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Humpback bottom-feeding is (somewhat) affected by shipping noise

Ocean, Science, Sonar No Comments »

AEI lay summary of:  Blair HB, Merchant ND, Friedlaender AS, Wiley DN, Parks SE. 2016. Evidence for ship noise impacts on humpback whale foraging behaviour. Biol. Lett. 12: 20160005. http://dx.doi.org/10.1098/rsbl.2016.0005

Sand lance 350pA new study looks for the first time at the impact of human noise on an important type of humpback whale foraging activity, bottom-feeding on sand lance.  The research took place in the Stellwagen Bank National Marine Sanctuary in the southern Gulf of Maine, where humpback whales routinely do deep dives at night, rolling to their sides when they reach the bottom to forage for the small fish.

To assess the whales’ responses to human noise, D-Tags were placed on ten individuals over the course of two years.  These temporary suction-cup tags record received sound levels that the animal is hearing, as well as tracking the details of their dives.  The tagged whales made 218 dives, 83 with ship noise exposure and 135 without ships nearby.

Here’s an example of the sort of picture that the D-tags can provide:

Blair 2016 Humpback side roll Dtag track plot

The results show a 29% decrease in the number of “bottom side-roll feeding events” as the received level of the ship noise increased, as well as a 13-14% decrease in both the descent and ascent rate of the dives.  Interestingly, the increase in received noise level was rather small overall (received level was higher when ship noise was present, but not statistically significantly higher), perhaps indicating that the ships were, on average, not all that close.  As is typical, the team used advanced statistical techniques to tease out modest effects from the subtle and varied data. (In case you’re wondering, they used “linear mixed-effects models” with data “square root transformed to approximate normality,” then calculated effects by “summing Akaike weights of all models.” Sounds good to me!)

The raw numbers put the effects into some more straightforward perspective.   Read the rest of this entry »

Belugas struggling in Cook Inlet, St. Lawrence rivers

Bioacoustics, Ocean, Science 2 Comments »

Two troubling reports have surfaced regarding beluga whale populations in waters that have become increasingly industrialized and noisy in recent years.  In Quebec’s Saguenay River, the major river system draining into the St. Lawrence, recent years have seen a sharp uptick in dead beluga babies and pregnant mothers; in 2015, these sensitive individuals were half of all known mortalities.  Increased noise is the primary culprit; according to the CBC, “The researchers are working from the theory that beluga calves have soft calls, which may be drowned out by the noise from ships, ferries and boats in the Saguenay and St. Lawrence rivers.”

In Alaska’s Cook Inlet, beluga range has shrunk dramatically over the past couple of decades (see map below), and accelerated in recent years, as ongoing port construction and oil and gas development has introduced increasing levels of noise into these key waters.  It’s unclear whether the smaller range is simply a reflection of a reduced local population, meaning they don’t need to range so far to avoid competing with each other for food, or if they are responding to the increasing chronic noise.  See previous AEInews coverage of the Cook Inlet belugas here.  Recent NMFS research papers on the changes can be accessed at this link, and this in-depth article from a couple years back is a good overview of the current development and research activities.

Beluga range Cook Inlet 1978-2014

Marine invertebrates also affected by ocean noise

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

Some of the most interesting new work in ocean noise is revealing the myriad ways that humanity’s sounds can have negative impacts on ocean life other than marine mammals.  Sure, everyone loves our warm-blooded kin, but there’s way more to the ocean ecosystem than dolphins, humpbacks, and seals.  AEInews has been covering this leading edge for years (see these posts on shellfish larvae, crabs, and squid).  Recently, at the triannual Effects of Noise on Aquatic Life conference, held this year in Dublin, a slew of new papers revealed further concerns.

blue-banded_hermit_crabThis post from NRDC summarizes the highlights.  One of the most striking findings was that 6 hours of shipping noise can damage the DNA in the cells of mussels, perhaps due to a stress response; similarly, protein structures in the sensory cells of cuttlefish were damaged by low-frequency noise.  These would be some of the most profound impacts yet discovered; note, though, that the brief summary here does not specify the sound levels—some research on health effects use much higher exposures than are likely in the wild, as a way of identifying possible effects for further study at lower exposure levels.  Other new studies followed on previous ones that suggest many animals respond to noise as if it were a predator; these responses often suggest increased stress, and are waste of precious energy, or disrupt feeding.  Also of note is a one-off anecdotal observation (not yet studied systematically) of a hermit crab exiting its shell after exposure to low-freqency sound; it appeared to be examining its shell, perhaps trying to determine the source of the disruption, or checking for physical damage. While out of its shell, it would be vulnerable to predation.

All this new research is both exciting, as it reveals the vast and subtle role of sound in the natural world, and sobering in facing us with the widespread consequences of our heedless sonic intrusions into wild ecosystems.

 

Wind farms increase stress in nearby badgers

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

Lay summary of
Rosanna CN Agnew, Valerie J Smith, Robert C Fowkes.  Wind Turbines Cause Chronic Stress in Badgers (Meles meles) in Great Britain.  Journal of Wildlife Diseases, 52(3), 2016. DOI: 10.7589/2015-09-231.  Download PDF

A new study out of Britain provides one of the clearest looks at whether wind farms create chronic stress in wildlife populations.  The results are striking—badgers living near turbines had stress levels 265% higher than the control groups—though not yet conclusive.

