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.

I’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.

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.

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.

“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.

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.

Driven by the rising public clamor about health effects reported by people living near wind farms, officials across the nation and around the world have been called on to assess the veracity of these claims.  This week’s contribution to the rapidly expanding genre of “wind farms and health” literature comes from the Massachusetts Departments of Health and of Environmental Protection.  In contrast to last week’s more comprehensive report from Oregon, the Massachusetts report follows in the pattern of the first two similar literature reviews (one funded by the American and Canadian Wind Energy Associations, and another from the Ontario Ministry of the Environment), in that it focuses solely on direct impacts and previously published research papers.  It also addresses a few of the more recent studies, including those by Pierpont, Nissenbaum, and Rand and Ambrose, generally offering them some affirmations for providing new information worth building on, but finding their results not yet solid enough to base siting policy on.

Except for the sections on these recent papers, there is no place in this report for consideration of actual experiences of people living near wind turbines, despite the presence of a neighborhood full of folks in Falmouth who were no doubt ready and willing to share their stories.  From what I’ve heard from these folks, they would offer cogent, detailed, and level-headed testimony about their experiences.

While I can understand why an expert panel might choose to focus only on published material (to avoid the quagmire of trying to assess the veracity of individuals’ reports), and I give the Massachusetts panel due credit for not artificially limiting itself to papers published in peer-reviewed journals, they dropped a crucial ball in neglecting to even mention the word “indirect” in the course of their 164 page report on health effects, let alone provide any sort of acknowledgement or analysis of the ways that annoyance, anxiety, sleep disruption, and stress could be intermediary pathways that help us to understand some of the reports coming from Massachusetts residents who say their health has been affected by nearby turbines.

While the report’s conclusions

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Two of the US’s most widely-respected ocean bioacousticians have called for a concerted research and public policy initiative to reduce ocean noise.  Christopher Clark, senior scientist and director of Cornell’s Bioacoustics Research Program, and Brandon Southall, former director of NOAA’s Ocean Acoustics Program, recently published an opinion piece on CNN that is well worth reading in full.  They stress the emerging scientific awareness that chronic moderate noise from shipping and oil and gas exploration is a more widespread threat to marine life than the rare injuries caused by loud sound sources like sonar.  Here are a couple of teasers:

Today, in much of the Northern Hemisphere, commercial shipping clouds the marine acoustic environment with fog banks of noise, and the near continuous pounding of seismic airguns in search of fossil fuels beneath the seafloor thunder throughout the waters. In the ocean’s very quietest moments, blue whales singing off the Grand Banks of Canada can sometimes be heard more than 1,500 miles away off the coast of Puerto Rico. But on most days, that distance is a mere 50 to 100 miles.

Whales, dolphins and seals use sounds to communicate, navigate, find food and detect predators. The rising level of cumulative noise from energy exploration, offshore development and commercial shipping is a constant disruption on their social networks. For life in today’s ocean, the basic activities that we depend on for our lives on land are being eroded by the increasing amount of human noise beneath the waves.

These stark realities are worrying. But emerging technologies for quantifying and visualizing the effects of noise pollution can help drive a paradigm shift in how we perceive, monitor, manage and mitigate human sounds in the ocean. Ocean noise is a global problem, but the U.S. should step up and lead the way.

Clark and Southall make three specific recommendations: to establish a more comprehensive network of acoustic monitoring stations in order to better understand our overall acoustic footprint in the seas; to encourage and accelerate development of noise-reduction technologies (especially to make ships quieter, and also to develop new technologies for oil and gas exploration and underwater construction that generate less noise); and a shift in federal regulations from avoiding acute injury, toward protecting ocean acoustic habitats and ecosystems.

A growing network of ocean observatories are adding hydrophones to their arrays of instruments, opening ears into the undersea world.  The data has been shared widely among scientists for the past few years, and a website, Listening to the Deep Ocean Environment, is now compiling the real-time acoustic streams from 15 of the observatories, allowing anyone to listen in; another 11 observatories will be added in the coming months.  This excites scientists and citizens alike. (Though truth to tell, most of the audio streams aren’t all that interesting to listen to most of the time!)

The US Navy isn’t quite so pleased, however. According to a recent BBC article, US Navy oceanographers have arranged to filter data from one of the largest ocean observatories, NEPTUNE, off the coast of British Columbia.  Citing concerns that the recordings will disclose areas of Navy operations, real-time recordings are cleansed of Navy ship (and presumably sonar) sounds, then returned to NEPTUNE operators for uploading to the web. 

