The article discusses different methods for figuring out what nutrients microalgae need to grow well. These methods include looking at the elements in the algae, doing experiments to see how they respond to added nutrients, studying how they take up nutrients, analyzing their biochemical makeup, using special equipment to see changes in their molecules, and measuring their chlorophyll fluorescence. Each method has its pros and cons, but they all help scientists understand how microalgae respond to different nutrient levels in their environment.