has been embroiled in a contentious dispute about its noise levels (image to left is the “Park” under construction).  In April 2013, five months after the 56 turbines began operating, 17 neighbors filed suit, claiming that wind farm noise, vibrations and flickering lights were adversely affecting their health. A few months later, after commissioning an independent sound study, the Mason County Planning Commission formally declared the wind farm out of compliance and demanded a mitigation plan; the developer, Consumers Energy, disputed the findings yet lost two appeals, one at the Zoning Board of Appeals and one in Circuit Court. During that series of challenges, Consumers developed a plan to modify turbine operations for 7 turbines closest to the four sites where they were found to be marginally too loud.

Marginal is indeed the word: the sound study found 4 locations where the sound level peaked at 0.3 to 1.2 decibels over the 45dBA noise limit (it takes 3dB for a difference between two sounds to be audible); when using 10-minute averages, there were no violations.  The various explanations by the consultant, Brian Howe, illustrated the fine line that the turbine operations were walking.  His report stressed “general compliance with sound level criteria,” and noted that the brief violations “do not represent a statistically significant portion of time and do not indicate a systemic exceedance.” In his initial testimony at an August Planning Commission meeting, he said that there are no recommendations to correct for these times because “there is not a situation where they are predictably going over 45.”  Later, in a November letter to the Commission, after learning that the county had previously decided NOT to allow for occasional exceedances, he stressed that “I can assure the County that competent, material and substantive evidence supports the conclusion that the turbines are not in compliance at certain residences on occasion” and elaborated:

And this is the first half of the central lesson here: it’s essential that enough of a safety factor is built in to the sound models to account for known variability in sound production (how loud the blades are in various unsteady wind conditions) and sound propagation (how far sound travels as it gradually loses power).  Regular readers will know that variability is indeed, as Howe mentioned, often more than the simplified 3dB margin of error that was neglected here (see AEI’s 2012 report). The second half the lesson is related: when noise limits—for the sound of the turbines when it reaches nearby homes—are set as high as 45dBA, they will be regularly audible at these homes, and likely well above night-time ambient sound levels.  As many acousticians have stressed for years, these situations are very apt to trigger a significant number of complaints, especially if there are dozens of homes in that nearby range.  Here, we had the worst of both worlds: turbine siting plans that pushed sound right at the limit into nearby homes, and a limit that was on the high end of tolerability for many neighbors.  Indeed, after one such cautionary report was presented to the Mason County Planning Board, it decided to lower the limit to 40dB, but that change was revoked after push-back from Consumers Energy.

With this backdrop, this week the 17 original plaintiffs in the noise nuisance lawsuit agreed to a settlement offer from Consumers;

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For several years, AEI has been excited about the ever-expanding networks of ocean observatories coming online around the world.  A recent article on LiveScience detailed some of the benefits of the arrays of research stations deployed offshore by Ocean Network Canada, which collect all manner of data: physical, chemical, biological, geological, and acoustic.  Their two networks, the offshore NEPTUNE (left below) and the near-shore VENUS (right below), consist of permanent installations on the floor (“nodes,” shown as orange squares below) as well as mobile moored sensors that may take measurements higher in the water column (yellow dots). A similar US network, dubbed Regional Scale Nodes, is being planned off the coast of Washington and Oregon.

While the observatories are enabling in-depth study of complex process in ways not previously possible (click that link for a glimpse of the amazing topics being explored…yes, do it!), the audio feeds coming from some of the nodes hold special excitement for many researchers. “If you want to study what’s going on in the ocean, the best tool by far is sound,” said Tom Dakin, an acoustic specialist at ONC’s sensors technology development office.”There are all kinds of sounds being made in the ocean, and they all have a telltale signature. . . . If you start putting in a bunch of external man-made noise, [whales] are going to have a hard time communicating,” Dakin said. It’s like trying to have a conversation with somebody at a rock concert — you have to shout, you can’t hold a conversation for very long and you wouldn’t be able to detect different inflections that you would normally be able to hear.  He has been diving when a big ship has gone by, and “it feels like somebody’s whacking you in the chest with a two-by-four,” he said.

