Print Article

·
—Calvin Luther Martin, PhD

If you’re a giant squid in the vicinity of a wind turbine being sunk into the ocean floor—you’re in serious trouble.  So suggests a research paper about to be published by the Ecological Society of America.

A team of bio-acousticians led by Dr. Michel André of the Technical University of Catalonia (Barcelona, Spain) is publishing the results of a study of giant squid wherein they duplicated the man-made undersea noise/vibration commonly experienced by marine life—acoustic pollution from naval exercises, sonar, seismic surveys, oil & gas exploration and extraction, pile driving and blasting, and a host of other industrial and shipping intrusions, including (in the authors’ words) “the operation of windmills” (M André et al, p. 5).

What they discovered surprised them: The delicate “vestibular” organs of squid and cuttlefish (together called cephalopods) are irreparably and dramatically destroyed by, in their words, “relatively low levels” of low-frequency sound (M André et al, p. 4).

Up till now, only high levels of low-frequency sound have been shown to damage marine life “hearing” structures.

Which brings us to the second big surprise for André and his team.  The neurological structures being destroyed are not used for hearing; they are motion, position, and balance detectors, with their attendant behavioral responses—as in “fight or flight” or “panic” response.

(Note to reader:  Does this sound familiar?)

In humans, these would be the vestibular organs of the inner ear:  saccule, utricle, and semi-circular canals.  In marine invertebrates like squid, however, they’re called “statocysts,” and they are evolutionarily similar to your and my vestibular organs.

Statocysts are fluid-filled, balloon-like structures that help these invertebrates maintain balance and position—similar to the vestibular system of mammals. The scientists’ results confirmed that statocysts indeed play a role in perceiving low-frequency sound in cephalopods. . . . “For example, we can predict that, since the statocyst is responsible for balance and spatial orientation, noise-induced damage to this structure would likely affect the cephalopod’s ability to hunt, evade predators and even reproduce; in other words, this would not be compatible with life.”  (From the Press Release by the Ecological Society of America, 4-11-11.)

Lateral view of interior of an Octopus statocyst (M André et al. 2011)

In other words, just as Dr. Alec Salt has demonstrated for humans, so for marine invertebrates:  “Even if you can’t hear the noise, it can indeed hurt you!”  (In the authors’ words, “The presence of lesions in the statocysts clearly points to the involvement of these structures in sound reception and perception,” M André et al, p. 4.)

Let it be clearly understood that these researchers were not duplicating noise/vibration from operating wind turbines, which, presumably, would be at lower sound pressure levels than André et al. used, although far more protracted and widespread.  (André’s team exposed squid to low-frequency bursts of sound for only 2 hours.)  What André duplicated was more akin to the blasting (dynamite) during the building of turbines:  a received sound pressure level of 157±5 dB in reference to 1 microPascal (μPa), peaking at 175 dB in reference to 1 μPa.

At the moment, nobody knows for certain what impact wind turbine low-frequency noise has on marine life, be it cephalopods (squid), whales (which include dolphins), fish, crustaceans, mollusks—or mermaids.  The same of course holds true for turbines installed in freshwater lakes.  (Nina Pierpont has conjectured—let’s call it an “educated” conjecture—that the effects are not good.  Click here and here.)

Still, it is not premature to ask, Can sea and aquatic life get “marine & aquatic” Wind Turbine Syndrome? Dr. Michel André and his colleagues have demonstrated the answer is, “Hmm, the likelihood is high.”

If the relatively low levels and short exposure applied in this study can induce severe acoustic trauma in cephalopods, the effects of similar noise sources [such as wind turbine arrays] on these species in natural conditions over longer time periods may be considerable.  Because invertebrates are clearly sensitive to noise associated with human activities, is noise, like other forms of pollution, capable of affecting the entire web of ocean life?  (M André et al, p. 5)

And that’s as far as we can take the research at the moment.

In any case, if you happened to be the unlucky squid exposed to Dr. André’s sound pressures, this is what your “vestibular” organs (statocysts) now look like.  (You don’t need to be a trained biologist to get the picture that something horrible has happened here.)

Immediately after exposure, damage was observed in the macula statica princeps and on the crista sensory epithelia. Kinocilia within hair cells were either missing or were bent or flaccid. A number of hair cells showed protruding apical poles and ruptured plasma membranes, most probably resulting from the extrusion of cytoplasmic material.

Hair cells were also partially ejected from the sensory epithelium, and spherical holes corresponding to missing hair cells were visible in the epithelium.

The cytoplasmic content of the damaged hair cells showed obvious changes, including the presence of numerous vacuoles and electron dense inclusions not seen in the control animals.

Underneath the hair cells, afferent nerve fibers were swollen and showed mitochondrial damage or complete degeneration. In some specimens, large holes in the sensory epithelium were also observed.

The appearance of these lesions became gradually more pronounced in individuals after 12, 24, 48, 72, and 96 hours.

Part of the cellular body of the damaged cells was extruded above the sensory epithelium into the statocyst cavity.

The most pronounced lesions were visible in specimens observed 96 hours after sound exposure. In these individuals, the sensory epithelium was severely damaged, with very few hair cells remaining; most of the hair cells had been extruded. The epithelium only presented supporting cells, creating a holed mosaic, where residual hair cells showed either very few bent, flaccid, or fused kinocilia, or none at all.  (M André et al, p. 3)

“Holed mosaic”?  Think “Swiss cheese.”

“The almost complete extrusion of the hair cells, as well as the holes present in the epithelium,” observe the authors, “are clear signs that the noise impact was acute and that hair-cell damage was immediate. In mammals and some fish species, such dramatic damage has only been observed after exposure to extremely high-intensity sound; low- to mid-intensity acoustic stimuli have to date not been known to lead to any obvious mechanical damage to the sensory epithelia” (M André et al, p. 3).

They go on:

In addition to hair-cell damage, the experimental animals showed swelling of afferent dendrites and neuronal degeneration, confirming that the neurons were also affected by the acoustic trauma.

In mammalian cochlea, swelling of afferent dendrites occurs during exposure to loud noise, and is the result of an excessive release of glutamate by the inner hair cell.  Under normal conditions, glutamate acts as a neurotransmitter among the inner hair cells, but has excito-toxic (toxicity to nerve cells and processes resulting from excess exposure to a neuro-transmitter) effects when secreted in large quantities.

The observed impacts on the stato-acoustic organs of the noise-exposed cephalopods suggests the occurrence of an excito-toxic process due to an excess of glutamate, which has also been identified as a neuro-transmitter in cephalopods.  (M André et al, p. 4)

In summary—again, I’ll let the authors speak for themselves:  “We present the first morphological and ultra-structural evidence of massive acoustic trauma, not compatible with life, in four cephalopod species subjected to low-frequency controlled-exposure experiments. Exposure to low-frequency sounds resulted in permanent and substantial alterations of the sensory hair cells of the statocysts, the structures responsible for the animals’ sense of balance and position.” (M André et al, Abstract, emphasis added)

“For the first time we are seeing the effects of noise pollution on species that apparently have no use for sound.  We were shocked by the magnitude of the trauma” (from UPI.com, 4-11-11).

Let’s rephrase Dr. André’s statement, to appreciate its full impact:  “For the first time we are seeing the effects of relatively low intensity low-frequency industrial noise on organs that are not used for hearing, but for motion, position, and balance sense—and we were shocked by the magnitude of the trauma!”

To all you human guinea pigs going nuts from Wind Turbine Syndrome, does this sound eerily familiar?  (Do you need the number for a good lawyer?)