Darlene Ketten - Academia.edu (original) (raw)
Papers by Darlene Ketten
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Journal of the Acoustical Society of America, Nov 1, 2001
In humans, hearing is lost with age, trauma, and disease. It is likely marine mammals sustain sim... more In humans, hearing is lost with age, trauma, and disease. It is likely marine mammals sustain similar damage, but currently we have little direct data on their incidence of hearing loss. Marine mammals represent an interesting hearing paradox. Because their ears are fundamentally the same as human ears, we expect they have similar loss mechanisms, but they evolved in a high noise environment and have adaptations that deter pressure-induced trauma. These adaptations may equate to ‘‘tougher’’ ears. This paper summarizes evidence from computerized tomography and histologic exams for grades and etiology of hearing loss in captive and wild marine mammals. The data indicate dolphins have hypertrophic inner ears elements (i.e., stria vascularis, spiral ligament, basement membrane) that imply greater robustness and faster recovery times than pinniped ears. However, older dolphins and seals alike develop degenerative pathologies, including neural, hair cell, support cell, and bony loss that parallel presbycusic changes in older humans and are consistent with substantial hearing loss. The results suggest whales and dolphins may be less subject to temporary threshold shifts than pinnipeds, but both are equally liable to hearing loss from severe trauma or age. [Work supported by ONR and NOAA Fisheries.]
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Journal of the Acoustical Society of America, Aug 1, 2020
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![Research paper thumbnail of Erratum: Evaluation of kurtosis-corrected sound exposure level as a metric for predicting onset of hearing threshold shifts in harbor porpoises (<i>Phocoena phocoena</i>) [J. Acoust. Soc. Am. <b>152</b>, 295–301 (2022)]](https://attachments.academia-assets.com/117828923/thumbnails/1.jpg)
](Journal of the Acoustical Society of America, Dec 1, 2022
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Aquatic Mammals, Dec 1, 2015
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J. Cetacean Res. Manage.
This review considers the effect of anthropogenic sound on beaked whales2. Two major conclusions ... more This review considers the effect of anthropogenic sound on beaked whales2. Two major conclusions are presented: (1) gas-bubble disease, induced in supersaturated tissue by a behavioural response to acoustic exposure, is a plausible pathologic mechanism for the morbidity and mortality seen in cetaceans associated with sonar exposure and merits further investigation; and (2) current monitoring and mitigation methods for beaked whales are ineffective for detecting these animals and protecting them from adverse sound exposure. In addition, four major research priorities, needed to address information gaps on the impacts of sound on beaked whales, are identified: (1) controlled exposure experiments to assess beaked whale responses to known sound stimuli; (2) investigation of physiology, anatomy, pathobiology and behaviour of beaked whales; (3) assessment of baseline diving behaviour and physiology of beaked whales; and (4) a retrospective review of beaked whale strandings.
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Bioinspiration & Biomimetics
Rotational behaviour has been observed when dolphins track or detect targets, however, its role i... more Rotational behaviour has been observed when dolphins track or detect targets, however, its role in echolocation is unknown. We used computed tomography data of one live and one recently deceased bottlenose dolphin, together with measurements of the acoustic properties of head tissues, to perform acoustic property reconstruction. The anatomical configuration and acoustic properties of the main forehead structures between the live and deceased dolphins were compared. Finite element analysis (FEA) was applied to simulate the generation and propagation of echolocation clicks, to compute their waveforms and spectra in both near- and far-fields, and to derive echolocation beam patterns. Modelling results from both the live and deceased dolphins were in good agreement with click recordings from other, live, echolocating individuals. FEA was also used to estimate the acoustic scene experienced by a dolphin rotating 180° about its longitudinal axis to detect fish in the far-field at elevatio...
