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Author Posting. © Acoustical Society of America, 2021. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 150(5),(2021): 3288–3301, https://doi.org/10.1121/10.0006973., Snapping shrimps are pervasive generators of underwater sound in temperate and tropical coastal seas across oceans of the world. Shrimp snaps can act as signals to conspecifics and provide acoustic information to other species and even to humans for habitat monitoring. Despite this, there are few controlled measurements of the acoustic parameters of these abundant acoustic stimuli. Here, the characteristics of snaps produced by 35 individuals of two species, Alpheus heterochaelis and Alpheus angulosus, are examined to evaluate the variability within and between the species. Animals were collected from the wild and the sound pressure and particle acceleration were measured at 0.2, 0.5, and 1 m from individual shrimp in controlled laboratory conditions to address the snap properties at communication-relevant distances. The source and sound exposure levels (at 1 m) were not significantly different between these two species. The frequency spectra were broadband with peak frequencies consistently below 10 kHz. The particle acceleration, the sound component likely detectable by shrimp, was measured across three axes. The directional amplitude variation suggests that the particle motion of snaps could act as a localization cue. The amplitudes of the snap pressure and acceleration decreased with distance, yet the levels remained sufficient for the predicted detection range by nearby conspecifics., This research was funded by the National Science Foundation Biological Oceanography Award No. 15-36782, the Defense Advanced Research Projects Agency, and the Woods Hole Oceanographic Institution., 2022-05-03

Author Posting. © Acoustical Society of America, 2021. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 150(1), (2021): 225–232, https://doi.org/10.1121/10.0005518., The sound-transmission, beam-formation, and sound-reception processes of a short-finned pilot whale (Globicephala macrorhynchus) were investigated using computed tomography (CT) scanning and numerical simulation. The results showed that sound propagations in the forehead were modulated by the upper jaw, air components, and soft tissues, which attributed to the beam formation in the external acoustic field. These structures owned different acoustic impedance and formed a multiphasic sound transmission system that can modulate sounds into a beam. The reception pathways composed of the solid mandible and acoustic fats in the lower head conducted sounds into the tympano-periotic complex. In the simulations, sounds were emitted in the forehead transmission system and propagated into water to interrogate a steel cylinder. The resulting echoes can be interpreted from multiple perspectives, including amplitude, waveform, and spectrum, to obtain the acoustic cues of the steel cylinder. By taking the short-finned pilot whale as an example, this study provides meaningful information to further deepen our understanding of biosonar system operations, and may expand sound-reception theory in odontocetes., This work was financially supported by the project supported by the National Key Research and Development Program of China (Grant Nos. 2018YFC1407505, 2018YFC1407504, 2016YFC0300802, and 2018YFC0308602), the National Natural Science Foundation of China (Grant Nos. 12074323 and 41422604), the Special Fund for Marine and Fishery Development of Xiamen (Grant No. 20CZB015HJ01), Water Conservancy Science and Technology Innovation Project of Guangdong (Grant No. 2020-16), the China Postdoctoral Science Foundation (Grant No. 2020M682086), and the China National Postdoctoral Program for Innovative Talents (Grant No. BX2021168)., 2022-01-12

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Li, J., Boiteau, R. M., Babcock-Adams, L., Acker, M., Song, Z., McIlvin, M. R., & Repeta, D. J. Element-selective targeting of nutrient metabolites in environmental samples by inductively coupled plasma mass spectrometry and electrospray ionization mass spectrometry. Frontiers in Marine Science, 8, (2021): 630494, https://doi.org/10.3389/fmars.2021.630494., Metabolites that incorporate elements other than carbon, nitrogen, hydrogen and oxygen can be selectively detected by inductively coupled mass spectrometry (ICPMS). When used in parallel with chromatographic separations and conventional electrospray ionization mass spectrometry (ESIMS), ICPMS allows the analyst to quickly find, characterize and identify target metabolites that carry nutrient elements (P, S, trace metals; “nutrient metabolites”), which are of particular interest to investigations of microbial biogeochemical cycles. This approach has been applied to the study of siderophores and other trace metal organic ligands in the ocean. The original method used mass search algorithms that relied on the ratio of stable isotopologues of iron, copper and nickel to assign mass spectra collected by ESIMS to metabolites carrying these elements detected by ICPMS. However, while isotopologue-based mass assignment algorithms were highly successful in characterizing metabolites that incorporate some trace metals, they do not realize the whole potential of the ICPMS/ESIMS approach as they cannot be used to assign the molecular ions of metabolites with monoisotopic elements or elements for which the ratio of stable isotopes is not known. Here we report a revised ICPMS/ESIMS method that incorporates a number of changes to the configuration of instrument hardware that improves sensitivity of the method by a factor of 4–5, and allows for more accurate quantitation of metabolites. We also describe a new suite of mass search algorithms that can find and characterize metabolites that carry monoisotopic elements. We used the new method to identify siderophores in a laboratory culture of Vibrio cyclitrophicus and a seawater sample collected in the North Pacific Ocean, and to assign molecular ions to monoisotopic cobalt and iodine nutrient metabolites in extracts of a laboratory culture of the marine cyanobacterium Prochorococcus MIT9215., This work was generously supported by the National Science Foundation grant OCE-1829761 to RB and OCE-1356747 and -1736280 to DR. DR also received generous support from the Simons Foundation Life Sciences Project Award 49476.

