A Comparison of Instantaneous and Continuous Rate Solute Additions Used to Estimate Nutrient Uptake in Streams

Lisle Snyder, current MS graduate student thesis research

This project will focus on comparing two methods used to quantify nutrient uptake in stream systems via nutrient additions. The traditional method of measuring nutrient uptake in streams involves the addition of nutrients to stream water at a regular rate, or Continuous Rate Addition, and measuring the extent to which those nutrients are "taken up" or transformed over a given stream length.

There has recently been interest in substituting this method with a less tedious Instantaneous Addition of solutes in order to estimate nutrient uptake in streams and rivers. Because Instantaneous Additions are both less time consuming and require a smaller total volume of solute, they result in less complication and financial cost for studying larger stream or river systems. There is, however, a knowledge gap pertaining to the comparison of Continuous Rate and Instantaneous Addition techniques for estimating nutrient uptake.

The goal of this research is to determine if Instantaneous Additions of solutes can legitimately replace the traditional Continuous Rate Additions for estimating nutrient uptake in streams and furthermore to contribute to the advancement of the Instantaneous Addition technique. The project is being carried out in Potash Brook, South Burlington, Vermont.