DOCSLIB.ORG

Australian Integrated Marine Observing System (IMOS) Acoustic Observatories1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Australian Integrated Marine Observing System (IMOS) Acoustic Observatories1 Australian Integrated Marine Observing System (IMOS) Acoustic Observatories1 Summary The Acoustic Observatories sub‐facility archives ocean noise from around Australia at three primary locations: 32o S off the east and west Australian coasts (since 2008 in Western Australia and 2010 in eastern Australia); and south of Portland, Victoria (since 2009) and makes the data publicly available. The facility has been “paused” in 2017‐218 pending Australian Commonwealth Government funding decisions. The moorings are, or were located near or on, the continental shelf break. A passive acoustic mooring comprises a calibrated (2 Hz to 2.5 kHz) autonomous sea noise logger set on the seabed recording 5 minute ocean noise samples at 6 kHz sample rate every 15 minutes for 11‐12 months. In several instances grids of three or four instruments have been set up for tracking purposes, although more recent deployments use one or two instruments only. Currently we have a fourth site being sampled, on the shelf edge west of Kangaroo Island in South Australia. The Western Australian Government funded three years of data collection (2012‐2015) at 15.5o S and 19.5o S on the shelf edge of the northern WA coast. The passive acoustic observatories record sound emitted by natural processes in the ocean, underwater noise sources of biological origin, such as marine mammals, crustaceans or fish, plus man‐made noise sources. Through analysis of these signals it is possible to discriminate and identify different animal species and to assess the relative number of animals present within the range of acoustic observation, which can then be linked to ocean productivity or yearly migratory passage for great whales. Sea noise can be visualised on the IMOS web page, small amounts downloaded or large amounts requested from IMOS. Data is currently supplied in its raw format only, although we are considering making available processed detection times of various whales for selected sites. Please note that if requesting data from IMOS the best format to ask for is the raw data (*.DAT files), IMOS will offer *.wav file versions of the data but without a list of magic numbers the *.wav data is uncalibrated, whereas the raw data is calibrated. Instrumentation and Data The passive acoustic observatories comprise a sea noise logger placed on the ocean floor attached to a mooring which on command, releases floats to the surface. The sea noise loggers were designed and built at Curtin University and are well proven fully calibrated instruments (see McCauley et al. 2017). Each mooring also has ancillary temperature loggers attached with one on the seafloor and one between 30‐50 m above the seafloor. Sea noise data sets can be viewed via the AODN web portal: https://acoustic.aodn.org.au/acoustic/ as time stacked spectrograms (~ 15 days, x‐scale) on a logarithmic frequency scale (y‐scale, 5 Hz to 3 kHz) with intensity colour coded. Choose a deployment then scroll through in time. By left clicking a location on the spectrogram an image of the nearest sample's spectrogram and its waveform are displayed (while this feature should work, it may not work for some browser types). The time‐stacked spectrograms are useful for easily visualising when major sources are present as the dominant sources have a unique frequency content, so fill certain bands of energy in the spectrograms. For example a section from the Perth Canyon 1 Provided by Dr. Robert McCauley, Curtin University, Australia – 21 February 2018 version 1 with nearby pygmy blue whale calling is shown on the figure below, with a full pygmy blue whale song type on the left and two days of stacked sea noise on the right. Figure showing on the left a pygmy blue whale three part song and on the right two days of sea noise containing thousands of pygmy blue whale calls. The frequency alignment can be easily seen here. A vessel passes during the middle time period. The archived sea noise contains information on whatever noise sources were active at the time, within the listening range of the receiver. What the listening range is for the receiver depends on a variety of factors, including the source type, its intensity, location in the water column, combined with the sound transmission environment along the path to receiver and the local ambient noise field. Typical detection ranges for the locations sampled are 50‐150 km for blue whales in the deep ocean and perhaps 20‐40 km back onto the continental shelf, or 10‐30 km for humpbacks on the shelf. Processing sea noise is not an easy task and to do it properly requires some degree of understanding of underwater acoustics and signal processing. There are