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The work was led by Anna W\u00e5hlin, a professor of oceanographic physics at University of Gothenburg<\/a>, coordinating the Ran missions in West Antarctica<\/a>. <\/p>\n Her research focuses on how ocean currents erode ice shelves from below, changing glacier stability and future sea level.<\/p>\n Ran is an autonomous underwater vehicle, a robot submarine that navigates alone under ice for hours.<\/p>\n During a 2022 campaign, Ran spent 27 days weaving under Dotson\u2019s floating ice, eventually reaching about eleven miles into the hidden cavity.<\/p>\n The mission aimed to explain the sharp contrast between Dotson\u2019s thick, slow-melting eastern side and its thinner, faster-melting western side.<\/p>\n Strange shapes under the ice<\/p>\n Using sonar, Ran mapped<\/a> 54 square miles of ice underside beneath Dotson Ice Shelf. The maps revealed flat plateaus, terraced steps, and teardrop-shaped pits, all carved by basal melt, melting that attacks the ice from below.<\/p>\n In the east and center, Ran saw icy terraces stacked like steps, while the west looked smoother, with channels and scooped depressions.<\/p>\n None of these terraces or teardrop pits show up on satellite images, so they had remained completely hidden until Ran\u2019s mission.<\/p>\n Warm deep water, uneven melting<\/p>\n Around Antarctica, Circumpolar Deep Water<\/a>, a warm salty current from the Southern Ocean, moves onto the shelf and melts ice shelves from below.<\/p>\n Satellite altimetry over Dotson shows that melt channels lose ice at about 40 feet per year, a thinning pattern linked to warm water.<\/p>\n Analysis<\/a> of measurements under Dotson indicates that this ice shelf added 0.02 inches to sea level between 1979 and 2017.<\/p>\n The under-ice maps show that this warm inflow focuses erosion on Dotson\u2019s western side, while colder water leaves the eastern flank protected.<\/p>\n Terraces, teardrops, and turbulence<\/p>\n Where currents move slowly, the base of the ice looks like stacked ledges, formed as melting eats away flats and leaves small steps.<\/p>\n In the fast outflow region, currents create smoother surfaces with grooves, where shear-driven turbulence, mixing caused by sliding water layers, drives rapid melting.<\/p>\n Some pits are teardrop shaped, 984 feet long and 164 feet deep, carved by currents near the ice base.<\/p>\n Elsewhere, the terraced plateaus probably record bursts of slightly warmer water entering the cavity, slowly peeling away layers of ice over many years.<\/p>\n Fractures that widen from below<\/p>\n Ran also imaged full-thickness fractures that slice through the ice shelf, many of them widened and smoothed at their bases by melting.<\/p>\n Satellite records show that some of these cracks have been open since the 1990s, and those older fractures carry the deepest melt scars.<\/p>\n In these narrow slots, faster moving water can channel extra heat against the ice walls, turning fractures into hidden highways for ice loss.<\/p>\n Because most computer models treat melt in broad strokes, they often overlook how fractures and channels steer warm water and concentrate damage.<\/p>\n Combined satellite and climate data<\/a> show that Antarctic ice loss has added about 0.55 inches of sea level since 1979.<\/p>\n Much of that loss comes from West Antarctica<\/a>, where ice shelves like Dotson float above deep basins that warm currents can reach.<\/p>\n When those floating shelves thin or break, they stop bracing the land-based ice behind them, so glaciers accelerate and sea levels climb faster.<\/p>\n Understanding how warm water eats away at Dotson\u2019s base now helps researchers judge how quickly distant glaciers might respond as the climate warms.<\/p>\n Dotson Ice Shelf difficulties<\/p>\n Ran worked without real time contact, because radio waves and GPS signals cannot pass through hundreds of feet of solid ice.<\/p>\n Instead, the vehicle relied on navigation systems and acoustic instruments to track its position against the seafloor and the underside of the ice.<\/p>\n Typical missions ranged between several hours and more than a day, meaning problems deep under the ice stayed invisible until Ran surfaced again.<\/p>\n Despite those hazards, the team completed 14 successful under-ice missions with Ran in 2022, bringing back a dataset for glaciologists and oceanographers.<\/p>\n When Ran submarine disappeared<\/p>\n When the researchers came back to Dotson, Ran was sent on a mission beneath ice to extend maps and measurements.<\/p>\n \u201cTo see Ran disappear into the dark, unknown depths below the ice, executing her tasks for over 24 hours without communication, is of course daunting,\u201d said W\u00e5hlin.<\/p>\n When Ran did not appear at the pickup point, attempts to contact the vehicle failed and searches found no signals or debris.<\/p>\n Because there was no feed, the team can speculate about the cause, ranging from mechanical failure to a collision with ice ridges.<\/p>\n Lessons from the Dotson Ice Shelf<\/p>\n Despite the loss, Ran\u2019s earlier missions transformed the team\u2019s view of how ice and ocean interact in this remote cavity.<\/p>\n Those maps show that the underside of an ice shelf can host terraces, channels, fractures, and teardrops, each responding differently to currents.<\/p>\n Incorporating terraces, fractures, and melt channels into models should help narrow predictions of how quickly West Antarctica<\/a> might lose ice in future climates.<\/p>\n For now, the detailed maps Ran sent home are a rare window on Antarctica\u2019s hidden melt machinery, reminding scientists how much remains unexplored.<\/p>\n The study is published in Science Advances<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"An unmanned submarine mapping West Antarctica\u2019s Dotson Ice Shelf reported strange under-ice structures, then went silent ten miles…\n","protected":false},"author":2,"featured_media":201875,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[273,111,139,69,147],"class_list":{"0":"post-201874","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-environment","9":"tag-new-zealand","10":"tag-newzealand","11":"tag-nz","12":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/201874","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=201874"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/201874\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/201875"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=201874"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=201874"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=201874"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Sketch](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2025\/12\/antarctica_dotson-ice-shelf_odd-structures_illustration_Science_1s.webp.webp\")
<\/a>Sketch showing the processes discussed in the paper on the Dotson Ice Shelf in Antarctica. Note that the vertical scale is exaggerated. Credit: Science\/ITGC. Click image to enlarge.Implications for future sea levels<\/p>\n