Cornell University’s Chris Clark doubts that the Navy’s approach will catch on at other observatories around the world.  According to a piece on The World, from PRI and the BBC, (sounds above from there; roll over tiny screens to ID the sounds), Clark says the US Navy doesn’t own the ocean acoustic environment and has to accept that what was once military technology is now in the hands of civilians.  “The cat’s out of the bag, the horses are out of the barn, whatever the metaphor is, it’s happening,” he says.  The piece notes that this is similar to what happened with satellite imagery. For decades, it too was sensitive military data, but now anyone can go on Google Earth and look down from space.

AEI lay summary of the following paper:
Risch D, Corkeron PJ, Ellison WT, Van Parijs SM (2012) Changes in Humpback Whale Song Occurrence in Response to an Acoustic Source 200 km Away. PLoS ONE 7(1): e29741. doi:10.1371/journal.pone.0029741
Read or download online (free)

An ongoing research project that monitors whale calls and shipping noise in Stellwagen Bank east of Boston Harbor has reported an unexpected reduction in humpback whale songs during an 11-day period in which their recorders picked up low frequency sounds from a fish-monitoring system 120 miles away.  If this data does indeed represent whales ceasing singing or moving away in response to the distant sonar, this would be the first clear-cut indication that discrete human noise events may affect marine mammal behavior outside the immediate area.  The authors note that these results could suggest that impact assessments need to consider effects at longer ranges, and that effects may occur at received sound levels much lower than those generally considered worthy of concern.  This study simply reports the reduction in singing; any longer-term effect that may have on the animals is unknown (these are not mating calls).

The reduction in songs occurred at a time of year (early fall) when humpback songs are beginning to increase in this area; on years when the fish sonar was not in operation, the numbers of songs steadily increased over the 33-day study period.  But in 2006, when the fish sonar was heard at Stellwagen Bank for 11 days (8 of which included sonar sounds for over 7 hours), the number of minutes per day when humpbacks were singing dropped, some days to zero.  The average (mean) number of hours of whale song dropped from about 75 in the previous 11 days to about 15 minutes during the time the fish sonar was heard, before increasing to close to 3 hours per day once the sonar transmissions ceased.

The figure below shows the data from each of three years.  For each year, there are 33 days of data, with the middle 11 days being the period (Sept. 26-Oct 6) in which the sonar sound occurred in 2006.  The open circles are the mean minutes/day for each 11-day period, with the rectangular boxes representing the upper and lower quartiles of data for each period; black dots represent one or two days in each period in which the calling rates for that day were unusually far outside the range for other days in that period.

Ed. note: Interpreting the results of vocalization studies is complicated by the fact that there is much variability in vocalizing rates, and response/sensitivity to human noise, from one animal to another; and similarly, in numbers of whales in the area from year to year.  (This acoustic data counts singing minutes, but not animal numbers, which must be monitored visually.)

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NOAA Fisheries has released its latest annual estimate of the beluga population in Alaska’s Cook Inlet, and the numbers are sobering.  Their 2011 estimate, 286 animals, is the second-lowest found in the 18 years of surveys, and is 20% lower than last year’s count.  However, NOAA officials stress that year-to-year counts are approximate, with differences in observing conditions and beluga distributions accounting for an error range of plus or minus as many as a hundred animals; long-range trends are more reliable indicators.  Officials say they did not see a large enough number of dead whales this year to suggest that there was indeed a 20% decline.

“Only three dead belugas were reported this year, which indicates that large numbers of mortalities did not occur in 2011,” said Alaska Fisheries Science Center Director Doug DeMaster (over the past ten years, an average of 10 whales a year have been found dead). “While NOAA remains concerned that this population is not showing signs of recovery, at this time we do not believe this estimate represents a marked decrease in the population.”  Indeed, twice before, the counts showed even larger declines, with later years suggesting that actual numbers were not so dire; the previous low count, 278, occurred one year after a count of 366, and two years later, counts were back up to 375. However, since then, counts have been at least 10% lower than that high.  This is especially worrisome, in that this genetically-distinct population of belugas has been listed as endangered, and NOAA designated much of Cook Inlet as critical habitat. (Many other beluga populations remain in other areas, including the western and northern coasts of Alaska, and northern and northeast Canada).

On the longer term, NOAA notes that there appears to be a continuing gradual decline in Cook Inlet beluga numbers, estimated at about 1% per year.  This population of belugas experienced a population crash in the 1980’s (from 1300 down to around 300) which is widely blamed on over-harvesting by native subsistence hunters, but has not recovered since the hunting was limited.  Pollution, limited salmon runs, and noise are all considered likely factors in the population’s struggle to survive.

