{"id":442,"date":"2019-03-06T17:08:12","date_gmt":"2019-03-06T21:08:12","guid":{"rendered":"http:\/\/sites.nd.edu\/biomechanics-in-the-wild\/?p=442"},"modified":"2023-04-05T12:40:14","modified_gmt":"2023-04-05T16:40:14","slug":"the-ship-of-pearl-jet-propulsion-in-the-chambered-nautilus","status":"publish","type":"post","link":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/2019\/03\/06\/the-ship-of-pearl-jet-propulsion-in-the-chambered-nautilus\/","title":{"rendered":"The Ship of Pearl \u2013 Jet Propulsion in the Chambered Nautilus"},"content":{"rendered":"\n<p>In the aptly titled <a href=\"https:\/\/www.poetryfoundation.org\/poems\/44379\/the-chambered-nautilus\">poem <em>The Chambered Nautilus<\/em><\/a>, Oliver Wendell Holmes Sr. praises the eponymous cephalopod for its elegant shape and vibrant colors. The <em>ship of pearl<\/em>, as Wendell calls it, might not be the swiftest vessel; but <a href=\"https:\/\/research-information.bristol.ac.uk\/en\/persons\/thomas-r-neil(8ebdb0d9-f54a-4d32-b4f4-6c8325ce07da).html\">Thomas R. Neil<\/a> and <a href=\"https:\/\/www.researchgate.net\/profile\/Graham_Askew2\">Graham N. Askew<\/a>\u2019s <a href=\"https:\/\/royalsocietypublishing.org\/doi\/pdf\/10.1098\/rsos.170467\">research<\/a> indicates that the chambered nautilus might be among the most energy efficient ships in the seven seas.<\/p>\n\n\n\n<!--more-->\n\n\n\n<p>The <a href=\"https:\/\/en.wikipedia.org\/wiki\/Chambered_nautilus\"><em>Nautilus pompilius<\/em><\/a> is constantly moving to depths up to 700 m. At such depths, oxygen concentration decreases significantly: only 30% of that available at the surface. In such harsh environments, the nautilus must find a way to use its oxygen reservoir most efficiently while still being able to carry out metabolic functions. As such, the nautilus has adapted to use jet propulsion in a most efficient manner.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><a href=\"https:\/\/royalsocietypublishing.org\/doi\/pdf\/10.1098\/rsos.170467\"><img loading=\"lazy\" decoding=\"async\" width=\"695\" height=\"404\" src=\"http:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-Anatomy-Diagram.jpg\" alt=\"Jet propulsion mechanism of the chambered nautilus\" class=\"wp-image-450\" srcset=\"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-Anatomy-Diagram.jpg 695w, https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-Anatomy-Diagram-300x174.jpg 300w\" sizes=\"auto, (max-width: 695px) 100vw, 695px\" \/><\/a><figcaption class=\"wp-element-caption\">modified from Neil &amp; Askew, Royal Society Open Science (2018)<\/figcaption><\/figure>\n<\/div>\n\n\n<p>Jet propulsion in the nautilus is achieved by the simultaneous contraction of the head retractor and funnel muscles (shown in diagram above). The compression of the mantle cavity causes a pressure difference with its surroundings, resulting in a jet of water being expelled from the mantle cavity via the funnel. The nautilus uses its flexible funnel to control its swimming direction as shown in the <a href=\"https:\/\/www.youtube.com\/watch?v=vR6G-ANma1w\">video<\/a>. Slower swimming is powered by rhythmic contractions of the funnel flaps that generates a wave that travels along the funnel wings. This produces a unidirectional flow across the gills. Although <a href=\"https:\/\/en.wikipedia.org\/wiki\/Jet_propulsion\">jet propulsion<\/a> is less efficient than <a href=\"https:\/\/s2.smu.edu\/propulsion\/Pages\/undulatory.htm\">undulatory swimming<\/a> (think of the swimming motion of a ray), the Nautilus converts chemical energy into hydrodynamic work for motion more efficiently than fellow cephalopods such as the squid and even salmons (at lower speeds).<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Chambered Nautilus Eating Krill\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/vR6G-ANma1w?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>In their study, Neil and Askew used <a href=\"https:\/\/en.wikipedia.org\/wiki\/Particle_image_velocimetry\">particle image velocimetry<\/a> (PIV) to study the wake of the nautilus\u2019s jet. PIV consists of spreading particles of aluminum oxide in a water tank and shinning a laser on them. As the nautilus moves, the particles in the tank move with the jet. A high-speed camera is used to take multiple pictures of the floating particles and the relative position of these between snapshots is used to determine a velocity profile of the nautilus\u2019s water jet.