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Global industry council forms new ocean noise working group

News, Ocean energy, Science, Seismic Surveys, shipping No Comments »

The World Ocean Council, an “international, cross-sectoral alliance for private sector leadership and collaboration in Corporate Ocean Responsibility,” has launched a new initiative to address ocean noise issues.  Planned to complement the ongoing efforts of the oil and gas industry’s Sound and Marine Life program and the International Maritime Organization’s ocean noise policy work addressing shipping noise, the WOO’s Marine Sound Working Group will be especially helpful in raising awareness of ocean noise issues among ocean industries—including ocean mining and port construction—that have been less involved in the issue over the past decade or so of intensive study.  

In an interview after the initial meeting of the Marine Sound Working Group, co-chair Brandon Southall noted efforts to find alternatives or noise-masking techniques for some noisy activities in which the noise is a by-product, rather than a necessary component of the work; he also stressed ongoing efforts to better understand the widespread effects of chronic moderate noise, in contrast to researchers’ earlier focus on localized, acute effects of specific loud noise sources.  See the full 6-minute interview with Brandon here.

Melting icebergs add to ocean cacophony

Ocean, Science No Comments »

A new study has found surprisingly high noise levels in a large iceberg tracked from the time it calved from the Antarctic ice sheet until it disintegrated and melted at sea.  Three kinds of sounds dominated: early on, the iceberg scraped against the seafloor; later, it collided with another iceberg; and finally, it cracked into pieces and disintegrated within a couple of months.  At times, the sounds were loud enough to be recorded thousands of miles away, near the equator, and during one especially loud day, the sound was equivalent to that of over 200 supertankers. 

“You wouldn’t think that a drifting iceberg would create such a large amount of sound energy without colliding into something or scraping the seafloor,” said Robert Dziak, a marine geologist at OSU’s Hatfield Marine Science Center in Newport, Ore., and lead author on the study, who has monitored ocean sounds using hydrophones for nearly two decades. “But think of what happens why you pour a warm drink into a glass filled with ice. The ice shatters and the cracking sounds can be really dramatic. Now extrapolate that to a giant iceberg and you can begin to understand the magnitude of the sound energy.” 

“The breakup of ice and the melting of icebergs are natural events, so obviously animals have adapted to this noise over time,” Dziak said. “If the atmosphere continues to warm and the breakup of ice is magnified, this might increase the noise budget in the polar areas. “We don’t know what impact this may have,” Dziak added, “but we are trying to establish what natural sound levels are in various parts of the world’s oceans to better understand the amount of anthropogenic noise that is being generated.”

AEI presents seminars to Sandia, NREL wind research teams

Human impacts, Science, Wind turbines 3 Comments »

Earlier this month, I arranged to visit the wind research teams at Sandia National Lab and the National Renewable Energy Lab’s National Wind Technology Center, both of which are relatively nearby here in the southern Rockies.  I’ve been following the work of many of these researchers for the past year or so—it was central to my 2012 Renewable Energy World conference paper and presentation on efforts to quiet turbines—and was very interested in learning more about their past, current, and future studies.  


In particular, the Sandia team has recently built a Scaled Wind Farm Testing (SWiFT) facility, at which they’ll be studying wake interactions between turbines, and they’ve long been on the forefront of developing new materials and experimental active systems to reduce load strains caused by inflow turbulence.  They’re also leading the development longer blades, which may have important noise implications. Their most exciting forward-looking project is a 5-year effort to re-activate development of vertical axis turbines, with the goal of moving toward 5-10MW scale vertical axis turbines for use offshore (this will be a 10-20 year project, if the first phase shows promise).  Meanwhile, at NREL’s NWTC, lots of research has looked at the pinpointing the sources of sound on turbine blades, as well as advanced modeling of sound propagation in various atmospheric conditions.  Researchers there have quantified the power-production trade-offs caused by wake interactions within wind farms, and are on the leading edge of new technology that might allow individual turbines to monitor incoming air flows and adapt their operations to minimize loads and noise.  All of this research has intrigued me, because of the likely role of wakes and atmospheric turbulence in wind turbine noise levels, and in creating some of the more intrusive sound qualities that neighbors find hard to live with.  My hope was to sit down with these researchers and learn more about their work, as well as draw on their experience to see whether they thought the turbulence factors they study to reduce stress on turbines may indeed also have an effect on the sounds.  

As it turns out, they were also intrigued by such a dialogue, and both labs asked me to present their teams with a seminar on what I’ve been learning about community responses to turbine sound.  Much of what I shared was new to them, and we had some great discussions.  One of the central take-aways from both teams was that very little research has really looked at the acoustic effects of inflow turbulence, and there was universal agreement that this is an important area for future study (as a start, the SWiFT facility will incorporate some acoustic measurements).  Many of them were especially interested in the varying sound quality of turbines, and the ways that this may trigger negative responses among neighbors; there was much speculation about the potential to identify the conditions that create the troublesome knocking, banging, thumping sounds, and perhaps adapt turbine operations to minimize or eliminate them.  As I’ve long found in my interactions with academic and agency researchers, there was an easy openness and curiosity in both rooms, with many questions tossed around, and an excitement about studies they hadn’t seen before. 

Read or download my presentation: The possible role of turbine, wake and shear effects on community response to wind farm noise  (This is the “director’s cut,” including a few slides deleted for length from the final version, along with some additional slides from the REW conference presentation that cover related topics) 

Community Response to Wind Farm Noise: The possible role of turbulence, shear, and wake effects by jimcummings

2008 UK stranding linked to Navy exercises

Effects of Noise on Wildlife, Ocean, Science, Sonar No Comments »

On June 9, 2008, 26 common dolphins, 21 of them infants, stranded and died in river estuaries around Falmouth Bay, as several days of Naval exercises involving over 30 ships wound down (see AIEnews coverage at the time).  A four-year study (read it online) has  concluded that unspecified Naval activities are “the most probable (but not definitive) cause” of the strandings, which involved at least 60 animals in all, with most of the adults re-floated and guided back to sea.  

The study ruled out other common causes of cetacean strandings, including foraging for fish in shallows, attack by orcas, illness, algal toxins, recreational boats, and earthquakes.  However, the researchers also could not identify a likely trigger among the Naval activities taking place on the morning of the strandings or the day preceding the discovery of the struggling animals.  Press reports at the time suggested that locals heard some large explosions on the day before and day of the strandings, though the researchers did not find records to indicate such activity. Mid-frequency sonar transmissions ended four days earlier; that or other ongoing activity is thought to have driven the dolphins into the bay, with unknown further disruptions triggering the fatal strandings early on the 9th.  According to lead author Paul Jepson, “Eyewitnesses described their behaviour as swimming continuously in tight circles, being vocal, fluke-slapping, leaning sideways, and often with one or more individuals attempting to strand.” 


The lack of a clear cause for the final stranding event during a relative pause in Naval activity on the day before the early-morning discovery of the floundering dolphins adds a familiar ambiguity to the situation.  A Naval spokesman noted that they disagreed with the report’s conclusion and stressed their decades of similar exercises in the area without mass strandings, while conservation groups including the NRDC and the UK-based Whale and Dolphin Conservation called for exercises to be redesigned. While cetaceans can often move away from unwanted noise, it’s long been known that strandings can occur when animals become trapped in areas with no escape route, such as apparently happened here.

Despite Naval denials of responsibility, this event did spur some changes that have led to later exercises being temporarily suspended when dolphins appeared on the verge of being trapped in a similar situation.  As detailed in the new study:

Following this MSE (Mass Stranding Event) and recommendations from the organisations involved in the rescue of dolphins in the MSE, the UK Ministry of Defence initiated the Marine Underwater Sound Stakeholders Forum in the UK to regularly meet with all interested stakeholders (scientists, other Government Departments like Defra and a range of non-Governmental organisations) to discuss these issues in some detail. A direct line of communication was also established after the Falmouth MSE to facilitate rapid exchange of information between cetacean strandings/sightings organisations and Royal Navy Naval Command Headquarters to report groups of pelagic cetaceans seen unusually close to shore and potentially at increased risk of stranding. This was used to report a near-MSE of over 20 common dolphins in the Fal estuary in April 2009 that was seen 15 minutes after RN sonar trials were initiated in the region. The RN immediately modified the naval exercise (including use of active sonars) until the group of dolphins had returned to open sea several hours later. The need to alter training excercises due to the presence of dolphins has not subsequently occurred in this region.