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The Journal of the Acoustical Society of America
Application of a kurtosis correction to frequency-weighted sound exposure level (SEL) improved pr... more Application of a kurtosis correction to frequency-weighted sound exposure level (SEL) improved predictions of risk of hearing damage in humans and terrestrial mammals for sound exposures with different degrees of impulsiveness. To assess whether kurtosis corrections may lead to improved predictions for marine mammals, corrections were applied to temporary threshold shift (TTS) growth measurements for harbor porpoises (Phocoena phocoena) exposed to different sounds. Kurtosis-corrected frequency-weighted SEL predicted accurately the growth of low levels of TTS (TTS1-4 < 10 dB) for intermittent sounds with short (1–13 s) silence intervals but was not consistent with frequency-weighted SEL data for continuous sound exposures.
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Polarforschung, 2004
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Journal of Morphology, 2022
In all mammals, the superior olivary complex (SOC) comprises a group of auditory brainstem nuclei... more In all mammals, the superior olivary complex (SOC) comprises a group of auditory brainstem nuclei that are important for sound localization. Its principal nuclei, the lateral superior olive (LSO) and the medial superior olive (MSO) process interaural time and intensity differences, which are the main cues for sound localization in the horizontal plane. Toothed whales (odontocetes) rely heavily on hearing and echolocation for foraging, orientation, and communication and localize sound with great acuity. The investigation of the SOC in odontocetes provides insight into adaptations to underwater hearing and echolocation. However, quantitative anatomical data for odontocetes are currently lacking. We quantified the volume, total neuron number, and neuron density of the LSO of six common dolphins (Delphinus delphis) using the Cavalieri principle and the unbiased stereology optical fractionator. Our results show that the LSO in D. delphis has a volume of 150 + (SD = 27) mm3, which is on a...
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The Anatomical Record, 2022
Cetacean behavior and life history imply a role for somatosensory detection of critical signals u... more Cetacean behavior and life history imply a role for somatosensory detection of critical signals unique to their marine environment. As the sensory anatomy of cetacean glabrous skin has not been fully explored, skin biopsy samples of the flank skin of humpback whales were prepared for general histological and immunohistochemical (IHC) analyses of innervation in this study. Histology revealed an exceptionally thick epidermis interdigitated by numerous, closely spaced long, thin diameter penicillate dermal papillae (PDP). The dermis had a stratified organization including a deep neural plexus (DNP) stratum intermingled with small arteries that was the source of intermingled nerves and arterioles forming a more superficial subepidermal neural plexus (SNP) stratum. The patterns of nerves branching through the DNP and SNP that distribute extensive innervation to arteries and arterioles and to the upper dermis and PDP provide a dense innervation associated through the whole epidermis. Some NF‐H+ fibers terminated at the base of the epidermis and as encapsulated endings in dermal papillae similar to Merkel innervation and encapsulated endings seen in terrestrial mammals. However, unlike in all mammalian species assessed to date, an unusual acellular gap was present between the perineural sheaths and the central core of axons in all the cutaneous nerves perhaps as mechanism to prevent high hydrostatic pressure from compressing and interfering with axonal conductance. Altogether the whale skin has an exceptionally dense low‐threshold mechanosensory system innervation most likely adapted for sensing hydrodynamic stimuli, as well as nerves that can likely withstand high pressure experienced during deep dives.
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Aquatic Mammals, 2018
© 2018 European Association for Aquatic Mammals. This erratum concerns Figure 9 of the original a... more © 2018 European Association for Aquatic Mammals. This erratum concerns Figure 9 of the original article in which the line delimiting two effect types ("Permanent hearing loss increasingly likely" and "Permanent hearing loss very likely") was misplaced. This error, which has now been corrected, affects neither the main text nor the conclusion of the study. The authors apologize for the error
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Scientific Reports, 2021
Dolphins use their biosonar to discriminate objects with different features through the returning... more Dolphins use their biosonar to discriminate objects with different features through the returning echoes. Cross-modal matching experiments were conducted with a resident bottlenose dolphin (Tursiops aduncus). Four types of objects composed of different materials (water-filled PVC pipes, air-filled PVC pipes, foam ball arrays, and PVC pipes wrapped in closed-cell foam) were used in the experiments, respectively. The size and position of the objects remained the same in each case. The data collected in the experiment showed that the dolphin’s matching accuracy was significantly different across the cases. To gain insight into the underlying mechanism in the experiments, we used finite element methods to construct two-dimensional target detection models of an echolocating dolphin in the vertical plane, based on computed tomography scan data. The acoustic processes of the click’s interaction with the objects and the surrounding media in the four cases were simulated and compared. The si...