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"alignleft\"><a href=\"https:\/\/www.nytimes.com\/2018\/02\/23\/science\/chambered-nautilus-jet-propulsion.html\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"608\" src=\"http:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-PIV-1024x608.jpg\" alt=\"Nautilus and its jet wake as seen in PIV\" class=\"wp-image-452\" srcset=\"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-PIV-1024x608.jpg 1024w, https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-PIV-300x178.jpg 300w, https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-PIV-768x456.jpg 768w, https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-PIV-1536x911.jpg 1536w, https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/files\/2019\/03\/Nautilus-PIV.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption class=\"wp-element-caption\">Photo by: Simon and Simon Photography, University of Leeds. Taken from Greenwood, The New York Times (2018)<\/figcaption><\/figure>\n<\/div>\n\n\n<p>The results from the study show that the whole cycle propulsive efficiency and thrust generation are related to the swimming orientation of the nautilus. The propulsive efficiency ranged between 30% and 75% for posterior-first swimming and 48% to 76% for anterior-first swimming (orientations defined in diagram above). Moreover, efficiency increases with greater speed in posterior-first orientation but decreases in anterior-first. This might have to do with energy losses associated with the re-orienting of the funnel that turns back on itself to move in the anterior orientation. Moreover, at low speeds, the nautilus spends more time jetting water than refilling, resulting in a lower jet speed but overall more efficient propulsion.<\/p>\n\n\n\n<p>Although not covered in their research, Neil and Askew\u2019s findings about jetting duty cycles and efficient propulsion at low speeds could be potentially applied to the design of more efficient <a href=\"https:\/\/en.wikipedia.org\/wiki\/Pump-jet\">hydrojets<\/a> to be used in underwater vehicles. Engineering seeks to imitate nature\u2019s most intelligent designs; and as Wendell puts it in his work, the nautilus proves to be a truly awe-inspiring creature worthy of imitation.<\/p>\n\n\n\n<p>Featured image by <a href=\"https:\/\/unsplash.com\/ko\/@breadboyshaun?utm_source=unsplash&amp;utm_medium=referral&amp;utm_content=creditCopyText\">Shaun Low<\/a> on <a href=\"https:\/\/unsplash.com\/photos\/Yy2cBOqUN_o?utm_source=unsplash&amp;utm_medium=referral&amp;utm_content=creditCopyText\">Unsplash<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the aptly titled poem The Chambered Nautilus, Oliver Wendell Holmes Sr. praises the eponymous cephalopod for its elegant shape and vibrant colors. The ship of pearl, as Wendell calls it, might not be the swiftest vessel; but Thomas R. Neil and Graham N. Askew\u2019s research indicates that the chambered nautilus might be among the [&hellip;]<\/p>\n","protected":false},"author":3308,"featured_media":3536,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[505479,505447],"tags":[356046,249559],"class_list":["post-442","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-2019-spring","category-text","tag-marine-biology","tag-swimming"],"_links":{"self":[{"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/posts\/442","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/users\/3308"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/comments?post=442"}],"version-history":[{"count":6,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/posts\/442\/revisions"}],"predecessor-version":[{"id":3538,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/posts\/442\/revisions\/3538"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/media\/3536"}],"wp:attachment":[{"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/media?parent=442"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/categories?post=442"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/wp-json\/wp\/v2\/tags?post=442"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}