According to the authors, “Such continual improvement of mitigation strategies by the military themselves is probably the best way to limit future environmental impacts of naval activities, including cetacean MSEs.”

Do negative expectations cause wind turbine health effects? (AEI analysis and commentary)

Health, Human impacts, Science, Wind turbines 5 Comments »

AEI lay summary of:

  • Simon Chapman, Alexis St. George, Karen Waller.  2013. Spatio-temporal differences in the history of health and noise complaints about Australian wind farms: evidence for the psychogenic, “communicated disease” hypothesis. Download this paper (pdf)
  • Crichton, F., Dodd, G., Schmid, G., Gamble, G., & Petrie, K. J. (2013, March 11). Can Expectations Produce Symptoms From Infrasound Associated With Wind Turbines? Health Psychology. Advance online publication. doi: 10.1037/a0031760 Read/download this paper (Scribd)

Click here to download a 12p PDF version of this extended post 

If the detail in this post is more than you can tackle, I encourage you to take a look at the first several paragraphs through the brief assessments, then click through and scroll all the way down to the final few paragraphs, which look beyond these two particular studies and reflect on the health effects issue and its role in the larger debate over wind farm siting 

In Australia, the debate about wind farm siting standards has ramped up beyond what we’ve seen in the US and Canada.  Several states have adopted more precautionary setbacks (2km, with some options for closer siting), and this has spurred some pushback from wind energy advocates.  Meanwhile, the Waubra Foundation has become a central repository for information on negative impacts, and has released a series of reports and statements highlighting health effects and home abandonments, while calling for an even more precautionary 10km setback standard.

Recently, two reports were released in Australia that have garnered worldwide attention for their claim that health effects around wind farms are caused primarily by negative expectations promulgated via the web and local chapters of groups such as Waubra.  One of these is a formal study published in the journal Health Psychology by a team from the University of Aukland, and the other is the latest (and most comprehensive) paper from Simon Chapman, a University of Sydney Professor of Public Health and outspoken skeptic about wind farm health claims.  

I’ve long been concerned that the adamantly contradictory statements of both wind advocates and concerned citizens groups are likely to be inadvertently contributing to anxiety and stress among wind farm neighbors, which could well be a major contributor to many of the most widespread health effects (especially headaches and sleep troubles).  These new papers are investigating plausible psychological factors, and both studies add some useful new insights; however, similar to my assessment of a recent peer-reviewed article touted as proof of health effects, digging into these two papers reveals data that is far less clear-cut and absolute than the conclusions drawn by the researchers, and especially as reflected in the simplified popular press accounts of the studies. 

The short version of my assessment of these papers:
The Chapman paper gathers a wealth of information about complaint rates around all the wind farms in Australia, and taken at face value, makes an apparently convincing case for Chapman’s preferred hypothesis about the differences he finds: that the presence of local and national groups harping on possible health effects is the proximate cause of health complaints, and indeed, for the actual appearance of the symptoms themselves among wind farm neighbors.  But Chapman’s insistence that the negative influence of “anti wind farm groups” can totally explain away all the noise problems is ludicrous. His paper frames all his data through this one lens, and makes no effort to consider other possible contributors to the differences he finds in complaint levels. At the same time, his inclusion of existing public health research on the nocebo effect and studies of psychologically-mediated responses to perceived environmental threats is a welcome addition to our consideration of wind farm noise issues; still, as I begin to dig into the actual academic studies that he cites, they seem to be at best suggestive of modest contributing factors, rather than offering data that’s strong enough to be posited as the sole or primary explanations for most noise complaints.

For example, the Crichton paper finds that expectations of negative health effects can create a statistically significant increase in the number and severity of symptoms reported by study subjects exposed to infrasound (and to sham infrasound).  However, the actual data shows only moderate changes in reported health responses, especially in symptom severity, rather than a dramatic difference between the subjects primed with negative expectations and those who were given reassuring information prior to exposure to the sounds.  The average severity of symptoms, rated on a scale of 0-6, averaged 1.67 for the group primed to expect no health effects, and an only slightly higher 1.94-2.13 among those primed to expect negative impacts—a far cry from the intolerable responses being reported by some wind farm neighbors.

Despite the fact that these papers don’t contain a “smoking gun” that explains away negative health effects, as wind advocates may be claiming, their findings can be seen as a likely part of the story.  The small differences found in the Crichton study may be due to averaging over all participants; perhaps some individuals responded more dramatically than her data shows; a stronger effect on some individuals could be embedded in the similarly subtle yet statistically significant trends in the Nissenbaum study that found worse sleep and psychological health among those closer to wind farms.  And the Chapman paper reminds us that those reporting health effects remain a small minority, even in areas with substantial community outcry.  As AEI has often mentioned, even empathetic researchers tend to suggest that significant health effects occur in only 5-10% of the nearby population; as discussed below, a divide is emerging between those who feel that such small numbers reflect insignificant impacts, and those who feel that we can and should avoid or better minimize such effects by increasing setbacks.

A local example of health effects: While statistical or laboratory studies can provide valuable insights, they can also distance us from the actual experiences under consideration. In Falmouth, MA, dozens of turbine neighbors have had enough sleep and health issues that the town is considering removing two turbines.  A bit over 10% of those living within a half mile have filed formal complaints; in some directions, 25% or more have had problems.  This recent article features quotes from a couple of these neighbors (including one, Neil Anderson, who is a longtime renewable energy supporter), and from state and local wind advocates.

Click on through for a more complete summary of these papers, and AEI’s current reflections on the health effects controversies

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WHOI researchers distill whale calls from seismic survey data

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, Seismic Surveys No Comments »

Researchers at Woods Hole Oceanographic Institution (WHOI) have completed a proof of concept study that appears to be able to identify individual whale calls in the data collected by seismic surveys.  In the initial data, the researchers were able to cull fin whale calls from the recordings made as airguns blasted their pulses of sound into the ocean floor.  Blue whales are also likely candidates for being heard on the recordings, since their calls also overlap with the frequencies of interest to seismic mapping efforts.

“We have a huge amount of data that can say, ‘Did they change their behavior? Did they stop feeding? Did they stop talking? Did they talk louder?’, and that’s what we want to know,” said WHOI seismologist Dan Lizarralde.

Lizarralde and collaborators are currently seeking funding to develop a computer algorithm that can help with the daunting task of extracting the whale calls from massive amounts of seismic survey data.

For the full story, including spectrograms and comments from other researchers, see this story on

Floating deepwater wind turbines on track in Maine

News, Ocean energy, Science, Wind turbines 1 Comment »

Ocean-based renewables are destined to be a huge piece of a future carbon-free energy system—tidal, wave, and offshore wind are all likely to become more technologically and economically viable over the coming decade or two. As these offshore renewables mature, they will reduce the current pressure to site wind farms in more populated areas closer to urban electricity load centers.

Statoil Hywind Turbine copyWatching the decade-long struggle in Massachusetts to build Cape Wind, the nation’s first offshore wind farm, researchers and state officials in Maine have chosen a different path: they decided to tackle the engineering challenges of building turbines that can float in deep water far offshore, rather than the social challenges of building wind farms in shallow water close to shore (which use fundamentally the same foundation designs as onshore turbines).  Floating deepwater turbines can take advantage of even stronger, more consistent winds than their nearshore counterparts; along most of the east coast, offshore wind is far more reliable than onshore locations.