Cook Inlet is a large waterway, leading from the southern Alaska coast inland to Anchorage and Wasilla; a major port expansion is underway, as well as oil and gas exploration and development.  For more on the backstory here, see these previous AEInews post from 2008-2011.

If AEI were a mass media outlet, publishing this on New Year’s Eve would be considered an attempt to “bury” the story on a weekend when few people are following the news.  But since our readership works on a longer time scale and are likely to find their way here over the next couple of weeks, I hope you’ll instead consider this a New Year present!  It’s taken many (many…) hours of work, and I hope it helps all those working on wind farm noise issues – including local and state regulators, environmental consultants, wind developers, and community groups – to make sense of the insanely confusing world of low-frequency noise and infrasound.  Here’s to a constructive 2012 as we continue to work toward siting policies that protect residents from unwanted changes to their sense of place while encouraging responsible and widespread growth of wind energy.

Download this extended post as a 22-page pdf file

As regular readers will know, AEI’s wind farm coverage has focused primarily on the ways that nearby neighbors respond to the audible noise from wind turbines, with far less emphasis on infrasound.  However, given the ongoing public dialogue about the contribution of infrasound and low-frequency sound to the annoyance, sleep disruption, or health effects reported by some wind farm neighbors, I do like to keep abreast of research into the lower end of the sound spectrum.  In this post, I’ll be summarizing several papers that have appeared in journals and conference proceedings over the past several months. This will be a much longer post than normal, but I encourage you to take the time to read through it, and to download the source papers for further study.  What you’ll find here is a close reading of work from both mainstream and more cautionary acousticians, which I believe will help you to understand the subtleties of our current state of understanding in a new and clearer way.

I think it’s fair to say that the bottom line continues to be roughly the same as it’s been: wind turbines clearly produce much of their sound energy at lower frequencies, including the low end of the audible spectrum (20-250Hz) and the infrasonic range (below 20Hz, which is generally below the range humans tend to hear, simply because it has to be very loud to be perceptible). Conventional wisdom continues to be that the infrasound in wind turbine noise is well below human perceptual limits, even of the more sensitive fringe of the population. This summary doesn’t directly challenge that idea, though as you’ll see, there are some indications that we may have been a bit too quick to entirely rule out any perception of infrasound produced by wind turbines.  Still, I hasten to stress that any possible connection between physically perceptible infrasound and health effects remains beyond the scope of most of these papers (with a couple of exceptions).

More importantly, though, it’s increasingly being recognized that low-frequency audible sound could very well be a key factor in widespread annoyance about wind farm noise. It’s important to not conflate infrasound and low-frequency sound; while the former is (always or mostly) imperceptible, the latter is clearly very audible in many situations, and indeed, is the dominant sound component of wind farm noise at moderate and larger distances.  It’s quite likely that much of the annoyance people report could be triggered by very low frequency, moderately audible noise, which can be more ear-catching (or perhaps even cause physiological reactions) when it contains one or more dominant tones or fluctuates rapidly.  Further, increasing evidence confirms neighbors’ reports that moderate but extremely bothersome low frequency noise can be more perceptible inside their homes than outside.  These elements are part of the reason that several of the papers here from relatively mainstream perspectives (and which consider infrasound a non- or minimal issue) recommend lower noise limits than the 45-50dB standard commonly used in the US; you’ll see in these papers that 40dBA is becoming a common recommendation. Most of the more cautionary acousticians tend to recommend 30-35dB; it’s striking to me that the gap between these two perspectives has narrowed considerably in the last year or so.

Among the highlights of the recent research is Møller and Pedersen’s finding that larger turbines produce more low-frequency sound (especially audible low-frequency), and that in many atmospheric conditions, sound levels will remain annoyingly high for much farther than often assumed by more idealized sound modeling. Also of note, Bray and James’ field measurements of wind turbine sound, using equipment designed to capture very short time segments, reveals a remarkable variability and surprisingly high peak sound levels in the low-frequency and infrasonic sound, to a degree that raises questions about our tendency to rely on longer-time-period averages that indicate infrasound is always well below perceptual limits. As we look more closely into low-frequency and infrasound data, both the mainstream papers and the more cautionary acousticians’ work suggest that these questions are far from settled.