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In this study, we compared the fluke geometries of male and female narwhals, which may be associa... more In this study, we compared the fluke geometries of male and female narwhals, which may be associated with hydrodynamic effects. Computerized tomography (CT) scanning was used to obtain data for analyses of the three-dimensional geometry of the flukes. The flukes from four narwhals (two males and two females) were obtained from aboriginal hunters in the vicinity of Broughton Island, Canada. The body lengths of the animals ranged from 2.98 to 3.60 m. Both males had erupted, upper left tusks. Standard body measurements were made including the span of the fluke (i.e., linear distance between fluke tips).
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Marine Mammal Science, 2020
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Aquatic Mammals, 2019
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Aquatic Mammals, 2019
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The Journal of the Acoustical Society of America, 2017
Anthropogenic underwater sounds create a potential risk to aquatic organisms. Many regulators req... more Anthropogenic underwater sounds create a potential risk to aquatic organisms. Many regulators require this risk to be assessed before allowing a sound-producing activity to proceed. Regulators typically set allowable exposure criteria for a range of acoustic parameters and require the assessment to address whether a given acoustic metric would exceed its specified threshold. While the value of the threshold is usually clear, the procedure required to calculate the metric is sometimes unspecified or described in insufficient detail, leading to ambiguity in interpretation. Processing and reporting procedures are described that enable intra- and inter-project consistency for processing and reporting of metrics. Quantities derived from sound pressure and sound particle motion are considered, resulting in metrics relevant to fish, aquatic invertebrates, and aquatic mammals. Specific metrics for which procedures are described include transient duration, zero-to-peak quantities, mean-squar...
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Journal of the Acoustical Society of America, Nov 1, 2001
In humans, hearing is lost with age, trauma, and disease. It is likely marine mammals sustain sim... more In humans, hearing is lost with age, trauma, and disease. It is likely marine mammals sustain similar damage, but currently we have little direct data on their incidence of hearing loss. Marine mammals represent an interesting hearing paradox. Because their ears are fundamentally the same as human ears, we expect they have similar loss mechanisms, but they evolved in a high noise environment and have adaptations that deter pressure-induced trauma. These adaptations may equate to ‘‘tougher’’ ears. This paper summarizes evidence from computerized tomography and histologic exams for grades and etiology of hearing loss in captive and wild marine mammals. The data indicate dolphins have hypertrophic inner ears elements (i.e., stria vascularis, spiral ligament, basement membrane) that imply greater robustness and faster recovery times than pinniped ears. However, older dolphins and seals alike develop degenerative pathologies, including neural, hair cell, support cell, and bony loss that parallel presbycusic changes in older humans and are consistent with substantial hearing loss. The results suggest whales and dolphins may be less subject to temporary threshold shifts than pinnipeds, but both are equally liable to hearing loss from severe trauma or age. [Work supported by ONR and NOAA Fisheries.]
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Journal of the Acoustical Society of America, Aug 1, 2020
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Journal of the Acoustical Society of America, Dec 1, 2022
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Aquatic Mammals, Dec 1, 2015
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J. Cetacean Res. Manage.
