Ecosystem health depends on balance between the growth and consumption of its organisms. This balance is found in its food web organization. In this lesson students will learn about the make-up of food webs, with an emphasis on primary producers. Specifically they will explore connections between primary production and nutrient availability through experimentation with diatoms (a single celled, primary producer). Nutrient limitation on primary production will be seen in real time as students grow diatoms under three different nutrient concentrations. Data collection and analysis will connect student observations with larger relationships between nutrients, primary production and food webs.