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The local fishermen never quite believed that picture. They returned frequently to a handful of spots far offshore, hauling up catches that hinted at something solid rising from the seabed below.<\/p>\n
Reefs beneath the sand<\/p>\n
Curiosity about those patches drew in a team led by Ileana Orteg\u00f3n-Aznar, a marine biologist and professor at the Autonomous University of Yucat\u00e1n (UADY<\/a>).<\/p>\n Using coordinates, they surveyed four sites. They found genuine rocky reefs, low ridges of hard rock rising four to seven feet off the seabed and pocked with caves.<\/p>\n No one had formally documented these structures on the Mexican Atlantic coast<\/a> before.<\/p>\n Mexico\u2019s coral reefs have drawn researchers for decades, especially the celebrated systems on the Caribbean side. <\/p>\n Rocky reefs cover even more seafloor, yet these had slipped past earlier surveys focused on sand<\/a> and dunes.<\/p>\n Listening to the locals<\/p>\n The reefs did not turn up by accident. For generations, fishermen along the northern Yucat\u00e1n<\/a> coast had worked from these patches of water, passing down their mental maps of the seafloor.<\/p>\n Orteg\u00f3n-Aznar\u2019s team treated that knowledge as a starting point, not folklore. <\/p>\n The fishermen led them to four productive grounds along the peninsula\u2019s Gulf-facing edge, roughly eight to 13 miles out in 30 to 50 feet of water.<\/p>\n Sonar mapping and underwater surveys turned those mental charts into measured data. The hunches built over years of hauling nets lined up closely with what the instruments recorded.<\/p>\n Mapping the ridges<\/p>\n To chart structures that had been unmapped, the team swept each site with sonar, pinging the bottom every second for depth profiles and rough 3D models. <\/p>\n Underwater surveys then photographed small plots of rock to log what grew there. Each reef looked different. <\/p>\n One near Dzilam rose as a single rocky mass honeycombed with caves. Another revealed a slab stretching close to a quarter mile. <\/p>\n A third, off Progreso, formed a maze of ridges and hollows across most of its area.<\/p>\n Across every site, the rock was strikingly complex, full of nooks and crannies that give marine life places to settle and hide. <\/p>\n Earlier research<\/a> shows complex reefs shelter more species, and these scored high.<\/p>\n A fight for space<\/p>\n Once the team catalogued the surfaces, one group dominated. Large seaweeds, known as macroalgae, blanketed close to two-thirds of the rock.<\/p>\n They were far ahead of sponges, scattered coral, and a low gritty mat the researchers call sediment-laden algal turf.<\/p>\n The two leaders rarely shared the same rock. Thick mats of turf dominated some areas, while sprawling seaweed dominated others.<\/p>\n Where turf spread, the seaweed thinned, showing a pattern. Competition is a plausible explanation, though the survey recorded only the association, not its cause.<\/p>\n Sediment tipped the balance. Finer sand paired with more seaweed, coarser grains with more turf, and the mix shifted from reef to reef. <\/p>\n A separate study<\/a> shows how seasonal swings in light and nutrients drive seaweed growth.<\/p>\n The Chicxulub crater<\/p>\n These reefs sit in geologically loaded ground. The northern Yucat\u00e1n rests on a vast limestone platform marked by the Chicxulub crater. <\/p>\n The crater is a roughly 110-mile-wide scar left by the asteroid that ended the dinosaurs about 66 million years ago.<\/p>\n Buried under roughly two-thirds of a mile of younger sediment, the crater shows at the surface only as a ring of water-filled sinkholes threading across the landscape.<\/p>\n Orteg\u00f3n-Aznar\u2019s team is careful not to oversell the idea. They studied the reefs\u2019 structure and living cover, not the rock\u2019s origin. <\/p>\n They say that only dedicated geological work could test whether the formations trace back to the impact.<\/p>\n Reefs under pressure<\/p>\n Newly described does not mean protected. Threats include sediment runoff that can bury the rock, pollution, anchor damage, and heavy fishing on the same flagged grounds.<\/p>\n All of these dangers are currently present, and warming water adds a slower danger. <\/p>\n A broad analysis<\/a> of reefs worldwide has tracked how rising sea temperatures trigger repeated, severe bleaching. Similar increases in algal turf have been observed at some Yucat\u00e1n sites.<\/p>\n This hints that these communities could tip toward collapse. Rocky reefs sit almost entirely outside Mexico\u2019s conservation plans, which were built around coral.<\/p>\n New maps and baseline numbers give managers evidence they lacked before. It may be enough to bring these habitats under protection before development or a warming Gulf alters them.<\/p>\n A coast redrawn<\/p>\n A stretch of seabed long written off as bare sand holds real rocky<\/a> reefs, mapped for the first time, complete with caves, ridges, and dense seaweed. <\/p>\n The first confirmed evidence of these habitats was found on Mexico\u2019s Atlantic side.<\/p>\n Researchers now have a starting line to track how the reefs fare, how they connect to the better-known coral systems offshore, and what their unusual geological<\/a> setting might mean. <\/p>\n That changes the working picture of the entire northern Yucat\u00e1n coast. It also vindicates the fishermen, whose generations of local knowledge led the team straight to the ecosystem.<\/p>\n The rock was never hidden from them. For generations, fishermen had worked these grounds and knew exactly where it lay. It had simply gone uncounted by science.<\/p>\n The study is published in PLOS ONE<\/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":"Sail north from the beach at Progreso, Mexico, and the seafloor appears unremarkable. Survey charts show a flat…\n","protected":false},"author":2,"featured_media":511363,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[61,60,82],"class_list":["post-511362","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ie","tag-ireland","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/511362","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=511362"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/511362\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/511363"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=511362"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=511362"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=511362"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}