**2. Materials and methods**

#### **2.1** *Daphnia* **and algae cultures**

### **2.1.1 Algae cultures**

Starter cultures of the green algae *Ankistrodesmus falcatus* were obtained from UTEX, The Culture Collection of Algae at The University of Texas (Austin, TX, USA). *A*. *falcatus* was grown in 2 L aerated, air-filtered culture vessels containing GTk media at 25ºC under continuous illumination. GTk contains the following macronutrients, 0.2 mM CaCl2, 2.5 mM KNO3, 0.3 mM MgSO4, 0.4 mM Na2HPO4 and the following micronutrients, 150 µM EDTA, Na2, 20 µM FeSO4, 2 µM ZnSO4, 1 µM NaMoO3, 0.6 µM CuSO4, CoCl2 and 14 µM MnCl2 (Leland Jahnke, Personal Communication).
