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Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA

Journal of Geophysical Research G: Biogeosciences

By:
, ,
DOI: 10.1029/2011JG001928

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Abstract

Dissolved organic carbon (DOC) concentration and chromophoric dissolved organic matter (CDOM) parameters were measured over a range of discharge in 30 U.S. rivers, covering a diverse assortment of fluvial ecosystems in terms of watershed size and landscape drained. Relationships between CDOM absorption at a range of wavelengths (a254, a350, a440) and DOC in the 30 watersheds were found to correlate strongly and positively for the majority of U.S. rivers. However, four rivers (Colorado, Colombia, Rio Grande and St. Lawrence) exhibited statistically weak relationships between CDOM absorption and DOC. These four rivers are atypical, as they either drain from the Great Lakes or experience significant impoundment of water within their watersheds, and they exhibited values for dissolved organic matter (DOM) parameters indicative of autochthonous or anthropogenic sources or photochemically degraded allochthonous DOM and thus a decoupling between CDOM and DOC. CDOM quality parameters in the 30 rivers were found to be strongly correlated to DOM compositional metrics derived via XAD fractionation, highlighting the potential for examining DOM biochemical quality from CDOM measurements. This study establishes the ability to derive DOC concentration from CDOM absorption for the majority of U.S. rivers, describes characteristics of riverine systems where such an approach is not valid, and emphasizes the possibility of examining DOM composition and thus biogeochemical function via CDOM parameters. Therefore, the usefulness of CDOM measurements, both laboratory-based analyses and in situ instrumentation, for improving spatial and temporal resolution of DOC fluxes and DOM dynamics in future studies is considerable in a range of biogeochemical studies.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA
Series title:
Journal of Geophysical Research G: Biogeosciences
DOI:
10.1029/2011JG001928
Volume
117
Issue:
G3
Year Published:
2012
Language:
English
Publisher:
American Geophysical Union (AGU)
Publisher location:
Washington, D.C.
Contributing office(s):
Branch of Regional Research-Central Region
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Country:
United States