Clams reveal ocean history Scientists from the University of Exeter<\/a> and collaborators analyzed shells of quahog clams and dog cockles, species that can live for centuries. <\/p>\n Each shell contains yearly layers, storing physical and chemical clues about the ocean\u2019s past. These archives allow researchers to trace changes over hundreds of years without gaps in data.<\/p>\n \u201cAnticipating a tipping point requires good data, covering a long period with no gaps,\u201d explained study lead author Dr. Beatriz Arellano Nava. <\/p>\n How ocean currents work<\/p>\n By reading shell bands, researchers reconstructed a continuous record of Atlantic circulation behavior, focusing on two critical systems: the Atlantic<\/a> Meridional Overturning Circulation (AMOC) and the Subpolar Gyre (SPG).<\/p>\n Both systems transport heat across the planet. The AMOC carries warm water northward, helping to keep Europe mild. The SPG stabilizes the North Atlantic climate by circulating cooler waters. <\/p>\n If the AMOC collapses, winters in Europe could become harsher, while rainfall patterns might change globally. A weakened SPG could still cause more storms and regional temperature swings.<\/p>\n Atlantic Ocean weakening<\/p>\n The study used 25 shell-based records from the North Atlantic<\/a> shelves, applying indicators such as autocorrelation and restoring rate to detect stability loss.<\/p>\n When these indicators rise over time, it means the system is taking longer to recover from disturbances \u2013 a sign of \u201ccritical slowing down,\u201d a known precursor to tipping points.<\/p>\n Across twelve key sites \u2013 from Newfoundland to Norway \u2013 scientists found two major destabilization periods. <\/p>\n The first occurred before the 1920s regime shift, suggesting an early crossing of a tipping point. The second began around 1950 and continues today, aligning with broader evidence of ocean weakening.<\/p>\n Evidence of change <\/p>\n The study revealed that the strongest instability occurred in areas sensitive to SPG temperature changes. This indicates that basin-scale processes, rather than local weather, drive the destabilization. <\/p>\n \u201cWhen a system is stable, there will still be variations \u2013 but we would typically see a rapid return to the normal state after a change,\u201d said Professor Paul Halloran, co-author of the study. <\/p>\n \u201cWhen a system destabilizes, it doesn\u2019t recover as quickly \u2013 and this could be a sign of an approaching tipping point.\u201d<\/p>\n Atlantic Ocean instability <\/p>\n Bivalve records show a rise in instability before 1920, followed by a decline and then another increase after 1950. <\/p>\n These patterns match ocean temperature data from modern models, confirming that the results are not artifacts of statistical processing but genuine climate signals.<\/p>\n The early 20th century destabilization coincided with a known North Atlantic regime shift that brought warmer conditions and biological changes, including shifts in fish populations. <\/p>\n The later destabilization, still ongoing, reflects the cumulative effects of human-driven climate change.<\/p>\n Lessons from the Atlantic Ocean<\/p>\n Researchers concluded that the SPG and AMOC may both be losing stability, but it is difficult to pinpoint which is closer to a critical state. <\/p>\n Evidence from the Science Advances study suggests the SPG might weaken first. A weaker SPG could alter ocean heat transport, disrupt regional ecosystems, and affect the AMOC\u2019s ability to circulate deep water.<\/p>\n \u201cMelting of polar ice due to climate change is certainly contributing to the weakening of ocean currents and pushing them closer to a tipping point,\u201d said Dr. Arellano Nava. <\/p>\n Rapid ice melt adds freshwater, disrupting density-driven circulation. This imbalance threatens to amplify instability across the entire Atlantic system.<\/p>\n An ocean under pressure <\/p>\n The research combines biology and physics, showing how long-lived marine organisms can record early warning signs of climate imbalance. <\/p>\n These shell records extend the timeline of ocean monitoring far beyond human observation. The findings emphasize that the Atlantic is already showing symptoms of declining resilience.<\/p>\n The study funded by the European Union\u2019s Horizon 2020 COMFORT and ARIA AdvanTip projects concludes that the North Atlantic may be entering a dangerous phase. \u201cRapidly reducing greenhouse gas emissions is the best way to prevent tipping points in the Atlantic Ocean,\u201d said Dr. Arellano Nava.<\/p>\n The clam shells, once silent witnesses of history, now speak urgently of an ocean under strain. Their layered memories warn us: if humanity does not act, the tides of change could become irreversible.<\/p>\n The study is published in the journal 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.\u00a0<\/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":"The Atlantic Ocean has always been a powerhouse of climate regulation. But new findings reveal that this vast…\n","protected":false},"author":2,"featured_media":65985,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[273,111,139,69,147],"class_list":{"0":"post-65984","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\/65984","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=65984"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/65984\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/65985"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=65984"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=65984"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=65984"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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