{"id":576925,"date":"2026-07-31T09:49:10","date_gmt":"2026-07-31T09:49:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/576925\/"},"modified":"2026-07-31T09:49:10","modified_gmt":"2026-07-31T09:49:10","slug":"the-arctic-ocean-keeps-permafrost-carbon-firmly-locked","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/576925\/","title":{"rendered":"The Arctic Ocean keeps permafrost carbon firmly locked"},"content":{"rendered":"

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Permafrost in the Arctic stores large quantities of organic carbon. When the frozen ground thaws or coastal sections erode, this carbon can enter the sea, where microorganisms can break it down and convert it into climate-damaging greenhouse gases.<\/p>\n

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Credit: Alfred-Wegener-Institut \/ Jaroslav Obu<\/p>\n

Permafrost in the Arctic stores large quantities of organic carbon. When the frozen ground thaws or coastal sections erode, this carbon can enter the sea, where microorganisms can break it down and convert it into climate-damaging greenhouse gases. The extent to which this carbon actually enters the atmosphere, however, and how much remains in the ocean has hardly been quantified to date. Researchers from the Alfred Wegener Institute and MARUM \u2013 Centre for Marine Environmental Sciences at the University of Bremen have now been able to answer this question for the first time for the permafrost coast of Qikiqtaruk (Herschel Island) in Canada. With the help of sediment cores, they discovered that considerable amounts of terrestrial carbon are stored in the seabed. It also became apparent that microorganisms are particular gourmets who decidedly prefer fresh marine carbon. The researchers published their findings in the journal\u00a0Nature Geoscience.<\/p>\n

Arctic terrestrial permafrost ecosystems store around 1,300 gigatonnes of carbon from organic sources, such as from the remains of plants. Sediments in oceans and river deltas contain a further 400 gigatonnes. Global warming, however, is taking its toll on this natural freezer: temperatures in the Arctic are rising faster than anywhere else on our planet, with the result that permafrost in the region is thawing rapidly. The carbon stored here can then enter the Arctic Ocean via rivers and eroding coastlines. \u201cConsequently, up to 0.02 gigatonnes are entering the sea each year, and according to forecasts, this outflow could rise by 70 to 150 per cent by the year 2100,\u201d says Dr Manuel Ruben, lead author of the study from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). \u201cHowever, how much of this is released back into the atmosphere as a greenhouse gas and how much is stored in the seabed has, until now, been largely unknown.\u201d Yet, this knowledge is essential for assessing the climate impact of thawing permafrost.\u00a0<\/p>\n

To get to the bottom of this unknown, the researchers retrieved and analysed sediment cores taken at various intervals off the coast of the Canadian island of Herschel Island. The cores contain deposits spanning around 50 years. Analysis of the sediments revealed something surprising:\u00a0\u201cAlthough the sea here carries away huge quantities of organic carbon from the coast, surprisingly little of it ends up in the ocean\u2019s active carbon cycle,\u201d says Manuel Ruben. \u201cMicroorganisms\u00a0convert\u00a0around ten per cent of the organic carbon from the sediments into gases, which rise into the water and can then enter our atmosphere.\u201d The major share, however, is stored in the seabed.\u00a0<\/p>\n

In conducting their analysis, the researchers first examined the composition of the sediment cores in detail and also investigated how rapidly permafrost deposits accumulate on the seabed. To this end, they measured how much inorganic dissolved carbon accumulates in tiny cavities within the sediment layers \u2013 known as pore water. This provides an indication of how much CO\u2082\u00a0microorganisms have \u2018exhaled\u2019 after \u2018digesting\u2019 the organic carbon. The isotopic composition of the pore water provides insights into which organic material from which source has been broken down. \u201dCarbon isotopes represent our atomic indicators that can identify the food source of the microorganisms,\u201d says Prof. Gesine Mollenhauer, a geochemist at the AWI and co-spokesperson for the\u00a0\u2018The Ocean Floor \u2013 Earth\u2019s Unexplored Interface<\/a>\u2019 cluster of Excellence. \u201cThe\u00a013C isotope, for example, tells us whether they have consumed carbon from land or from the sea. By way of the\u00a014C isotope, we were able to determine whether the single-celled organisms preferred old organic carbon from permafrost or fresh organic carbon from algae remains.\u201d\u00a0<\/p>\n

One explanation for this lies in the eating habits of these tiny organisms: \u201cThe sediment is home to \u2018gourmet\u2019 bacteria that apparently prefer fresh carbon stemming from, for example, more recent algal remains over the \u2018old\u2019 carbon from permafrost deposits,\u201d explains Gesine Mollenhauer. This suggests that the organic carbon entering the sea from land contributes less to the amount of greenhouse gases in the atmosphere than originally feared. \u201cHowever, we do need further research here. This is because some of the organic carbon from the permafrost may already have been broken down before it reaches the seabed.\u201d\u00a0<\/p>\n

In addition to the impact of land-ocean carbon transport on atmospheric greenhouse gas levels, further effects are possible. For instance, this transport influences the biogeochemistry of coastal waters, which also play an important role in providing food for the local population. This is because the sediments alter the amount of sunlight available: on the one hand, the freshly broken-off fragments cloud the coastal ocean, while on the other hand, the organic carbon they contain discolours the water as it dissolves into it. Single-celled organisms such as algae, however, need light to convert this into biomass and oxygen. This primary production, in turn, forms the foundation for marine life such as fish, crustaceans and seals. The researchers aim to investigate these complex interrelationships, among other things, as part of the international \u2018Arctic Pulse<\/a>\u2019 campaign planned for 2027. Through coordinated measurement campaigns aboard the Polarstern research icebreaker, using the AWI\u2019s research aircraft and on land, they will investigate how rapid environmental change is altering ecosystems in the Arctic.\u00a0<\/p>\n

\u201cOur study shows, more precisely than ever before, how much carbon is safely stored in the seabed \u2013 and just how much of the decomposed material actually originates from the old permafrost,\u201d says\u00a0Manuel Ruben.\u00a0\u201cThis provides an important foundation for climate models that can predict the consequences of permafrost thawing for the global climate.\u201d<\/p>\n

Journal<\/p>\n

Nature Geoscience<\/p>\n

Article Title<\/p>\n

Limited remineralization of Arctic permafrost-derived organic carbon in nearshore marine sediments<\/p>\n

Article Publication Date<\/p>\n

31-Jul-2026<\/p>\n

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.<\/p>\n","protected":false},"excerpt":{"rendered":"image:\u00a0 Permafrost in the Arctic stores large quantities of organic carbon. When the frozen ground thaws or coastal…\n","protected":false},"author":2,"featured_media":576926,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[61,60,82],"class_list":["post-576925","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\/576925","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=576925"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/576925\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/576926"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=576925"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=576925"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=576925"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}