This review considers the effect of anthropogenic sound on beaked whales2. Two major conclusions ... more This review considers the effect of anthropogenic sound on beaked whales2. Two major conclusions are presented: (1) gas-bubble disease, induced in supersaturated tissue by a behavioural response to acoustic exposure, is a plausible pathologic mechanism for the morbidity and mortality seen in cetaceans associated with sonar exposure and merits further investigation; and (2) current monitoring and mitigation methods for beaked whales are ineffective for detecting these animals and protecting them from adverse sound exposure. In addition, four major research priorities, needed to address information gaps on the impacts of sound on beaked whales, are identified: (1) controlled exposure experiments to assess beaked whale responses to known sound stimuli; (2) investigation of physiology, anatomy, pathobiology and behaviour of beaked whales; (3) assessment of baseline diving behaviour and physiology of beaked whales; and (4) a retrospective review of beaked whale strandings.
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Bioinspiration & Biomimetics
Rotational behaviour has been observed when dolphins track or detect targets, however, its role i... more Rotational behaviour has been observed when dolphins track or detect targets, however, its role in echolocation is unknown. We used computed tomography data of one live and one recently deceased bottlenose dolphin, together with measurements of the acoustic properties of head tissues, to perform acoustic property reconstruction. The anatomical configuration and acoustic properties of the main forehead structures between the live and deceased dolphins were compared. Finite element analysis (FEA) was applied to simulate the generation and propagation of echolocation clicks, to compute their waveforms and spectra in both near- and far-fields, and to derive echolocation beam patterns. Modelling results from both the live and deceased dolphins were in good agreement with click recordings from other, live, echolocating individuals. FEA was also used to estimate the acoustic scene experienced by a dolphin rotating 180° about its longitudinal axis to detect fish in the far-field at elevatio...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
The Journal of the Acoustical Society of America
Application of a kurtosis correction to frequency-weighted sound exposure level (SEL) improved pr... more Application of a kurtosis correction to frequency-weighted sound exposure level (SEL) improved predictions of risk of hearing damage in humans and terrestrial mammals for sound exposures with different degrees of impulsiveness. To assess whether kurtosis corrections may lead to improved predictions for marine mammals, corrections were applied to temporary threshold shift (TTS) growth measurements for harbor porpoises (Phocoena phocoena) exposed to different sounds. Kurtosis-corrected frequency-weighted SEL predicted accurately the growth of low levels of TTS (TTS1-4 < 10 dB) for intermittent sounds with short (1–13 s) silence intervals but was not consistent with frequency-weighted SEL data for continuous sound exposures.
Bookmarks Related papers MentionsView impact
Polarforschung, 2004
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Journal of Morphology, 2022
In all mammals, the superior olivary complex (SOC) comprises a group of auditory brainstem nuclei... more In all mammals, the superior olivary complex (SOC) comprises a group of auditory brainstem nuclei that are important for sound localization. Its principal nuclei, the lateral superior olive (LSO) and the medial superior olive (MSO) process interaural time and intensity differences, which are the main cues for sound localization in the horizontal plane. Toothed whales (odontocetes) rely heavily on hearing and echolocation for foraging, orientation, and communication and localize sound with great acuity. The investigation of the SOC in odontocetes provides insight into adaptations to underwater hearing and echolocation. However, quantitative anatomical data for odontocetes are currently lacking. We quantified the volume, total neuron number, and neuron density of the LSO of six common dolphins (Delphinus delphis) using the Cavalieri principle and the unbiased stereology optical fractionator. Our results show that the LSO in D. delphis has a volume of 150 + (SD = 27) mm3, which is on a...
