A Flourometric Technique for Sampling in Large-River Ecosystems

Abstract

Boat-mounted equipment for detecting the movement of rhodamine WT was used in Pool 6 of the upper Mississippi Rover, between navigation dams at Trempealeau, Wisconsin and Winona, Minnesota, to develop a procedure for sampling on paths of turbulent flow in large-river ecosystems. A means of relating sampling points in space and time is described. The expression Cm = (c2 . n) -c1/n-1 where c1 and c2 are concentrations of suspended or dissolved materials on upstream and downstream transects and n is a measure of dilution, can be used to obtain the mean concentration of material in suspension or solution in the water between points that are separated by at least as much as 2400 meters. This procedure in combination with conventional sampling programs in quiet backwaters may allow for more rigorous analysis of large-river ecosystems than has been achieved.