The researchers used what appears to be a very solid study design, testing cortisol levels in badger hair among 25 badger “setts” (dens, occupied by one or more badger families) separated into two groups: 9 “affected” setts were within 1km of wind farms, and 16 control setts were more than 10km from any wind farm.  They made an effort to assure that control setts were comparable in their habitat types, distance from roads, and geographic spread across Britain.

Agnew 2016 badger cortisol 1km and controlThe overall results are fairly clear-cut.  Here’s a graph of the two groups; the boxes show the 3 quartiles of results in each group (the bottom of the box being the level that 75% of the animals were above; the line across the box showing the level where half the animals were above, half below; and the top of the box the level that 25% of the animals were above), with the bars outside the box showing the remaining scatter of individuals.  The mean among controls was .87, and among the affected group the mean was 3.16

Agnew 2016 badger cortisol and distanceA closer look at the results suggests that, as usual in field studies, there is a lot more going on than the means and medians suggest.  Here we see a plot of the 9 affected setts, with distance to nearest turbine on the bottom axis.  Interestingly, there is a wide scatter of results, with some setts (2 of the 9) showing levels very similar to the controls, about half (4 of the 9) having somewhat elevated levels, and only 3 setts being highly elevated, above the highest of the control setts.  Our first image shows this skew, with the upper quartile of the affected box stretching far above the middle line (and thus pulling up the mean to a significant degree).

This skewing does not invalidate the results; such scatter is very typical of most impact studies.  But it does remind us that there is rarely a simple, universal cause-and-effect.  The authors address many factors that could have contributed to anomalous results, and consider most of them to be quite unlikely; as they summarize, “Although certain intrinsic factors, such as sex, age, and disease status, have been thought to influence cortisol levels, it is very unlikely that the 264% cortisol increase experienced by affected badgers is a result of these factors alone.” Still, these and the other possible confounding factors will deserve closer scrutiny in followup studies.

The authors presume that vibration and noise, and likely infrasound, are the primary stressors, but did not do sound measurements as part of the study.  There was no mention of whether badgers are stressed by tall structures, as some small mammals are (due to predation by hawks).  While it seems likely that badgers are too large to be at risk from above, some confirmation of this would have been helpful to add, if true.

The researchers suggest that their results could have implications for controversies about humans who have reported negative reactions to wind farms, noting that badger hearing range is similar to humans.  A final finding was that the badgers did not appear to acclimate to the wind farms: setts near new wind farms had only slightly higher stress levels than those near long-established ones, where the mean remained well above that of the controls.

AEI presentation at Ecoacoustics 2016

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, Wildlands 1 Comment »

I recently returned from the 2016 Ecoacoustics Congress, the 2nd meeting of the new International Society of Ecoacoustics, held this year at Michigan State University in Lansing. It was a very informative gathering of fascinating researchers from around the world; several traveled from Australia, a couple from Taiwan, many from Europe, and some from South America. I’ll add more here soon about this rapidly-advancing field, but for now, I wanted to quickly post a PDF version of my presentation:

Saving High-quality Acoustic Habitat: Identifying areas of relative natural quiet by Jim Cummings

Top researchers urge US to hold off on Atlantic seismic surveys

Bioacoustics, Ocean, Ocean energy, Science, Seismic Surveys No Comments »

Oceana Right Whale map250WEBIn a second letter to the Obama administration, 28 top ocean noise and whale researchers have raised serious concerns about planned seismic surveys along the east coast of the U.S.  The scientists cite several recent studies that shed light ways that the long term health and reproductive rates of right whales have been affected by temporary stresses, and suggest that the planned seismic program could push this extremely endangered species over the edge.  With only 500 individuals remaining, the loss of each individual creates a significant impact on long term population viability.  According to the letter,

Notably, according to analysis by the New England Aquarium, even a small decline of only ten percent in right whale health can impair reproduction or eliminate it entirely. A newly published study shows that a population-wide deterioration in North Atlantic right whale health from 1998 to 2000 was correlated with a drastic drop in calving rates, further indicating that factors influencing health can be responsible for suppressing reproduction.

With previous studies showing noise causing lasting stress in right whales, and that whales that have been through an entanglement experience with fishing gear show lasting health effects and reduced reproduction, the researchers conclude:

In light of the desperate level of endangerment of the North Atlantic right whale and the serious consequences of entanglement, it is critical that other major stressors are minimized or removed to ensure the recovery and long-term survival of this species. The additional stress of widespread seismic airgun surveys may well represent a tipping point for the survival of this endangered whale, contributing significantly to a decline towards extinction.

A year ago, 75 scientists wrote to the Obama administration to urge them to reject plans for seismic surveys and oil and gas development along the Atlantic seaboard.  In March of this year, plans to offer drilling leases for the five-year period 2017-2021 were abandoned.  A future administration may re-open the area for later five-year planning periods, and the oil and gas industry wants to conduct new surveys in the meantime.  Currently, four companies have applied to the Bureau of Ocean Energy and Management (BOEM) for permits to conduct surveys in the Atlantic (see maps above and below).  This new letter from 28 of the same researchers who wrote last year asks the administration to follow up its announcement to keep the Atlantic closed to drilling, by now also withdrawing the 2014 decision to open the area to new surveys, in the light of the new research that is not included in the previous environmental impact statement—or at the very least, to refrain from issuing any permits until after NOAA’s planned 2017 right whale status review, which may confirm whether recent slowdowns in the species’ population growth have continued.

