{"id":5860,"date":"2015-01-17T16:50:11","date_gmt":"2015-01-17T15:50:11","guid":{"rendered":"http:\/\/www.grandesterresbio.com\/?p=5860"},"modified":"2015-01-17T16:50:11","modified_gmt":"2015-01-17T15:50:11","slug":"pour-lutter-contre-le-rechauffement-des-oceans-des-coraux-sorganisent","status":"publish","type":"post","link":"https:\/\/claire-jannot.com\/?p=5860","title":{"rendered":"Pour lutter contre le r\u00e9chauffement des oc\u00e9ans, des coraux s&rsquo;organisent"},"content":{"rendered":"<h2><span style=\"color: #000000;\">Une forte hausse de la temp\u00e9rature de la mer peut provoquer un \u00ab\u00a0blanchissement\u00a0\u00bb catastrophique du corail mais une \u00e9tude publi\u00e9e mercredi a identifi\u00e9 plusieurs facteurs susceptibles de rendre certains coraux plus r\u00e9sistants que d&rsquo;autres.<\/span><\/h2>\n<p><span style=\"color: #000000;\"><a style=\"color: #000000;\" href=\"https:\/\/i0.wp.com\/www.grandesterresbio.com\/wp-content\/uploads\/2015\/01\/corailblanc.png\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-5861 \" src=\"https:\/\/i0.wp.com\/www.grandesterresbio.com\/wp-content\/uploads\/2015\/01\/corailblanc.png?resize=360%2C270\" alt=\"corailblanc-www.grandesterresbio.com\" width=\"360\" height=\"270\" srcset=\"https:\/\/i0.wp.com\/claire-jannot.com\/wp-content\/uploads\/2015\/01\/corailblanc.png?w=800&amp;ssl=1 800w, https:\/\/i0.wp.com\/claire-jannot.com\/wp-content\/uploads\/2015\/01\/corailblanc.png?resize=300%2C225&amp;ssl=1 300w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a>Cinq facteurs peuvent d\u00e9terminer si un r\u00e9cif est condamn\u00e9 ou non apr\u00e8s un blanchissement, un <strong>ph\u00e9nom\u00e8ne mena\u00e7ant la\u00a0biodiversit\u00e9<\/strong>, le tourisme et la p\u00eache, indiquent des chercheurs dans <strong>la revue Nature<\/strong>.<\/span><\/p>\n<p><span style=\"color: #000000;\">\u00ab\u00a0La profondeur de l&rsquo;eau, la structure physique du r\u00e9cif avant la perturbation, les niveaux de nutriment, les volumes\u00a0consomm\u00e9s par les poissons et la survie de jeunes coraux pourraient <strong>aider \u00e0 pr\u00e9voir la gu\u00e9rison<\/strong> du corail\u00a0\u00bb, \u00e9crit Nicholas\u00a0Graham, de l&rsquo;universit\u00e9 australienne <strong>James Cook University<\/strong>, qui a dirig\u00e9 l&rsquo;\u00e9tude.<\/span><\/p>\n<p><span style=\"color: #000000;\">L&rsquo;un des <strong>pires \u00e9pisodes de blanchissement massif a touch\u00e9 60 pays tropicaux en 1998<\/strong>, ann\u00e9e qui a connu un \u00e9pisode de\u00a0type Ni\u00f1o exceptionnel. <strong>El Ni\u00f1o est un courant chaud du Pacifique<\/strong> qui appara\u00eet tous les cinq \u00e0 sept ans en moyenne et exerce\u00a0une forte influence sur le climat du globe.\u00a0Les coraux d\u00e9pendent d&rsquo;algues microscopiques, les <strong>dinoflagell\u00e9s<\/strong>, qui vivent en vastes colonies \u00e0 leur surface.\u00a0Elles se nourrissent d&rsquo;azote, de phosphore et autres nutriments fournis par le corail, et utilisent la lumi\u00e8re pour transformer\u00a0cette nourriture en \u00e9nergie.\u00a0<\/span>La photosynth\u00e8se lib\u00e8re aussi de l&rsquo;\u00e9nergie dans les tissus du corail, lui permettant de construire le squelette de calcium qui\u00a0abrite ces algues unicellulaires.<\/p>\n<p><strong><span style=\"color: #000000;\">Quand le corail est soumis \u00e0 un stress, comme une hausse importante de la temp\u00e9rature de l&rsquo;eau, il se d\u00e9barrasse des\u00a0dinoflagell\u00e9s et p\u00e2lit car ce sont ces algues qui contiennent des pigments lui donnant sa couleur.