Periphyton Production and Grazing Rates in a Stream Measured with a 32 P Material Balance Method

作者：Jerry W. Elwood, Daniel J. Nelson · 发表于：Oikos · 年份：1972 · DOI：10.2307/3543167 · 被引用次数：83 · 研究领域：Soil and Water Nutrient Dynamics、Freshwater macroinvertebrate diversity and ecology、Fish Ecology and Management Studies

Net production rates and standing crops of periphyton and grazing rates on periphyton were measured in a small, woodland stream in southeastern United States using a material balance method. The material balance of radioactive phosphorus was followed at three times during the year in periphyton, consumer organisms, and stream water for up to six weeks following a one-hr release of 32PO4 to the stream. Rates of decrease of 32p in periphyton per unit weight, per unit area of substrate, and in the entire study reach of stream were used to compute biomass turnover rates of periphyton and fractions of periphyton standing crop grazed per unit area per unit time. Periphyton standing crops in July, September, and November were estimated at 200, 198, and 658 mg ash-free dry weight m-2, respectively, while estimates of net production rates were 22, 24, and 16 mg ash-free dry weight m-2 day-1, respectively. Estimated grazing rates on periphyton during these periods were 23, 15, and 14 mg ash-free dry wt m-2 day-1, respectively. Biomass turnover rates of periphyton were in the range of those computed from other stream ecosystems which had higher standing crops and production rates of periphyton. This suggests that grazing limited periphyton production rates in this stream by controlling the standing crop of periphyton. The method is of wide applicability since less than maximum permissible concentrations of radioactive phosphorus were used in the spike releases.