After several years of planning, 2013 will see two floating turbine projects in the water off the Maine coast.  A one-eighth scale (57-foot tall) prototype will be tested in a relatively sheltered bay near Castine; the small model must be sited in waves that are proportionately smaller as well, to simulate how a larger unit will do with bigger offshore waves.  Meanwhile, Statoil will be installing 4 3-MW turbines two miles off the coast of Boothbay Harbor; this close-to-shore site will allow for closer monitoring and testing of the units’ durability.  Both projects are aiming toward the eventual construction of large-scale wind farms, likely using 6-8MW turbines, in waters far offshore, though likely not for another decade or so.  The Bangor Daily News puts the big dream in perspective: “to harness the Gulf of Maine’s winds by 2030, placing a full-scale wind farm of about 170 turbines, each taller than the Washington Monument, in the Gulf of Maine. That farm would bring 5 gigawatts, or the equivalent of about five nuclear power plants, of wind energy to Maine’s shore.”

UPDATE, 5/9/13: University of Maine researchers unveiled their 1/8 scale floating turbine foundation.  See article and video here.

UPDATE, 7/12/13: Late-session political maneuvering in the Maine state legislature has led Statoil to put a hold on its plans for floating offshore development in the state.  Governor Paul LaPage, a vocal critic of Statoil’s plans, vetoed an energy bill and in order to move it forward, demanded that an existing contract with Statoil be temporarily shelved to allow the University of Maine to file a bid as well.  LaPage and other fiscal conservatives have objected to the contract approved by the state PUC,  which pays Statoil a higher rate than other Maine electricity sources (the logic being that this small surcharge now will lay the groundwork for a new job base in the state as offshore industrial wind matures over the coming couple of decades).  The Statoil contract approved by the PUC uses up all the state incentives that have been approved for offshore wind in Maine.  It’s unclear whether the UMaine team wants to submit a bid; many see long-term cooperation between Statoil and UMaine researchers as the more fruitful way forward. An ideal scenario may find both projects getting contracts from the PUC, and thus be able to compete for some upcoming federal incentives for offshore wind development. In any case, the bill only holds up the commitment to Statoil for a few months, so the company’s sudden announcement of a hiatus may be more posturing than a fatal blow to Maine’s ambitious offshore vision. Local coverage here, here, and here.

MAJOR UPDATE, 11/7/13:  Since July, Statoil has definitively abandoned its project in Maine, citing political uncertainty that agreements will be upheld, and the University of Maine has released its plan, which aims to develop a 12MW pilot floating turbine project in the next few years, with the long-term goal of 500MW of deep water turbines by 2030, generating power at ten cents or less per kilowatt.  Here’s the latest.

The challenges for floating offshore wind are well-summarized in a recent article from

Floating turbines cost less to install than conventional tower-based designs. They can be assembled onshore and then towed out to the installation site, eliminating the expensive and arduous process of building them out in the open ocean. On the flip side, the huge amount of steel needed to make turbines sturdy and heavy enough to withstand rough waves is too expensive. Engineers are working on solutions to get around that, such as intelligent systems that pump ballast water from one tank to the next as a way to stabilize turbines.

One thing that’s clear is the need for specialized turbine blades that can produce energy even as they rock and tilt on ocean waves. All that motion means more wear and tear and can also interfere with power generation. For now, all these designs are performing well, the question is more about which can be produced reliably at the lowest cost.

There has been some local resistance in Maine, especially about the power purchase agreements between Statoil and Central Maine Power for the energy from the pilot project near Boothbay Harbor, for which Maine’s electricity customers will be paying a premium.  State officials maintain that the small extra cost is a worthwhile investment in an offshore wind industry that could pay huge dividends in manufacturing and construction jobs in the years to come.  This is also a long-term investment in an electricity-generating future that can wean us from fossil fuels.  

While Maine’s electricity is already relatively climate-friendly, thanks to significant hydroelectric resources, the development of floating offshore wind in the Gulf of Maine could send lots of clean electricity to Boston and other New England cities.  Onshore wind in the Maine hills faces significant resistance as well, with locals feeling that the price paid by industrializing ridgetops and building new transmission corridors is not worth the modest benefit in green energy for neighboring states; the much smaller impacts of offshore wind may change that cost-benefit equation.   First, though, floating turbines will have to prove themselves durable, and the materials cost must be trimmed.  While that research is underway, offshore wind planners will need to insure that wind farm locations don’t interfere with key fishing habitat.

New NMFS Navy “take” permits: outrageous or reasonable?

Effects of Noise on Wildlife, News, Ocean, Science, Sonar No Comments »

The release of Proposed Rules to govern US Navy training and testing operations in the waters of the Atlantic, Gulf of Mexico, Southern California, and Hawaii from 2014-2019 has put the National Marine Fisheries Service (NMFS) in the crosshairs of an outraged response from environmental groups.  NRDC, the Center for Biological Diversity, and others point to the staggering numbers of “Level B” harassment that will be allowed: over 31 million incidents, along with “Level A” injury predictions including permanent hearing loss numbering in the thousands, capped by several hundred deaths.  These numbers reflect far more than sonar training; also included in these permits are impacts from ongoing training and testing of systems used in live gunnery and torpedo exercises, explosive mine-neutralization, air, surface, and submarine battle exercises, and ship-shock trials (in which large explosives are set off near ships to test their resilience).


“We’re talking about a staggering and unprecedented amount of harm to more than 40 species of marine mammals that should give any federal agency involved, be it the Navy or the National Marine Fisheries Service, pause,” NRDC attorney Zak Smith said in a statement.  The take numbers are generally about twice as high as those in the last round of permitting, which covered a five year period from 2009-2013.

“We absolutely share the concern about protecting marine mammals,” said Alex Stone, an environmental program manager with the Navy’s Pacific Fleet. “We think that the mitigation measures are effective, but it’s true, you’re never going to see every marine mammal that’s there. But in terms of impacts on species, we really haven’t seen any of those after years and years of doing these same types of training and testing activities in these same areas.”

“That’s always been a dubious argument but in light of new information it’s wearing especially thin,” said Michael Jasny of the Natural Resources Defense Council, in a KQED segment. “We now know that beaked whales off California are declining precipitously. We know that blue whales aren’t recovering.” Jasny says the Navy should avoid key areas, like gray whale migration routes and the summer feeding grounds of endangered blue and fin whales. “Southern California is a globally important feeding habitat for them,” said Jasny. “It should be elementary common sense to avoid the core feeding habitat of blue whales. “

How could NMFS sign off on such a seemingly devastating number of permitting takes?  Well, as is often the case, the picture isn’t quite as clear as the headlines may make it seem.  Indeed, we are once again thrust into a funhouse-mirror world of wildly divergent ways of framing the proposed plans.  Press releases and resultant popular press headlines trumpet the NMFS rule as “allowing the Navy to harm whales, dolphins more than 31 million times,” with the permitted incidental takes being described as including “a wide range of harms, including destruction of habitat, physical injury and death.”  The Navy’s statement offers a much more sanguine perspective on the tens of millions of behavioral takes, describing these effects as “e.g., turning head, changing swim direction.”  Huh? What to make of all this?

I dug into the Draft EISs and Letter of Authorization requests developed by the Navy, and the two Proposed Rules announced in January, in order to try to understand how Navy and NMFS biologists could have approved the scary numbers.  I came away far less freaked out, though still disappointed that the Navy and NMFS don’t appear ready or willing to keep noisy Navy activities out of some biologically rich areas.  This has been one of the central points of contention pushed by environmental groups for the past few years, and it remains valid to ask why this practical protective step has not been taken, at least regarding explosive activities with a higher risk of injury. (The vast distances over which some of these sounds travel likely means that exclusion zones to avoid behavioral “takes” may need to extend up to 50-100 miles from the regions of concern in order to provide full protection from noise disruptions; the practicality of such large exclusion zones may be harder to establish, though worthy of discussion.)