The NRDC elaborates on the expertise of these researchers:

The statement is signed by some 28 marine biologists with particular expertise on the right whale, from such institutions as Cornell, Duke, the New England Aquarium, Wildlife Conservation Society (the conservation arm of the Bronx Zoo), UNCW, and Woods Hole Oceanographic Institution. For right whales, it doesn’t get much more authoritative than this.

The map at the top of this post highlights designated right whale Essential Habitat (red) and Seasonal Management Areas (blue cross-hatches).  Note that the areas largely overlap; this duplication of effort and noise is among the concerns expressed by regional and national ocean advocacy organizations; oil and gas exploration companies routinely duplicate each others’ surveys, with everyone’s data being held as proprietary information.  The larger map below shows designated Essential Habitat for a wide range of Atlantic species.  One of the proposed survey areas is well offshore, fifty or more miles from the key right whale habitat, while the other three come right to the edge of the designated habits, or even overlap with them.  Seismic survey sounds can routinely extend for tens of miles from the survey vessels (and up to 1500 miles in deep offshore waters), so concerns about increased stress—especially in the nursery areas along the southwest coast—apply to all the proposed survey areas, if they take place when whales are present.

For more from the researchers involved, see this press release that includes several quotes, and for more on the maps, produced by Oceana, see this article from the Coastal Review and this page on Oceana’s website.

Oceana Essential Habitat Map Atlantic500WEB

Using gliders to listen for whales 24/7

Bioacoustics, Ocean, Science No Comments »

gliderWEBOver the past few years, researchers have developed an increasingly diverse set of platforms for listening in on the world beneath the ocean’s waves.  Now, in addition to recorders deployed in key areas for months at a time and temporary suction-cup acoustic tags on individual whales, a long-anticipated mobile option is moving into more widespread use.  Autonomous gliders offer an enticing combination of attributes: they can operate for weeks or months at a time, exploring a region rather than staying in one place; they can be outfitted with a range of sampling capabilities; and they are relatively inexpensive to build and deploy.  Subsea gliders can dive to 200 meters deep and resurface periodically to transmit data to data centers on shore; they’ve been used for physical sampling of oceanographic data (temperature, salinity, etc.) for many years, but it’s only more recently that acoustic sampling has become common.

The most exciting thing about putting recorders on gliders is that they can operate around the clock, monitoring for whales even in bad weather and at night, when ship-based researchers cannot.  Plus, the cost of operating research ships means that field studies are short and targeted to areas already known to be hot spots for whale activity, while gliders can be used to explore regions that we know less about. In particular, we know that whales tend to move around season-to-season in search of the best feeding opportunities; on the Scotian Shelf in the Canadian Atlantic, some areas that are protected feeding habitat have been largely abandoned in recent years due to lack of prey.  Gliders can help identify where the alternative feeding grounds may be, so they, too, can be protected.

This spring the Canadian WHaLE project (Whales, Habitat, and Listening Experiment) is expanding to the west coast. For three weeks, a six-foot glider will explore waters off Vancouver Island.

“Ocean gliders are a new technique for gaining insights into whale ecology on Canada’s West Coast,” says David Duffus, who leads the west coast project. “Many species of concern under Canada’s Species at Risk Act are termed ‘data deficient.’ We need more information on whale habitats and whale feeding ‘hot spots’ so we can put in protective measures, such as real time whale-alerts for shipping traffic.”

In addition to the longer-term goal of increasing our understanding of changing habitat use patterns, the gliders could also help reduce ship strikes. There is hope that in some especially busy shipping lanes, gliders may offer a new way to let ship captains know when whales are nearby; this is especially important for the critically-endangered North Atlantic right whale.

New maps offer more detail to ocean planners about how animal concentrations change during the year

Ocean, Science No Comments »

An ongoing challenge for ocean regulators has been our relatively coarse understanding of where ocean animals are at any given time.  For many species, we’ve been limited to relatively broad-brush data, such as regional population estimates or having a moderately clear idea about particular feeding or breedings areas, with limited knowledge of where these same animals go at other times of year.  All this has made the crucial task of estimating the impacts of human activities (Naval sonar and explosives exercises, oil and gas seismic surveys, construction of new shipping ports) somewhere between difficult and impossible—leading to a mountain of EISs, agency determinations, and court filings over the question of how best to protect ocean life from our noisy actions at sea. Confounding matters for all concerned, on the matter of protecting key habitat, the Navy has sometimes prevailed and sometimes lost in recent challenges.

Over the past decade or so, several projects have been bringing data together from a slew of historical studies, along with doing new surveys in the field that flesh out our understanding of animal distributions.  These efforts are beginning to bear fruit.

baleen two seasonsWEB500

This week, a team from Duke University’s Marine Geospatial Lab released a series of maps and new mapping tools to the public and to other researchers, making available data they’ve been compiling for use in the current round of environmental analysis for the Navy’s east coast and Gulf of Mexico training ranges, and for inclusion in NOAA’s ongoing Cetacean and Sound Mapping project (also known as CetSound).

