{"id":28999,"date":"2024-12-26T01:00:03","date_gmt":"2024-12-25T19:30:03","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=28999"},"modified":"2025-04-08T23:44:41","modified_gmt":"2025-04-08T18:14:41","slug":"ocean-anoxic-event-1a-oae-1a","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/ocean-anoxic-event-1a-oae-1a\/","title":{"rendered":"Ocean Anoxic Event 1a (OAE 1a)"},"content":{"rendered":"<h2><strong>What is Ocean Anoxic Event 1a (OAE 1a)?<\/strong><\/h2>\n<ul>\n<li><strong>Definition<\/strong>: OAE 1a occurred during the <strong>Cretaceous Period (145\u201366 million years ago)<\/strong>, marking a time when <strong>Earth\u2019s oceans became depleted of oxygen<\/strong>. This led to severe disruptions in <strong>marine ecosystems<\/strong>.<\/li>\n<li><strong>Causes<\/strong>: Triggered by <strong>massive volcanic eruptions<\/strong>, which released large amounts of <strong>carbon dioxide (CO\u2082)<\/strong>, resulting in <strong>global warming<\/strong> and <strong>oxygen depletion<\/strong> in the oceans.\n<ul>\n<li>These conditions created <strong>anoxic marine basins<\/strong>, where oxygen levels were nearly absent.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Impacts<\/strong>: The interaction of <strong>CO\u2082 and seawater<\/strong> formed <strong>carbonic acid<\/strong>, dissolving marine organisms\u2019 shells and reducing oxygen levels.\n<ul>\n<li>This resulted in the extinction of several marine species, particularly <strong>plankton<\/strong>, and led to the formation of <strong>black shales<\/strong>, organic carbon-rich layers preserved in geological records.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Anoxic marine basins: <\/strong>Bodies of water, often in <strong>deep ocean regions<\/strong>, where oxygen levels are extremely low or absent.\n<ul>\n<li><strong>Characteristics<\/strong>: Favor the survival of specialized microbes and fungi while inhibiting most aerobic life forms.<\/li>\n<li><strong>Carbon Sequestration<\/strong>: Low oxygen levels slow the decomposition of organic matter, aiding in <strong>long-term carbon sequestration<\/strong>, which helps reduce atmospheric CO\u2082 levels.<\/li>\n<li><strong>Examples<\/strong>: <strong>Black Sea<\/strong>, <strong>Cariaco Basin<\/strong> (Caribbean Sea), and <strong>Orca Basin<\/strong> (Gulf of Mexico).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Key Highlights of the Recent Study<\/strong><\/p>\n<ul>\n<li><strong>Timing<\/strong>: The event began <strong>119.5 million years ago<\/strong>, confirmed through isotopic analysis of <strong>volcanic tuffs<\/strong> from Japan\u2019s Hokkaido Island.\n<ul>\n<li>OAE 1a lasted approximately <strong>1.1 million years<\/strong>, indicating the extended recovery period for oceans after CO\u2082-driven warming and anoxia.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Volcanic activity<\/strong>: Linked to massive volcanic eruptions, such as the <strong>Ontong Java Nui complex<\/strong>, which released significant CO\u2082 into the atmosphere and oceans.<\/li>\n<li><strong>Modern relevance<\/strong>: Highlights parallels between ancient volcanic CO\u2082 emissions and <strong>current human-induced warming<\/strong>.\n<ul>\n<li>Warns that rapid modern warming could trigger similar disruptions in <strong>marine ecosystems<\/strong> and potentially lead to a <strong>Holocene extinction event<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<hr \/>\n<h3>Q1) What is the National Institute of Ocean Technology (NIOT)?\u00a0<\/h3>\n<p>NIOT was established in November 1993 as an autonomous society under the Ministry of Earth Sciences, Government of India. NIOT is managed by a Governing Council and the Director is the head of the Institute.\u00a0<\/p>\n<p><strong>Source:<\/strong> <a href=\"https:\/\/phys.org\/news\/2024-12-prehistoric-japan-reveals-clues-major.html#:~:text=By%20studying%20prehistoric%20rocks%20and,cause%20significant%20extinction%2C%20especially%20among\" target=\"_blank\" rel=\"noopener noreferrer nofollow\"><strong>PHYS<\/strong><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>OAE 1a occurred during the Cretaceous Period (145\u201366 million years ago), marking a time when Earth\u2019s oceans became depleted of oxygen. This led to severe disruptions in marine ecosystems.<\/p>\n","protected":false},"author":5,"featured_media":29000,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":{"0":"post-28999","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-prelims-current-affairs","8":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/28999","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=28999"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/28999\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/29000"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=28999"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=28999"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=28999"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}