The influence of upstream nutrient loading on organic drift from a riffle to a pool.

Abstract

The affect of elevated nitrate (NO3) levels in the west branch of the Maple River, as compared to the east branch, on organic production can take many forms. This experiment considered core samples and the colonization rates of artificial substrates by comparing ash-free dry mass (AFDM) to determine settling rates of fine particulate organic matter (FPOM). Ten shallow core samples, 2 cm in depth, were taken from a pool area and a riffle area each from the west branch and the east branch and then clay tiles were laid down. After 3 days, the tiles were removed and ten more core samples were taken. AFDM were then developed. The results obtained showed an increase in FPOM and settling rate in the east branch but a decrease in settling rate along the west branch.