Interactive Effects of Temperature and Nutrients on Periphyton Assemblages from a Low-pH South Carolina Stream

摘要

Periphyton that accumulated on glass slides in a flow-through, artificial stream system at the Thermal Effects Laboratory, Savannah River Laboratory, were studied for their response to continuously elevated temperatues and to nutrient additions. Although the stream water used in these experiments was low in nutrients, addition of nutrients rarely increased periphyton biomass or carbon-uptake rates. The most consistent stimulation occurred in July at 12 exp 0 C above ambient temperature. Large day-to-day variations in chlorophyll a and rate of carbon-uptake of the assemblages were observed at ambient temperatures and at elevated temperatures. Temperature and available carbon varied on approximately the same time scale as the algal parameters. It is concluded that nutrient imitation, if it exists in this system, is masked by the effects of temperature and, in summer, possibly by limitation of carbon to the periphyton. (ERA citation 06:024364)