SEASONAL AND SPATIAL PATTERNS IN MACRONUTRIENT AND MICRONUTRIENT LIMITATION IN JOE-POOL LAKE, TEXAS

The roles of nitrogen, phosphorus, silicon, and trace nutrients in limiting algal growth were studied over a 1-yr period in three sites of a recently impounded, warm monomictic reservoir in north-central Texas using factorial dilution assay experiments. When lake temperature was > 15-degrees-C, nutrients limited realized growth rates to half or less of potential growth. Nutrient limitation was obliterated in the fall by floods. Density stratification was not a prerequisite to nutrient limitation in spring. Both macro- and micronutrients were important in terms of frequency of experiments showing limitation and in terms of quantitative degree of limitation. Horizontal variability in the degree of limitation was absent; however, shallower sites showed more incidence of multiple nutrient limitation compared to a deep, near-dam site.