tools developed for this (see links below) and to simplify interpretations we are intending to load onto the AODN portal time stamps of detection algorithm outputs with identification of when different whale types occurred, initially along the eastern Australian coast using the NSW receiver data. The archived sea noise contains an invaluable record of the vocalising and physical noise sources. Applications of Data Examples of applications of the data include: An air craft crashing into the ocean may generate underwater sound by its impact at the surface or by debris imploding as it sinks. A signal was detected on two IMOS receivers coincident with the best estimate of the time of the loss of Malaysian aircraft MH370. After identification on the Perth Canyon IMOS receiver this signal was found in the Comprehensive Test Ban Treaty Organisation (CTBTO) hydrophone sensors at the Cape Leeuwin (HA01) site which gave a bearing consistent with the believed crash area. The signal falls almost precisely at the believed crash time but is not located along the search path given by analysis of the aircraft satellite communications (so called "7th arc"). Using data from the IMOS Scott Reef, IMOS Perth Canyon and CTBTO hydro‐acoustic stations the source location is some 8000 km from the Perth Canyon, slightly west of the Maldives assuming the same source was received at each site. The signal was later found on the CTBTO Diego Garcia hydrophones where it had arrived by horizontally refracting around the Diego Garcia Island group. This is a good example of long range ducting of signals in the open ocean due to the "deep sound channel" created 2 by a minimum sound speed at around 1000 m depth in the deep ocean which traps sound energy over a narrow frequency band (5 ‐100 Hz) by refraction. Sound energy over this frequency band suffers practically no absorption losses so can travel ocean scale distances losing energy only by 2‐dimensional spreading. Currently we believe this signal was generated by a small earthquake and was not related to the loss of MH370 although no matching earth tremor signals have yet been identified on the earthquake seismic network. References are Duncan et al. (2014 a & b). An example of the types of sources commonly found in the IMOS passive acoustic observatories was published in Erbe et al. (2015). Using four years of data this paper summarises the major contributors to sea noise in the Perth Canyon, these being whales, fish, wind, rain and ships. Statistics of the sea noise are given along with examples of the contribution of these sources to sea noise, their spectral characteristics, temporal patterns and how the sea noise can be used to define physical and biological parameters. A comprehensive analysis of fish chorusing behaviour from the Perth Canyon has been carried out, with the aim of identifying the chorus source (McCauley and Cato, 2016). Fish chorusing behaviour in the oceans is common but hardly reported or known of in mainstream biological sciences. The paper by Erbe et al. (2015) mentioned above presents a summary of the Perth Canyon fish choruses while the McCauley and Cato (2016) paper gives details of this chorus and suggest the most likely source is fish of the family Myctohidae. The detailed analysis suggest the chorus, which encompasses spatial scales in excess of the tens of nautical miles sampling program carried out and which occurs nightly and year round, is associated with the rise of the deep scattering layer and is found in regions of known highest secondary productivity in the Perth Canyon. This chorus is currently believed to be produced by small fishes foraging high in the water column. A figure showing the trends in this chorus over 4.3 years of IMOS data and its regular, nightly and seasonal occurrence is shown below. Figure showing the trend in fish chorus level activity in the Perth Canyon over a 4.3 year period using IMOS data. The top plot shows the level across an evening in the fish chorus frequency band stacked over 1,574 days with each evenings times zeroed to time of local sunset and intensity as the colour scale. The heavy black line is the time of sunrise. The lower plot shows the level in the chorus frequency band each evening over 0.4 to 5 hours post sunset. Several PhD students are making use of IMOS data. This includes further work on fish chorusing patterns, fin whale patterns around Australia or studies onto how sea noise derived indexes of whale calling can be turned into density estimates of the number of whales present in the listening range of 3 the sea noise logger. These are works in progress. The 2014 Perth Canyon IMOS sea noise data is being used by one of the students to correlate against a high resolution tag attached to a pygmy blue whale by the Centre for Whale Research (WA), which gave eight days of fine scale whale diving behaviour.