<\/span><\/strong><\/p>\n<p><span style=\"color: #000000;\">A ce stade, les r\u00e9cifs ne sont pas morts mais ils deviennent plus sensibles aux maladies et mourront s&rsquo;ils ne retrouvent pas\u00a0ces algues. Leur disparition a un fort impact sur les populations de poissons.<\/span><\/p>\n<p><span style=\"color: #000000;\">Pour l&rsquo;\u00e9tude, les auteurs ont examin\u00e9 des donn\u00e9es recueillies durant <strong>17 ans aux Seychelles<\/strong>, dont plus de 90% des coraux\u00a0avaient blanchi en 1998.<\/span><\/p>\n<p><span style=\"color: #000000;\"><strong>Douze des 21 r\u00e9cifs coralliens des Seychelles ont retrouv\u00e9 la sant\u00e9, mais neuf n&rsquo;y sont pas parvenus<\/strong>: en analysant cette\u00a0situation, les chercheurs ont pu \u00e9tablir pour les diff\u00e9rents param\u00e8tres des seuils au-del\u00e0 desquels les coraux n&rsquo;avaient pas\u00a0surv\u00e9cu.<\/span><\/p>\n<p><span style=\"color: #000000;\">Ces r\u00e9sultats devraient permettre \u00e0 l&rsquo;avenir de \u00ab\u00a0pr\u00e9dire quels coraux ont la capacit\u00e9 de redevenir sains\u00a0\u00bb et cela \u00ab\u00a0est tr\u00e8s\u00a0important pour cartographier les gagnants et les perdants et analyser les risques\u00a0\u00bb, estime Shaun Wilson, l&rsquo;un des coauteurs de\u00a0l&rsquo;\u00e9tude.<\/span><\/p>\n<address><span style=\"color: #000000;\">Source :\u00a0PARIS, 14 jan 2015 (AFP)<\/span><\/address>\n<address><span style=\"color: #000000;\">Cr\u00e9dit :\u00a0By Samuel Chow (originally posted to Flickr as Bleached Coral) [CC BY 2.0 (http:\/\/creativecommons.org\/licenses\/by\/2.0)], via Wikimedia Commons<\/span><\/address>\n<address>\u00a0<\/address>\n<address>\u00a0<\/address>\n<address>\u00a0<\/address>\n<address>\u00a0<\/address>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Une forte hausse de la temp\u00e9rature de la mer peut provoquer un \u00ab\u00a0blanchissement\u00a0\u00bb catastrophique du corail mais une \u00e9tude publi\u00e9e mercredi a identifi\u00e9 plusieurs facteurs susceptibles de rendre certains coraux plus r\u00e9sistants que d&rsquo;autres. Cinq facteurs peuvent d\u00e9terminer si un &hellip; <a href=\"https:\/\/claire-jannot.com\/?p=5860\">Continuer la lecture <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[2],"tags":[4,5,52],"class_list":["post-5860","post","type-post","status-publish","format-standard","hentry","category-ecologie","tag-ecologie2","tag-environnement","tag-oceans"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5jjt5-1ww","_links":{"self":[{"href":"https:\/\/claire-jannot.com\/index.php?rest_route=\/wp\/v2\/posts\/5860","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/claire-jannot.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/claire-jannot.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/claire-jannot.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/claire-jannot.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5860"}],"version-history":[{"count":1,"href":"https:\/\/claire-jannot.com\/index.php?rest_route=\/wp\/v2\/posts\/5860\/revisions"}],"predecessor-version":[{"id":5862,"href":"https:\/\/claire-jannot.com\/index.php?rest_route=\/wp\/v2\/posts\/5860\/revisions\/5862"}],"wp:attachment":[{"href":"https:\/\/claire-jannot.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5860"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/claire-jannot.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5860"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/claire-jannot.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5860"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}