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Li, S. ; Harir, M. ; Schmitt-Kopplin, P. ; Machado-Silva, F.* ; Gonsior, M.* ; Bastviken, D.* ; Enrich-Prast, A.* ; Valle Das Neves, J. ; Hertkorn, N.

Distinct non-conservative behavior of dissolved organic matter after mixing Solimões/Negro and Amazon/Tapajós river waters.

ACS ES&T Wat. 3, 2083-2095 (2023)
Publ. Version/Full Text DOI PMC
Open Access Gold (Paid Option)
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Positive and negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and 1H NMR revealed major compositional and structural changes of dissolved organic matter (DOM) after mixing two sets of river waters in Amazon confluences: the Solimões and Negro Rivers (S + N) and the Amazon and Tapajós Rivers (A + T). We also studied the effects of water mixing ratios and incubation time on the composition and structure of DOM molecules. NMR spectra demonstrated large-scale structural transformations in the case of S + N mixing, with gain of pure and functionalized aliphatic units and loss of all other structures after 1d incubation. A + T mixing resulted in comparatively minor structural alterations, with a major gain of small aliphatic biomolecular binding motifs. Remarkably, structural alterations from mixing to 1d incubation were in essence reversed from 1d to 5d incubation for both S + N and A + T mixing experiments. Heterotrophic bacterial production (HBP) in endmembers S, N, and S + N mixtures remained near 0.03 μgC L-1 h-1, whereas HBP in A, T, and A + T were about five times higher. High rates of dark carbon fixation took place at S + N mixing in particular. In-depth biogeochemical characterization revealed major distinctions between DOM biogeochemical changes and temporal evolution at these key confluence sites within the Amazon basin.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Biogeochemical Cycling ; Decomposition ; Ft-icr Ms ; Mixing Zones ; Nmr ; Transformation ; Transport; Dark Carbon Fixation; Heterotrophic Bacterial Production; Resolution Mass-spectrometry; Solid-phase Extraction; Amazon River; Molecular Characterization; Photochemical Degradation; Amino-acids; Rio-negro; Hot-spots
ISSN (print) / ISBN 2690-0637
e-ISSN 2690-0637
Journal ACS ES and T Water
Quellenangaben Volume: 3, Issue: 8, Pages: 2083-2095 Article Number: , Supplement: ,
Publisher American Chemical Society (ACS)
Publishing Place 1155 16th St, Nw, Washington, Dc 20036 Usa
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Research Unit BioGeoChemistry and Analytics (BGC)
Grants Swedish Research Council
Formas
CNPq (Universal and Ciencias sem Fronteiras)
FAPERJ (Cientista do Nosso Estado)
CAPES
Chinese Scholarship Council
European Research Council ERC
Swedish Research Council for Sustainable Development, FORMAS
Alexander von Humboldt Foundation