Load more

Recommended publications
  • Chinese Mooring and Buoy Observations in the Open-Ocean
    Chinese mooring and buoy observations in the open-ocean Chujin Liang Second Institute of Oceanography, SOA May 28, 2013 Seoul Main oceanographic institutions of China First Institute of Oceanography Qingdao State Oceanic Administration Second Institute of Oceanography Hangzhou /SOA Third Institute of Oceanography Xiamen Polar Institute of China ShanghaiFirst Institute of Oceanography, FIO Institute of Oceanography Qingdao Chinese Academy of Science /CAS South China Sea Institute of Oceanography GuangzhouSecond Institute of Oceanography, SIO China Ocean University, Xiamen University Qingdao/Third Institute of Oceanography,Ministry of Education TIO Xiamen Tongji University, East China Normal university, Shanghai/ Tsinghua University, Peiking University, etc. Beijing Second Institute of Oceanography State Oceanic Administration State Oceanic Administration, SOA First Institute of Oceanography, FIO Second Institute of Oceanography, SIO Third Institute of Oceanography, TIO Second Institute of Oceanography State Oceanic Administration FIO is operating 2 buoy stations and 1 mooring at 2 sites Long-term buoy station in eastern Indian Ocean operated by FIO FIO-AMFR 中国 海洋一所 FIO Progress Report 1. Surface buoy at (100E, 8S) • In place since 30 May 2010 • Daily data will be posted on PMEL and FIO website soon • Data includes the meteorological parameters: wind speed and direction, air temperature, relative humidity, air pressure, shortwave radiation, long wave radiation, unfortunately precipitation missed due to damage in the deployment • Data includes
    [Show full text]
  • Single Particle Analysis of Particulate Pollutants in Yellowstone National Park During the Winter Snowmobile Season
    SINGLE PARTICLE ANALYSIS OF PARTICULATE POLLUTANTS IN YELLOWSTONE NATIONAL PARK DURING THE WINTER SNOWMOBILE SEASON. Richard E. Peterson* and Bonnie J. Tyler** * Dept. of Chemistry and Biochemistry **Dept. of Chemical Engineering Montana State University, Bozeman, MT 59717, USA [email protected] Introduction: Particulate, or aerosol, pollution is a complex mixture of organic and inorganic compounds which includes a wide range of sizes and whose composition can vary widely depending on the time of year, geographical location, and both local and long range sources. Aerosol are important because of participation in atmospheric electricity, absorption and scattering of radiation (i.e. sunlight and thus affecting climate and visibility), their role as condensation nuclei for water vapor (and thus affecting precipitation chemistry and pH), and health effects. Particles greater than 2 micrometers in diameter (coarse) are generally formed by mechanical processes while smaller particles (fine) are formed by gas to particle conversion and accumulation/coagulation of these smallest aerosol. Because particles smaller than 2.5 micrometers (USEPA PM2.5) can become trapped deep in the lungs, it is of particular interest to identify toxic substances, such as heavy metals and polyaromatic hydrocarbons, that may be present in particles of this size range. Epidemiological studies have typically used particle size as the metric for identifying adverse health effects of particulate matter (PM), largely because data on PM size is available. Data on particle composition or other characteristics are less well known, if known at all in many cases. We are evaluating the potential for using Time of Flight Secondary Ion Mass Spectroscopy (TOF-SIMS) to study the composition of single particles from atmospheric aerosol.