After a few hours of reading and digesting several hundred pages of environmental analysis and permitting documents, I was able to distill a few of the key take-aways that may help readers to understand NMFS’s reasoning, as well as the shortcomings of the plans.  Click through for my ten-minute version of what’s in these permits.

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Cooperative Wisconsin turbine noise study breaks new ground

Health, Human impacts, News, Science, Wind turbines No Comments »

In December, four acoustic consulting firms collaborated to study wind turbine noise at three Brown County, Wisconsin homes that had been abandoned by their owners after the nearby Shirley Wind Project began operations.  The study, organized by regional environmental group Clean Wisconsin and paid for by the state Public Regulatory Commission, will help inform the PRC’s consideration of a proposed new wind farm in the area.  

Two things stand out about this new study.  The first is the choice to bring together several acousticians who have previously been widely cited by opposite sides of the turbine siting debate. The study team included one firm  (Hessler and Associates) commonly hired to do sound assessments for wind developers, another (Rand Acoustics) that has become widely championed by concerned citizens groups because of its much more cautionary assessment of turbine noise, and a third (Schomer and Associates) whose work has often been in the middle ground, with particular papers being seized on by each side in the siting debate; the fourth firm (Channel Islands Acoustics) has worked much less on wind farm issues than the other three.  This diverse group of acousticians produced a 13-page consensus report (edited to 12 pages in the final version submitted to the PSC), along with an appendix report from each team, all of which focus on different aspects of the study that they found most compelling. 

The second virtue of this study is that it clearly documented, for the first time, specific sources of infrasound (sound at frequencies below 20Hz) and low-frequency noise (audible sound above about 20Hz) from turbines that are consistently measurable inside homes. The data they collected clearly showed peaks in the sound spectrum that correspond to the “blade passing frequency” (BPF) of just under 1Hz, or one pulse per second, and several harmonics of the BPF up to about 5Hz.  These pulses showed up both inside and outside the closest home, 1280 ft from the nearest turbine.  In addition, they measured a more modest infrasound and low-frequency peak at 15-30Hz, which reflects the natural resonance and flexibility of typical home construction; this peak may have been triggered by turbine sound or by wind or other outdoor sound sources. One of the acousticians, Rand, notes in his appendix a possibly corresponding pulse of outdoor sound in the 9-14Hz range that can be associated with inflow turbulence hitting turbines.  Still, the infrasound that was measured in this study, as in most other similar measurements of wind turbine noise, is at lower dB levels than what is typically considered perceptible by humans. (Ed. note: two emerging yet still limited bodies of work suggest that turbine infrasound may have rapid peaks that approach standard perceptual thresholds, and that our ears may respond physiologically to sounds at lower levels than are perceived; nothing in this Wisconsin study address these questions, though later analysis of the data may contribute to the study of short-term peaks.)

Since the study took place in homes that were abandoned by homeowners who all complained of debilitating health effects, including sleeplessness, nausea, and depression, part of the goal of the study was to see whether they could identify any possible acoustic triggers for these negative responses.  The authors collectively noted that “the issue is complex and relatively new” and concluded that this work “was extremely helpful and a good start to uncover the cause of such severe adverse impact reported at this site.”  

The consensus report, signed by all members of the team, introduces a new hypothesis, based on a US Navy study that found that vibrations can trigger nausea in pilots when in the frequency range of up to 0.5-0.9 Hz, with the peak “nauseogenicity” occurring at 0.2 Hz.  Of particular concern is that as turbine blades get longer, the BPF is being reduced; only the recent generation of turbines has dropped below 1Hz (thus perhaps helping to explain the recent surge of health complaints among a subset of turbine neighbors), and planned larger blades will drop close to that 0.2Hz range of maximum inducement of nausea.  While stressing that this is, as yet, a very preliminary supposition, especially since it involves a study based on physically vibrating the body, while turbine infrasound is a vibration of the air around a body, the authors still agreed that:

The four investigating firms are of the opinion that enough evidence and hypotheses have been given herein to classify LFN and infrasound as a serious issue, possibly affecting the future of the industry. It should be addressed beyond the present practice of showing that wind turbine levels are magnitudes below the threshold of hearing at low frequencies.

In particular, the research team agreed that a further literature search for studies related to vibration-induced nausea should take place (Paul Schomer is working on this), and that a “threshold of perception” test should be conducted, to see what proportion of residents are able to perceive the faint signals in either audible or infrasonic ranges.  Only one of the five acousticians, Rand, could detect sound at all residences; he also reported headache and/or nausea (it is also noted that he is the only one among the five researchers who suffers from motion sickness).

As often happens, the reaction to this study ranged from “this changes everything” to “this is nothing new,” with some saying it proves negative effects and others that it proves wind energy is safe.  For a run-down of the reactions, a brief look at each of the four appendices, and links to download the study, click on through… 

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Detailed new maps highlight excessive shipping noise in Puget Sound, BC coast

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, shipping No Comments »

OrcasTankerHaroBeamreachIn the wake of NOAA’s large-scale ocean noise mapping project, two much more detailed studies from the Pacific Northwest have highlighted the likelihood that current shipping noise is already pushing the limits of what biologists think many ocean creatures can cope with.

The first study recorded the sound from several types of boats and ships traversing Admiralty Inlet, between Whidbey Island and Port Townsend, WA, and used these recordings, correlated with ship traffic records, to model sound levels throughout the area.  The Seattle Times summarizes this work, which found that at least one large vessel (container ship, ferry, or large tug) was in the area at least 90% of the time, and that the average noise level was about 120 decibels, which is the threshold above which federal agencies begin being concerned about behavioral impacts on some ocean species.  

“Continuous noise at that level is considered harassment of marine mammals,” said University of Washington’s Christopher Bassett, one of the authors of the paper. “About 50 percent of the time, we even exceed that threshold.”

“It is concerning that the noise levels are so high,” said Marla Holt, a research biologist at Seattle’s Northwest Fisheries Science Center. “When you see how often this happens and how chronic the noise exposure is, that’s when you start to say, ‘Wow.'”

Interlude: Brief OrcaLab recording of threatened Northern Resident killer whales in Caamano Sound, BC, chatting with each other and then being drowned out by a cruise ship:

To the north, another study mapped shipping noise in the Salish Sea (south and east of Vancouver Island), and on up the British Columbia coast to the port of Prince Rupert.  This work, funded by World Wildlife Fund-Canada, introduces a comprehensive approach to modeling sound transmission from ships, incorporating differences between vessel types, transmission loss in a variety of bathymetric and seabed conditions, and temperature-driven variations in sound speed during different seasons. (Download a PDF presentation summarizing the full WWF-Canada report here; a shorter version appeared in JASA in November). Here, too, large areas are subject to excessive shipping noise; the maps below show total sound levels, and the areas where the annual average of two specific low frequencies are above the 100dB threshold that the European Union considers the target for biologically sensitive areas:

Erbe JASA 2012 BC ship noise 500px

But now, check out that lighter colored patch about halfway between BC’s two big offshore islands.  

Erbe closeup 150That’s an inland waterway that heads up to Kitimat, the proposed site of a major new port, the Northern Gateway, which would serve as the primary port for shipping tar sands oil to Asia.  An annual total 220 super-tankers would head though that currently mostly-yellow zone, all the way up that long, narrow channel that points to the upper right hand corner of this close-up (and leave againso more than one passage a day on average).  As you might imagine, there is widespread concern about the risks of accidents and spills in these often treacherous passages, but the increase in shipping noise is also being raised as a question.