© 2020 The Authors, some rights reserved. To maximize energy transmission from a source through a media, the concept of impedance matching has been established in electrical, acoustic, and optical engineering. However, existing design of acoustic impedance matching, which extends exactly by a quarter wavelength, sets a fundamental limit of narrowband transmission. Here, we report a previously unknown class of bioinspired metagel impedance transformers to overcome this limit. The transformer embeds a two-dimensional metamaterial matrix of steel cylinders into hydrogel. Using experimental data of the biosonar from the Indo-Pacific humpback dolphin, we demonstrate through theoretical analysis that broadband transmission is achieved when the bioinspired acoustic impedance function is introduced. Furthermore, we experimentally show that the metagel device offers efficient implementation in broadband underwater ultrasound detection with the benefit of being soft and tunable. The bioinspired two-dimensional metagel breaks the length-wavelength dependence, which paves a previously unexplored way for designing next-generation broadband impedance matching devices in diverse wave engineering.

Author Posting. © Company of Biologists, 2020. This article is posted here by permission of Company of Biologists for personal use, not for redistribution. The definitive version was published in Journal of Experimental Biology 223 (2020): jeb217885, doi:10.1242/jeb.217885., Assessment of the compressibility of marine mammal airways at depth is crucial to understanding vital physiological processes such as gas exchange during diving. Very few studies have directly assessed changes in cetacean and pinniped tracheobronchial shape, and none have quantified changes in volume with increasing pressure. A harbor seal, gray seal, harp seal, harbor porpoise and common dolphin were imaged promptly post mortem via computed tomography in a radiolucent hyperbaric chamber. Volume reconstructions were performed of segments of the trachea and bronchi of the pinnipeds and bronchi of the cetaceans for each pressure treatment. All specimens examined demonstrated significant decreases in airway volume with increasing pressure, with those of the harbor seal and common dolphin nearing complete collapse at the highest pressures. The common dolphin bronchi demonstrated distinctly different compression dynamics between 50% and 100% lung inflation treatments, indicating the importance of air in maintaining patent airways, and collapse occurred caudally to cranially in the 50% treatment. Dynamics of the harbor seal and gray seal airways indicated that the trachea was less compliant than the bronchi. These findings indicate potential species-specific variability in airway compliance, and cessation of gas exchange may occur at greater depths than those predicted in models assuming rigid airways. This may potentially increase the likelihood of decompression sickness in these animals during diving., This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors., 2021-02-10

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dong, E., Zhang, Y., Song, Z., Zhang, T., Cai, C., & Fang, N. X. Physical modeling and validation of porpoises' directional emission via hybrid metamaterials. National Science Review, 6(5), (2019): 921-928, doi:10.1093/nsr/nwz085., In wave physics and engineering, directional emission sets a fundamental limitation on conventional simple sources as their sizes should be sufficiently larger than their wavelength. Artificial metamaterial and animal biosonar both show potential in overcoming this limitation. Existing metamaterials arranged in periodic microstructures face great challenges in realizing complex and multiphase biosonar structures. Here, we proposed a physical directional emission model to bridge the gap between porpoises’ biosonar and artificial metamaterial. Inspired by the anatomical and physical properties of the porpoise's biosonar transmission system, we fabricated a hybrid metamaterial system composed of multiple composite structures. We validated that the hybrid metamaterial significantly increased directivity and main lobe energy over a broad bandwidth both numerically and experimentally. The device displayed efficiency in detecting underwater target and suppressing false target jamming. The metamaterial-based physical model may be helpful to achieve the physical mechanisms of porpoise biosonar detection and has diverse applications in underwater acoustic sensing, ultrasound scanning, and medical ultrasonography., E.D., Y.Z., Z.S., T.Z. and C.C. acknowledge the financial support in part by the National Key Research and Development Program of China (2018YFC1407504), the National Natural Science Foundation of China (41676023, 41276040 and 41422604). N.X.F. acknowledges the support from the MIT Energy Initiative grant. Z.S. thanks the China Scholarship Council for the financial support of his oversea study in Woods Hole Oceanographic Institution.

