Document Type

Article

Publication Date

10-2017

DOI

10.1038/s41598-017-12729-1

Publication Title

Scientific Reports

Volume

7

Issue

1

Pages

13064 (11pg.)

Abstract

Arctic river watersheds are important components of the global climate system and show an amplified response to climate change. Here, we characterize origins and transformations of dissolved organic matter (DOM) in five major Arctic rivers (Kolyma, Lena, Yenisei, Ob, Mackenzie) over 3 years with seasonal sampling periods using measurements of carbohydrates, amino acids, bacterial biomarkers (D-amino acids), and plant protein biomarkers (hydroxyproline). A strong seasonal cycle of bioavailable DOM export was observed that correlated with discharge, vegetation, river morphology and water residence time. The chemical composition of bioavailable DOM was different among rivers reflecting unique characteristics of Arctic river watersheds. Trends in specific bacterial biomarkers were synchronous to changes in bacterial community compositions demonstrating that bacterial communities responded to the seasonal shifts in organic matter quality and chemical composition. Extensive heterotrophic processing of plant and soil-derived DOM resulted in major inputs of bacterial detritus, and bacterial organic matter accounted for 21-42% of DOC in all watersheds. Dissolved organic nitrogen sources were dominated by bacterially-derived nitrogen and important contributions of soluble plant protein during the Spring freshet. Overall, our results demonstrated the importance of watershed characteristics and bacterial metabolism in regulating DOM composition, reactivity and carbon fluxes in Arctic river watersheds.

Rights

© The Author(s) 2017

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Data Availability

Article states: "We note that there are no data sharing issues since all numerical information is provided in figures and tables. Supporting data are included as four tables and four figures in an SI file."

Supporting information is available online at https://doi.org/10.1038/s41598-017-12729-1.

Original Publication Citation

Kaiser, K., Canedo-Oropeza, M., McMahon, R., & Amon, R. M. W. (2017). Origins and transformations of dissolved organic matter in large Arctic rivers. Scientific Reports, 7(1), 13064. doi:10.1038/s41598-017-12729-1

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