Short-Term Effects of Nitrogen and Extracellular Protease Amendment on Algal Productivity in Nitrogen-Deprived Periphyton

ABSTRACT

A nutrient enrichment/¹⁴ C-uptake bioassay technique was used to measure the effects of enhanced supply of dissolved inorganic nitrogen, dissolved organic nitrogen, and extracellular protease on primary productivity in nitrogen-deprived periphyton communities. Addition of dissolved inorganic nitrogen rapidly and consistently doubled primary productivity, but the addition of dissolved organic nitrogen did not increase primary productivity within the experimental timeframe. Experimental additions of protease had little effect on primary productivity, and simultaneous addition of protease + protein also had no effect.