(I should clarify that my use of the word “mainstream” is meant to simply mean studies by folks working with techniques and perspectives on bothersome noise levels that have been standard in noise control assessment for many community noise sources.  And conversely, the use of the term “cautionary acousticians” does not imply they are less qualified or biased in any way.  Indeed, most of them have decades of noise control experience and have been drawn to the study of wind farm noise only because of the unexpectedly robust complaints that have arisen, and are professionally interested in trying to ascertain the reasons, either by using innovative measurement techniques or closely assessing annoyance patterns.  They may be more “cautionary” in their recommended noise limits simply because they’ve looked more closely at specific problems, rather than keeping their distance and approaching the issue through standard noise modeling and analysis techniques.)

Some of the papers I’m summarizing here address aspects of annoyance and sound characteristics of wind farm noise that are not limited to low frequency and infrasound issues (especially including acknowledgement of the extreme variability of the overall sound levels); these papers provide important perspectives that may help us to understand why wind farms are producing more annoyance reactions than we might expect, considering their moderate sound levels.

For more (much more…but worth it!), click on through to read lay summaries of the following recent papers:

• Møller and CS Pedersen. Low-frequency noise from large wind turbines. J. Acoust. Soc. Am. 129 (6), June 2011, 3727-3744.
• O’Neal, Hellweg, Lempeter.  Low frequency noise and infrasound from wind turbines. Noise Control Eng. J. 59 (2), March-April 2011.
• Bolin et al. Infrasound and low frequency noise from wind turbines: exposure and health effects. Environ. Res. Lett. 6 (2011) 035103
• Bray and James. Dynamic measurements of wind turbine acoustic signals, employing sound quality engineering methods considering the time and frequency sensitivities of human perception.  Noise-Con 2011.
• Stephen E. Ambrose and Robert W. Rand. The Bruce McPherson Infrasound and Low Frequency Noise Study: Adverse health effects produced by large industrial wind turbines confirmed. December 14, 2011.
• David Hessler, Best Practices Guidelines for Assessing Sound Emissions From Proposed Wind Farms and Measuring the Performance of Completed Projects. Prepared for the Minnesota Public Utilities Commission, under the auspices of the National Association of Regulatory Utility Commissioners (NARUC). October 13, 2011.
• Knopper and Ollsen. Health effects and wind turbines: A review of the literature. Environmental Health 2011, 10:78
• Kroesen and Schreckenberg. A measurement model for general noise reaction in response to aircraft noise. J. Acoust. Soc. Am. 129 (1), January 2011, 200-210.
• HGC Engineering, Low frequency noise and infrasound associated with wind turbine generator systems: A literature review. Ontario Ministry of the Environment RFP No. OSS-078696.
• Bob Thorne. The Problems with “Noise Numbers” for Wind Farm Noise Assessment. Bulletin of Science Technology and Society 2011 31: 262.

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Over the past few years, new and relatively inexpensive new hydrophone systems have allowed biologists to place autonomous recorders in far more locations, collecting vast amounts of acoustic data that can help them to understand the population dynamics of marine mammals, as well as to monitor interactions and effects of human noise on marine mammal communication.  They’re also looking forward to learning more about individual and pod communication patterns.

But this flood of new data hits a bottleneck when it needs to be assessed by human listeners.  There are several robust automated call detection programs available, but even these must be checked by humans, who can hear similarities in calls or see patterns in the sonograms that present the complex calls as pictures of the frequency patterns.

To the rescue comes a new crowdsourcing project from Scientific American and Zooniverse, WhaleFM.  Individuals from around the world are invited to join the research teams from Woods Hole and the University of St. Andrews by matching new recordings of orcas and pilot whales with  known calls or call types (often associated with particular behaviors). While orca society is moderately well-understood, with many call types already identified, this aspect of pilot whale research is at an earlier stage, and users will help to decide which Pilot Whale calls match, and help in discovering whether the same call is make by one individual, one group, or across broad areas. For more on the project, check the link above, or this blog post from Scientific American.

Research summary of Francis, C.D., Ortega, C.P., Cruz, A. 2011. Noise pollution filters bird communities based on vocal frequency. PLoS ONE 6(11):e27052.

An ongoing research project in New Mexico continues to shed more detailed light on the question of how moderate human noise affects nearby wildlife.  In a study design that effectively separates out the impact of the noise from other habitat disruption effects, Clint Francis and his colleagues are finding that some species are displaced, while others seem to thrive in areas with coalbed methane compressor stations creating noise around the clock.  The most recent paper to be published by Francis et al finds that species that sing at lower frequencies are most likely to avoid the noisy areas, while those who vocalize at higher frequencies are more apt to be unaffected or even thrive.

