\ud83e\uddca The Arctic is currently at the epicenter of dramatic global change. Unprecedented warming and its intensification in the region are leading to rapid sea ice retreat and irreversible losses of glacial ice, which already account for more than a quarter of the total rise in global sea levels. Climate models predict that by the middle of the 21st century, the Arctic Ocean will be \u201cblue\u201d (ice-free) in summer, which will have a huge impact on marine ecosystems.<\/p>\n
A key question is how these ecosystems will respond to an increasingly warm future. Arctic fjords, which are among the most productive ecosystems in the Arctic, contain a high-resolution geological record that allows us to study dynamic changes during past warm periods, known as "greenhouse" climate states.<\/p>\n
The study, which focused on the Kongsfjorden fjord in the northwest of the Svalbard archipelago, which is currently rapidly deglaciating, used organic geochemical biomarkers stored in sediments. These biomarkers serve as chemical fossils<\/strong>, ktor\u00e9 umo\u017e\u0148uj\u00fa sledova\u0165 pr\u00edspevok r\u00f4znych skup\u00edn plankt\u00f3nu k organick\u00e9mu uhl\u00edku v sedimentoch po\u010das posledn\u00fdch 14 000 rokov. Medzi analyzovan\u00e9 biomarkery patria napr\u00edklad IP25 (indik\u00e1tor diat\u00f3mov morsk\u00e9ho \u013eadu), HBI III (indik\u00e1tor diat\u00f3mov otvoren\u00fdch v\u00f4d), metylalken\u00f3ny C37 (indik\u00e1tor prymnesiofytov, s %C37:4 ako indik\u00e1torom rozsahu morsk\u00e9ho \u013eadu), dinosterol (indik\u00e1tor dinoflagel\u00e1tov) a brassikasterol (indik\u00e1tor diat\u00f3mov). Anal\u00fdzou t\u00fdchto biomarkerov spolu s \u010fal\u0161\u00edmi parametrami vedci dok\u00e1zali, \u017ee phytoplankton community structures changed dramatically in response to variable sea ice cover and glacial ice loss<\/strong>.<\/p>\n Examining past climate states provides valuable analogies for understanding the future.<\/p>\n At the end of the Younger Dryas<\/strong> (approximately 11,600 years ago), a period of cold, the fjord was covered by extensive seasonal sea ice, with very limited biological production. However, with the retreat of the glaciers, it became free nutrient supply<\/strong>, which dramatically changed the structure of phytoplankton and led to a significant revival of primary production, especially diatoms.<\/p>\n Subsequently, during the Holocene Thermal Maximum (HTM)<\/strong> (approximately 10,000\u20136,000 years ago), a period of exceptional warmth in Svalbard, saw further sea ice loss. Warmer waters from the Atlantic significantly affected the hydrography of the fjord. Despite the expected higher phytoplankton productivity in ice-free waters, biomarkers showed that in the warmer, stratified ocean high utilization rate of available nutrients<\/strong>An important finding was also significant increase in limestone organisms<\/strong> (zooplankton and benthos), which probably led to high grazing pressure on decreasing organic biomass<\/strong>That probably limited carbon transfer<\/strong> from the illuminated zone to the seabed, reducing the efficiency of carbon storage. HTM serves as a powerful analogue for understanding ecosystem dynamics in future warmer conditions<\/strong>.<\/p>\n Today, we face a rapidly warming Arctic. Our results suggest that fjords remain important sites for carbon transport and storage during the transition phase, when glaciers change from marine to land-based. However, in the future, when fjords become landlocked and ice-free, they will likely lose this effectiveness<\/strong>It is assumed that future ice loss in Svalbard is likely to increase primary production in the \u201cblue\u201d scenario, but the potential of fjords to serve as hotspots for storing marine organic carbon is likely to be limited<\/strong>. The reasons are warmer, stratified waters and reduced supply of critical nutrients from melting ice. The dominance of Atlantic waters and the loss of sea ice may also lead to a shift in dominant phytoplankton groups, for example, to a predominance of prymnesiophytes, which can weaken the "biological pump"<\/strong> (the process of transferring carbon from surface waters to depths and sediments).<\/p>\n Understanding the response of the marine ecosystem in the "blue" Arctic to an increasingly warmer future is a globally significant issue. Studying the past provides us with crucial insights into how Arctic fjords and their ecosystems have adapted and are likely to change in the coming decades. Spring<\/strong><\/em><\/p>\n Glossary of key terms<\/strong><\/p>\n \ud83e\uddca The Arctic is currently at the epicenter of dramatic global change. Unprecedented warming and its intensification in the region are leading to rapid sea ice retreat and irreversible losses<\/p>","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-35095","post","type-post","status-publish","format-standard","hentry","category-klimaticka-zmena"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/posts\/35095","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/comments?post=35095"}],"version-history":[{"count":0,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/posts\/35095\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/media?parent=35095"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/categories?post=35095"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/tags?post=35095"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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