    [Show full text]
  • Linking Mesopelagic Prey Abundance and Distribution to the Foraging
    Deep–Sea Research Part II 140 (2017) 163–170 Contents lists available at ScienceDirect Deep–Sea Research II journal homepage: www.elsevier.com/locate/dsr2 Linking mesopelagic prey abundance and distribution to the foraging MARK behavior of a deep-diving predator, the northern elephant seal ⁎ Daisuke Saijoa,1, Yoko Mitanib,1, , Takuzo Abec,2, Hiroko Sasakid, Chandra Goetsche, Daniel P. Costae, Kazushi Miyashitab a Graduate School of Environmental Science, Hokkaido University, 20-5 Bentencho, Hakodate, Hokkaido 040-0051, Japan b Field Science Center for Northern Biosphere, Hokkaido University, 20-5 Bentencho, Hakodate, Hokkaido 040-0051, Japan c School of Fisheries Science, Hokkaido University, 3-1-1 Minato cho, Hakodate, Hokkaido 041-8611, Japan d Arctic Environment Research Center, National Institute of Polar Research, 10-3, Midori-cho, Tachikawa, Tokyo 190-8518, Japan e Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, CA 95060, United States ARTICLE INFO ABSTRACT Keywords: The Transition Zone in the eastern North Pacific is important foraging habitat for many marine predators. Deep-scattering layer Further, the mesopelagic depths (200–1000 m) host an abundant prey resource known as the deep scattering Transition Zone layer that supports deep diving predators, such as northern elephant seals, beaked whales, and sperm whales. fi mesopelagic sh Female northern elephant seals (Mirounga angustirostris) undertake biannual foraging migrations to this myctophid region where they feed on mesopelagic fish and squid; however, in situ measurements of prey distribution and subsurface chlorophyll abundance, as well as the subsurface oceanographic features in the mesopelagic Transition Zone are limited. While concurrently tracking female elephant seals during their post-molt migration, we conducted a ship-based oceanographic and hydroacoustic survey and used mesopelagic mid-water trawls to sample the deep scattering layer.
    [Show full text]
  • MBARI's Buoy Based Seafloor Observatory Design (PDF)
    MBARI’s Buoy Based Seafloor Observatory Design Mark Chaffey, Larry Bird, Jon Mike Kelley, Lance McBride, Tom O’Reilly, Walter Paul*, Erickson, John Graybeal, Andy Ed Mellinger, Tim Meese, Mike Risi, and Wayne Hamilton, Kent Headley, Radochonski Monterey Bay Aquarium Research Institute * Dept. of Applied Ocean Physics and Engineering 7700 Sandholdt Road Woods Hole Oceanographic Institution Moss Landing CA 95039 Woods Hole, MA 02543 Abstract - There has been considerable discussion and planning in the oceanographic community toward the installation of long-term seafloor sites for scientific observation in the deep ocean. The Monterey Bay Aquarium Research Institute (MBARI) has designed a portable mooring system for deep ocean deployment that provides data and power connections to both seafloor and ocean surface instruments. The surface mooring collects solar and wind energy for powering instruments and transmits data to shore-side researchers using a satellite communications modem. A specialty anchor cable connects the surface mooring to a network of benthic instrumentation, providing the required data and power transfer. Design details and results of laboratory and field testing of the completed portions of the observatory system are described. I. INTRODUCTION Fig. 1 Buoy and seafloor network. MBARI has undertaken a major effort to develop the technology and techniques for building deep ocean of reliability, fault tolerance, and remote diagnostic seafloor observatories under the in-house Monterey capability. Ocean Observing System (MOOS) program. A key The overall functional and design requirements of the component of the overall observatory technology effort is MOOS mooring have previously been described in detail a moored surface buoy connected to the seafloor using [1] and can be summarized as a portable system, an anchor cable that incorporates mechanical strength configurable to a wide range of experiments, providing elements, copper conductors for power transfer, and episodic event response using on-board processing, and optical elements for communications.
    [Show full text]
  • Censusing Non-Fish Nekton
    WORKSHOP SYNOPSIS Censusing Non-Fish Nekton Carohln Levi, Gregory Stone and Jerry R. Schubel New England Aquarium ° Boston, Massachusetts USA his is a brief summary of a "Non-Fish SUMMARIES OF WORKING GROUPS Nekton" workshop held on 10-11 December 1997 at the New England Aquarium. The overall goals Cephalopods were: (1) to assess the feasibility of conducting a census New higher-level taxa are yet to be discovered, of life in the sea, (2) to identify the strategies and especially among coleoid cephalopods, which are components of such a census, (3) to assess whether a undergoing rapid evolutionary radiation. There are periodic census would generate scientifically worth- great gaps in natural history and ecosystem function- while results, and (4) to determine the level of interest ing, with even major commercial species largely of the scientific community in participating in the unknown. This is particularly, complex, since these design and conduct of a census of life in the sea. short-lived, rapidly growing animals move up through This workshop focused on "non-fish nekton," which trophic levels in a single season. were defined to include: marine mammals, marine reptiles, cephalopods and "other invertebrates." During . Early consolidation of existing cephalopod data is the course of the workshop, it was suggested that a needed, including the vast literatures in Japanese more appropriate phase for "other invertebrates" is and Russian. Access to and evaluation of historical invertebrate micronekton. Throughout the report we survey, catch, biological and video image data sets have used the latter terminology. and collections is needed. An Internet-based reposi- Birds were omitted only because of lack of time.
