The river as a chemostat: fresh perspectives on dissolved organic matter flowing down the river continuum

Canadian Journal of Fisheries and Aquatic Sciences
Federal Program
By: , and 

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Abstract

A better understanding is needed of how hydrological and biogeochemical processes control dissolved organic carbon (DOC) concentrations and dissolved organic matter (DOM) composition from headwaters downstream to large rivers. We examined a large DOM dataset from the National Water Information System of the US Geological Survey, which represents approximately 100 000 measurements of DOC concentration and DOM composition at many sites along rivers across the United States. Application of quantile regression revealed a tendency towards downstream spatial and temporal homogenization of DOC concentrations and a shift from dominance of aromatic DOM in headwaters to more aliphatic DOM downstream. The DOC concentration–discharge (C-Q) relationships at each site revealed a downstream tendency towards a slope of zero. We propose that despite complexities in river networks that have driven many revisions to the River Continuum Concept, rivers show a tendency towards chemostasis (C-Q slope of zero) because of a downstream shift from a dominance of hydrologic drivers that connect terrestrial DOM sources to streams in the headwaters towards a dominance of instream and near-stream biogeochemical processes that result in preferential losses of aromatic DOM and preferential gains of aliphatic DOM.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The river as a chemostat: fresh perspectives on dissolved organic matter flowing down the river continuum
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2014-0400
Volume 72
Issue 8
Year Published 2015
Language English
Publisher National Research Council Canada
Publisher location Ottawa, Canada
Contributing office(s) John Wesley Powell Center for Analysis and Synthesis, New York Water Science Center, California Water Science Center, National Research Program - Central Branch
Description 14 p.
First page 1272
Last page 1285
Country United States
Online Only (Y/N) N
Additional Online Files (Y/N) N