Erbe monthly increase 250A second study by the same research team, led by Christine Erbe, took a close look at current and likely increases in shipping noise, should Northern Gateway go forward, and what they found is not reassuring.  Noise levels will increase by up to 6dB in the approach lanes in Caamano Sound, and by 10-12dB in the narrow fjord into Kitimat (see map on right).  In the western channel (the wider approach), where sound would likely increase 3-6dB (representing a doubling to quadrupling of sound energy), Humpbacks would hear tankers and their accompanying two tugboats for 43% of daylight hours, and orcas (due to thier higher-frequency hearing, less intruded upon by low-frequency ship noise) would hear the tankers 25% of the time.  Fewer whales venture all the way up the fjords, but some would likely be present in the bend in the route, where noise levels would increase by 10dB, representing a 10-fold increase in sound energy.

“There is a worry they will go away and not come back to these fiords,” says Erbe. “This is critical habitat, important to them. Are they going to be able to feed elsewhere? We can only answer that with long-term monitoring.”

These studies, one of which utilized four seasons of recordings, and the other presenting a comprehensive and verifiable sound modeling approach, both offer exciting steps forward in the study of coastal and oceanic acoustic habitats.  Let’s hope that coming years produce many more studies from other regions around the world that continue to develop these innovative techniques.

Detailed Northern Gateway study: Erbe, C., Duncan, A., and Koessler, M. 2012. Modelling noise exposure statistics from current and projected shipping activity in northern British Columbia. Report submitted to WWF Canada by Curtin University, Australia.

BC sound modeling study: Erbe, C., MacGillivray, A., and Williams, R. 2012. Mapping Ocean Noise: Modelling Cumulative Acoustic Energy from Shipping in British Columbia to Inform Marine Spatial Planning. Report submitted to WWF Canada by Curtin University, Australia.
Shorter version:   Erbe, C., MacGillivray, A., and Williams, R. 2012. Mapping cumulative noise from shipping to inform marine spatial planning.  J. Acoust. Soc. Am. 132 (5), November 2012. 423-428.

Puget Sound study: Bassett, C., Polagye, B., Holt, M., Thomson, J. 2012. A vessel noise budget for Admiralty Inlet, Puget Sound, Washington (USA). J.Acoust.Soc.Am. 132(6), December 2012

Kathy Heise and Hussein Alidina.  Ocean Noise in Canada’s Pacific Workshop, January 31-February 1, 2012.  Summary Report.  WWF-Canada.  54pp.  Read or download PDF

WWF-Canada Submission to Enbridge Northern Gateway Joint Review Panel, 9/19/12. (mostly terrestrial impacts; some ocean noise sections) Read or download PDF

New NOAA maps offer compelling picture of ocean noise

Bioacoustics, Ocean, Ocean energy, Science, shipping, Sonar No Comments »

NOAA noise mapsIn December, NOAA announced the release of the first large-scale ocean noise maps, which have been in development for the past two years.  The Underwater Sound Field Mapping Working Group modeled many sources of sound occurring within 200 miles of the US coast (including ships, seismic surveys, sonar, pile driving, and oil platform decommissioning), as well as modeling shipping noise in full ocean basins (including the Atlantic, pictured at left).  Data  is compiled in several depths and frequency ranges, to account for the full spectrum of various species’ habitat usage and hearing/vocalization ranges.

Dr. Leila Hatch, co-chair of the Working Group, said too many areas of the ocean surface (where sea mammals and whales spend most of their time) are orange in coloration, denoting high average levels. “It’s like downtown Manhattan during the day, only not taking into account the ambulances and the sirens,” she said. “I’d be happier saying it was like a national park.”

Michael Jasny, a senior policy analyst with the Natural Resources Defense Council, which has sued the Navy to reduce sounds that can harm marine mammals, praised the maps as “magnificent” and their depictions of sound pollution as “incredibly disturbing.”

“We’ve been blind to it,” Mr. Jasny said in an interview. “The maps are enabling scientists, regulators and the public to visualize the problem. Once you see the pictures, the serious risk that ocean noise poses to the very fabric of marine life becomes impossible to ignore.”

NOAA has set up a website where this ongoing work will be made available.  In addition, an 85-page report brings together presentations and recommendations from a two-day symposium held last May, at which the Working Group presented their draft results to a couple hundred other experts from agencies, the Navy, oil and gas industry, academia, and nonprofit groups (I was fortunate to be invited to participate in that meeting).

Equally exciting is a companion project by a Cetacean Density and Distribution Mapping Working Group, also introduced at the May symposium, that is working to compile all known studies of whale and dolphin population distribution.  Tens of thousands of cetacean observations are being compiled into month-by-month distribution charts and maps for various ocean regions around the US.  In addition, seasonally biologically important areas (e.g., for breeding, feeding, or mating) are being compiled as part of this work.

The two mapping projects will provide a robust new foundation for assessing the impacts of noise sources, and hopefully to encourage efforts to reduce human noise, especially in biologically important areas.  A New York Times article introducing the noise mapping project includes encouraging words from Michael Bahtiarian, an adviser to the United States delegation to the International Maritime Organization, which is looking at ways to reduce ship noise and vibrations.  “Right now we’re talking about nonbinding guidelines,” he said  “At a minimum, the goal is to stop the increases.”  See earlier AEInews coverage of the IMO efforts from 2008, 2009, and 2012.

SEE ALSO: Detailed ocean noise maps take this approach further in Puget Sound, BC coastal waters 

WHOI researchers initiate long-term sound study at Cape Wind site

Effects of Noise on Wildlife, Ocean, Ocean energy, Science, Wind turbines No Comments »

Researchers from Woods Hole Oceanographic Institute have begun a 2-3 year project that will monitor the soundscape at the Cape Wind site before, during, and after construction of the planned 130 wind turbines.  This is the first time such a long-term acoustic monitoring study has taken place at an offshore wind site.  

“We want to evaluate the importance of this kind of research for future offshore wind farm development, which is a rapidly growing field of interest in the U.S.,” Aran Mooney said. He and his colleagues are outlining a methodology for how acoustic monitoring may occur in other wind farm construction. Mooney said, “That will be valuable for industry, policymakers, and the public.”

Two kinds of acoustic recorders are being used: one records the full range of frequencies continuously for a week at a time; the other samples one minute of sound every ten minutes for 2-3 months, at frequencies up to 40kHz (thus missing echolocation clicks but capturing most other vocalizations of interest). “So we’re making the best of both worlds, putting one device out to get a really in-depth look for one week, and then we continue with the other device to get a sampling period of several months, then we replace both,” Mooney said.

During wind farm construction, pile driving will add significantly to existing human noise in the area; at European wind farm sites, some species tend to move  as far as 20km away during construction.  During operation of the wind farm, noise is not expected to be audible at distances more than a few tens or hundreds of yards, but this study will help to quantify exactly what frequencies are propagating into the waters.

Mooney would like to see the project also contribute to a growing research focus on using sounds to monitor overall environmental health of various habitats.  “Animals make sounds when they attract mates or reproduce, and you can track those activities just by listening,” Mooney said. “What I’d love to do with this project is to look at biological diversity. In a nice healthy habitat, you have a spectrum of sounds: low-frequency sounds of fish, then invertebrates a little bit higher, and then the seals and the dolphins.” The soundscape of an undersea area under an environmental stress would sound different; the impacts could be assessed by listening to what’s missing, for example.

For more on the project, see this page on the WHOI website, which also includes recordings of more than a dozen species of ocean creatures.

AEI’s 3rd annual wind farm noise report now available

Effects of Noise on Wildlife, Human impacts, Science, Wind turbines No Comments »

At long last, I’ve completed this year’s overview of science and policy developments on wind farm noise issues.  It features over 50 pages of new material, along with about the same in Appendices consisting of three research summaries I wrote earlier in the year.  You can download a pdf version of Wind Farm Noise 2012 here

AEI’s three Wind Farm Noise annual reports go into depth on different topics, and they complement each other quite well, though each one clearly engages the issues with more detail and reflects a more nuanced appreciation of the topic than the ones that came before. You can access all three, and AEI’s other publications on the issue, on our Wind Farm Noise Resources page.

But today, this is the one you should take a look at! AEI Wind Farm Noise 2012: Science and policy overview

Ancient whale song: louder than modern human-caused ocean noise?

