Spatial variability of CO2 concentrations and biogeochemistry in the Lower Columbia River

Inland Waters
By: , and 

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Abstract

Carbon dioxide (CO2) emissions from rivers and other inland waters are thought to be a major component of regional and global carbon cycling. In large managed rivers such as the Columbia River, contemporary ecosystem changes such as damming, nutrient enrichment, and increased water residence times may lead to reduced CO2 concentrations (and emissions) due to increased primary production, as has been shown in another large North American river (Upper Mississippi). In this work, spatial patterns of water quality, including dissolved CO2 concentrations, were assessed in the Lower Columbia River (LCR) and major tributaries using underway measurements from a small research vessel during July 2016. We observed near-equilibrium CO2 conditions and overall weak supersaturation of CO2 in the main channel (average 133.8% saturation) and tributaries. We observed only weak correlations between CO2 saturation, chlorophyll a fluorescence, and turbidity, thus not strongly supporting our hypothesis of primary productivity controls. In general, the LCR was clear (low turbidity, mean = 1.48 FNU) and had low chlorophyll fluorescence (mean = 0.177 RFU) during the sampling period. As a whole, the LCR was homogeneous with respect to biogeochemical conditions and showed low spatial variability at >100 km scales. Overall, we find that the LCR is likely a weak summertime source of CO2 to the atmosphere, in line with findings from other altered rivers such as the Upper Mississippi.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Spatial variability of CO2 concentrations and biogeochemistry in the Lower Columbia River
Series title Inland Waters
DOI 10.1080/20442041.2017.1366487
Volume 7
Issue 4
Year Published 2017
Language English
Publisher Taylor & Francis
Contributing office(s) National Research Program - Central Branch, Wisconsin Water Science Center
Description 11 p.
First page 417
Last page 427
Country United States
Other Geospatial Columbia River