Skip to Main Content
Spiraling down the river continuum: stream ecology and the U-shaped curveAuthor(s): Jackson R. Webster
Source: J. N. Am. Benthol. Soc., Vol. 26(3): 375-389
Publication Series: Miscellaneous Publication
PDF: View PDF (3.03 MB)
DescriptionThe spiraling concept provides an explicit approach to modeling the longitudinal linkages within a river continuum. I developed a spiraling-based model for particulate organic C dynamics in the Little Tennessee River to synthesize existing data and to illustrate our current understanding of ecosystem processes in river ecosystems. The Little Tennessee River is a medium-sized river Bowing -100 km through the southern Appalachian Mountains of northern Georgia and western North Carolina (VSA). Across this distance, allochthonous inputs decrease and autochthonous production increases, resulting in a U-shaped curve of energy input. The model was set up as an advecting section compartment interacting with 3 benthic compartments: coarse benthic organic matter, fine benthic organic matter, and autotrophs. Model-estimated ecosystem respiration was consistently lower than measured values, suggesting a need to evaluate our measurements of whole-stream metabolism. Also, model-predicted seston concentrations were generally lower than measured values, reflecting a need to consider additional sources of organic C in the model. For the whole river system, leaves accounted for 19% of inputs, primarily near the headwaters, and the remaining input was from instream primary production in the lower reaches of the river. Almost H of the input was respired, 28% by autotrophic respiration and 21% by heterotrophic respiration, and the remaining 51% was transported downstream. Ecosystem efficiency was -50% along the length of the river, and hunover length increased from several hundred meters at the headwaters to >I00 km downstream. Based on various measures, the transition from heterotrophy to autotrophy ranged from 25 to >I00 km downstream from the headwaters. As this model illustrates, a consequence of downstream transport is that much of the particulate C in streams is metabolized a considerable distance downstream from where it enters the stream. This longitudinal linkage is essential to our understanding of stream ecosystems.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationWebster, Jackson R. 2007. Spiraling down the river continuum: stream ecology and the U-shaped curve. J. N. Am. Benthol. Soc., Vol. 26(3): 375-389
Keywordsstream, model, metabolism, spiraling, river continuum, Little Tennessee River
- Longitudinal patterns of metabolism in a southern Appalachian river
- Inter-regional comparison of land-use effects on stream metabolism
- Comprehensive multiyear carbon budget of a temperate headwater stream
XML: View XML