Open AccessAmmonium and nitrate uptake lengths in a small forested stream determined by {sup 15}N tracer and short-term nutrient enrichment experiments
Author(s) -
Patrick J. Mulholland,
Jennifer L. Tank,
Diane M. Sanzone,
J. R. Webster,
Wilfred M. Wollheim,
Bruce J. Peterson,
J. L. Meyer
Publication year - 1998
Language(s) - English
Resource type - Reports
DOI - 10.2172/290966
Subject(s) - nutrient , environmental chemistry , environmental science , tracer , nitrate , nutrient cycle , ammonium , streams , ecosystem , chemistry , heterotroph , ecology , biology , physics , organic chemistry , nuclear physics , computer network , genetics , computer science , bacteria
Nutrient cycling is an important characteristic of all ecosystems, including streams. Nutrients often limit the growth rates of stream algae and heterotrophic microbes and the decomposition rate of allochthonous organic matter. Nutrient uptake (S{sub W}), defined as the mean distance traveled by a nutrient atom dissolved in stream water before uptake by biota is often used as an index of nutrient cycling in streams. It is often overlooked, however, that S{sub W} is not a measure of nutrient uptake rate per se, but rather a measure of the efficiency with which a stream utilizes the available nutrient supply. The ideal method for measuring S{sub W} involves short-term addition of a nutrient tracer. Regulatory constraints often preclude use of nutrient radiotracers in field studies and methodological difficulties and high analytical costs have previously hindered the use of stable isotope nutrient tracers (e.g., {sup 15}N). Short-term nutrient enrichments are an alternative to nutrient tracer additions for measuring S{sub W}