Assess understanding of nitrogen and phosphorus biogeochemical cycles and how their interactions drive eutrophication in temperate freshwater lakes. Scope includes microbial transformations (fixation, mineralization, nitrification, denitrification), external versus internal loading, seasonal stratification and hypolimnetic oxygen dynamics, nutrient stoichiometry (N:P) and limitation, algal bloom formation and ecological consequences (hypoxia, food-web impacts), common monitoring metrics (TN, TP, chlorophyll‑a, Secchi) and basic mitigation strategies.