But while scientists are keen to hear what the new undersea recordings have to tell us, the US and Canadian Navies are far less enthusiastic.  They’re concerned that the audio feeds, which are freely available to scientists and the public as downloads and via live online feeds, will reveal sensitive information about submarine and ship movements, navy training activities, and even the sound signatures of individual vessels. The two navies have arranged with researchers to have an audio bypass switch that allows them to divert the audio streams into a secured military computer—sitting in a locked cage at the research facility where the data comes ashore—at times when their ships are nearby (and also at some random other times, so that their diversions don’t give away any secrets on their own!).  This article from The Atlantic dug into the way this system works, along with a quick look at naval concerns about sound from as far back as 1918.  The data diversions from Ocean Networks Canada’s system (often triggered by the US Navy) occur several times a month and last from hours to days. As noted by The Atlantic:

While the Canadian military has yet to return a request for comment, the U.S. Navy reminds me that naval ship movements are classified information, and the fact that those movements might potentially be broadcast on the internet is obviously of concern. “The value of having a cabled system is that it releases data live to the internet,” says U.S. Navy oceanographer Wayne Estabrooks. “But there are some times where we want to protect information, so we have to do diversions.”

…

“There’s a long tradition of the ocean being the exclusive domain of the militaries and the fishing community, and we’re more or less interlopers in this world,” says [Kim] Juniper, the microbiologist who showed me the photo of the computer in the cage. “The world is changing. . . It’s going to come to a point in the future where this is no longer going to be feasible for the navies to put resources into sorting all this data,” he later says. The hydrophones alone generate 200 gigabytes of raw data each day, and there are other, similar networks of Internet-connected sensors that already exist, or are soon to come online.

Dakin notes, though, that only 4% of the data is lost, and is returned to the science pipeline, often immediately and nearly always within a week.  The military filters out their ship noise, but leaves the rest of the data intact (at least, whatever data is not also in the frequency range of the navy ships or other sensitive sonic activities). “At end of the day, we hardly miss any data at all,” he says.  You can listen to live streams of ONC acoustic data here, and, since that’s rarely very exciting, to a collection of highlights of images and sounds here.

We’ve all heard that humpback whale songs have complex, repeating structures, and that the themes evolve over course of months and years. Yet listening to the gruts, guffaws, and groans of humpback recordings, it’s hard for most of us to really hear the large-scale structure that ties together these deeply alien sounds. In an article recently published on Medium David Rothenberg and Mike Deal have built on work done back in the 1970s by Scott McVay, and created a visual representation for humpback songs that makes it all suddenly and delightfully clear.

For starters, Deal created glyphs to represent particular “song units.” Each of these distinctive utterances is shown in a different color; the shapes mimic the shape of the sonogram of the sound. Following on McVay’s work with Roger and Katie Payne, Deal and Rothernberg show how these units are combined to create “phrases” lasting 20-40 seconds; several phrases create a “theme,” and a sequence of themes lasting 5-30 minutes is the “song.” Deal and Rothenberg take McVay’s work one step further by overlaying the units on an expanded musical staff to represent the frequqency of each phrase (each utterance of the whales includes a broad range of tones, like a chord with many audible overtones, so the glyphs stretch over a substantial span of the musical staff).

Finally, they present full songs in this new notational language:

As Rothenberg notes, “The pattern in the phrases starts to seem like an alien language. But even eerier is how much more human-like the order appears than most known animal vocal behaviors.” Go read the full article; it includes several videos of note, including one that animates the above notation while the 8-minute song is played, and one that explores the compelling similarities between humpback song and mockingbird songs. Also featured are many of the original notations done by McVay, which inspired this new take on it, and exceprts from a recent lecture by Katie Payne (see it here) that dives deep into the questions of cultural change and linguistics that are raised by the extraordinary nature of the these songs.