caa a22 4500 60551674X CHVBK 20210128100715.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s10533-014-0032-9 doi (NATIONALLICENCE)springer-10.1007/s10533-014-0032-9 Downstream alteration of the composition and biodegradability of particulate organic carbon in a mountainous, mixed land-use watershed [Elektronische Daten] [Byung-Joon Jung, Laurent Jeanneau, Christine Alewell, Bomchul Kim, Ji-Hyung Park] Despite increasing recognition of storm-induced organic carbon (C) export as a significant loss from the terrestrial C balance, little is known about the biodegradation and chemical transformation of particulate organic carbon (POC) in mountainous river systems. We combined analyses of C isotopes, solution-state 1H NMR, and lipid biomarkers with biodegradable dissolved organic C (BDOC) measurements to investigate downstream changes of POC composition and biodegradability at a mountainous, mixed land-use watershed in South Korea. Water and suspended sediment (SS) samples were collected in a forested headwater stream, a downstream agricultural stream, and two downstream rivers during peak flow periods of four storm events, using either sequential grab sampling from the headwater stream to the most downstream river within a few hours around the peak flow or sediment samplers deployed during the whole storm event. DOC concentrations exhibited relatively small changes across sites, whereas POC concentrations were highest in the agricultural stream, and tapered along downstream reaches. The δ13C and δ15N of SS in the agricultural stream were distinct from up- and downstream signatures and similar to those for erosion source soils and lake bottom sediment, although increases in radiocarbon age indicated continuous compositional changes toward the lake. 1H NMR spectra of SS and deposited sediment exhibited downstream decreases in carbohydrates and lignin but enrichment of organic structures related to microbial proteins and plant wax. The downstream sediments had more microbial n-alkanes and lipid markers indicating anthropogenic origin such as coprostanol compared to the forest soil n-alkanes dominated by plant wax. While the BDOC concentrations of filtered waters differed little between sites, the BDOC concentrations and protein- to humic-like fluorescence ratios of DOC leached from SS during a 13-day incubation were higher in downstream rivers, pointing to contribution of labile POC components to the enhanced biodegradation. Overall, inputs of microbial and anthropogenic origin, in interplay with deposition and mineralization, appear to substantially alter POC composition and biodegradability during downstream transport, raising a question on the conventional view of mountainous river systems as a passive conduit of storm pulses of POC. Springer International Publishing Switzerland, 2014 Biodegradation nationallicence Carbon isotopes nationallicence Dissolved organic carbon nationallicence 1H-NMR nationallicence Lipid biomarker nationallicence Particulate organic carbon nationallicence Jung Byung-Joon Department of Forest Environment Protection, Kangwon National University, 200-701, Chuncheon, Republic of Korea aut Jeanneau Laurent UMR 6118 Geosciences Rennes, Université de Rennes 1, CNRS, Rennes, France aut Alewell Christine Environmental Geosciences, Department of Environmental Sciences, University of Basel, 4056, Basel, Switzerland aut Kim Bomchul Department of Environmental Science, Kangwon National University, 200-701, Chuncheon, Republic of Korea aut Park Ji-Hyung Department of Environmental Science & Engineering, Ewha Womans University, 120-750, Seoul, Republic of Korea aut Biogeochemistry Springer International Publishing 122/1(2015-01-01), 79-99 0168-2563 122:1<79 2015 122 10533 https://doi.org/10.1007/s10533-014-0032-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-014-0032-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jung Byung-Joon Department of Forest Environment Protection, Kangwon National University, 200-701, Chuncheon, Republic of Korea aut NATIONALLICENCE 700 1- Jeanneau Laurent UMR 6118 Geosciences Rennes, Université de Rennes 1, CNRS, Rennes, France aut NATIONALLICENCE 700 1- Alewell Christine Environmental Geosciences, Department of Environmental Sciences, University of Basel, 4056, Basel, Switzerland aut NATIONALLICENCE 700 1- Kim Bomchul Department of Environmental Science, Kangwon National University, 200-701, Chuncheon, Republic of Korea aut NATIONALLICENCE 700 1- Park Ji-Hyung Department of Environmental Science & Engineering, Ewha Womans University, 120-750, Seoul, Republic of Korea aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 122/1(2015-01-01), 79-99 0168-2563 122:1<79 2015 122 10533