Bioacoustics, Ocean, Ocean energy, Science, shipping No Comments »

AEI lay summary:
M.S. Stocker, J.T. Reuterdahl. Is the ocean really getting louder? 164th Meeting of the Acoustical Society of America, Oct. 22-26, 2012.  ASA press release

A paper presented at this fall’s Acoustical Society of America meeting has triggered a wave of provocative headlines about how whale-filled oceans of the past may have been “as loud as a rock concert” or how “Noisy whales made FAR MORE oceanic racket than humans do.”  The paper does indeed ask an innovative question: what was the ocean soundscape like in the pre-whaling days?  And its answer, while couched in a high degree of uncertainty, is also eye and ear-opening: ten times as many whales made a lot more noise than today’s diminished populations, perhaps adding up to overall noise levels that match those caused by today’s shipping, oil and gas exploration, and other human activities in the seas.

It’s probably a bit too acoustics-geeky for me to object to the “rock concert” comparison, but for the record, the paper itself never uses those two words alone or together!  (Though somehow the phrase slipped into the ASA press release; we’ll have to blame the editor or an author’s pre-conference sleep deprivation for the slip…)  In fact, thanks to their differences in density, measurements of sound in water are about 62dB higher than a similar sound level in air; thus, the mention of 126dB of whale sounds filling the ancient oceans would not be equivalent to a rock concert, but more like the 64dB sounds of laughter or a loud conversation.  Which, as it turns out, much better captures the essence of the historic soundscape as described by the authors:

The bio-acoustic environment of the pre-industrial whaling ocean could be correlated to the animal sounds in any biologically diverse and well populated habitat wherein the riot of birdcalls, the stridulation of insects, and the mammal vocalizations are the dominant noise contributors to the soundscape.

The question of ancient ocean sound levels is relevant because much of today’s thinking about the impact of human noise is predicated on research that shows global shipping increasing the ambient noise levels in the oceans by 10dB or more since the 1950’s.  This just happens to be the era in which whale populations were at their nadir, with several species having already become rare enough that it was no longer worth the effort to find and hunt them.  But as the authors stress in their conclusion, an ancient ocean full of whale song — along with the more widespread  sounds of the onomatopoeia-ic large fish, Grunts and Drums, or the “great schools of tuna miles across (that) would churn up the sea surface for days as they migrated past California’s Channel Islands” noted by early 20th century fishermen, which the authors note “would likely be as loud as or louder than even the most tempestuous sea state” — is a very different place than an ocean full of the noise of ship engines and airgun reverberations.

Animals have evolved to fill distinct acoustic niches, with their songs and calls at different frequencies, made at different times or the day or year, and using distinct rhythmic pulses; each species’ hearing is especially tuned, or filtered, to pick out the calls of its own species from the voices of others.  But, as the authors note, “the signature of mechanized ocean noise interference from shipping is broad-band, pervasive, and chronic, and more likely to mask across animal frequency and/or time domain filters throughout large areas of the ocean.”

Or as put so well by Tim Baribeau, it’s important to remember that “we could still be disorienting whales with our bizarre and intrusive industrial sounds. But it’s incredible to think that the oceans may once have been filled with a cacophonous background chatter of animal noise.”

On the water with orca D-tag research crew

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, shipping No Comments »

Oregon Public Broadcasting recently sent reporter Ashley Ahearn out with the researchers that are listening in on orca activity underwater (covered here last month), and her wonderful, detailed report is now online; check it out!  It includes two videos, one showing a tagged orca’s swimming track, along with every boat in its vicinity over the several hour journey, and the other offering a “poles-eye view” of attaching the D-tag to an orca:

D-TAG study listens to what Puget Sound orcas hear

Bioacoustics, Effects of Noise on Wildlife, Science No Comments »

OrcapictureBrad Hanson and colleagues at NOAA’s Northwest Fisheries Science Center are currently conducting a second year of exciting new acoustics field research with the Southern Resident killer whales of Puget Sound.  As they did last year, researchers are attaching suction-cup digital acoustic recording tags (DTAGs) to orcas; the tags remain attached for up to four hours, all the while collecting both dive profile data and recording the sound heard (and made) by the animal.  Hanson says that “we’re interested in trying to figure out if the noise levels are interfering with the whale’s ability to communicate effectively during foraging and or actually interferes with their foraging.”

New paper quantifies shipping noise impact on whale communication space

Effects of Noise on Wildlife, Ocean, Science No Comments »

The latest paper to be published by the research team that’s been studying noise levels in and around the Stellwagen Bank National Marine Sanctuary concludes that in the waters off Boston, increasing shipping noise has reduced the area over which whales can hear each other to about one-third of what it used to be.

“We had already shown that the noise from an individual ship could make it nearly impossible for a right whale to be heard by other whales,” said Christopher Clark, Ph.D., director of Cornell’s bioacoustics research program and a co-author of the work. “What we’ve shown here is that in today’s ocean off Boston, compared to 40 or 50 years ago, the cumulative noise from all the shipping traffic is making it difficult for all the right whales in the area to hear each other most of the time, not just once in a while. Basically, the whales off Boston now find themselves living in a world full of our acoustic smog.”

Below: Ship tracks for one month, in and out of Boston; Stellwagen Bank National Marine Sanctuary outlined in white, bottom-mounted recording units in yellow. (Graphics from NOAA’s Passive Acoustic Monitoring website)

Sb nopp ais tracks

“A good analogy would be a visually impaired person, who relies on hearing to move safely within their community, which is located near a noisy airport,” said Leila Hatch, Ph.D., NOAA’s Stellwagen Bank National Marine Sanctuary marine ecologist. “Large whales, such as right whales, rely on their ability to hear far more than their ability to see. Chronic noise is likely reducing their opportunities to gather and share vital information that helps them find food and mates, navigate, avoid predators and take care of their young.”

Nine hours in Stellwagen:

Sbnms nopp ani

Kathy Metcalf of the Chamber of Shipping of America said her group has no doubt noise is increasing and affecting the whales. But measures such as slowing down ships or retrofitting them with new, more efficient propellers are costly and may not even work, she said. A better remedy would be devising and incorporating quieter designs in the hulls and propellers of new vessels.  “We’re kind of a slow industry,” Metcalf said. “But the bottom line is if we could do something now that can be used as guidelines for new construction, 15 years from now, half the world’s fleet would have already been built that way.”

Bonus:  2010 Science magazine audio interview with Leila Hatch, lead author of the new paper.

Listening to the undersea world

Ocean, Science No Comments »

A great post over on Artemia, a University of British Columbia blog, from Jessi Lehman, reflecting on listening to the LIDO online undersea sound streams.  Go read the whole thing for sure!

A teaser:

…These ocean observatory networks are about science and whale conservation but also about industry, development, and geopolitics.

But I want to come back to the experience of listening. What is it, exactly, that we hear? Mostly just faint static, like the sound of rain falling. Mostly I find myself listening in apprehension, for what could be there. Some would call this kind of undersea listening remote sensing, but it feels more like interspecies or even otherworldly eavesdropping. To be honest, it feels a bit weird. And it’s not just that I’m so far from the ocean, in a place dry and hot and decidedly un-marine. I can’t say that I understand the undersea environment better by listening to these sounds (though I can’t preclude the possibility that on some level I do). Mostly I am made aware that this is a world I don’t know, can’t know, and can only access thanks to complex technological mediations – and even then only marginally. This makes the experience of listening even stranger.