While this research studies an area with oil and gas development noise, it’s likely that similar effects would occur in and near wind farms, which also produce predominantly low-frequency noise. And, as the authors note to conclude their paper: “At the community-level, we must still determine whether noise is an agent of ecological filtering for other taxa that rely on acoustic communication.”

Rather than doing the full AEI lay-summary of the most recent paper, I want to point you to the great summary already written by Caitlin Kight, biologist who studies the effects of anthropogenic disturbances on animals; it was recently featured on her Anthrophysis blog.

IBM is collaborating with The Sustainable Energy Authority Ireland to measure the noise output from a wave energy installation of the west coast of Ireland, which is one of the world’s most promising areas for wave power development.  The acoustic data will be collected in real-time, and will will produce one of the largest continuous collections of underwater acoustic data ever captured. This data will be made available to marine researchers and regulatory agencies to further advance knowledge of natural and man-made underwater sound, and help develop standards and reporting, benefitting marine environmental agencies as well as industries including renewable energy, shipping, and offshore oil and gas.

“Underwater noise is a global environmental issue that has to be addressed if we are to take advantage of the huge potential of ocean energy,” said European Union Commissioner for Research, Innovation and Science Máire Geoghegan-Quinn.  “This project is a great example of collaboration among global companies, industry experts and government agencies, and will help us make real progress toward practical and sustainable ocean energy systems.  I’m delighted to see Ireland playing a lead role in this area, which has great importance for meeting the EU’s energy challenges.”

David Dunn is a longtime friend and colleague to AEI here in Santa Fe, and in fact his underwater insect recordings were my first taste of the sounds of the natural world having the potential to be deeply strange and amazing, rather than “just” beautiful. So when he discovered that the bark beetles chewing their way through the piñon pines in the hills of New Mexico were making all sorts of bizarre sounds, and suggested publishing a CD to benefit AEI, I was all for it.

Since then, the bark beetle inquiry has taken on a life of its own, becoming a perfect expression of David’s longtime conviction that artists can contribute in significant ways to science.  The acoustic behavior and communication of bark beetles was previously unstudied by entomologists, and now he’s being called to consult with scientists studying not only the piñon pine beetle, but also the mountain pine beetles ravaging larger higher-elevation and higher-latitude pines, as well as insect pests of the non-beetle persuasion.

This past week, a long article appeared in several Canadian newspapers, providing the most detailed look yet at David’s beetle odyssey.  It’s an excerpt from a new book by Andrew Nikiforuk, Empire of the Beetle: How Human Folly and a Tiny Bug Are Killing North America’s Great Forests.  The article dubs David “the tree whisperer,” though so far he hasn’t quite figured out how to calm the outbreaks; in fact, the research so far seems to be leading more toward driving beetles crazy than calming them.  But after forgiving the headline writer, we can sink into he article itself, which is the most detailed, entertaining version yet of David’s beetle adventures.

A really fascinating multi-year study is underway at the Kenai National Wildlife Refuge which sits on a peninsula along the south side of the Cook Inlet in Alaska (Anchorage and Wasilla are at the innermost tip of Cook Inlet).  Tim Mullet, a Ph.D. student at what looks like an amazing program at the Institute of Arctic Biology, is undertaking what may well be the most comprehensive soundscape analysis ever undertaken on a landscape scale. “As far as I know, nobody has attempted to model sound in the landscape,” says Mullet. “We could encounter some big surprises there.”

Over several summers and winters, he is collecting recordings with 13 units placed in different areas of the refuge; some are permanent locations, and others he moves around in order to explore the soundscape in more areas. He already has 85,000 hours of sound data, and hopes to expand his recorder array to 23 units this year as well. These two articles provide a great overview of what Tim’s up to.

Snowmobile density in the Kenai NWR (red most, blue least); note that the shaded areas on the east side are nominally closed to snowmobile traffic, yet show some sign of activity.

“At this point, I’ve got an idea that 30 to 40 percent of Kenai’s wilderness could be affected by human–made noise,” says Mullet. The study goes beyond simple decibels (loudness), though. It is a foray into the emergent field of soundscape ecology, which examines the interplay of anthrophony (human–induced sounds) and biophony (natural sounds).

Loudness is “a piece of this study,” says Morton, “but another piece is the origin of sound—whether it’s human or nature—and developing a ratio between the two. It’s definitely cutting edge.” Understanding the relationship between anthrophony and biophony is important to the refuge and wildlife conservation in general, Morton says, because “human–generated noise can drown out natural noises—and that can be a huge deal, to the point where animals can’t actually hear themselves.”

