{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T12:31:38Z","timestamp":1789129898771,"version":"build-2803163510"},"reference-count":37,"publisher":"Acoustical Society of America (ASA)","issue":"3","license":[{"start":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T00:00:00Z","timestamp":1789084800000},"content-version":"vor","delay-in-days":10,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"TOSSIT","award":["94 033\/314"],"award-info":[{"award-number":["94 033\/314"]}]}],"content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,9,1]]},"abstract":"<jats:p>It is commonly accepted that ocean noise from marine traffic is mostly confined to low frequencies. This article empirically demonstrates that large (length &amp;gt;120 m) vessels equipped with electrically driven \u201cAzipod\u201d propulsion systems generate loud mid-frequency (3\u201315 kHz) tonal and mid-frequency narrowband and tonal sounds (MF-NTS). The study focuses on six Azipod-equipped tourist vessels operating in the Antarctic Peninsula; it relies on opportunistic passive acoustic measurements collected there during the 2024\u20132025 Austral summer. The six vessels considered here all radiate MF-NTS, which are interpreted as the acoustic signature of the Azipod (data below 2 kHz are not considered in this study). This signature dominates the ambient sound for several kilometers around the vessel, and can be acoustically detected at ranges exceeding 5\u2009km.<\/jats:p>","DOI":"10.1121\/10.0046465","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T11:51:42Z","timestamp":1789127502000},"page":"2210-2222","update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Azipod-equipped vessels in the Antarctic Peninsula radiate underwater continuous mid-frequency narrowband and tonal sounds"],"prefix":"10.1121","volume":"160","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5142-3159","authenticated-orcid":false,"given":"Julien","family":"Bonnel","sequence":"first","affiliation":[{"name":"Marine Physical Laboratory, Scripps Institution of Oceanography, University of California 1 , San Diego, La Jolla, California 92093,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alex","family":"Mira","sequence":"additional","affiliation":[{"name":"Team Image Num\u00e9rique et R\u00e9alit\u00e9 Virtuelle \u2013 Laboratoire Arts des Images et Art Contemporain 2 , Universit\u00e9 Paris 8, 93200 Saint-Denis,","place":["France"]},{"name":"Laboratoire d'Oc\u00e9anographie Physique et Spatiale 3 , Ifremer\u2013CNRS\u2013IRD\u2013UBO, 29280 Plouzan\u00e9,","place":["France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alessandro","family":"Bocconcelli","sequence":"additional","affiliation":[{"name":"Department of Applied Ocean Physics & Engineering, Woods Hole Oceanographic Institution 4 , Woods Hole, Massachusetts 02543,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9429-4350","authenticated-orcid":false,"given":"Daniel","family":"Zitterbart","sequence":"additional","affiliation":[{"name":"Department of Applied Ocean Physics & Engineering, Woods Hole Oceanographic Institution 4 , Woods Hole, Massachusetts 02543,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"231","published-online":{"date-parts":[[2026,9,11]]},"reference":[{"key":"2026091107513727000_c1","unstructured":"ABB (2012). \u201cProduct introduction: Azipod XO2100 and XO2300,\u201d Technical Report, Doc. no. 3AFV6016618 rev. C."},{"key":"2026091107513727000_c2","unstructured":"ABB (2026). \u201cAzipod electric propulsion,\u201d https:\/\/new.abb.com\/marine\/systems-and-solutions\/azipod (Last viewed September 2, 2026)."},{"key":"2026091107513727000_c3","unstructured":"Andersson, V. (2024). \u201cAlternative modulation techniques to reduce acoustic noise from electric drives in podded propulsion systems: Silencing the elegance pod at Kongsberg Maritime,\u201d Master's thesis, KTH Royal Institute of Technology, Stockholm, Sweden."},{"issue":"2","key":"2026091107513727000_c4","doi-asserted-by":"publisher","first-page":"592","DOI":"10.1109\/JOE.2022.3211294","article-title":"Geoacoustic inversion using simple hand-deployable acoustic systems","volume":"48","year":"2023","journal-title":"IEEE J. Ocean. 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