In addition to an open-access paper published in Nature Scientific Reports, a set of comprehensive species-specific supplemental reports (each one running to over a hundred pages), and a good layman’s overview using the Story Map platform, the Lab also has an online mapping portal, OBIS-SEAMAP, that displays annual animal densities for marine mammals, seabirds, sharks, rays, turtles, and even a few lizards of conservation concern.  OBIS-SEAMAP—short for the Ocean Biogeographic Information System: Spatial Ecological Analysis of Megavertebrate Populations—archives hundreds of surveys, satellite telemetry datasets, and photo-ID collections, and has now expanded to include long-term archival of species distribution models. Read the rest of this entry »

1st recordings from deepest spot in ocean: whales, typhoon, ships

Ocean, Science No Comments »

challenger deepWEB250A team of researchers from Oregon State University has made the first-ever recordings of what the soundscape is like in the ocean’s deepest spot: the Challenger Deep.  This part of the Mariana Trench is more than 36,000 feet below the surface, but it’s not all that isolated from the normal cacophony of the seas.  As lead investigator Robert Dziak says,

“You would think that the deepest part of the ocean would be one of the quietest places on Earth. Yet there is almost constant noise. The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales, and the clamor of a category 4 typhoon that just happened to pass overhead.”

deep graphic WEB500They also heard large ships coming in “loud and strong,” and even the calls of a smaller  toothed whale or dolphin relatively near the surface; you can listen to short sound clips here.  It may seem surprising that sound penetrates so deep.  But of course, seven miles is not really all that far in the ocean; whales routinely communicate over larger distances, and several human sounds sources are readily heard for tens of miles around (or hundreds when caught in a sound-reflecting layer).  What sets the ocean’s depths apart is the extreme density of the water, which can facilitate sound transmission.  Still, it’s a bit disconcerting to realize that no part of the sea is truly free of the acoustic footprints of man.

 

New paper pinpoints “opportunity sites” for acoustic habitat protection near proposed oil sands shipping route

Bioacoustics, Ocean, Science, shipping No Comments »

AEI lay summary of Rob Williams, Christine Erbe, Erin Ashe, Christopher Clark. Quiet(er) marine protected areas. Marine Pollution Bulletin (2015), http://dx.doi.org/10.1016/ j.marpolbul.2015.09.012  View or download paper online

Over the past decade or so, concern about ocean noise has expanded from its initial focus injuries and deaths caused by periodic loud events, such as sonar or seismic surveys.  Many researchers are now working to understand the ways that widespread, chronic shipping noise affects marine creatures’ behavior, foraging success, and stress levels.  Long-term deployment of hydrophones, sound models that extrapolate from shipping data, and slow-but-steady improvements in our knowledge of the hearing ranges and population densities of particular species have all combined to open exciting new avenues for research that can inform policy decisions in the years to come.

Using these new measurement and modeling techniques, researchers can quantify the “acoustic quality” of marine habitats.  This starts with charting the extent of shipping noise, while also considering the different auditory ranges of various species of interest.  Next, researchers map where animals tends to congregate in various seasons, to identify areas that are especially important to each species.

Of particular importance is identifying areas that have, so far, remained relatively free of shipping noise.  If at all possible, we’ll want to avoid extending the human noise footprint into these increasingly rare acoustic havens.  A research team that’s been active on Canada’s southwest coast over the past few years has been at the forefront of these techniques, and has just published a new paper that introduces the concept of “opportunity sites”—areas used by each species that are still relatively quiet, and so have high long-term conservation value.

“We tend to focus on problems in conservation biology. This was a fun study to work on, because we looked for opportunities to protect species by working with existing patterns in noise and animal distribution, and found that British Colombia offers many important habitat for whales that are still quiet,” said Dr. Rob Williams, lead author of the study. “If we think of quiet, wild oceans as a natural resource, we are lucky that Canada is blessed with globally rare pockets of acoustic wilderness. It makes sense to talk about protecting acoustic sanctuaries before we lose them.”

Below left: population density of harbor porpoise in coastal waters of British Columbia; below center: ship noise, weighted to harbor porpoise hearing; below right: opportunity sites to preserve high-quality acoustic habitat for harbor porpoises. Red indicates “highest”, blue “lowest” on all maps.

A WEB  B WEB  c WEB

These new opportunity maps make it painfully obvious how little of each species’ habitat is free of excessive shipping noise. In the example above, harbor porpoises can only find high quality acoustic habitat in a couple of small areas.  Without some concerted effort to protect these areas, they will continue to shrink.

While recognizing that many areas of critical habitat are already too loud (in particular, the entire Seattle/Vancouver region), the authors acknowledge that reducing existing noise is difficult—limiting shipping, or reducing the noise made by boats, has social and economic costs that can be hard to accept.  By contrast, the areas they’ve identified merely need to be maintained in close to their current acoustic condition, which will be far easier to accomplish.  As the authors note:

In our professional opinion, if two places are equally important to whales, with one being noisy and the other being quiet, it would be helpful to identify those areas and present that information to decision-makers. The noisy area may require mitigation, whereas the quiet area may make a more attractive or convenient candidate for critical habitat protection, either because it represents higher quality habitat to the animals or because it imposes lower economic costs to society to mitigate anthropogenic threats.

This may not mean excluding new activities from these regions, because, again in the authors’ words, “a particular marine environment could be dominated by anthropogenic underwater noise that is perceived as being loud to one species, but quiet to another.” Indeed, the opportunity maps differ for each species (though that area on the eastern side of the large island of Haida Gwaii recurs in most).  So, we will need to pay close attention to what species are present, how well they’ll hear the new noise sources, and the ways they may respond.

