High nutrient loading threatens water quality for many reservoirs. Within Arkansas, Brewer Lake serves as the drinking water reservoir for over 80,000 residents. External and internal nutrient loading may influence this reservoir’s occasional algal blooms and seasonal taste/odor issues. To investigate the lake’s internal loading, we collected sediment cores during May of 2024. Nutrient release rates (mg/m2/d) were calculated following an incubation experiment, where the cores experienced oxic and anoxic treatments to represent the lake’s seasonally mixed and stratified periods, respectively. The anoxic sediment cores had greater ammonium release rates than the oxic cores (18.2±12.2 mg/m2/d and -6.6±4.1 mg/m2/d, respectively) while the oxic cores had greater nitrate release rates than the anoxic cores (12.9±5.1 mg/m2/d and -4.1±1.0 mg/m2/d). Mineralization continuously releases ammonium, but nitrification can only proceed in oxic conditions, possibly driving this contrast. However, phosphate release rates were not different between the anoxic and oxic treatments (3.3±3.8 mg/m2/d and 0.3±0.1 mg/m2/d). Preliminary analysis of the anoxic sediment cores shows substantial spatial variation of phosphate internal loading rates, where higher release rates occur among sediments from the deepest section of the lake. Various forms of mobile and nonmobile phosphorus fractions can be unequally distributed throughout lake sediment, so future experimentation to quantify these phosphorus fractions may explain the variation of phosphate release rates. Further spatial analysis of nutrient loading may allow for more targeted management action. Overall, this information and continued nutrient analysis may help explain algal blooms and taste/odor events in Brewer Lake and other reservoirs.