This is a fascinating video about the life and survival of plankton. While it focuses mainly on regular plankton, it briefly mentions phytoplankton and other algae, which all live in a similar way.
Research is being done into alternative crops for biofuels. A very promising alternative is algae. This video explains why.
This lesson has an introduction, prior knowledge assessment, algae experiment "A habitat switching Experiment" Answer sheet not provided.