Generally, large ship noise is far more audible for baleen whales (humpback, fin, etc.) than for smaller toothed whales (dolphins, orca), which vocalize and hear at higher frequencies. That’s not to say that the smaller whales don’t hear big ships; they often do, and in many cases, they respond at a lower sound level than larger whales, so even if the ships are “fainter” to their ears, their reactions may be similar.

humpback opportunityWhile this paper steers clear of any sort of advocacy tone, and does no more than present the new “opportunity sites” analysis and mapping technique, the waters being studied are at the center of a contentious public policy debate.  The proposed Northern Gateway pipeline from the oil sands region of Alberta would dramatically increase tanker traffic to the existing deep-water port at Kitimat (yellow arrow, left).  Such an increase through Caamano Sound (red arrow, left) would threaten the humpback whale opportunity site (map, left) identified just south of the Sound.  Several years ago, co-author Rob Williams told reporters, “Caamano Sound may be one of the last chances we have on this coastline to protect an acoustically quiet sanctuary for whales. … We don’t exactly know why this area is so rich, but there are some long, narrow channels that serve as bottlenecks for food, making it easier for whales to feed.” A consortium of environmental organizations is currently challenging the Canadian government’s approval of the pipeline, claiming that the approval did not take into account the humpback recovery plan, identifying Hecate Strait (the larger area between the mainland and the large offshore island) as a critical humpback feeding ground.  The pipeline is being challenged on several fronts (including strong opposition from B.C. First Nations communities); considering acoustic habitat protection, limiting new ship traffic during the times of year when the current opportunity sites are being heavily used would seem to be the least we can do.

 

 

Listening to the sounds of a phantom oil field

Effects of Noise on Wildlife, Science No Comments »

080615TB_NoiseWEBSomewhere out in the vast expanse of the Snake River plain this summer, the sounds of a natural gas compressor floats across the sage-strewn landscape.  Look around though, and you won’t see any wellpads or boxy compressor stations.  If your eyes are sharp, you may spy the source of the intrusive sound: a large solar-powered speaker.

It’s part of phase two of a study looking into the effects of human noises on wildlife.  Phase one was the “Phantom Road,” a half-mile string of speakers set up in an Idaho forest, which found that traffic noise caused notable changes in the makeup of the nearby bird population.  About half of the species in the area showed some avoidance of the sounds, with two species nearly absent when the speakers were on (one species preferred the noisy periods).  This study was summarized in AEI’s 2014 poster that summarized research on “The Effects of Chronic Moderate Noise on Animal Behavior and Distribution.”

By using speakers, rather than studying actual roads or oil development sites, researchers are able to separate out the effect of noise from the effects of the physical disruptions of the habitat (the loss of plant cover at the site itself, and access roads to the facilities).

The oil field study, which includes a six sites with speakers and six control sites with no added noise, is looking at effects of the noise on birds, bats, and insects.  And, they’ve brought birders out to their sites to see how oil development may affect their ability to hear birds and enjoy the landscape.  Some of the birders were surprised at how much even distant compressor noise interfered.  “The whole thing has been ear-opening, shall we say,” said Jim Lyons of Boise. “To be part of this is very stimulating, very interesting. I am going to think about it from now on.”

Acoustic monitoring increases in US northeast waters

Bioacoustics, Ocean, Science No Comments »

Several independent research projects that are listening to fish and whales in waters along the coast from New Jersey to Maine have joined together as the NorthEast Passive Acoustic sensing Network (NEPAN).  This map shows the location of the various research programs that will be taking place through 2017:

NEPAN_labels_MT

The NEPAN website offers a good overview of the aims of each of these projects.  Of particular interest is a real-time buoy deployed near a Coast Guard gunnery range off Rhode Island, which will help the Coast Guard to avoid initiating live-explosive exercises when any of the few remaining critically endangered North Atlantic right whales are in the area.  The array of long-term recorders along the edge of the continental shelf will also provide some key new information on seasonal presence of many whale species, as well as helping clarify how far offshore they tend to be during migration (again, especially crucial information for the right whales).

Navy, NMFS slammed by judge over training permits

News, Ocean, Science, Sonar No Comments »

The Navy and NMFS suffered a stunning legal defeat over the latest 5-year EIS and permits governing training exercises in Hawaii, California, and waters in between.  In marked contrast to other recent court rulings, which found fault with some procedural issues but largely backed the Navy and NMFS’s collaborative planning results (see detailed AEI summaries of 2014 rulings on the Pacific Northwest training range and global low-frequency sonar permits), US District Court Judge Susan Moki Olway vehemently rejected several key aspects of the permitting for the Hawaii-Southern California Training and Testing (“HSTT”) Study Area. (Note: while sonar has been the focus of most public concern, these trainings also involve live ammunition, explosions, etc., that are responsible for most of the anticipated behavioral disruptions and nearly all the injuries and deaths.)

120511bighsttregionWEB

The primary target of the legal challenges was the National Marine Fisheries Service (NMFS), which issues the permits (Letters of Authorization) and the Biological Opinion that underly the permit conditions and take numbers. The Navy’s Environmental Impact Statement (EIS) was not directly challenged (a Supreme Court ruling has left the Navy with broad discretion and little room for legal challenges), but the EIS is accepted as sufficient by NMFS, and Judge Olway made a point of chastising NMFS for being too quick to simply adopt much of the Navy’s reasoning about both the impact on animal populations and the practicality (or lack thereof) of keeping training activities out of some areas.