Bookmarks Related papers MentionsView impact
The Anatomical Record, 2022
Cetacean behavior and life history imply a role for somatosensory detection of critical signals u... more Cetacean behavior and life history imply a role for somatosensory detection of critical signals unique to their marine environment. As the sensory anatomy of cetacean glabrous skin has not been fully explored, skin biopsy samples of the flank skin of humpback whales were prepared for general histological and immunohistochemical (IHC) analyses of innervation in this study. Histology revealed an exceptionally thick epidermis interdigitated by numerous, closely spaced long, thin diameter penicillate dermal papillae (PDP). The dermis had a stratified organization including a deep neural plexus (DNP) stratum intermingled with small arteries that was the source of intermingled nerves and arterioles forming a more superficial subepidermal neural plexus (SNP) stratum. The patterns of nerves branching through the DNP and SNP that distribute extensive innervation to arteries and arterioles and to the upper dermis and PDP provide a dense innervation associated through the whole epidermis. Some NF‐H+ fibers terminated at the base of the epidermis and as encapsulated endings in dermal papillae similar to Merkel innervation and encapsulated endings seen in terrestrial mammals. However, unlike in all mammalian species assessed to date, an unusual acellular gap was present between the perineural sheaths and the central core of axons in all the cutaneous nerves perhaps as mechanism to prevent high hydrostatic pressure from compressing and interfering with axonal conductance. Altogether the whale skin has an exceptionally dense low‐threshold mechanosensory system innervation most likely adapted for sensing hydrodynamic stimuli, as well as nerves that can likely withstand high pressure experienced during deep dives.
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Aquatic Mammals, 2018
© 2018 European Association for Aquatic Mammals. This erratum concerns Figure 9 of the original a... more © 2018 European Association for Aquatic Mammals. This erratum concerns Figure 9 of the original article in which the line delimiting two effect types ("Permanent hearing loss increasingly likely" and "Permanent hearing loss very likely") was misplaced. This error, which has now been corrected, affects neither the main text nor the conclusion of the study. The authors apologize for the error
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Scientific Reports, 2021
Dolphins use their biosonar to discriminate objects with different features through the returning... more Dolphins use their biosonar to discriminate objects with different features through the returning echoes. Cross-modal matching experiments were conducted with a resident bottlenose dolphin (Tursiops aduncus). Four types of objects composed of different materials (water-filled PVC pipes, air-filled PVC pipes, foam ball arrays, and PVC pipes wrapped in closed-cell foam) were used in the experiments, respectively. The size and position of the objects remained the same in each case. The data collected in the experiment showed that the dolphin’s matching accuracy was significantly different across the cases. To gain insight into the underlying mechanism in the experiments, we used finite element methods to construct two-dimensional target detection models of an echolocating dolphin in the vertical plane, based on computed tomography scan data. The acoustic processes of the click’s interaction with the objects and the surrounding media in the four cases were simulated and compared. The si...
Bookmarks Related papers MentionsView impact
In this study, we compared the fluke geometries of male and female narwhals, which may be associa... more In this study, we compared the fluke geometries of male and female narwhals, which may be associated with hydrodynamic effects. Computerized tomography (CT) scanning was used to obtain data for analyses of the three-dimensional geometry of the flukes. The flukes from four narwhals (two males and two females) were obtained from aboriginal hunters in the vicinity of Broughton Island, Canada. The body lengths of the animals ranged from 2.98 to 3.60 m. Both males had erupted, upper left tusks. Standard body measurements were made including the span of the fluke (i.e., linear distance between fluke tips).
Bookmarks Related papers MentionsView impact
Marine Mammal Science, 2020
Bookmarks Related papers MentionsView impact
Aquatic Mammals, 2019
Bookmarks Related papers MentionsView impact
Aquatic Mammals, 2019
Bookmarks Related papers MentionsView impact
The Journal of the Acoustical Society of America, 2017
Anthropogenic underwater sounds create a potential risk to aquatic organisms. Many regulators req... more Anthropogenic underwater sounds create a potential risk to aquatic organisms. Many regulators require this risk to be assessed before allowing a sound-producing activity to proceed. Regulators typically set allowable exposure criteria for a range of acoustic parameters and require the assessment to address whether a given acoustic metric would exceed its specified threshold. While the value of the threshold is usually clear, the procedure required to calculate the metric is sometimes unspecified or described in insufficient detail, leading to ambiguity in interpretation. Processing and reporting procedures are described that enable intra- and inter-project consistency for processing and reporting of metrics. Quantities derived from sound pressure and sound particle motion are considered, resulting in metrics relevant to fish, aquatic invertebrates, and aquatic mammals. Specific metrics for which procedures are described include transient duration, zero-to-peak quantities, mean-squar...
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