Quantity and Quality of Suspended Particulate Organic Matter Upstream and Downstream of a Series of Surface-Release Impoundments on the Upper Mississippi River
Through the continual flow of water in lotic systems, upstream impacts may be observed in downstream reaches. The River Continuum Concept classifies and describes abiotic and biotic processes as a river flows from headwaters to mouth. Disruptions of the theoretical system by impoundments are described by the Serial Discontinuity Concept that predicts, among other things, changes in biotic and abiotic stream processes. This study observed four surface-release impoundments on the Upper Mississippi River and documented impacts on the quantity and quality of fine particulate organic matter (FPOM) and looked for evidence of the Serial Discontinuity Concept. It was hypothesized that there would be an increase in the FPOM downstream of the impoundments, that there would be an impact on the quality of the FPOM, and that there would be evidence to support the Serial Discontinuity Concept. Three scenarios were observed in the quantity of the FPOM. 1) No difference between above and below sampling sites, 2) higher amounts of FPOM above the impoundments, and 3) higher amounts of FPOM below the impoundments. The hypothesis that there would be an increased amount of FPOM was supported by the third scenario. The results did not support the hypothesis that there would be an impact on the quantity of FPOM, there were no significant differences in phosphorus content between sampling sites. Disconnected sections of the river were found in support of the Serial Discontinuity Concept