French philosopher Jean-Luc Nancy writes “to be listening is always to be on the edge of meaning”…

Quite of few of the posters on Artemia seem to be giving a lot of consideration to sound.  Of special note is this project preview from a student who’s right now on the central coast of British Columbia aiming to bring some of Steve Feld’s ideas about acoustemology into the underwater world of cetacean sound-making:

My project puts the concept to work at a whale research laboratory, Cetacea Lab, located on a remote island in Caamaano Sound, Northern, BC. Through a seven-week fieldwork residency (August- September 2012), I hope provoke thoughts on how broader knowledges relate to sustained acts of whale listening. In particular, I will pursue two questions 1. how work in acoustemology, hitherto focused on Indigenous encounters in the developing world, can be challenged and extended by an outdoor laboratory science setting, (Feld, 1996, 2003; Daniels, 2008; Maxwell, 2008; Ramnarine, 2009); 2. to understand how Cetacea Lab’s activities produce an acoustemology of Caamano Sound and its environs.

The central actors of the pilot study are the scientists who conduct Cetacea Lab’s activities. Since 2001, Cetacea Lab scientists have been monitoring whale activity through a network of radio-linked hydrophones, remote observation, and boat-based surveys. Every summer, their efforts are supplemented by two groups of volunteers (5-7 per group), who live at Cetacea Lab for 6-8 week periods (May-July; late July-September). These volunteers provide crucial support for the monitoring activities required during ‘peak’ times of cetacean activity: In late summer especially, Caamano Sound, and neighbouring Campania Sound and Whale Channel play host to an array of migratory and resident fin, humpback, and killer whales variously involved in annual mating, feeding, and socializing… (Ford et al, 1989, 2007). Hearing all the complex sonic activity generated by these creatures is perhaps the most pronounced feature of daily life at Cetacea Lab…

Astonishing bowhead whale song diversity discovered

Bioacoustics, Science 1 Comment »

FramWhen a University of Washington researcher listened to the audio picked up by a recording device that spent a year in the icy waters off the east coast of Greenland, she was stunned at what she heard: whales singing a remarkable variety of songs nearly constantly for five wintertime months.  In a paper just published in the journal Endangered Species Research, and freely available online, Kate Stafford and her co-authors report on acoustic monitoring that took place in the winter of 2008-9 in the Fram Strait, between Greenland and Spitzbergen, a key channel for water circulation between the Arctic and Atlantic Oceans.  

Quite unexpectedly, Stafford found that bowhead whales were singing “almost constantly from the end of November until early March,” with over 60 distinct songs being recorded during these months of deep winter darkness.  It is presumed that these were mating calls, as are the famous humpback whale songs.  However, the researchers stress:

The song diversity noted here is unprecedented for baleen whales. Whether individual singers display 1, multiple, or even all call types, the size of the song repertoire for Spitsbergen bowheads in 2008 to 2009 is remarkable and more closely approaches that of songbirds than other baleen whales.

Also fascinating is the stark difference in types of calls in the two recording locations.  The diverse and continuous singing took place under “a dense canopy of ice cover, (which) may provide a better acoustic habitat for the transmission and reception of song when compared to loose pack ice.” Lead author Kate Stafford notes, “It’s clear there’s a habitat preference. As Arctic sea ice declines, there may be some places like this that are important to protect in order to preserve a breeding ground for the bowhead whales.” 

Download the paper
Read a summary of the work from University of Washington
Listen to a couple of sound samples


Whales can dampen hearing: implications for ocean noise concerns

Animal Communication, Bioacoustics, Effects of Noise on Wildlife, Ocean, Science No Comments »

You may have noticed a recent flurry of press reports about research in Hawaii that begins to quantify a long-suspected quality of cetacean hearing: the ability to dampen hearing sensitivity so that loud sounds don’t cause damage.  Given the extremely loud volume of many whale calls, which are meant to be heard tens or hundreds of miles away, researchers have long speculated that animals may have ways of protecting their ears from calls made by themselves or nearby whales, perhaps using a muscle response to reduce their hearing sensitivity (not unlike a similar muscular dampening mechanism in humans).  Indeed, earlier studies by Paul Nachtigall’s team had found that some whales could do indeed reduce their auditory response to the sharp clicks they use for echolocation.  In the new study, Nachtigall trained a captive false killer whale named Kina to reduce her hearing sensitivity by repeatedly playing a soft trigger sound followed by a loud sound.  Eventually, she learned to prepare for the loud sound in advance by reducing her hearing sensitivity.  “It’s equivalent to plugging your ears…it’s like a volume control,” according to Nachtigall.

Well, that sounds like a pretty useful trick, given all the concern about human sounds in the sea.  And the media, led by the New York Times, jumped on board with headlines following on the Times‘ assertion that suggested whales  already “are coping with humans’ din” using this method. (Among the exciting headline variations: Whales Can Ignore Human Noise, Whales Learning to Block Out Harmful Human Noise, and UH Scientists: Whales Can Shut Their Ears.)

Oops, they did it again!  Grab some interesting new science and leap to apply a specific finding to a broad public policy question, often, as this time, giving us a false sense of security that the “experts” have solved the problem, so there’s no need to worry our little selves over it any more (as stressed in this NRDC commentary).  To be fair, the Times piece included a few cautionary comments from both scientists and environmental groups, but the headline rippled across the web as the story was picked up by others.

Two key things to keep in mind:  First, this whale was trained to implement her native ability, meant for use with her sounds or those of nearby compatriots, and to apply it to an outside sound made by humans.  This doesn’t mean that untrained whales will do the same.  

And second: If whales can dampen their hearing once a loud sound enters their soundscape, this could indeed help reduce the physiological impact of some loud human sounds, such as air guns or navy sonar. If indeed this ability translates to wild cetaceans, the best we could hope for is that it would minimize hearing damage caused by occasional and unexpected loud, close sounds that repeat.  There would be no protection from the first blast or two, but perhaps some protection from succeeding ones; or, if the sound source was gradually approaching or “ramping up,” as often done with sonar and air guns, animals may be able to “plug their ears” before sounds reach damaging levels, if for some reason they can’t move away.  Even then, the animals are very likely to experience rapidly elevated stress levels, as they would be less able to hear whatever fainter sounds they had been attending to before the intrusion. Yet research in the field suggests that most species of whales and dolphins prefer to keep some distance from such loud noise sources; this hearing-protection trick doesn’t seem to make them happy to hang around loud human sounds.  

Most crucially, these occasional loud sounds are but a small proportion of the human noises whales are trying to cope with. Noise from shipping, oil and gas production activities, offshore construction, and more distant moderate sounds of air guns all fill the ocean with sound, reducing whales’ communication range and listening area, and likely increasing stress levels because of these reductions.  This is the “din” of chronic moderate human noise in the sea, and Kina’s ability would not help her cope with any of it.  We’re a long way from being able to rest easy about our sonic impacts in the oceans.

To end this rant with a bit of credit where due, here’s what may be the more important take-away from the Times article:

Peter Madsen, a professor of marine biology at Aarhus University in Denmark, said he applauded the Hawaiian team for its “elegant study” and the promise of innovative ways of “getting at some of the noise problems.” But he cautioned against letting the discovery slow global efforts to reduce the oceanic roar, which would aid the beleaguered sea mammals more directly.

Health effects of wind farms: summary of recent research

Health, Human impacts, Science, Wind turbines 1 Comment »

Here we go again!  As in AEI’s similarly long recap of 2011 research on low frequency noise and infrasound published in December, I’ve tackled a similar task with close to a dozen papers published in 2011 on health effects of living near wind farms.  Rather than publish the entire thing as a blog post, I’ve created a 26-page PDF that can be downloaded or viewed online.  Here, I’ll reprint the 4-page introduction (note that even the intro has many important footnotes viewable only in the PDF version).
See pdf of Wind Farm Noise and Health: Lay summary of new research released in 2011

In February of this year, I wrote a column for the Renewable Energy World website that addressed the recent increase in claims that wind farms are causing negative health effects among nearby neighbors.  The column suggested that while many of the symptoms being reported are clearly related to the presence of the turbines and their noise, the relationship between wind farms and health effects may most often (though not always) be an indirect one, as many of the symptoms cropping up are ones that are widely triggered by chronic stress. In recent months, the dialogue around these issues has hardened, with both sides seemingly intent on painting the question in simple black and white—community groups assert that turbines “are making” people sick, while government and industry reports insist that there’s “no evidence” that turbines can or do make people sick. The gulf between the conclusions of formal health impact studies and the experiences of some neighbors has widened to the point that both sides consider the other to be inherently fraudulent.  I suggested that the rigidity of both sides’ approach to this subtle and complex issue is likely increasing the stress and anxiety within wind farms communities that may in fact be the actual primary trigger for health reactions.

