The importance of nutrient supply by fish excretion and watershed streams to a eutrophic lake varies with temporal scale over 19 years

Nitrate, ammonium, and phosphorus drive seasonal nutrient limitation of chlorophytes, cyanobacteria, and diatoms in a hyper‐eutrophic reservoir

“…High springtime and low summertime discharge can alter the extent to which algae in downstream lakes and reservoirs are limited by N or P (Bukaveckas and Crain ; Royer et al ; Vanni et al ). In temperate regions, high baseline stream discharge in spring often results in elevated nutrient loading to aquatic ecosystems and is associated with high N:P loading ratios that can promote P limitation, especially in agriculturally impacted systems (Mulholland and Hill ; Williamson et al ). In contrast, lower stream discharge during the summer reduces nutrient loading and N:P ratios, promoting N limitation (Williamson et al ).…”

“…In temperate regions, high baseline stream discharge in spring often results in elevated nutrient loading to aquatic ecosystems and is associated with high N:P loading ratios that can promote P limitation, especially in agriculturally impacted systems (Mulholland and Hill ; Williamson et al ). In contrast, lower stream discharge during the summer reduces nutrient loading and N:P ratios, promoting N limitation (Williamson et al ). However, storm driven high discharge events, which occur more in spring than in summer, may reduce N:P for short periods of time because stream P increases disproportionately compared to N during storm events (Williamson et al ; Kelly et al ).…”

“…In contrast, lower stream discharge during the summer reduces nutrient loading and N:P ratios, promoting N limitation (Williamson et al ). However, storm driven high discharge events, which occur more in spring than in summer, may reduce N:P for short periods of time because stream P increases disproportionately compared to N during storm events (Williamson et al ; Kelly et al ).…”

“…Internal nutrient loading often supplies a substantial fraction of nutrient demand, and also varies seasonally in both magnitude and stoichiometric ratio (Orihel et al ; Bormans et al ; Wu et al ). Remineralization by animals and microbes can be an important source of limiting nutrients, especially during relatively warm and dry periods with low watershed discharge (Williamson et al ). During these periods, consumer biomass and metabolic rates are often high, and internal nutrient loading from consumers can exceed external nutrient sources (Shostell and Bukaveckas ; Williamson et al ).…”

“…Remineralization by animals and microbes can be an important source of limiting nutrients, especially during relatively warm and dry periods with low watershed discharge (Williamson et al ). During these periods, consumer biomass and metabolic rates are often high, and internal nutrient loading from consumers can exceed external nutrient sources (Shostell and Bukaveckas ; Williamson et al ). Though variable, consumers often supply limiting nutrients at relatively low N:P ratios when compared to discharge driven externally derived nutrient sources (Downing and McCauley ; Vanni and McIntyre ; Williamson et al ).…”