    [Show full text]
  • The Official Magazine of The
    OceTHE OFFICIALa MAGAZINEn ogOF THE OCEANOGRAPHYra SOCIETYphy CITATION Smith, L.M., J.A. Barth, D.S. Kelley, A. Plueddemann, I. Rodero, G.A. Ulses, M.F. Vardaro, and R. Weller. 2018. The Ocean Observatories Initiative. Oceanography 31(1):16–35, https://doi.org/10.5670/oceanog.2018.105. DOI https://doi.org/10.5670/oceanog.2018.105 COPYRIGHT This article has been published in Oceanography, Volume 31, Number 1, a quarterly journal of The Oceanography Society. Copyright 2018 by The Oceanography Society. All rights reserved. USAGE Permission is granted to copy this article for use in teaching and research. Republication, systematic reproduction, or collective redistribution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of The Oceanography Society. Send all correspondence to: [email protected] or The Oceanography Society, PO Box 1931, Rockville, MD 20849-1931, USA. DOWNLOADED FROM HTTP://TOS.ORG/OCEANOGRAPHY SPECIAL ISSUE ON THE OCEAN OBSERVATORIES INITIATIVE The Ocean Observatories Initiative By Leslie M. Smith, John A. Barth, Deborah S. Kelley, Al Plueddemann, Ivan Rodero, Greg A. Ulses, Michael F. Vardaro, and Robert Weller ABSTRACT. The Ocean Observatories Initiative (OOI) is an integrated suite of instrumentation used in the OOI. The instrumented platforms and discrete instruments that measure physical, chemical, third section outlines data flow from geological, and biological properties from the seafloor to the sea surface. The OOI ocean platforms and instrumentation to provides data to address large-scale scientific challenges such as coastal ocean dynamics, users and discusses quality control pro- climate and ecosystem health, the global carbon cycle, and linkages among seafloor cedures.
    [Show full text]
  • Guidance for Using Continuous Monitors in Pm Monitoring
    United States Office of Air Quality EPA-454/R-98-012 Environmental Protection Planning and Standards May 1998 Agency Research Triangle Park, NC 27711 Air GUIDANCE FOR USING CONTINUOUS MONITORS IN PM2.5 MONITORING NETWORKS GUIDANCE FOR USING CONTINUOUS MONITORS IN PM2.5 MONITORING NETWORKS May 29, 1998 PREPARED BY John G. Watson1 Judith C. Chow1 Hans Moosmüller1 Mark Green1 Neil Frank2 Marc Pitchford3 PREPARED FOR Office of Air Quality Planning and Standards U.S. Environmental Protection Agency Research Triangle Park, NC 27711 1Desert Research Institute, University and Community College System of Nevada, PO Box 60220, Reno, NV 89506 2U.S. EPA/OAQPS, Research Triangle Park, NC, 27711 3National Oceanic and Atmospheric Administration, 755 E. Flamingo, Las Vegas, NV 89119 DISCLAIMER The development of this document has been funded by the U.S. Environmental Protection Agency, under cooperative agreement CX824291-01-1, and by the Desert Research Institute of the University and Community College System of Nevada. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. This draft has not been subject to the Agency’s peer and administrative review, and does not necessarily represent Agency policy or guidance. ii ABSTRACT This guidance provides a survey of alternatives for continuous in-situ measurements of suspended particles, their chemical components, and their gaseous precursors. Recent and anticipated advances in measurement technology provide reliable and practical instruments for particle quantification over averaging times ranging from minutes to hours. These devices provide instantaneous, telemetered results and can use limited manpower more efficiently than manual, filter-based methods.
