What might happen to the food web below if the number of phytoplankton drastically decreased?

The correct answer for the given question above would be, the entire food web would be affected. When the number of phytoplankton drastically decreased, this would affect the entire food web. Phytoplanktons are considered as producers because they can produce their own energy through photosynthesis. When these planktons decrease, this would affect the other consumers in the food web such as the small fishes.