Determining the lotic ecosystem nutrient and trophic status of three streams in eastern Oklahoma over two seasons

Nutrient limitations in three streams in the Upper Illinois River Basin in eastern Oklahoma (Peacheater, Tyner and Battle Creek) were measured using the Matlock periphytometer in April and September, 1995. The Matlock periphytometer was also used to measure baseline primary productivity and maximum primary productivity of the three streams over two seasons. The measured maximum primary productivity was interpreted to represent the rate of periphytic growth when the nutrients are not limiting. We calculated a lotic ecosystem trophic status index using the ratio of baseline and nutrient enriched growth to MPP. This index is by definition a functional index and may provide a classification tool for lotic ecosystem trophic status. We observed fluctuations in nutrient limitations in the streams over time and detected co-limitations of nitrogen and phosphorus in two of the three streams.