Sources and distributions of anic matter in the Columbia River drainage basin, Washington and Oregon.pdf

Ltmnol. Oceanogr., 29(l), 1984, 35-46
0 1984, by the American Society of Limnology and Oceanography, Inc
Sources and distributions of anic matter in the
Columbia River drainage basin, Washington and Oregon’
John I. Hedges
School of Oceanography, WB-10, University of Washington, Seattle 98 195
H. J. Turin2
Department of Geological and Geophysical Sciences, Princeton University, Princeton, N. J. 08544
John R. Ertel
School of Oceanography, WB- 10, University of Washington
Abstract
Nonwoody angiosperm tissues and gymnosperm woods are the major types of vascular plant
debris in bottom sediments from 16 sites within the Columbia River and its tributaries. In tributary
sediments relative abundances of these types of tissue vary regionally and are consistent with
drainage basin vegetation. Within the extensively dammed main river, vascular plant debris mix-
tures are more uniform, indicating downstream mixing of sedimentary material from reservoir to
reserwoir. Vascular plant tissues account for an average of a third of the total anic
matter at the 16 river sites. The anic material has an atomic C:N of 10-l 5 and a
stable carbon position similar to “average” land plants. Organic matter in sediments
of the Columbia River system is generally enriched in nonwoody angiosperm tissues and lignin-
anic matter parison to Columbia River-anic matter in modern marine
sediments from the southern Washington continental shelf.
Organic matter in riverine systems is positions to those in modern sediments
interest as a potential food for aquatic or- from the southern Washington continental
ganisms, as a source of biogenic materials shelf (Hedges and Mann 19793) that receive
to the sea, and as an indicator of vegetation detrital constituents almost exclusively from
and climate within drainage basins (Likens the Columbia River (Gross et al. 1967; Nit-
et al. 198 1). In view of these importances trouer 1978). The information is