    [Show full text]
  • (Mooring – Tide Gauge) Is ~22 Mm
    Updated Results from the In Situ Calibration Site in Bass Strait, Australia Christopher Watson1 , Neil White2,, John Church2 Reed Burgette1, Paul Tregoning 3, Richard Coleman 4 1 University of Tasmania ([email protected]) 2 Centre for Australian Weather and Climate Research, A partnership between CSIRO and the Australian Bureau of Meteorology 3 The Australian National University 4 The Institute of Marine and Antarctic Studies, UTAS OSTM/Jason-2 OST Science Team Meeting Updated Data Stream Presentation 1 San Diego OSTST Meeting October 2011 Impossible d'afficher l'image. Votre ordinateur manque peut-être de mémoire pour ouvrir l'image ou l'image est endommagée. Redémarrez l'ordinateur, puis ouvrez à nouveau le fichier. Si le x rouge est toujours affiché, vous devrez peut-être supprimer l'image avant de la réinsérer. Methods Recap Bass Strait • Primary site is located on Pass 088 in Bass Strait. Contributing bias estimates to the SWT/OSTST since the launch of T/P . • Secondary site along track in Storm Bay Storm Bay 2 Methods Recap • We adopt a purely geometric technique for determination of absolute bias. • The method is centred around the use of GPS buoys to define the datum ofhihf high preci si on ocean moori ngs. • Outside of available mooring data, all available mooring SSH data are used to correct tide gauge SSH to the comparison point. 3 Instrumentation (Bass Strait): Tide Gauge and CGPS • Tide gauge part of the Australian baseline array, located in Burnie. • Vertical velocity not significantly different from zero. • CGPS time series shows a quasi-annual periodic signal (amplitude ~3-4 mm).
    [Show full text]
  • 2021 Connecticut Boater's Guide Rules and Resources
    2021 Connecticut Boater's Guide Rules and Resources In The Spotlight Updated Launch & Pumpout Directories CONNECTICUT DEPARTMENT OF ENERGY & ENVIRONMENTAL PROTECTION HTTPS://PORTAL.CT.GOV/DEEP/BOATING/BOATING-AND-PADDLING YOUR FULL SERVICE YACHTING DESTINATION No Bridges, Direct Access New State of the Art Concrete Floating Fuel Dock Offering Diesel/Gas to Long Island Sound Docks for Vessels up to 250’ www.bridgeportharbormarina.com | 203-330-8787 BRIDGEPORT BOATWORKS 200 Ton Full Service Boatyard: Travel Lift Repair, Refit, Refurbish www.bridgeportboatworks.com | 860-536-9651 BOCA OYSTER BAR Stunning Water Views Professional Lunch & New England Fare 2 Courses - $14 www.bocaoysterbar.com | 203-612-4848 NOW OPEN 10 E Main Street - 1st Floor • Bridgeport CT 06608 [email protected] • 203-330-8787 • VHF CH 09 2 2021 Connecticut BOATERS GUIDE We Take Nervous Out of Breakdowns $159* for Unlimited Towing...JOIN TODAY! With an Unlimited Towing Membership, breakdowns, running out GET THE APP IT’S THE of fuel and soft ungroundings don’t have to be so stressful. For a FASTEST WAY TO GET A TOW year of worry-free boating, make TowBoatU.S. your backup plan. BoatUS.com/Towing or800-395-2628 *One year Saltwater Membership pricing. Details of services provided can be found online at BoatUS.com/Agree. TowBoatU.S. is not a rescue service. In an emergency situation, you must contact the Coast Guard or a government agency immediately. 2021 Connecticut BOATER’S GUIDE 2021 Connecticut A digest of boating laws and regulations Boater's Guide Department of Energy & Environmental Protection Rules and Resources State of Connecticut Boating Division Ned Lamont, Governor Peter B.
