Phosphorus Limitation, Uptake, and Turnover in Benthic Stream Algae

Phosphorus is essential for life and is often considered either the primary limiting or colimiting nutrient in freshwater ecosystems. In this chapter, we describe experiments that examine how to (1) assess whether or not benthic stream algal growth is limited by phosphorus; (2) measure phosphorus uptake from stream water by benthic algae; and (3) measure turnover rates of phosphorus mediated by benthic algae. Although we use the term "benthic algae," we recognize that the benthic community consists of much more than algae, and this caveat is acknowledged throughout the chapter. Our experimental design involves sampling benthic algae from high-phosphorus and low-phosphorus streams to determine how the communities differ in their nutrient dynamics.