In addition to collecting and mapping sounds, Mullet is studying whether moose who live closer to high levels of sound show higher stress levels than those in more sonically pristine areas.  While some snowmobiling advocates seem concerned that Mullet’s work may lead to new restrictions on their access to the refuge, Mullet himself understands and appreciates the key role of snowmobiles in Alaskan recreation, and aims to simply clarify what the various cumulative impacts of noise may be. Snowmobile trails create other impacts as well, especially compacting snow, which can benefit wildlife by offering travel paths, though biologists are also interested in how this easier travel may shift some predator/prey relationships.

More info: See two articles written by Mullet, one on the many qualities of snow, and the other exploring our different ways of listening, and introducing the Kenai study.  Also of interest from Tim is this research proposal, which summarizes previous research into both the impacts of noise and other snowmobile impacts (unfortunately, the sections of the proposal that are yellow-highlighted come through on the pdf as blocked out).

A Japanese research effort that’s been around for a while has gotten a blast of media fame this week, claiming the potential to triple power generation by using a ring around the blade-swept disc that focuses wind past the blades, as well as, I think, capturing some of the energy off the blade tips.  Sounds great in a headline, but as with most new turbine design “breakthroughs,” this one is early in R&D: the field trial models are only 5kw, with two 100kw, 13m-diameter, models recently erected. Whether the design can scale up, or be constructed economically in large arrays of smaller units, remains to be seen.  The weight of the ring has to be a challenging design feature when it comes to actually building large versions of this in the real world. Nearly every efficiency-improvement approach also touts a reduction in noise output as one of the benefits.

The best coverage of the “Wind Lens” research appeared on Clean Technica; they included these links to the lab’s research page and a conference poster. For good measure, here’s a couple other new approaches to increasing turbine efficiency previously covered in Clean Technica, with equally uncertain futures.  More power to all these researchers, whether in university labs or backyards.  Just don’t assume that a catchy headline means the revolution is neigh.  (Being a dreamer, I remain quite fond of ongoing research in California that seeks to harness extra energy by mimicking fish schooling patterns with small vertical-axis turbines, as covered previously here.)

Here’s a great fifteen-minute radio feature from Voice of America that digs into the issue of shipping noise and its effects on ocean life.  It features Michael Jasny of NRDC, recordings of shipping noise off Vancouver Island, NOAA’s Michael Bahtiarian on their quiet research ships, and Kathy Metcalf of the Chamber of Shipping of America.

Give a listen!

(transcript also included at that page link)

For the second of a planned five summers, a team of researchers is spending a couple weeks in waters off southern California, attaching suction-cup acoustic tags to whales, then playing sounds underwater to see how they respond to different sounds and intensities. Another two weeks of field work will occur in late September. As Brandon Southall notes on his SEAblog, which provides excellent coverage of the trip, the team is “interested in testing the differences in responses of marine mammals in the various kinds of habitats in which they live and are exposed to human sounds.” After several years of study, the research is moving beyond simply getting one or two examples of any given species, toward the development of a wide array of examples of each species, in different circumstances (at least for the easier-to-tag species). The study is known as a Behavioral Response Study (BRS), which used to be called Controlled Exposure Experiments (CEE), with the CEE term still in use as the name of each individual playback to a tagged animal. This year’s southern California version goes by the name of SOCAL-11. The acoustic tags used in the study allow researchers to record the actual sounds heard by the animals (including of course their own foraging and communication vocalizations), while also tracking their swimming speed and dive patterns.

It’s always easier to find and approach the large whales, such as blue and fin whales, so the team tends to focus on these species when waves are higher; in light seas, they are largely seeking the harder-to-locate, and much harder to approach beaked whales, as well as Risso’s dolphins. Here’s a taste of what you’ll find if you follow the study on the SEAblog (the picture above is the animal he’s so enthused about):

Rissos dolphins are among our focal species for SOCAL-11 experiments.  We conducted one CEE on this species last year in SOCAL-10 and have been hoping for more this year.  This species has also proven somewhat difficult to tag in the past and our tags on last year were for just a few hours, so to get a nine hour deployment spanning several different behavioral modes was pretty exciting.  The tag came off late into the evening, but quite close to our anchorage and we made a beautiful late night ride in very calm seas and a red-yellow moon out to safely retrieve it.

