{"id":555388,"date":"2026-06-26T15:07:12","date_gmt":"2026-06-26T15:07:12","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/555388\/"},"modified":"2026-06-26T15:07:12","modified_gmt":"2026-06-26T15:07:12","slug":"geological-land-use-and-biological-influences-on-carbon-cycling-and-co2-degassing-in-the-danube-river","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/555388\/","title":{"rendered":"Geological, land use and biological influences on carbon cycling and CO2 degassing in the Danube River"},"content":{"rendered":"<p>River systems form critical interfaces in the terrestrial-atmospheric carbon cycle, yet basin-scale constraints on the spatial and seasonal controls of inorganic carbon dynamics and CO2 exchange remain limited. We present a multi-seasonal longitudinal assessment of dissolved inorganic carbon (DIC), its stable isotopes (\u03b413CDIC), and aqueous CO2 partial pressure (pCO2(aq)) along the entire Danube River. Five sampling campaigns captured seasonal variability along the main stem and major tributaries of this geologically diverse basin. DIC comprised\u2009&gt;\u200990% of total carbon, showing limited longitudinal and seasonal variability (0.3 to 5.3 mmol L\u2212\u20091), with highest concentrations in the upper Danube due to groundwater inputs and carbonate weathering, followed by downstream homogenization. In contrast, \u03b413CDIC increased downstream from \u2212\u200913.3 to -8.7\u2030, indicating cumulative CO2 degassing, with deviations linked to tributary inflows and biological activity. C4 plant inputs may have contributed up to 27.2% to the \u03b413CDIC. River pCO2(aq) ranged from \u223c260 to 3,770 \u00b5atm, predominantly supersaturated, with CO2 fluxes of 0.975\u20131.993 Gg C d\u207b\u00b9, confirming the Danube as a persistent CO2 source. Near-equilibrium conditions in spring and summer coincided with enriched \u03b413CDIC, consistent with episodic photosynthetic uptake. These results reveal how groundwater inputs, in-stream photosynthesis, and air-water exchange regulate inorganic carbon dynamics and CO2 emissions in large rivers.<\/p>\n","protected":false},"excerpt":{"rendered":"River systems form critical interfaces in the terrestrial-atmospheric carbon cycle, yet basin-scale constraints on the spatial and seasonal&hellip;\n","protected":false},"author":2,"featured_media":555389,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[77],"tags":[26594,237657,18705,237656,237650,6130,18,3297,237654,237653,1099,41664,19,17,1100,237652,237651,133,237655],"class_list":["post-555388","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-biogeochemistry","tag-c3-c4-isotope-mass-balance","tag-climate-sciences","tag-co2-fluxes","tag-dissolved-inorganic-carbon-dic","tag-ecology","tag-eire","tag-environmental-sciences","tag-freshwater-research","tag-groundwater-surface-interactions","tag-humanities-and-social-sciences","tag-hydrology","tag-ie","tag-ireland","tag-multidisciplinary","tag-n-pco2aqn","tag-n-n-13cdic-stable-isotope-analyses","tag-science","tag-weathering"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/116817038420100264","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/555388","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=555388"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/555388\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/555389"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=555388"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=555388"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=555388"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}