Source to sink : evolution of lignin composition in the Madre de Dios River system with connection to the Amazon basin and offshore
Wang, Renée Z.
Berelson, William M.
Nottingham, Andrew T.
West, A. Joshua
MetadataShow full item record
KeywordLignin phenols; Dissolved organic matter (DOM); Particulate organic matter (POM); Andes; Amazon; Depth profile
While lignin geochemistry has been extensively investigated in the Amazon River, little is known about lignin distribution and dynamics within deep, stratified river channels or its transformations within soils prior to delivery to rivers. We characterized lignin phenols in soils, river particulate organic matter (POM), and dissolved organic matter (DOM) across a 4 km elevation gradient in the Madre de Dios River system, Peru, as well as in marine sediments to investigate the source-to-sink evolution of lignin. In soils, we found more oxidized lignin in organic horizons relative to mineral horizons. The oxidized lignin signature was maintained during transfer into rivers, and lignin was a relatively constant fraction of bulk organic carbon in soils and riverine POM. Lignin in DOM became increasingly oxidized downstream, indicating active transformation of dissolved lignin during transport, especially in the dry season. In contrast, POM accumulated undegraded lignin downstream during the wet season, suggesting that terrestrial input exceeded in-river degradation. We discovered high concentrations of relatively undegraded lignin in POM at depth in the lower Madre de Dios River in both seasons, revealing a woody undercurrent for its transfer within these deep rivers. Our study of lignin evolution in the soil-river-ocean continuum highlights important seasonal and depth variations of river carbon components and their connection to soil carbon pools, providing new insights into fluvial carbon dynamics associated with the transfer of lignin biomarkers from source to sink.
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 121 (2016): 1316–1338, doi:10.1002/2016JG003323.
Showing items related by title, author, creator and subject.
Spatial variability in the abundance, composition, and age of organic matter in surficial sediments of the East China Sea Wu, Ying; Eglinton, Timothy I.; Yang, Liyang; Deng, Bing; Montlucon, Daniel B.; Zhang, Jing (John Wiley & Sons, 2013-11-15)Understanding the sources and fate of organic matter (OM) sequestered in continental margin sediments is of importance because the mode and efficiency of OM burial impact the carbon cycle and the regulation of atmospheric ...
Organic matter in river-influenced continental margin sediments : the land-ocean and climate linkage at the Late Quaternary Congo fan (ODP Site 1075) Holtvoeth, Jens; Wagner, Thomas; Schubert, Carsten J. (American Geophysical Union, 2003-12-31)Late Quaternary sections (1.2 Ma) of ODP-Site 1075 from the Congo deep-sea fan are investigated to reconstruct variations of terrigenous organic matter supply to the eastern equatorial Atlantic. To characterize the organic ...
Marine sedimentary organic matter : delineation of marine and terrestrial sources through radiocarbon dating; and the role of organic sulfur in early petroleum generation Benitez-Nelson, Bryan C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-05)This thesis details two years of research conducted with the guidance and support of three advisors: Dr. J. K. Whelan, Dr. J. S. Seewald and Dr. T. I. Eglinton. Each of the three chapters represents a different, ...