Dissolved organic matter in the Lena Delta in 2009

• Main Authors: Dubinenkov, Ivan, Flerus, Ruth, Schmitt-Kopplin, Philippe, Kattner, Gerhard, Koch, Boris P
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: AWI_Coast; AWI Arctic Land Expedition; Carbon; organic; dissolved; Coastal Ecology @ AWI; DATE/TIME; Depth; bathymetric; water; High temperature catalytic oxidation; LATITUDE; Lena2009; Lena Delta; Siberia; Russia; LenaDelta2009; Location type; LONGITUDE; MULT; Multiple investigations; Nitrogen; total dissolved; RU-Land_2009_Lena; Sample ID; Arctic; Arctic Ocean; Laptev Sea; Khaya; Buor-Khaya; Ice; laptev; lena delta; lena river; permafrost
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.831765; https://doi.org/10.1594/PANGAEA.831765

Large Arctic rivers discharge significant amounts of dissolved organic matter (DOM) into the Arctic Ocean. We sampled natural waters of the Lena River, the Buor-Khaya Bay (Laptev Sea), permafrost melt water creeks, ice complex melt water creeks and a lake. The goal of this study was to characterize the molecular DOM composition with respect to different water bodies within the Lena Delta. We aimed at an identification of source-specific DOM molecular markers and their relative contribution to DOM of different origin. The molecular characterization was performed for solid-phase extracted DOM by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Average dissolved organic carbon concentrations in the original samples were 490±75 µmol C/L for riverine and bay samples and 399±115 µmol C/L for permafrost melt water creeks. Average TDN concentrations were elevated in the permafrost melt waters (19.7±7.1 µmol N/L) in comparison to the river and the bay (both 13.2±2.6 µmol N/L). FT-ICR MS and statistical tools demonstrated that the origin of DOM in the Lena Delta was systematically reflected in its molecular composition. Magnitude weighted parameters calculated from MS data (O/Cwa, H/Cwa, C/Nwa) highlighted preliminary sample discrimination. The highest H/Cwa of 1.315 was found for DOM in melt water creeks in comparison to 1.281 for river and 1.230 for the bay samples. In the bay samples we observed a higher fraction of oxygen-rich components which was reflected in an O/Cwa ratio of 0.445 in comparison to 0.425 and 0.427 in the river and creeks, respectively. From the southernmost location to the bay a relative depletion of nitrogenous molecular markers and an enrichment of oxidized DOM components occurred. The highest contribution of nitrogenous components was indicative for creeks reflected in a C/Nwa of 104 in comparison to 143 and 176 in the river and bay, respectively. These observations were studied on a molecular formula level using principal component and indicator value analyses. The ...