In wave physics and engineering, directional emission sets a fundamental limitation on conventional simple sources as their sizes should be sufficiently larger than their wavelength. Artificial metamaterial and animal biosonar both show potential in overcoming this limitation. Existing metamaterials arranged in periodic microstructures face great challenges in realizing complex and multiphase biosonar structures. Here, we proposed a physical directional emission model to bridge the gap between porpoises' biosonar and artificial metamaterial. Inspired by the anatomical and physical properties of the porpoise's biosonar transmission system, we fabricated a hybrid metamaterial system composed of multiple composite structures. We validated that the hybrid metamaterial significantly increased directivity and main lobe energy over a broad bandwidth both numerically and experimentally. The device displayed efficiency in detecting underwater target and suppressing false target jamming. The metamaterial-based physical model may be helpful to achieve the physical mechanisms of porpoise biosonar detection and has diverse applications in underwater acoustic sensing, ultrasound scanning, and medical ultrasonography. ©2019 The Author(s) 2019. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.

Odontocetes have evolved for millions of years to own a unique echolocation system. The exceptional performance of odontocetes echolocation system can provide reference to artificial sonar systems, acoustic metamaterials and sound control designs. Research on odontocetes biosonar requires interdisciplinary effort, including acoustics, biology, biomimetics, anatomy, physiology and signal analysis. In this paper, we review odontoctes’ biosonar emission process from aspects of anatomy, biosonar signal and beam formation. To begin, computed tomography scanning and untrasound measurements are combined to reconstruct the sound speed and density distributions. To follow, efforts are thrown to probe into the biosonar signal and its corresponding acoustic behavior. Numerical simulations are used to investigate the odontocetes’ biosonar beam formation. The secret of exceptional performance of odontocetes’ echolocation system lies in their unique anatomy. Odontocete integrates acoustic structures with different acoustic impedances, namely solid bony structures, air space and soft tissues as a whole emission system to efficiently modulate sound propagation and sound beam formation. These acoustic structures are well organized in the forehead, forming a natural acoustic metamaterial to perform a good control of sounds. These results can enlighten artificial sonar designs.

Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Bioinspiration & Biomimetics 14 (2019): 016004, doi:10.1088/1748-3190/aaeb01., Sound transmission and reception are both vital components to odontocete echolocation and daily life. Here, we combine computed tomography (CT) scanning and Finite Element Modeling to investigate the acoustic propagation of finless porpoise (Neophocaena asiaorientalis sunameri) echolocation pulses. The CT scanning and FEM wave propagation model results support the well-accepted jaw-hearing pathway hypothesis and suggest an additional alternative auditory pathway composed of structures, mandible (lower jaw) and internal mandibular fat, with different acoustic impedances, which may also conduct sounds to the ear complexes. The internal mandibular fat is attached to the ear complex and encased by the mandibles laterally and anteriorly. The simulations show signals in this pathway initially propagate along the solid mandibles and are transmitted to the acoustically coupled soft tissue of the internal mandibular fat which conducts the stimuli posteriorly as it eventually arrives at ear complexes. While supporting traditional theories, this new bone-tissue-conduction pathway might be meaningful to understand the hearing and sound reception processes in a wide variety of odontocetes species., This work is financially supported in part by the National Natural Science Foundation of China (Grants No. 41276040, No. 11174240, and No. 41676023) and the Natural Science Foundation of Fujian Province of China (Grant No. 2012J06010).

Yangtze finless porpoises (Neophocaena asiaeorientalis) are known to use the narrowband signals for echolocation. In this study, a finite-element model was configured based on computed tomography imaging technique and tissue physical properties measurement to simulate biosonar signal emission and transmission processes through animal’s head. The roles of the main structures in the head such as the air sacs, melon, bony structures, connective tissue, blubber, mandibular fat on the biosonar beam formation were investigated, and the relative importance of these structures was compared. The biosonar beam properties of this neonate porpoise were compared with those of adult ones. The method in this paper suggested an effective way for investigating the acoustic processes in the heads of the neonate odontocetes.