Here, I’ll expand on that shorter column by taking a closer look at the few surveys and studies that have attempted to directly assess the prevalence of health effects around wind farms, including a detailed look at recent papers from Carl Phillips, Daniel Shepherd, Bob Thorne, Michael Nissenbaum, Nina Pierpont, and Stephen Ambrose and Robert Rand, along with consideration of publications from Eja Pedersen, Frits van den Berg, Geoff Leventhall, Roel Bakker, and the Waubra Foundation.

Even as the public becomes increasingly concerned about health effects, with a lot of focus on the role of inaudible infrasound, it’s been striking to me to that the researchers investigating health effects – even clearly sympathetic researchers – are not talking about infrasound much at all, and are instead focusing on stress-related symptoms.

Read the rest of this entry »

AEI invited to shape renewables conference agenda, NOAA ocean noise mapping effort

News, Ocean, Science, Wind turbines No Comments »

My dance card is filling up for the spring!  AEI’s years of working hard to play a constructive role in public and professional dialogue about policy responses to noise-related environmental issues has been rewarded with two invitations that I’m very excited about.

The first was an invite to server on the Wind subcommittee of the program committee for this year’s Renewable Energy World North America conference.  The big event takes place in December, but this week the program committee began its work with a conference call, and during April we’ll be assessing presentation proposals and coming together to meet for two days in Orlando.  I’m honored and pleased that the good folks at Renewable Energy World, the premier trade magazine for all renewables, thought that my input would be valuable.

Chronic Noise NE US oceanI’ve also been invited to participate in a small, invitation-only symposium being convened by NOAA (National Oceanic and Atmospheric Administration) and BOEM (Bureau of Ocean Energy and Management) to gather feedback on NOAA’s recent efforts to engage in ocean sound and cetacean distribution mapping, and to discuss ideas about how to use and develop these new tools to inform future ocean management decisions.  As a long-time advocate of more concerted mapping of current human sound in the oceans, I’m especially excited to participate in this event. We’ll gather in DC for two days in late May.  I got the good news on this invitation earlier this week while attending a BOEM workshop on the effects of noise on fish and invertebrates; I hope to post a brief summary of the proceedings later this week.


Ocean noise assessment needs to look past dB, to context of exposure

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, Seismic Surveys, shipping, Sonar No Comments »

A paper recently published in Conservation Biology suggests that current ocean noise regulations are likely not providing sufficient protections against impacts on marine life.  The authors note that current regulations are based on preventing direct physical injury from very close exposure to sound, while considering behavioral impacts to decrease consistently with greater distance, or the “zones of influence” approach to noise impact assessment.  However, some key impacts, such as interruptions in feeding or temporary abandonment of important habitat, are not accounted for.

Rather than fully summarizing the paper here, I’ll turn you over once again to Caitlin Kight of Anthropysis, who has recently been providing excellent coverage of anthropogenic noise issues as part of her larger focus on human impacts in the natural world.  Please see her full post to get the whole story; here’s a teaser:

In a previous study on behavioral responses of marine animals to noise, one of the authors of the current paper found that the “zones-of-influence approach did not reliably predict animal responses.” Furthermore, we know from terrestrial studies that a variety of additional factors–an animal’s past experience and conditioning, current behavioral state, acoustic environment, and type of exposure, to name a few–all affect the extent to which it will be impacted by noise pollution.

…(Studies in terrestrial and ocean environments have shown that) noise can have more subtle, but equally important, effects on wildlife. For instance, abundance and diversity may shift as animals flee from, or learn to avoid, particularly noisy areas; individuals may alter their behaviors in counterproductive or even dangerous ways; and noise may make important acoustic signals difficult to hear, even in the absence of actual deafness. In short, the researchers write, the current marine noise concept “ignores a diverse suite of environmental, biological, and operation factors” that can impact both perception of, and response to, anthropogenic noise. Thus, they argue, it is necessary to overhaul the system and “[incorporate] context into behavioral-response assessment.”

Ellison, W.T., Southall, B.L., Clark, C.W., and Frankel, A.S. 2012. A new context-based approach to assess marine mammal behavioral responses to anthropogenic sounds. Conservation Biology, online advance publication.

5-yr wind farm health study begins in Ontario

Health, Human impacts, News, Science, Wind turbines No Comments »

Researchers from the University of Waterloo are planning to begin canvassing several Ontario counties this spring, marking the beginning of a multi-year effort to assess health-related changes in the vicinity of wind farms.  The research program in Renewable Energy Technologies and Health will include a wide array of scientific, technological, and health-related topics surrounding wind, solar, hydro, and bio-energy. The health-related surveys will be overseen by epidemiologist Philip Bigelow, who has spearheaded similar projects assessing appropriate noise thresholds for other common community noise sources.

Bigelow“This one is actually a little different,” says Bigelow, “because you have this continuous noise and you have the wind changing, of course, but you have this continuous thumping and swishing, and that’s really irritating to people.”  Bigelow notes that, “when you average it all out, wind turbines are going to be worse than traffic noise for annoyance, and that’s already been well established because of the character of it.”

To balance the study, a group of people who don’t live anywhere near turbines will be included. Bigelow said the team ideally hopes to study people in areas where turbines are planned, then follow up with them after the turbines are up and running. “Those people we really want to follow up with.”

The study will assess low frequency and audible noises as well as vibration; field measurements of turbine noise will take place, with an extensive GPS mapping component, as well. After an initial round of surveys, Phase Two of the research will involve bringing in a registered nurse and physician to head a field study.  “They will actually go talk to residents and administer a symptom and physical impact checklist,” said Bigelow.  “They will then do an assessment and collect some biological materials like saliva to look for biological stress,” including sleep studies that will measure both awakening and non-waking arousals.  Phase Two will involve a smaller sampling of residents identified during the Phase One surveys.

The eventual value of this study will depend on how successful researchers are at achieving a representative sample of local residents.  This will require both researchers and citizens to come at it with as open a mind as possible.  Bigelow’s introductory comments to local newspapers, as quoted above (see the two links in the first sentence for much more), indicate an good understanding of the situation, including the roles of annoyance, stress, and sleep disruption; one comment mentioned in passing needs clarification, though.  The Owen Sun-Times noted that he said he wanted to find participants who don’t have an agenda; while I can understand this concern, due to the extreme polarization triggered by the issue across rural Ontario, I would hope and expect that the study would involve a truly random sample, and not exclude people who are upset because of symptoms that may have cropped up for them.  Equally troubling, at least one other health survey in Ontario was met with widespread distrust among those with health concerns, leading some to urge residents to not participate.  If either the researchers or anti-wind activists limit participation by the significant proportion of the population that has previously been engaged in this issue, the integrity of the survey’s results would likely be affected.


UK researchers examine effects of noise on fish, crustaceans

Effects of Noise on Wildlife, Ocean, Ocean energy, Science 2 Comments »

A research project in England is preparing to do some of the first field studies designed to see how human-made sound may affect non-cetaceans.  While many field studies have tracked the responses of whales and dolphins in both opportunistic and controlled settings, and some lab studies have noted how fish or other sea creatures react to noise when introduced into tanks, a team from the University of Hull is preparing to project human sounds from a research vessel and see how fish and crustaceans (crabs and lobsters) respond.

The researchers plan to film animals while playing the sounds of ships, concrete pile driving, or operating wind turbines; the results will provide data for far more accurate environmental impact assessments of offshore construction and renewable energy projects.

For more, see this recent article from OffshoreWind.