The ruling seems to call for a fairly substantial revision of the EIS, the Biological Opinion, and the take numbers authorized by the permits; still, it may be likely that these documents can indeed be revised to fix the shortcomings identified by the Court, without substantially reducing the training activities being planned.  Also, an appeal to a higher court is possible, or likely, given the broad implications of the ruling.

UPDATE, September 2015: As it turned out, the Navy and NRDC negotiated a settlement, adding a few exclusion zones for the duration of the current five-year authorization. It remains to be seen how the larger issues raised by the ruling may affect the next round of Navy EIS and NMFS authorizations.

Nonetheless, this ruling is the most fundamental challenge to the current Navy and NMFS planning process since the original lawsuits that helped trigger the Navy to begin producing EISs and NMFS to issue permits.  Among the key issues that were successfully challenged:

Read the rest of this entry »

AEI poster for the Wind and Wildlife Research Meeting

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

Next week in Denver, the American Wind and Wildlife Institute and National Wind Coordinating Collaborative will be hosting their 10th Wind and Wildlife Research Meeting.  For the second time, I put together a research summary poster for the event (here’s the first one).  Most of the presentations at this meeting are focused on direct mortality (birds or bats hitting turbines) and habitat-disruption issues; in recent years, concerns about the sage grouse on the northern plains and the Fish and Wildlife Service’s new eagle permit process have also been hot topics.

As usual, my contribution is one of the few looking at the effects of the moderate noise around wind farms.  It offers an overview of the current state of our understanding of the ways chronic moderate noise can change animal behavior and communication, shift population structure, and increase physiological stress.  It includes data from studies on sage grouse, frogs, mammals, and songbirds, as well as discussion of other considerations, uncertainties, and future research needs.

Effects of chronic moderate noise on animal behavior and distribution

More evidence that ship noise can have dramatic impacts on non-cetacean sea life

Animal Communication, Bioacoustics, Human impacts, Ocean, Science, shipping No Comments »

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

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

eelsWEB

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

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

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

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

Read the rest of this entry »

Ocean observatory audio streams: navies nix bits of data that scientists savor

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

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

NEPTUNE VENUS

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

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

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

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

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

Fantastic ocean noise presentation from Leila Hatch of NOAA

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

Earlier this month, Leila Hatch, one of NOAA’s leading experts on ocean acoustics and a long-time researcher in and around Stellwagen Bank National Marine Sanctuary, presented an hour-long talk on ocean noise.  It’s been archived on the Open Channels website, and is available for streaming and download on Vimeo.  

It’s by far the best introduction I’ve seen to this wide-ranging topic, including some basic information on ocean noise, along with a good summary of ongoing work at NOAA to map ocean noise and to learn more about how shipping noise, in particular, can impinge on whales’ communication space. Highly recommended!!

Listening to our Sanctuaries: Understanding and Reducing the Impacts of Underwater Noise in Marine Protected Areas from OpenChannels on Vimeo.

New research listening in on whales as they hunt

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

Two new research projects are taking important next steps in understanding the importance of sound, and clear listening, to whales.  In recent years, ocean bioacousticians have introduced the concept of “communication space” or “effective listening area” to scientific parlance. This began as a conceptual framework for thinking about how human sounds (especially shipping noise) may reduce the area across which whales can hear and be heard; researchers are now digging into more of the details of how this may actually impact animals in their daily lives.  After several recent studies that focused on whales hearing each other (and so framing their results in terms of “communication space”), two new studies are gathering initial data that may inform considerations of the ways whales listen for the presence of prey.  While whales can, and do, change some of their communication signals or patterns in order to be better heard by other whales in noisy conditions, there’s no such compensation that can help a whale hear their prey through a wash of noise.

Both of the new studies are taking advantage of acoustic tags to allow scientists to listen in on whales as they are foraging.  These tags are about the size of a large cell phone, and are attached to the animals with suction cups; they remain attached for up to 16 hours, then float to the surface for retrieval.  While attached, they record all sounds the whales hear and make, as well as logging swimming speed and dive orientation.

Orca attack seal near shoreWEBOne study is further along, having just published its first results, which confirm that orcas can hunt in near-total darkness, apparently relying only on zeroing in on their prey (in this case, seals) by listening for their mating calls.  These orcas do not use echolocation while hunting (other orcas, hunting salmon, do echolocate); they hunt in stealth mode, then dispatch their victims with a swat of their tail flukes.  This initial evidence is not totally conclusive; followup studies will confirm that orcas do, indeed, seek out seal sounds.  And, this sort of study is but the first step toward quantifying the extent to which ocean noise may limit the range over which orcas can hear seals while hunting.

The second study will begin next year, and will be putting the acoustic tags on large whales, to see whether they’re using acoustic cues to help locate aggregations of fish.  According to Dr. Rochelle Constantine:

“Acoustics within the marine space are really important for many organisms, yet we don’t know a lot about how it drives organisms’ interaction with their environment. We’re interested in looking at how the larger animals use the acoustic environment, particularly for food, and testing the hypothesis that food patches have specific sound signatures.”