    [Show full text]
  • Meridional Patterns in the Deep Scattering Layers and Top Predator Distribution in the Central Equatorial Pacific
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Publications, Agencies and Staff of the U.S. Department of Commerce U.S. Department of Commerce 2010 Meridional patterns in the deep scattering layers and top predator distribution in the central equatorial Pacific Elliott L. Hazen NOAA SWFSC Pacific Fisheries Environmental Lab, [email protected] David W. Johnston Duke University Marine Lab, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/usdeptcommercepub Part of the Environmental Sciences Commons Hazen, Elliott L. and Johnston, David W., "Meridional patterns in the deep scattering layers and top predator distribution in the central equatorial Pacific" (2010). Publications, Agencies and Staff of the U.S. Department of Commerce. 275. https://digitalcommons.unl.edu/usdeptcommercepub/275 This Article is brought to you for free and open access by the U.S. Department of Commerce at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications, Agencies and Staff of the U.S. Department of Commerce by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. FISHERIES OCEANOGRAPHY Fish. Oceanogr. 19:6, 427–433, 2010 SHORT COMMUNICATION Meridional patterns in the deep scattering layers and top predator distribution in the central equatorial Pacific ELLIOTT L. HAZEN1,2,* AND DAVID W. component towards understanding the behavior and JOHNSTON1 distribution of highly migratory predator species. 1 Division of Marine
    [Show full text]
  • Blue-Sea Thinking
    TECHNOLOGY QUARTERLY March 10th 2018 OCEAN TECHNOLOGY Blue-sea thinking 20180310_TQOceanTechnology.indd 1 28/02/2018 14:26 TECHNOLOGY QUARTERLY Ocean technology Listening underwater Sing a song of sonar Technology is transforming the relationship between people and the oceans, says Hal Hodson N THE summer of 1942, as America’s Pacific has always been. The subsurface ocean is inhospitable fleet was sluggingit out at the battle ofMidway, to humans and their machines. Salt water corrodes ex- the USS Jasper, a coastal patrol boat, was float- posed mechanisms and absorbs both visible light and ALSO IN THIS TQ ing 130 nautical miles (240km) off the west radio waves—thus ruling out radar and long-distance UNDERSEA MINING coast of Mexico, listening to the sea below. It communication. The lack of breathable oxygen se- Race to the bottom was alive with sound: “Some fish grunt, others verely curtails human visits. The brutal pressure Iwhistle or sing, and some just grind their teeth,” reads makes its depths hard to access at all. FISH FARMING the ship’s log. The discovery of the deep scattering layer was a Net gains The Jasper did not just listen. She sang her own landmark in the use of technology to get around these song to the sea—a song of sonar. Experimental equip- problems. It was also a by-blow. The Jasperwas not out MILITARY ment on board beamed chirrups of sound into the there looking for deepwater plankton; it was working APPLICATIONS depths and listened for their return. When they came out how to use sonar (which stands forSound Naviga- Mutually assured back, they gave those on board a shock.
    [Show full text]
  • The Development of SONAR As a Tool in Marine Biological Research in the Twentieth Century
    Hindawi Publishing Corporation International Journal of Oceanography Volume 2013, Article ID 678621, 9 pages http://dx.doi.org/10.1155/2013/678621 Review Article The Development of SONAR as a Tool in Marine Biological Research in the Twentieth Century John A. Fornshell1 and Alessandra Tesei2 1 National Museum of Natural History, Department of Invertebrate Zoology, Smithsonian Institution, Washington, DC, USA 2 AGUAtech, Via delle Pianazze 74, 19136 La Spezia, Italy Correspondence should be addressed to John A. Fornshell; [email protected] Received 3 June 2013; Revised 16 September 2013; Accepted 25 September 2013 Academic Editor: Emilio Fernandez´ Copyright © 2013 J. A. Fornshell and A. Tesei. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The development of acoustic methods for measuring depths and ranges in the ocean environment began in the second decade of the twentieth century. The two world wars and the “Cold War” produced three eras of rapid technological development in the field of acoustic oceanography. By the mid-1920s, researchers had identified echoes from fish, Gadus morhua, in the traces from their echo sounders. The first tank experiments establishing the basics for detection of fish were performed in 1928. Through the 1930s, the use of SONAR as a means of locating schools of fish was developed. The end of World War II was quickly followed by the advent of using SONAR to track and hunt whales in the Southern Ocean and the marketing of commercial fish finding SONARs for use by commercial fisherman.
    [Show full text]