In addition to increasing the data set of carefully measured behavioral responses to sound, the researchers are testing two leading-edge technologies: a next-generation acoustic tag, and a towed hydrophone system deployed from a sailboat that’s being used to try to find animals for possible tagging by hearing them from afar.  Plus, associated research is underway, including a study of the prey and oceanographic conditions around tagged animals, which aims to learn something about how the ocean conditions relate to where the prey is, and thus where the whales are, as well as to see whether behavior in response to sound is different when prey is present or not.

You can learn more about the SOCAL BRS study, including powerpoints describing last year’s findings, at the SOCAL-BRS web page.  Or, get more current updates by following the study on the SEAblog, or on the SOCAL-11 Facebook page (which includes some videos):

http://www.facebook.com/home.php#!/pages/Behavioral-Response-Studies-of-Marine-Mammals/153316228012219

This post is an AEI lay summary of the following paper:

McCarthy, Moretti, Thomas, DiMarzio, Morrisey, Jarvis, Ward, Izzi, Dilley.  Changes in spatial and temporal distribution and vocal behavior of Blainville’s beaked whales (Mesoplodon densirostris) during multiship exercises with mid-frequency sonar.  Marine Mammal Science, Volume 27, Issue 3, July 2011.

For the past several years, ongoing research at the US Navy’s AUTEC training range in the Bahamas has been providing data that confirms what many had long suspected: that beaked whales move away from active sonar transmissions.  A recent paper published in Marine Mammal Science quantifies the changes in more detail than has occurred before.

Using recordings from the permanently-installed hydrophones lining the seafloor of AUTEC, the researchers charted the foraging vocalizations of Blainville’s beaked whales before, during, and after extended Naval training exercises (85 hours in 2007, 65 hours in 2008). In 2007, when activity was high prior to the exercises, animals returned to the range in somewhat lower numbers within 24 hours:

in 2008, when there was less activity prior to the exercises, very few animals returned in the first three days, but many were there shortly thereafter:

Among animals who continued foraging while sonars were nearby, they appeared to tolerate received levels ranging from 101 to 157db, which correlate to sonar transmisisons from ships 2-28km away.  A key question considered is whether the animals left the area, ceased vocalizing, or were masked by the exercise sounds. Because of the way that vocalizations increased first around the edges of the range, moving toward the center, the researchers are confident that the animals predominantly left the range; the decreased levels of vocalizations even around the edges imply that most animals moved more than 6km from the range (the limit of confidently knowing they’ll be heard by hydrophones along the perimeter).

The paper concludes by summarizing related ongoing research, including studies that aim to determine whether decreased foraging, especially directly after exercises, is due to fewer beaked whales in the area, or less preay (ie, was the prey moved off the range by the exercise activity and noise?).  The authors also note many as-yet unanswered questions that are triggered by their results, including whether the displaced animals continue feeding elsewhere during their absence from the range, and whether this particular population is more habituated to the sonar sounds, so that they either tolerate it better or are less apt to exhibit the presumably more dangerous behavioral responses that lead to strandings.

A very cool research program is underway in the Bahamas this summer.  In an attempt to understand whether exposure to ocean noise sources creates stress in whales, a team from the New England Aquarium is collecting fecal matter for stress hormone testing (the photo at left shows Roz Rolland surfacing after a successful collection dive).  Increased stress can lead to many secondary issues for any animal, including health impacts and reduced reproductive success. A series of blog posts from their two weeks on site is a fun read.  The work is continuing in the Bahamas, though this team has headed home.

Here also is an MSNBC article on the research.

The first field results from a Caltech research team led by John Dabiri have been published, and they suggest that Dabiri’s new approach to wind generation may be just what rural communities have been hoping for: the ability to proceed with widespread wind energy development without changing the character of local landscapes and soundscapes.

Dabiri’s team is looking at wind energy efficiency from an entirely new perspective: rather than designing individual turbines to capture as much of the wind energy passing through their blades as possible, they’re looking to capture as much of the wind energy in the projects footprint as possible.  Instead of the 300-400 foot 3-armed turbines we’re used to, the Caltech team is optimizing a tightly-packed array of 30-foot spinning vertical tubes (vertical-axis turbines) that look more like egg beaters or old-fashioned lawnmowers turned on end.  Inspired by fish schooling, the turbines use the air flow from one another to optimize energy capture and efficiency; by contrast, giant horizontal-axis turbines (the standard design we’re familiar with) need to be very far apart so that their turbulent wakes don’t interfere with each other.