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of the Acoustical Society of America 141 (2017): 4179–4187, doi: 10.1121/1.4983663., Harbor porpoises (Phocoena phocoena) use narrow band echolocation signals for detecting and locating prey and for spatial orientation. In this study, acoustic impedance values of tissues in the porpoise's head were calculated from computer tomography (CT) scan and the corresponding Hounsfield Units. A two-dimensional finite element model of the acoustic impedance was constructed based on CT scan data to simulate the acoustic propagation through the animal's head. The far field transmission beam pattern in the vertical plane and the waveforms of the receiving points around the forehead were compared with prior measurement results, the simulation results were qualitatively consistent with the measurement results. The role of the main structures in the head such as the air sacs, melon and skull in the acoustic propagation was investigated. The results showed that air sacs and skull are the major components to form the vertical beam. Additionally, both beam patterns and sound pressure of the sound waves through four positions deep inside the melon were demonstrated to show the role of the melon in the biosonar sound propagation processes in the vertical plane., This work was financially supported in part by the National Science Foundation of China (Grant Nos. 41276040, 11174240, 31170501, and 31070347), the Natural Science Foundation of Fujian Province of China (Grant No. 2012J06010), Ministry of Science and Technology of China (Grant No. 2011BAG07B05-3) and State Oceanic Administration of China (Grant No. 201105011-3). The Project was sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

Vocalizations of a wild finless porpoise (Neophocaena asiaeorientalis sunmeri) were recorded within the dolphin natural reserve, in the western coast of the Taiwan Strait, China. The subsequent acoustical analyses suggested that the porpoise (N. p. sunameri) produced typical phocoenid clicks, with the peak frequency ranging from 123.4 to 141.4 kHz, averaging at 132.8±4.02 kHz (n = 193). The durations of these typical signals ranged from 97 to 130 microseconds, averaging at 111.6±8.49 (n = 193) microseconds. The 3 dB bandwidth had a scope from 5.8 to 15.6 kHz, averaging at 10.49±1.84 kHz (n = 193). For typical clicks, the energy converged on a narrowband frequency range with peak frequency over 120 kHz. The acoustic parameters of the signals were compared with those of signals emitted by finless porpoises from other living regions. Besides, the broadband clicks were also recorded and reported here. The sound energy was more diffuse in frequency domain for the broadband clicks than typical narrowband ones, extending to below 50 kHz and above 180 kHz. During the recordings, the reverberations influenced the signals, shown in both time and frequency domains. The reverberations could disperse the energy of the original narrowband and broadband clicks into several peak frequency ranges. For the signals used by porpoise for echolocation, the noise caused by man-made activities could influence the marine mammal negatively. The researches into porpoise's signals could provide references to protect the animal.

A finite element method was used to investigate the temperature influence on sound beams of the Indo-Pacific humpback dolphin. The numerical models of a dolphin, which originated from previous computed tomography (CT) scanning and physical measurement results, were used to investigate sound beam patterns of the dolphin in temperatures from 21 °C to 39 °C, in increments of 2 °C. The -3 dB beam widths across the temperatures ranged from 9.3° to 12.6°, and main beam angle ranged from 4.7° to 7.2° for these temperatures. The subsequent simulation suggested that the dolphin's sound beam patterns, side lobes in particular, were influenced by temperature.

Computed tomography (CT) imaging and ultrasound experimental measurements were combined to reconstruct the acoustic properties (density, velocity, and impedance) of the head from a deceased Indo-Pacific humpback dolphin (Sousa chinensis). The authors extracted 42 soft forehead tissue samples to estimate the sound velocity and density properties at room temperature, 25.0 °C. Hounsfield Units (HUs) of the samples were read from CT scans. Linear relationships between the tissues' HUs and velocity, and HUs and density were revealed through regression analyses. The distributions of the head acoustic properties at axial, coronal, and sagittal cross sections were reconstructed, suggesting that the forehead soft tissues were characterized by low-velocity in the melon, high-velocity in the muscle and connective tissues. Further, the sound velocities of melon, muscle, and connective tissue pieces were measured under different temperatures to investigate tissues' velocity response to temperature. The results demonstrated nonlinear relationships between tissues' sound velocity and temperature. This study represents a first attempt to provide general information on acoustic properties of this species. The results could provide meaningful information for understanding the species' bioacoustic characteristics and for further investigation on sound beam formation of the dolphin.