Effects of nutrient limitation on biochemical constituents of Ankistrodesmus falcatus

Cell size and volume changed as a function of the type of resource limitation, with nitrogen‐limited cells being smaller and less dense and phosphorus‐limited cells being larger and more dense than non‐limited cells. 2. The major biochemical constituents of the green alga Ankistrodesmus falcatus varied as a function of nitrogen or phosphorus limitation (15% of maximum growth rate) compared to cells growing at their maximum rate. Nitrogen‐limited cells had much lower protein content and phosphorus‐limited cells had higher carbohydrate and lipid contents than cells growing under no limitation. 3. Phosphorus‐limited cells had a higher total lipid content than either nitrogen‐limited or non‐limited cells, but the lipid class composition was similar. 4. The protein : lipid ratio was lowest (0.38) in the nitrogen‐limited cells, intermediate in the phosphorus‐limited cells (0.44) and highest in the non‐limited control cells (1.14).