In the first field season, last summer, a tiny test plot of just six turbines was arrayed in various configurations, so the  team could find what works best.  This summer, 24 turbines are being used in the second year of field tests.  Last summer’s results, while clearly preliminary, are exciting: the array produced 21-47 watts of electricity per square meter.  That may not sound like much, but a bit of high school math reveals that if this design scales up (even assuming just 30 watts/meter), a 1km by 1km plot of land (a bit over a half mile on each side) would produce as much electricity as one of today’s wind farms with two hundred 1.5MW 300-foot towers spread over many square miles. Put another way, a patch of land 200 feet on each side would produce the same amount of electricity as a single 1.5MW turbine, which generally needs a safety buffer of at least 500 feet on all sides.  The downsides of the new approach are that the productive wind installation would use all of the land in its footprint, unlike current wind farms in which the distantly-spaced turbines leave plenty of room for grazing or planting.  Horizontal axis turbines can also suffer more stress under high winds, though undoubtedly new materials and engineering approaches will address this issue.

There’s clearly a long way to go to bring this new design to utility-scale wind production, but of all the new approaches to wind energy, this is one of the most promising!

For more on Dabiri’s work, see this Caltech press release and visit Dabiri’s lab’s web page, which includes a video and links to a Powerpoint and the recently published paper.

The Syracuse Post-Standard reports that a study of real estate sales in three upstate New York counties has found that being closer to wind turbines can lead to reduced sales prices.  In two of the three counties, property values appear to have dropped by 8-15% for homes situated a half mile from the nearest turbine (which usually means several more are within a mile or two); the price drop was only slightly less for homes within a mile, while there was a smaller, 2-8% drop for homes within 3 miles of a turbine.  However, the third county studied showed no price reduction after the wind farm was constructed; the authors found that in this county, prices actually rose a bit just after construction, then settled  back to no significant change. This study uses a hedonic analysis methodology similar to two previous studies (Hoen and Hinman) that found no significant price change.  This new study, by Martin Heintzelman and Carrie Tuttle of Clarkson University, differs from the previous studies in that it does not combine all results, but rather looks at each county individually.

The Heintzelman study is still being finalized; an earlier version that combined all locations into an overall negative impact has circulated since March, but a new version that separates the locations and finds the more nuanced results is now available.

After long months of gestation, examination, and procrastination, this year’s Wind Farm Noise report is ready to share!  So, here it is.

It’s also viewable here on SlideShare. And, you can download the 55-page report, and much of the source material, on the new AEI Wind Farm Noise Resources page. Lemme know what you think of it!

AEI_WindFarmNoise2011

Ongoing pressure from environmental groups has spurred the National Marine Fisheries Service to take a closer look at the effects of seismic surveys on whales in the Gulf of Mexico.  The Obama administration has announced that NMFS will prepare a Letter of Authorization, which will look more closely at the question of whether current seismic survey practices comply with the Marine Mammal Protection Act.  Up until now, Gulf oil exploration has only been monitored for effects on endangered species.

Meanwhile, the Department of Interior and a coalition of environmental groups are engaged in settlement talk in a separate lawsuit filed earlier this year, which challenged the first new exploration permits issued for the Gulf since the Deepwater Horizon accident.

These legal challenges resemble the successful challenges to Navy sonar training exercises, which also called on the government to do more complete environmental impact studies of practices which were widespread and had been going on with minimal oversight for decades.  While the Navy did complete the EIS’s, it’s worth noting that they have not led to major changes in how sonar training takes place; environmental assessments often lead to determinations of “negligible impacts” on wildlife, and it’s common that the most protective alternatives considered in an EIS or EA process is not the one chosen as the final outcome.   Read the rest of this entry »

The past week has seen a flurry of new reports and articles that aim to debunk the idea that wind farm noise should be taken seriously as a concern when siting new wind farms.  AEI’s upcoming Wind Farm Noise 2011 report will address the issue in great depth when it’s released in about a week, but for now I wanted to make a few comments about the recent releases.

Two reports came from Canadian environmental groups that advocate expansion of wind energy and are frustrated by local resistance, especially in Ontario.  I share their support for wind energy providing an increasing percentage of our electrical generating capacity, and have little problem with the bulk of these reports; but in each case, I feel that their treatment of noise issues misdirects attention away from the very real problem at the core of the debate: when wind turbines are built closer than a kilometer or so from homes in rural areas, a high proportion of those nearby neighbors experience significant quality of life impacts due to audible turbine noise.

Sierra Club Canada released a 40-page report Read the rest of this entry »