20.500.12556/DiRROS-24862 Carbon cycling dynamics in the headwater Radovna stream recharged by Lipnik springs, a carbonate catchment in the Julian Alps, Slovenia, based on stable isotope analysis Dinamika kroženja ogljika v zgornjem toku potoka Radovna, ki ga napajajo izviri Lipnik, znotraj karbonatnega zaledja v Julijskih Alpah (Slovenija), na podlagi analize stabilnih izotopov Carbon cycling was investigated monthly (July, August, September, October, November, March and May) from July 2023 to May 2024 in the Radovna stream originating from the permanent Lipnik spring in the Julian Alps, Slovenia using isotopic composition of carbon in dissolved inorganic carbon (δ13CDIC) and particulate organic carbon (δ13CPOC). The investigated catchment is composed of massive coarse - crystal dolomite and limestone. Total alkalinity ranged from 2.2 to 2.7mM and is characteristic for carbonate pristine environments. In-situ parameters e.g. dissolved oxygen ranged from 11.0 to 12.0mg/L, pH from 7.9 to 8.1 and specific electrical conductivity from 275 to 318μS/cm, respectively. The values of dissolved oxygen reflect that the water system is well oxygenated. CO2 presented a source of carbon to the atmosphere during all investigated months. Oversaturation with CO2 is 1.01 to 4.1 times of atmospheric value. δ13CDICranged from -11.8 to -9.7‰. This indicates that dissolved inorganic carbon under different discharge conditions mainly originates from the dissolution of carbonates (from 50.3 % to 57.3%), followed by the degradation of organic matter (from 42.8% to 49.7%). Equilibration with atmospheric CO₂ has a negligible impact, ranging from 0.01% to 0.11%. δ13CPOC in river water indicate sources such as plant debris, with δ13CPOC of -29.4‰, and highly degraded soil organic matter, with δ13CPOC of -24.9‰. The δ13CDIC and δ13CPOC values are typical for a forest stream flowing over a limestone substrate. Strong statistical negative significant correlation was obtained between electrical conductivity and water temperature, mass of total suspended solids (mTSS) and pH. Ogljikov cikel smo preučevali mesečno (julij, avgust, september, oktober, november, marec, maj) od julija 2023 do maja 2024 v potoku Radovne, ki izvira iz stalnega izvira Lipnik v Julijskih Alpah, Slovenija, z uporabo izotopske sestave ogljika v raztopljenem anorganskem ogljiku (δ13CDIC) in partikulatnem organskem ogljiku (δ13CPOC). Raziskano porečje je sestavljeno iz masivnega grobo-kristalnega dolomita in apnenca. Totalna alkalnost se je spreminjala od 2,2 do 2,7mM in je značilna za karbonatna naravna okolja. In-situ parametri kot je raztopljen kisik so se spreminjali od 11,0 do 12,0mg/L, pH od 7,9 do 8,1mg/L, specifična elektroprevodnost pa od 275 do 318μS/cm. Vrednosti raztopljenega kisika odražajo, da je vodni sistem dobro prezračen s kisikom. CO2 predstavlja sproščanje ogljika v atmosfero iz potoka v vseh preiskanih mesecih. Prenasičenost s CO2 je 1,01 do 4,1 krat večja od atmosferske vrednosti. δ13CDIC se je spreminjala od -11,8‰ do -9,7‰. To kaže, da raztopljeni anorganski ogljik pri različnih pretokih vode večinoma izvira iz raztapljanja karbonatov (od 50,3% do 57,3%), sledi pa razgradnja organske snovi (42,8% do 49,7 %). Uravnoteženje z atmosferskim CO₂ ima zanemarljiv vpliv, v razponu od 0,01% do 0,11%. Partikulatni organski material (POC) izvira iz površinskega in podzemnega toka. δ13CPOC v odvzeti vodi je odražal vir iz rastlinskih ostankov z δ13CPOC -29,4‰ in razgrajenega preperinskega organskega materiala z δ13CPOC -24,9‰. Vrednosti δ13CDIC in δ13CPOC so tipične za gozdni potok, ki teče po apnenčasti podlagi. Močna, statistično značilna negativna korelacija je bila ugotovljena med elektroprevodnostjo in temperaturo vode, maso celotne suspendirane snovi (mTSS) in pH. total alkalinity stable isotopes carbon pCO2 headwater stream Julian Alps totalna alkalnost stabilni izotopi ogljik pCO2 zgornji tok porečja Julijske Alpe true false true Geološki zavod Slovenije Angleški jezik Slovenski jezik Neznano 2025-12-23 03:58:37 2025-12-23 10:46:07 2025-12-24 04:01:09 0000-00-00 00:00:00 2025 0 0 str. 201-219 no. 2 vol. 68 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2025-12-10 556.3 0016-7789 10.5474/geologija.2025.008 261789955 1936-Article_Text-12342681-1-10-20251210.pdf 1936-Article_Text-12342681-1-10-20251210.pdf 1 A78B84F6F96057488F696E85F5F2FD2D 5f87aa87e875a84de251356bb5048f1b032f3f5bd2a669974456b1b116acfaf8 71384217-dfe4-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=37220 Geološki zavod Slovenije Geologija 0 0 0