Lunging Brydes Wha 300WEBShe said the sound of “bait balls” of prey, such as schools of fish, could be greatly heightened when a feeding frenzy involving larger fish and seabirds broke out.  Dr Constantine said whales had been observed swimming rapidly from over a kilometre away toward prey aggregations, “so we’re very interested to find out if there are specific acoustic cues they home in on”.

This study plans to play recorded sounds of fish aggregations and other prey sounds while the tags on the whales.  (I suppose if they happen to get lucky and have an actual feeding event occur while tags are attached, that will be a bonus, but the playback will serve as a reliable testing condition.)  This team is also interested in using acoustic tags on large fish and sharks, to explore the ways they may rely on listening, as well.

NPS to study how soundscape quality affects park visitors

Effects of Noise on Wildlife, Human impacts, News, Science, Wildlands No Comments »

Equipment GRSA squareWEBFor over a decade, the National Park Service has been on the forefront of public lands agencies in addressing the role of sound and noise on both wildlife and park visitors.  NPS’s Natural Sounds and Night Skies Division has catalyzed baseline acoustic monitoring in seventeen parks, and carried out groundbreaking research on the effects of noise on wildlife.

Now, NPS is planning a national survey on how the quality of park soundscapes affects visitation at national parks, and the economies of gateway communities.  An August 9 Federal Register notice is seeking public comment on the value such a study, with the hope of doing a small-scale pilot survey in 2014, in preparation for the full study in 2015.  The last time NPS sought comments on a similar proposal, they received no public comments and did not proceed.  Now’s the time to chime in, as comments close on September 9.  (Go here, and be sure to note the topics they want input on, and send your comments to both email addresses listed.)

“In addition to parsing out the extent to which visitors value being able to hear the sounds of nature, the study will provide other useful information such as how acoustic conditions affect the likelihood of repeat visitation to national parks,” the agency said in a summary of the survey.  

At a daylong public outreach workshop on Noise in Communities and Natural Areas earlier this month (which I was fortunate to attend), Kurt Fristrup and Frank Turina outlined some of the ongoing soundscape work in parks. Turina described a pilot project at Rocky Mountain National park that uses flashing signs to notify motorcyclists of the noise levels of their bikes (much like instantaneous speed-tracking signs), with the goal of encouraging riders to moderate their noise while enjoying park roads.  Fristrup shared some fascinating research revealing that hikers on the Hermit Trail at the Grand Canyon nearly universally reported lower levels of overall satisfaction with their visitor experience after overflight helicopters start flying each morning. Hikers were asked to rate their experience on a 7-point scale, from Very Pleasant to Very Unpleasant.  Prior to the start of flights, Very Pleasant (7) received was the most chosen rating, with no one choosing the lower Unpleasant to Very Unpleasant ratings of 3, 2, or 1.  After flights began, the graph of responses shifted distinctly toward the less pleasant ratings: the number of people rating their experience at 7 dropped dramatically and the lower ratings, all the way down to 1, joined the mix.

Crabs affected by shipping noise, too

Effects of Noise on Wildlife, Science, shipping 1 Comment »

CrabWEBAdd crabs, and perhaps by extension other crustaceans, to the list of animals negatively affected by shipping noise in the world’s oceans.  

A new study has found that ship noise markedly changes some important crab behaviors:

Working with the same common shore crabs that children delight in catching on crablines in UK harbours, the team found ecologically-critical effects of ship noise-playback on behaviour.

Matt Wale from the University of Bristol said: “Crabs feeding on mussels were often distracted when ship noise was playing compared to quiet harbour recordings. Furthermore, crabs took longer to retreat to shelter after simulated attacks in noisy treatments, and if turned upside-down they flipped back far quicker in noisy conditions rather than turning slowly to avoid attracting attention of potential predators.”

Dr Steve Simpson from Biosciences at the University of Exeter said: “We have already found that ship noise raises the metabolic rate and energetic needs of crabs. If coupled with reduced foraging and worsened responses to predators, this cocktail of impacts may negatively affect growth, fitness, survival and, ultimately, harvested populations and whole ecosystems.”

Cetaceans (whales and dolphins), fish, and larvae of reef creatures have previously been found to respond to shipping noise in ways that can increase energy expenditures and stress levels; this is the first clear indication that crustaceans are also negatively affected.

SOCAL begins 2013 behavioral response study

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

The 2013 field season of the 5-year Southern California Behavioral Response study is underway now.  This research applies suction-cup tags to whales, which track the whales’ movements (dive patterns, speed, direction, etc.) while also recording the sounds the whales are hearing, including sounds of mid-frequency active sonar played underwater by the researchers under carefully controlled conditions.  Earlier years’ results have begun to quantify the level of sound that can spur behavioral reactions in several species of whales, including the beaked whales that have appeared to be more sensitive to sonar sound, resulting in several stranding incidents over the past fifteen years.  Most recently, two new papers reported that both blue whales and Cuvier’s beaked whales seem to avoid sonar sounds, and at times stop feeding, at sound levels below most current regulatory thresholds.

SOCAL researchers will be posting updates from the field here.

Behavioral Response Study – Tagging Beaked Whales from Brandon Southall on Vimeo.

Blue, beaked whales stop foraging when exposed to sonar?

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

AEI lay summary of:
Goldbogen JA, Southall BL, DeRuiter SL, Calambokidis J, Friedlaender AS, Hazen EL, Falcone EA, Schorr GS, Douglas A, Moretti DJ, Kyburg C, McKenna MF, Tyack PL. 2013 Blue whales respond to simulated mid-frequency military sonar. Proc R Soc B 280: 20130657. http://dx.doi.org/10.1098/rspb.2013.0657 (download here)
and
DeRuiter SL, Southall BL, Calambokidis J, Zimmer WMX, Sadykova D, Falcone EA, Friedlaender AS, Joseph JE, Moretti D, Schorr GS, Thomas L, Tyack PL. 2013 First direct measurements of behavioural responses by Cuvier’s beaked whales to mid-frequency active sonar. Biol Lett 9: 20130223. http://dx.doi.org/10.1098/rsbl.2013.0223 (download here

Results from studies off Southern California have quantified for the first time the reactions of Blue whales and Cuvier’s beaked whales to simulations of naval mid-frequency active sonar.  In both cases, scientists found that whales tended to move away from sonar signals, and appeared to suspend feeding activity for an hour or more at times.   

The Cuvier’s beaked whale results marked the first time this species had successfully been monitored during a controlled exposure to sound while wearing a temporary suction-cup “D-TAG” that allows researchers to track animal dive and movement patterns while also recording the sound level of the sonar signal that the animal is hearing. As with similar experiments done on other species of beaked whale, the two whales tagged in this study changed their normal dive patterns, paused or stopped echolocating for food, and waited longer at the surface after the sonar sound ended before they began diving normally again.  The pause in foraging lasted for 6 hours in one whale, and at least 90 minutes for the other.  

The whales’ behavior was changed at sound levels (89-127dB) that are far below the levels typically considered problematic by regulators (typically 160-180dB; though some Navy EIS’s use 120dB for beaked whales, because of their previously observed noise sensitivity).
CORRECTION, 1/31/14: The current round of Navy EISs and NOAA permits consider exposures down to 120dB in their analysis of behavioral “takes” for all species.

Researchers concluded that “The observed responses included vigorous swimming and extended time without echolocation-based foraging, imposing a net energetic cost that (if repeated) could reduce individual fitness.”  While they did not see rapid ascents from dives that would support an early theory that some beaked whales may suffer tissue damage similar to what human divers experience as “the bends,” they suggest that the disruption of normal dive and surface-resting patterns could affect the animals’ dive metabolism in ways we don’t yet understand.  Also of interest in this study was an unexpected period during which a tagged animal was exposed to sound from a distant (over 100km) naval exercise; in that case, the animal showed no response, though received levels were similar (78-106dB); researchers suggest that the animals could tell that these signals were much more distant than the test signals, which were under 10km away.

The Blue whale results were a bit more ambiguous, as there was significant individual variation among the 12 whales that were tagged and exposed to sonar-like sounds. Some whales were foraging at the surface, some were deep-diving feeding, and some were diving but not feeding.  Whales at the surface showed little response, while diving animals reacted more strongly, including some instances of clear avoidance (i.e., swimming away, or “horizontal displacement” in the research parlance).  

While the Blue whale results were not as uniform as the Cuvier’s results, this is the first time that blue whales have been studied to see how they respond to mid-frequency sonar, and the researchers consider even the modest effects to be significant, especially since blue whale populations are not rebounding similarly to other large whales.  As the  researchers conclude: “our results suggest that frequent exposures to mid-frequency anthropogenic sounds may pose significant risks to the recovery rates of endangered blue whale populations, which unlike other baleen whale populations (i.e. humpback, grey and fin whales), have not shown signs of recovery off the western coast of North America in the last 20 years.” 

Using a complex set of measurements of 54 behavioral metrics (including such factors as orientation angle to the sound, change in pitch or angle of descent or ascent, and the number of lunges per dive), and applying a statistical formula that resulted in the average “response” ratings on the left axis of the charts below, researchers found statistically significant changes three key areas.  The chart below shows the clear, yet subtle, changes in dive patterns (a), body orientation (b), and horizontal displacement (c), especially among the deep-feeding animals:

CEE blue whales500

Researchers note that the whale that showed the largest reaction stopped feeding as soon as hearing the sonar signal and swam away from the sound; it did not begin feeding again for an hour, during which time it would have eaten over a ton of krill, which is about the minimum amount a whale needs per day (i.e., it’s a metabolically significant loss).  

The responses noted occurred at average peak received levels of 130-160dB, again, notably lower than most regulatory thresholds for behavioral responses, which range from 160-180dB. CORRECTION, 1/31/14: The current round of Navy EISs and NOAA permits consider exposures down to 120dB in their analysis of behavioral “takes” for all species; in fact, the bulk of behavioral responses for “low frequency cetaceans,” such as blue whales, is expected at exposures similar to those here. There was a large range of response ratings for both dive patterns and body orientation (the chart above shows the average among all individuals); the avoidance responses showed a more modest range of variability, except for the one extreme response noted above.  Overall, the results confirm previously-observed importance of behavioral context: “Since some of the most pronounced responses occurred near the onset of exposure but other, higher level exposures provoked no response, the data suggest that the use of received level alone in predicting responses may be problematic and that a more complex dose – response function that considers behavioural contexts will be more appropriate. Management decisions regarding baleen whales and military sonar should consider the likely contexts of exposure and the foraging ecology of animals in predicting responses and planning operations in order to minimize adverse effects.”

 

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.  

NWTC

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